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Sandbox:VANT151/2026/Capstone/APSC/Team3

2026-06-26T05:55:33Z

ZiruiDou:

== Home ==

=== Welcome ===
Welcome to the wiki page of Team 3 of VANT151 2026S. Our team consists of 13 members divided into six sub-teams: mechanical, structural, electrical, coding, thermal, and documentation. Together, we designed and built a 1:5 scale electric cycle prototype. This page documents our design process, subsystem development, prototype construction, and final design details.

=== Introduction ===
Transportation is a major contributor to greenhouse gas emissions at UBC Okanagan, with commuting making up a significant part of the university’s overall carbon footprint. According to UBCO’s Climate Action Plan 2030, reducing transportation emissions is important for achieving the university’s sustainability goals.

Although cycling is an environmentally friendly transportation option, many commuters face challenges such as poor weather conditions, limited storage space, safety concerns, theft, and rider comfort. To address these issues, our project focuses on designing an innovative electric cycle that provides a more practical, comfortable, and sustainable commuting experience.

As part of the VANT151 Multidisciplinary Engineering Design Project, our team developed a 1:5 scale prototype based on the Fucare Libra electric bicycle platform. The objective of this project is to demonstrate a transportation concept that supports sustainable commuting while improving rider protection, usability, and convenience.

=== Team Requirements ===

==== Functions ====

* Carry a rider.
* Allows the rider to be active during the commute.
* Carry the usual items needed in school – books, laptop, lunch, coat, sports equipment, a change of clothes, etc.
* Usable when raining or snowing.
* Keep rider cool in summer, warm in winter.
* Has adequate illumination for the visibility of the rider and other road users.
* Has a means of preventing theft.

==== Objectives ====

* Maximize commuter safety
* Minimize injury risk
* Maximize rider effort
* Minimize commute time
* Maximize weather protection
* Maximize rider comfort
* Minimize preparation time
* Maximize vehicle speed

==== Constraints ====

* Width ≤ 240 mm
* Size 430 × 279 mm
* Fit 360 mm rider
* Power ≤ 9.6 V, 2.8 A
* Drive straight & complete figure-8 path

=== Gantt Chart ===
The team Gantt chart was used to organize the project timeline and divide tasks between each sub-team. It shows the planned schedule for mechanical, structural, electrical, coding, thermal, and documentation work. This helped the team track progress, manage deadlines, and make sure each part of the e-cycle project was completed in the correct order.[[File:151 group 3 (final) (2).jpg|thumb|center]]
= Mechanical Sub-team =
The mechanical sub-team focused on designing the moving systems of the e-cycle prototype, including the suspension, steering, and drive mechanism. Our goal was to make the prototype stable, functional, and easy to assemble. We considered different design options and selected a simple mechanical system that supports smooth movement while fitting within the size and material constraints of the project.

== Requirements ==

=== Functions ===

* Keep the vehicle stable on uneven ground.
* Reduce vibration and excessive body movement.
* Keep the wheels in contact with the ground.
* Transfer motor power to the wheels through the chain-drive system.
* Allow the vehicle to steer and move along the required path.

=== Objectives ===

* Maximize vehicle stability and wheel contact with the ground.
* Maximize steering control and traction.
* Maximize drivetrain efficiency and starting torque.
* Maximize the balance between speed and torque.
* Minimize vibration and excessive body movement.
* Minimize power loss in the gear and chain-drive system.
* Minimize stress on the frame, mannequin, and internal components

=== '''Constraint''' ===

* Width must not exceed 240 mm.
* Prototype must fit within a 430 × 279 mm footprint.
* Chassis must accommodate a 360 mm mannequin.
* Power must stay within 9.6 V and 2.8 A.
* Vehicle must complete straight and figure-8 paths.
* Steering, wheel alignment, and traction must remain stable.

* Drivetrain must provide enough torque with minimal power loss.

== Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.
[[File:8c938f9f8624896cc9918448ba7635a1.png|thumb|Early sketch for a simple solid-axle layout|center]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.
[[File:Screenshot 2026-06-18 at 9.57.54 AM.png|thumb|Selected mechanical layout sketch: independent front motion with a simpler rear drive axle|center]]
[[File:Front wheel.png|center|thumb]]

== Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:69c565f2704efebc5b9f604fa5ee29d6.jpg|thumb|Example CAD part for a red frame or linkage component|center|401x401px]]

== Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.
[[File:Screenshot 2026-06-18 at 9.58.42 AM.png|thumb|Gear design used as a drivetrain reference for the mechanical protoype.|center|437x437px]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.
[[File:Screenshot 2026-06-18 at 10.01.38 AM.png|thumb|Solidwork single gear system |center|373x373px]]
[[File:08137fe3df2fd4a00ae0586f3961e6c8.png|center|thumb]]

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.
[[File:5065a4e2c4020bb53a00365a49e16639.png|center|thumb]]

== Steering System Design ==
'''6.1''' The selected steering system is a suspension-mounted servo steering system. The servo is fixed at the center of the front suspension frame. When the servo rotates, the servo horn swings left or right. This motion is transferred through a popsicle-stick linkage, which pushes or pulls the front steering joints and turns the front wheels.
{| class="wikitable" style="width:100%; text-align:center;"
!Step 1
!→
!Step 2
!→
!Step 3
!→
!Step 4
|-
|'''Servo fixed on suspension frame'''
The servo body stays in place
|→
|'''Servo horn swings'''
The horn moves left or right
|→
|'''Linkage transfers motion'''
The popsicle-stick linkage pushes or pulls
|→
|'''Front wheels turn'''
The steering joints rotate the wheels
|}

=== 6.2Steering Design Comparison ===
[[File:75e80df2733967106b9243eda49cdf7e.jpg|center|thumb]]
[[File:B68af1e441a399f3a8da1e51a2745021.jpg|center|thumb|311x311px]]
{| class="wikitable" style="width:100%;"
!Category
!Rack-and-Pinion Steering
!Linkage / Pivot Steering
|-
|'''Advantages'''
|Precise control; smooth motion; compact design
|Easy to build; simple materials; easy to repair
|-
|'''Disadvantages'''
|Harder to build; requires accurate gear alignment
|Less precise; joints may loosen; uneven wheel angles
|-
|'''Motion Transfer'''
|Servo rotates gear → rack moves left/right → wheels turn
|Servo horn swings → linkage pushes/pulls → wheels turn
|}
The linkage / pivot steering system was selected because it is easier to build with simple materials and fits better with the handmade suspension frame.

The linkage / pivot steering system was selected because it is easier to build with simple materials and fits better with the handmade suspension frame.

== Chassis Design Process ==
'''7.1'''The chassis design was developed through an iterative process. The goal was to create a structure that could support the mannequin, suspension, steering system, motor, battery, and transmission while staying within the project size limits.
{| class="wikitable" style="width:100%; text-align:center;"
!Step 1
!→
!Step 2
!→
!Step 3
!→
!Step 4
!→
!Final Design
|-
|'''Identify constraints'''
Footprint, width limit, mannequin size, and component placement
|→
|'''Initial chassis design'''
Simple flat frame with space for drivetrain parts
|→
|'''Evaluate problems'''
Limited strength, difficult alignment, and insufficient support
|→
|'''Improve structure'''
Add stronger mounting areas and better space for suspension and transmission
|→
|'''Final chassis'''
Stronger, easier to assemble, and better for component integration
|}

=== 7.2First Chassis Design ===
The first chassis design used a simple flat structure. It was easy to design and manufacture, but it did not provide enough space and suitable mounting points for the components from other sub-teams.

This design was not selected because it could not integrate well with the suspension system, steering system, drivetrain, and electrical components. Since the final vehicle needed all sub-team systems to work together, the first chassis design was not practical for the complete prototype.
[[File:4da8f2cc37bf0233f7bc1867f8d1f0ff.png|center|thumb]]

=== 7.3Second Chassis Design ===
(<nowiki>*</nowiki> <nowiki>'''</nowiki>Design basis:<nowiki>'''</nowiki> The selected mechanical design is based on the project constraints, including the 430 x 279 mm footprint, 240 mm width limit, 360 mm mannequin size, and 9.6 V / 2.8 A power limit. Because the prototype needs to drive straight and complete a figure-8 path, the design prioritizes stability, steering clearance, wheel contact, and reliable torque transfer over maximum speed.)

The second chassis design was developed after considering the requirements of the other sub-teams. It provided better mounting areas for the suspension, steering system, drivetrain, motor, and battery. It also made the overall structure easier to assemble and test.

The second chassis design was selected because it supported system integration better and gave the mechanical sub-team more flexibility during assembly.
[[File:885e54dfe303635ca654c2896c2e6a40.png|center|thumb]]

== Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}
== Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

= Structural Sub-team =
The structural sub-team focused on designing the main frame of the e-cycle prototype, including the support structure, hardware protection, and weight distribution. Our goal was to make the prototype strong, lightweight, balanced, and easy to assemble and maintain. We considered several structural design options and compared how well each option could support the internal hardware, protect key components, and maintain proper balance. Based on these considerations, we selected a simple and reliable frame design that can withstand expected operational impacts and vibrations while fitting within the size and material constraints of the project.

== Requirements ==

=== '''Functions''' ===

* Support and securely house all internal hardware within the two-wheeled robot vehicle.
* Provide essential physical protection through a durable outer enclosure.
* Maintain precise weight distribution to ensure the mechanical prototype can balance effectively.

=== '''Objectives''' ===
* Optimize the strength-to-weight ratio when selecting the enclosure materials and frame components.
* The structural design must withstand the maximum expected operational impacts and vibrations.
* Design the framework for straightforward assembly, disassembly, and easy maintenance access to internal electronics.

=== '''Constraints''' ===
* The frame must strictly conform to the dimensional limits required for a two-wheeled balancing system.
* The total mass of the structural design must not exceed the designated weight budget to preserve motor efficiency.
* Material selection and fabrication are limited by the available manufacturing tools and the project budget.

== The Design ==

=== '''Transmitter Hardware''' ===
* '''Structural Focus:''' Dedicated mounting brackets for the transmitter hardware, ensuring secure placement and verifying that the enclosure materials do not cause signal interference.

=== '''Operating Sequence''' ===
* '''Structural Focus:''' The step-by-step physical assembly sequence: constructing the core frame, mounting the drive system, integrating the electronics, and attaching the outer enclosure.

=== Suspension Design Alternatives ===

==== Frame design ====
{| class="wikitable"
|+
!Options
!Description
!Pros
!Cons
|-
|[[File:Option2 Struc.jpg|thumb]]Monocoque Chassis
|'''A single-piece shell that integrates structural support and enclosure.'''
|'''High rigidity, low part count, aerodynamic efficiency.'''
|'''Difficult to repair, complex manufacturing, limited internal layout flexibility.'''
|-
|[[File:Option 1 Struc.jpg|thumb]]Space Frame Truss
|'''A lattice of thin tubes forming a lightweight, rigid skeleton.'''
|'''Excellent strength-to-weight ratio, easy to fabricate with basic tools.'''
|'''Requires additional enclosure panels, higher assembly time.'''
|-
|[[File:截屏2026-06-18 上午10.25.04.png|thumb]]Box Beam Frame
| '''rectangular hollow-section frame with bolted joints and modular brackets.'''
|'''Balanced rigidity and weight, easy to assemble/disassemble, compatible with standard fasteners, cost-effective materials.'''
|'''requires careful joint design to avoid stress concentrations.'''
|}

==== Weighted Decision Matrix ====
{| class="wikitable"
!Criteria
!weight
!Monocoque Chassis
!Space Frame Truss
!Box Beam Frame
|-
|Cost
|0.25
|0.1
|0.1
|0.2
|-
|Function
|0.3
|0.2
|0.15
|0.2
|-
|Protect
|0.45
|0.2
|0.15
|0.35
|-
|total
|1
|0.5
|0.4
|0.75
|}
The Box Beam Frame received the highest score of 0.75 because it provides the best balance of cost, function, and protection. Therefore, it was selected as the final design.

==== Door design ====
{| class="wikitable"
|+
!Options
!Description
!Pros
!Cons
|-
|[[File:Screenshot 2026-06-23 113345.png|thumb|center|Top-Track Sliding Door]]
| '''The door translates horizontally along a fixed upper rail via a roller/slider assembly, maintaining parallel alignment with the vehicle chassis.'''
|'''Simple and easy to build & provides full interior access.'''
|'''Requires overhead clearance & needs support to stay open.'''
|-
|[[File:Screenshot 2026-06-23 113311.png|thumb|center|Top-Hinged Gullwing Door]]
| '''The door rotates vertically upwards around a single horizontal hinge axis mounted at the upper roofline.'''
|'''No swing space required & door remains stable when open.'''
|'''Requires extra side space & prone to jamming if misaligned.'''
|-
|[[File:Screenshot 2026-06-25 215316.png|thumb|No Door Design]]
|'''The original door opening is replaced with a fixed transparent panel, providing full visibility while eliminating any moving door mechanism.'''
|'''Simple and lightweight design & provides clear visibility of the interior.'''
|'''No direct access to internal components & maintenance requires removing the panel.'''
|}

==== Weighted Decision Matrix ====
{| class="wikitable"
|+
!Criteria
!weight
!Top-Track Sliding Door
!Top-Hinged Gullwing Door
!No Door Design
|-
|Structural Simplicity
|0.35
|0.20
|0.25
|0.35
|-
|Accessibility
|0.2
|0.20
|0.18
|0.1
|-
|Protection
|0.45
|0.30
|0.20
|0.45
|-
|total
|1
|0.72
|0.56
|0.82
|}

====== '''Functions''' ======

* Acts as the vehicle’s canopy enclosure.
* Improves aerodynamics while providing visibility and protection.

== Extra Feature ==

=== Rear Wing ===
This is a design makes the car look more sporty and creative. The idea comes from real car aerodynamic designs. It helps represent downforce and stability, which are common concepts in automotive engineering. It also improves the appearance of the rear section and makes the overall design look more balanced.
[[File:截屏2026-06-18 上午10.19.58.png|thumb|center]]

= Coding Sub-team =

== Introduction ==
Coding team is mainly responsible for the code of the Adurino Nano. Main task is to realize the remote control of the cycle, especially the motor and servo. Our goal is optimize and simplify the operator's work when controlling the cycle and adding extra features to enable the cycle to be muti-functional and useful in the real life.

== Requirements ==

==== Functions ====

* Enable bidirectional communication between the transmitter and receiver.
* Read joystick input from the transmitter.
* Control the steering servo based on left and right joystick movement.
* Control the motor in forward and reverse directions.
* Stop the motor when the joystick is released or within the neutral zone.
* Control the three temperature modes: off, heating, and cooling.

==== Objectives ====

* Minimize the turning radius to less than 600 mm.
* Maximize steering accuracy and responsiveness to left and right joystick inputs.
* Maximize communication reliability between the transmitter and receiver.
* Minimize delay between joystick input and vehicle response.
* Maximize safe and stable motor control.
* Minimize unintended movement when the joystick is in the neutral position.

==== Constraints ====

* Maximum electrical consumption in transmitter: 9,6V 2.8A.
* Maximum electrical consumption in receiver less than 12V.
* Only 2 Nanos, every of them has total 13 Digital pins and 7 Analog pins

==== Extra Features ====

# Statement display(Temperature, humidity, gears mode, air-conditioner mode)
# Temperature and humidity measurement
# Reverse Gear
# Horn

== The Design ==

=== Transmitter Hardware ===
The transmitter is the handheld controller used by the operator. It includes an Arduino Nano, a joystick module, a push button, and the required wiring connections. The purpose of the transmitter is to collect user input and convert it into control commands for the tricycle.

The joystick is the main input device for vehicle movement. The vertical direction of the joystick controls forward and backward motion. When the joystick is pushed forward, the tricycle moves forward. When the joystick is pulled backward, the tricycle reverses. The horizontal direction of the joystick controls steering. Moving the joystick left or right sends a turning command to the tricycle.

The push button is used to control the Peltier-based temperature control device. Each press of the button changes the operating mode. This allows the user to switch between cooling and heating without needing extra controls.

The transmitter hardware was designed to be compact and easy to use. Since the controller only needs a few input components, the circuit can remain simple and organized. This also makes troubleshooting easier during testing.

==== Overall figure ====
The overall transmitter system is shown in Figure 1. The joystick and button are connected to the Arduino Nano as input devices. The Arduino reads these input signals and converts them into commands for movement, steering, and temperature control.

Figure 1. Overall layout of the transmitter hardware system.

The joystick provides two analog inputs: one for forward and backward control, and one for left and right steering control. The button provides a digital input for switching the Peltier system mode. Together, these components allow the user to control the main functions of the tricycle through one simple remote controller.

==== Arduino Nano ====
Arduino Nano is used for packing everything, including the position of joystick, buttons state, in to the Struct Signal and delivered it to receiver. At the mean time, receiving the ack pack delivered by receiver and display it onto LCD screen to demostrate the overall state of the e-cycle.

==== joystick ====
The joystick is the main input device used to control the movement of the tricycle. It is powered by the Arduino Nano and provides position data in two directions. The X-position is used for steering control, while the Y-position is used for forward and backward movement.

The joystick outputs are connected to the Arduino Nano through input pins such as A0 and A1. The press function of the joystick can also be connected to another input pin, such as A2, depending on the final wiring design. The Arduino reads these values continuously and converts them into movement commands.

When the joystick is pushed forward or backward, the transmitter sends a command for the vehicle to move forward or reverse. When the joystick is moved left or right, the transmitter sends a steering command. A neutral zone is included in the program so that small joystick noise does not accidentally move the tricycle.

The joystick is powered by nano, information of X position and Y position and the press condition is transmitted to A0, A1, A2 and port into the adurino nano.

LCD is used for displayinig statement including temperature, humidity, the whether reverse gear is on and which temperature mode is on. LCD display compared to LED lights is more flexible to edit, intuitive to person.

==== LCD display ====
LCD is used for displayinig statement including temperature, humidity, the whether reverse gear is on and which temperature mode is on. LCD display compared to LED lights is more flexible to edit, intuitive to person.

==== nRF24L01 modules ====
The nRF24L01 modules are used for wireless communication between the transmitter and the receiver. One module is connected to the transmitter, and another module is connected to the receiver. These two modules allow the joystick positions, button states, and system feedback data to be transferred wirelessly.

On the transmitter side, the nRF24L01 sends the structured control packet from the Arduino Nano to the receiver. This packet includes movement commands, steering commands, and temperature-control commands. On the receiver side, the module receives these commands and sends feedback information back to the transmitter.

The nRF24L01 module is powered by the 3.3 V pin on the Arduino Nano. A capacitor is added to the circuit to help stabilize the power supply and reduce communication problems caused by voltage drops. This improves the reliability of the wireless connection.

=== Receiver Hardware ===

===== Arduino Nano =====
The Arduino Nano is used as the main controller in the receiver system. Its role is to process the control commands from the transmitter and send the correct signals to the output components on the tricycle. Based on the received joystick command, the Arduino controls the driving motor and the steering servo. Based on the button command, the Arduino controls the temperature system.

The Arduino Nano was chosen because it is small, lightweight, and easy to integrate into the tricycle circuit. It has enough input and output pins to connect to the servo, motor control circuit, MOSFET, and relay module. Since the tricycle is a small prototype, the compact size of the Arduino Nano also helps reduce the space needed for the receiver hardware.

Another advantage of using the Arduino Nano is that it can be tested and programmed easily. During testing, the coding group can check whether the Arduino is receiving the correct commands and whether each output component responds correctly. This makes debugging more organized and helps the team identify problems in either the software or hardware.

===== Servo =====
The servo is used to control the steering direction of the tricycle. When the user moves the joystick left or right, the receiver Arduino sends a signal to the servo. The servo then rotates to the required angle, allowing the front wheel or steering mechanism to turn.

The servo was selected because it can rotate to specific positions instead of only turning on or off. This is useful for steering because the tricycle needs controlled left and right movement. For example, when the joystick is moved slightly, the servo can turn by a smaller angle. When the joystick is moved further, the servo can turn by a larger angle.

In the program, the joystick value is mapped to a servo angle. A neutral joystick position keeps the servo near the center position, so the tricycle moves straight. This design makes the steering control more intuitive for the user and easier to adjust during testing.

===== Motor =====
The motor is used to provide the driving force for the tricycle. It allows the vehicle to move forward and backward based on the joystick input from the transmitter. When the joystick is pushed forward, the receiver activates the motor to move the tricycle forward. When the joystick is pulled backward, the motor direction is changed so the tricycle can reverse.

The motor requires more current than the Arduino Nano can safely provide directly. Because of this, the motor is controlled through a separate driving circuit instead of being connected directly to the Arduino output pin. This protects the Arduino and allows the motor to receive enough power from the battery.

The motor control is designed to respond to clear joystick commands. When the joystick returns to the neutral position, the motor stops. This makes the tricycle safer during testing because the vehicle should not continue moving when the user is not giving a movement command.

===== MOSEFT =====
The MOSFET is used as an electronic switch for controlling higher-power components in the receiver system. Since the Arduino Nano can only provide a small amount of current from its output pins, it cannot directly power components such as the motor or the Peltier device. The MOSFET solves this problem by allowing the Arduino to control a larger current using a small control signal.

When the Arduino sends a signal to the MOSFET gate, the MOSFET allows current to flow through the connected load. When the Arduino signal is off, the MOSFET stops the current flow. This makes the MOSFET useful for turning high-power devices on and off safely.

Using a MOSFET also improves the reliability of the system because it separates the Arduino control circuit from the higher-power output circuit. This reduces the risk of damaging the Arduino and makes the circuit more suitable for a working tricycle prototype.

==== Relay ====
The relay is used to switch the operating mode of the Peltier-based temperature control system. A Peltier module can provide cooling or heating depending on the direction of current flow. Therefore, the relay helps change the circuit connection so that the system can switch between cooling and heating modes.

The relay is controlled by the Arduino Nano based on the button command from the transmitter. When the user presses the button, the Arduino changes the relay state. This allows the temperature control system to switch modes without the user needing to manually change any wiring.

The relay was included because it provides a simple and clear way to control a higher-power circuit using a low-power Arduino signal. It also helps keep the temperature control system separate from the main logic circuit, which makes the design safer and easier to test.

==== Remote Control Display{{YouTube|id=8xli9cMYe5c}}Program Flowchart ====
[[File:Coding flowchart.png|center|thumb|Transmitter side Flow chart]]
[[File:Coding Flowchart 2.png|center|thumb|Receiver side Flow chart]]

=== Extra Features ===
DHT Temperature and Humidity Sensor. It is used for <u>detecting the temperature and humidity</u> inside the car to better detect the statement of the car.

LCD display. <u>Acknowledgement Payload</u> is used for transmiting the data of the vehicle back to the transmitter and display the car statement on the LCD screen.

=== Design Alternatives ===
{| class="wikitable"
|+
!Alternative A
!Alternative B
|-
|[[File:Transmitter shell applied.png|thumb]]
|[[File:Transmitter shell not applied.jpg|thumb]]
|}
The first design is like a box, which is easy to create and alter. The second one referred to an X box controller, which is more comfortable to use.

The following is the WDM matrix to judge the final application
{| class="wikitable" style="width:100%; font-size:120%;"|+
!
! colspan="2" |Alternative A
! colspan="2" |Alternative B
|-
!
!Score
!Weight
!Score
!Weight
|-
|Comfortable
|5
|0.2
|8
|0.2
|-
|Manufacturing simplicity
|9
|0.4
|5
|0.4
|-
|Modifiability
|9
|0.4
|4
|0.4
|-
|Total Score
| colspan="2" |8.2
| colspan="2" |5.2
|}
According to the table, aternative A has more scores. So we choose alternative A for our final design.

=== Code ===
Code is uploaded and there's access in appendix.

= Electrical Sub-team =
The electrical sub-team focused on designing the power and control system of the e-cycle prototype, including the Arduino, wiring, relay, motors, LEDs, and other electronic components. Our goal was to make the electrical system safe, reliable, and easy to troubleshoot. We considered different circuit design options and selected a simple Arduino-controlled system that can send signals to the required outputs while keeping the wiring organized.

== Project context ==
This electrical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The electrical sub-team is responsible for powering and controlling the electronic parts of the prototype. This includes the Arduino, wiring, vehicle board, relay, motors, fans, and other electronic components. The electrical system must work together with the coding, mechanical, structural, and thermal systems so that the final prototype can operate safely and reliably.

== Requirements ==
The electrical/electronic system was designed based on functions, objectives, and constraints.

=== Functions ===
The electrical/electronic system should be able to:

* Control the main electronic components of the prototype
* Provide power to the required electrical components
* Send output signals to motors, LEDs, fans, and actuators
* Receive input signals from the controller, sensors, or switches
* Connect the coding system to the physical prototype
* Support the vehicle board and receiver/autonomous control system
* Provide safe wiring for thermal components such as fans or the Peltier circuit, if used

=== Objectives ===
The electrical/electronic design should achieve these objectives:

* Provide reliable electronic control
* Keep wiring simple, organized, and easy to follow
* Reduce power consumption where possible
* Make troubleshooting easier during testing
* Create safe connections between the power supply, Arduino, relay, and electronic components
* Allow the circuit to fit inside the prototype frame
* Support testing and improvement throughout the project

=== Constraints ===
The electrical/electronic system shall:

* Use only components and tools provided or approved for the project
* Stay within the project budget
* Fit within the physical space of the prototype
* Avoid short circuits and loose wiring
* Not interfere with the mechanical or structural systems
* Be safe for team members to test and handle
* Be simple enough to build within the project timeline

== Design Description ==
The final electrical design uses the Arduino as the main controller. Input signals are sent to the Arduino from the controller, switches, or sensors. The Arduino processes these signals using the uploaded program and sends output signals to components such as motors, LEDs, fans, or other actuators.

The main electrical components include:

* Arduino board
* Power supply
* Vehicle board
* Relay
* Motor connections
* LED connections
* Fan wiring
* Peltier circuit wiring, if used
* Receiver/autonomous control system
* Wires and breadboard/prototype board

The wiring layout was designed to be simple and organized. This helps reduce wiring mistakes and makes it easier to troubleshoot the system if something does not work during testing.

{| class="wikitable"
|+
!Layer 1
!Layer 2
!Layer 3
|-
|[[File:Layer 1 elec.jpg|thumb]]
|[[File:Layer 2 elec.jpg|thumb]]
|[[File:Layer 3 elec.jpg|thumb]]
|}

== Circuit Design ==
The circuit connects the Arduino to the input and output components. The input components send signals to the Arduino. The Arduino then processes these signals and controls the outputs.

A relay was included in the circuit design to help control components that require more power than the Arduino can safely provide directly. This helps protect the Arduino and allows the prototype to control higher-power components, such as motors.
[[File:Ac0449e75b2c9fb8e6dc6939597fd3d3.jpg|thumb|center|401x401px]]
Breadboard testing was used before final installation. This allowed the team to test the circuit, check connections, and fix wiring problems before placing the components inside the prototype.

== Program Logic ==
The basic program logic is:

# The system is powered on.
# The Arduino receives power.
# The Arduino reads the input signal.
# The Arduino processes the input using the uploaded program.
# The Arduino sends output signals to the required components.
# The output components respond, such as motors turning, LEDs lighting, or fans operating.
# The system continues operating until the power is turned off.

This logic connects the coding system to the electrical hardware. It allows the prototype to respond to commands and operate in a controlled way.
[[File:Image 20260618163340 254 8.png|center|thumb|371x371px]]

== Testing Process ==
# Test each component individually.
# Build and test the circuit on a breadboard.
# Upload and test the Arduino code.
# Check that the wiring is safe and organized.
# Test the electrical system with the mechanical and structural parts.

== Final Design ==
[[File:C77044990972a3f6c0135f1919c17b2d.jpg|thumb|center|345x345px]]
[[File:Image 2026-06-18 162135 075.jpg|center|thumb|343x343px]]
The final electrical/electronic design uses an Arduino-based control system with simple wiring and safe connections. The design supports the operation of the prototype and can be tested and improved during the project.

= Thermal Sub-team =
The thermal sub-system was designed to improve the comfort of the passenger cabin. It focused on controlling heat inside the cabin by using an air-conditioning module, shading, natural ventilation, and SolidWorks Flow Simulation.

The main purpose of this sub-system was to reduce the cabin temperature during hot conditions and provide a possible heating function when needed. The design used a Peltier module with heat sinks and fans. One side of the Peltier module worked as the hot side, while the other side worked as the cold side. Because of this, the airflow paths had to be separated carefully.

The thermal sub-system included four main parts: aircon mounting, shading, natural ventilation, and flow simulation.

== Requirements ==

=== Functions ===
The thermal sub-system should be able to:

* Provide cooling for the passenger cabin
* Provide heating for the passenger cabin if needed
* Move air through the heat sinks
* Guide conditioned air into the cabin
* Keep the hot-side airflow and cold-side airflow separated
* Prevent hot air and cold air from mixing
* Allow natural ventilation so warm air does not stay trapped inside the cabin
* Reduce direct sunlight entering the cabin by using a shading part
* Lower the heat gain from sunlight to improve the cooling effect

=== Objectives ===
[[File:截屏2026-06-18 上午10.37.01.png|thumb]]
The main objectives of the thermal design were to:

* Improve thermal comfort inside the cabin
* Keep the air-conditioning system compact and simple
* Fit the thermal module into the limited space of the prototype
* Place the fans and heat sinks in a way that improves airflow
* Make the system easy to mount
* Make the system easy to connect with other sub-systems
* Keep the system light enough for the prototype
* Use SolidWorks Flow Simulation to estimate airflow direction
* Use SolidWorks Flow Simulation to estimate temperature change
* Check whether the design could cool the cabin before physical testing

=== Constraints ===
The thermal design had several constraints:

* The available space inside the vehicle was limited
* The air-conditioning module, fans, heat sinks, and ducts had to be compact
* The Peltier module required electrical power
* The system could not use too much power
* The system had to work with the electrical sub-system
* The hot side and cold side of the Peltier module had to be separated
* The hot airflow and cold airflow could not mix together
* The duct and fan layout had to guide air in the correct direction
* The components had to be easy to install on the prototype
* The system had to be light enough for the 1:5 scale prototype

== The Design ==

=== Aircon Mounting ===
[[File:截屏2026-06-18 上午10.36.48.png|thumb]]
[[File:D5c786ffb7a158f160ee93e72c1f47c0.jpg|thumb]]
The air-conditioning module was mounted close to the passenger cabin so that cool or warm air could be directed into the cabin. The module included a Peltier device, two heat sinks, and fans.

The Peltier device created a temperature difference between its two sides. One side became hot, and the other side became cold. The heat sinks helped transfer heat between the Peltier module and the air. The fans forced air through the heat sink fins to improve heat transfer.

The mounting design needed to hold all components securely. It also needed to make sure that the hot-side airflow and cold-side airflow did not mix. The final layout placed the fans on the side of the heat sinks. This allowed air to move through the fins and leave the system in a controlled direction.

On the cabin side, the fan pushed conditioned air into the passenger space. On the outside side, the fan removed unwanted heat from the hot side.

=== Shading ===
Shading was used to reduce the amount of direct sunlight entering the cabin. Direct sunlight can increase the cabin temperature and make the cooling system less effective.

The shading design used the roof and side panels to block part of the sunlight. The goal was not to make the cabin completely dark, but to reduce strong sunlight while keeping the cabin visible for demonstration.

This feature was simple, lightweight, and easy to combine with the vehicle body. It helped reduce heat gain without adding much complexity to the design.

=== Natural Ventilation ===
Natural ventilation was included to allow air exchange between the cabin and the outside environment. This helped prevent warm air from being trapped inside the cabin.

The ventilation openings allowed air to enter from one side and leave from another side. This created a simple airflow path through the cabin. When the vehicle moved or when the fans were operating, the ventilation openings helped improve air circulation.

Natural ventilation also worked as a backup method when the air-conditioning module was not running. It made the cabin more comfortable without using extra electrical power.

=== SolidWorks Flow Simulation ===
[[File:E9f6d6eea9306b1f01a2954dd8ab4d30.png|thumb]]
SolidWorks Flow Simulation was used to predict airflow and temperature change in the thermal system. The simulation helped the team check whether the fans, heat sinks, and air paths were arranged properly.
In the simulation, the inlet air temperature was set to 25 °C. The hot side of the Peltier module released heat, while the cold side removed heat from the cabin airflow. The simulation showed the airflow direction through the heat sinks and the temperature change near the outlet.

The main points studied in the simulation were the airflow path, the hot-side outlet temperature, the cold-side outlet temperature, and the separation between the hot and cold airflows.
[[File:27a4350ce318389ab34e5426554f5c8e.png|thumb]]
In the preliminary result, the hot-side outlet air reached about 55 °C, while the cold-side outlet air reached about 15 °C. This showed that the Peltier module could create a noticeable temperature difference. However, the simulation result still needs to be compared with real prototype testing.

A temperature probe should be placed near the cabin air outlet during testing. This measured value can be compared with the simulation result to check the accuracy of the model.

== Extra Features ==
One extra feature of the thermal system was the possibility of switching between cooling and heating. Since a Peltier module can reverse its hot and cold sides when the current direction changes, the same module could potentially be used for both cooling and heating.

Another possible feature is adding a temperature sensor inside the cabin. This would allow the team to measure the cabin temperature during testing. The measured data could be used to improve the simulation and evaluate the real performance of the thermal system.

= Sustainability =
Sustainability was considered because the e-cycle is designed to be a smaller and more energy-efficient transportation option for short-distance commuting. Compared with a full-size electric car, an e-cycle is lighter, uses fewer materials, and requires less energy to move.

== Energy Use Comparison ==
The sustainability comparison was based on the following assumptions:

* Distance: 20 km/day
* Travel time: 1 hour/day
* Frequency: 6 days/week
* Time period: 5 years
* Average electric car energy use: 189 Wh/km
* E-cycle battery: 48 V, 10.4 Ah
* E-cycle range: 88 km
* Air conditioner power: 450 W

{| class="wikitable"
!Item
!Calculation
!Result
|-
|Total distance
|20 × 6 × 52 × 5
|31,200 km
|-
|Electric car energy
|189 Wh/km × 31,200 km
|5,896.8 kWh
|-
|E-cycle battery energy
|48 V × 10.4 Ah
|499.2 Wh
|-
|E-cycle energy/km
|499.2 Wh ÷ 88 km
|5.67 Wh/km
|-
|E-cycle driving energy
|5.67 Wh/km × 31,200 km
|176.9 kWh
|-
|AC energy
|0.45 kW × 1,560 hours
|702 kWh
|-
|Total e-cycle energy with AC
|176.9 + 702
|878.9 kWh
|-
|Energy saved
|5,896.8 − 878.9
|5,017.9 kWh
|}
Based on this estimate, the e-cycle with air conditioning uses much less energy than an average electric car over 5 years. The e-cycle uses about 878.9 kWh, while the electric car uses about 5,896.8 kWh. This means the e-cycle could reduce energy use by about 85%.

This analysis is only an estimate because the final impact depends on the actual battery, material choices, electricity source, and air-conditioning power. However, the result shows that a smaller electric vehicle can be a more sustainable option for daily commuting.

= Appendices =

=== PDF Drawings ===
Parts drawing: [[File:Parts Drawing.pdf|thumb]]

Assembly drawing:
[[File:E-Cycle Assembly drawing.pdf|thumb]]
=== Gantt Chart ===
[[File:APSC 151 Gantt Chart.pdf|alt=VANT151 Gantt Chart|thumb]]

=== Test Video ===
{{#widget:YouTube|id=1RLFi5PB7XU|width=640|height=360}}

=== Arduino Code ===
[[File:Transmitter code.docx|thumb]]

[[File:Receiver code.docx|thumb]]

=== Rendering ===
{{#widget:YouTube|id=CFRkhRMMamM|width=640|height=360}}

[[File:Assembly files.pdf|alt=Assemble|thumb]]

=== References ===
[[File:Sustainabillity report.docx|thumb]]

= About Us =

=== Sub-teams: ===
{| class="wikitable"
! colspan="3" |Documentation
|-
|Gam Inthoong[[File:Gam Inthoong.jpg|thumb|267x267px|center]]Hi, my name is Gam Inthoong, and I am a member of the Documentation Sub-team for Team 3 in VANT151. My responsibilities included maintaining and organizing our project wiki, documenting the design process, creating the project Gantt chart to track progress, and assisting with the SolidWorks assembly of our electric cycle prototype. Through these tasks, I strengthened my technical communication, project planning, and CAD skills while supporting the successful completion of our team project.
|Hanrui Jia[[File:Hanrui.jpg|thumb|267x267px|center]]Hi, my name is Hanrui Jia, and I am a member of the Documentation sub-team. My main responsibility was to create the SolidWorks assembly and the engineering drawings for both the individual parts and the final project model. Besides that, I also helped my teammates create the Gantt chart. Through these tasks, I improved my SolidWorks skills and learned the importance of teamwork and communication. This project also helped me develop better time management and problem-solving skills.
|
|-
! colspan="3" |Structural
|-
|Leo Jia[[File:Leo Jia.jpg|thumb|center|267x267px]]I am Leo Jia, a member of the Structural Sub-team. My primary responsibility was contributing to the overall frame design of the e-cycle prototype, including the support structure, hardware protection, and special design features. Throughout the project, I focused on improving the stability, balance, and practicality of the structure while keeping the frame strong but lightweight. I also considered how the design could allow easier assembly, disassembly, and maintenance. This experience strengthened my understanding of structural design principles and helped me develop my problem-solving, communication, and teamwork skills. I believe the knowledge and skills gained from this project will be useful in my future academic and professional development.
|Jackson Li[[File:Jackson Li.jpg|thumb|267x267px]]Hi, my name is Jackson Li, and I am a member of the Structural Sub-team for our project in VANT151. My responsibilities included designing the vehicle doors using SolidWorks and manufacturing the external enclosure components through vacuum forming for our prototype. Through these tasks, I strengthened my CAD proficiency, hands-on manufacturing abilities, and structural design skills while supporting the successful completion of our team project.
|Guangyan Liu
[[File:Guangyan.jpg|thumb|center|267x267px]]I am Guangyan Liu, a member of the Structural Sub-team. My primary responsibility was developing alternative solutions for the overall structural design. Throughout the project, I addressed challenges related to structural stability, feasibility, and design optimization. This experience strengthened my understanding of structural analysis and engineering design principles while also improving my problem-solving and teamwork skills. I believe the knowledge and skills gained from this project will be valuable in my future academic and professional development.
|-
! colspan="3" |Electrical
|-
|Xiyao Yang[[File:Weixin Image 20260619123335 239 250.jpg|center|thumb|223x223px]]My name is Xiyao Yang, and I was a member of the electrical sub-team. My main responsibility was designing and building the receiver circuit for our RC vehicle. I worked with components such as the Arduino Nano, the nRF24L01 wireless receiver, the servo motor, the IRF520 MOSFET, and the DC motor. During the project, I helped connect the circuit, test the wiring, and troubleshoot electrical issues to make sure all the components worked together correctly. This project gave me valuable hands-on experience with circuit design and hardware integration. It also improved my problem-solving skills and showed me the importance of teamwork and communication
|Wenhao Chen[[File:Wenhao.jpg|thumb|267x267px]]
|
|-
! colspan="3" |Mechanical
|-
|Zirui Dou[[File:Zirui.jpg|thumb|267x267px|center]]My name is Zirui Dou, and I mainly worked on the mechanical aspects of our project. My responsibilities included helping with the design, construction, and adjustment of the vehicle’s physical components. While working on the project, I had to think carefully about how different mechanical parts would fit and function together. This process gave me useful experience in turning design ideas into real working parts. It also taught me the importance of communication and cooperation within a team. Overall, this project helped me build practical engineering skills that I can continue to use in the future.
|Zehao Zhao[[File:Zehao.jpg|thumb|center|267x267px]]I am Zehao, and I contribute to the mechanical part of the project. As a member of the mechanical sub-team, I was responsible for designing, assembling, and improving mechanical components. During this project, I faced many challenges related to the vehicle structure and mechanical system. Through solving these problems, I learned a lot of practical skills, especially in mechanical design, manufacturing, and teamwork. This experience helped me develop both my technical knowledge and communication skills. I hope to apply these skills in my future career and working environment.
|Zihao Yin[[File:Zhiyin.jpg|thumb|267x267px|center]]I was responsible for the solidwork design of all part in frame, wheels and suspension part. I also help assemble the suspension system and chasis. This project has taught me how to work in a big groups in an organized and peaceful way. It has also improved my modeling skills and my understanding of mechanical engineering. These skills will be useful in jobs in the engineering field.
|-
! colspan="3" |Coding
|-
|Hao Shu[[File:Shuhao.png|center|thumb|233x233px]]Hi, I'm Hao Shu, I'm contributing to the coding part of the cycle. To be detailed, I was mainly responsible for receiver part of the remote control system. During this project, I had a much more understanding of the remote control modules, coding. I faced lots of challenge for example how to realize mutual communication between the cycle and the controller to transit the information back. This project helps me improve my technique, communication skills and also the skills of discovering problems.
|Jiacheng Sun[[File:Jiacheng.jpg|thumb|237x237px|center]]I am jiacheng sun, and I mainly contributed to the coding and control system of our tricycle project. My work focused on programming the transmitter and receiver, reading joystick and button inputs, and using the nRF24L01 wireless module to send control signals.

During this project, I learned more about Arduino programming, wireless communication, and how to connect code with real hardware. I also gained experience in teamwork, testing, and problem-solving. This project helped me understand how electrical and coding design can work together in a real engineering system.
|
|-
! colspan="3" |Thermal
|-
|Hekai Zeng[[File:Weixin Image 20260619125612 241 250.jpg|center|thumb|239x239px]]Hi, I'm Hekai Zeng, and I was the only member of the Thermal sub-team in our VANT 151 tricycle project. I mainly contributed to the thermal design of the vehicle, including the HVAC system, airflow design, sun shading, and natural ventilation. My work focused on improving the comfort inside the vehicle by considering how air could move through the cabin and how heat could be reduced.

During this project, I also worked on the thermal analysis part. I used SolidWorks Flow Simulation to predict the air temperature and airflow inside the vehicle. I also considered the effect of the Peltier module, fans, and ventilation openings on the cooling performance. Since I was the only person in the Thermal group, I had to plan, design, test, and improve this part by myself while also communicating with the electrical and structural teams.

Through this project, I learned more about heat transfer, airflow, thermal simulation, and how thermal design connects with real hardware. I also gained experience in independent problem-solving, testing, and teamwork. This project helped me understand how thermal, electrical, and structural design can work together in a real engineering system.
|
|
|}

== Contact Information ==
* Gam Inthoong: ginthoon@student.ubc.ca
* Guangyan Liu: lgy2025@student.ubc.ca
* Hanrui Jia: dottore7@student.ubc.ca
* Hekai Zeng: franci66@student.ubc.ca
* Jackson Li: jiahao18@student.ubc.ca
* Jiacheng Sun: sungra01@studemt.ubc.ca
* Leo Jia: jia629@student.ubc.ca
* Shu hao: shuhao11@student.ubc.ca
* Wenhao Chen:
* Xiyao Yang: xyang105@student.ubc.ca
* Zehao Zhao: zhao103@student.ubc.ca
* Zhihao Yin: zhihaoy9@student.ubc.ca

* Zirui Dou: zdou01@student.ubc.ca

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2026-06-26T05:54:32Z

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Sandbox:Team 3 Mechanical sub-team

2026-06-18T02:45:28Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou || Zehao Zhao || Zhihao Yin

== Project Context ==
This mechanical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The mechanical sub-team focuses on the parts that physically support motion: chassis layout, suspension, steering clearance, wheel contact, and the gear/chain drive.
[[File:Team3_mech_axle_wheel_assembly.png|center|thumb|689x689px|Prototype axle and wheel assembly concept used for the mechanical layout.]]'''Real look'''
[[File:微信图片 20260618095939.jpg|center|thumb|586x586px|The whole car before inserting the basis]]
[[File:微信图片 20260618095826.jpg|center|thumb|614x614px]]
[[File:微信图片 20260618100040.jpg|center|thumb|607x607px|motor system]]

== 1. Mechanical Goals ==
The mechanical system has five main goals:

# '''Keep the vehicle stable on uneven ground''' so the prototype can drive without tipping or excessive body movement.
# '''Reduce vibration from the road''' to protect the rider model, frame, and internal components.
# '''Keep the wheels in contact with the ground''' so steering and traction stay consistent.
# '''Transfer motor torque to the wheels efficiently''' using a reliable gear/chain drive.
# '''xChoose a gear ratio that balances speed and torque''' instead of only maximizing top speed.

== 2. Design Constraints from the Project ==
The design must stay within the main project limits:
{| class="wikitable"
!Constraint
!Mechanical meaning
|-
|Width <= 240 mm
|The frame, wheels, steering linkage, and suspension arms must stay within the allowed width.
|-
|Fit within a 430 x 279 mm footprint
|The full prototype layout must be compact, especially the wheelbase and rear drive area.
|-
|Accommodate a 360 mm mannequin
|The chassis and upper frame must support the rider model without blocking steering or drivetrain parts.
|-
|Power limit: 9.6 V, 2.8 A
|The drivetrain should reduce losses and provide enough starting torque within limited motor power.
|-
|Complete straight driving and figure-8 path
|Steering geometry, wheel alignment, and traction must be stable during both straight and turning motion.
|}

== 3. Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.
[[File:微信图片 20260605021854.jpg|center|thumb|Early sketch for a simple solid-axle layout.]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.
[[File:微信图片 20260618101427.jpg|center|thumb|Selected mechanical layout sketch: independent front motion with a simpler rear drive axle.]]

== 4. Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:Team3 mech red frame link.jpg|center|thumb|Example CAD part for a red frame or linkage component.]]

== 5. Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.
[[File:微信图片 20260618102518.jpg|center|thumb|Gear design used as a drivetrain reference for the mechanical prototype.]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.
[[File:微信图片 20260618102344.jpg|center|thumb|solidwork single gear system]]

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.

== 6. Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== 7. Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}
'''<big>8. Final Recommendation</big>'''

<nowiki>*</nowiki> <nowiki>'''</nowiki>Design basis:<nowiki>'''</nowiki> The selected mechanical design is based on the project constraints, including the 430 x 279 mm footprint, 240 mm width limit, 360 mm mannequin size, and 9.6 V / 2.8 A power limit. Because the prototype needs to drive straight and complete a figure-8 path, the design prioritizes stability, steering clearance, wheel contact, and reliable torque transfer over maximum speed.
[[File:微信图片 20260618101436.png|center|thumb|basis]]

== 9. Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

Sandbox:Team 3 Mechanical sub-team

2026-06-18T02:36:05Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou || Zehao Zhao || Zhihao Yin

== Project Context ==
This mechanical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The mechanical sub-team focuses on the parts that physically support motion: chassis layout, suspension, steering clearance, wheel contact, and the gear/chain drive.
[[File:Team3_mech_axle_wheel_assembly.png|center|thumb|689x689px|Prototype axle and wheel assembly concept used for the mechanical layout.]]'''Real look'''
[[File:微信图片 20260618095939.jpg|center|thumb|586x586px|The whole car before inserting the basis]]
[[File:微信图片 20260618095826.jpg|center|thumb|614x614px]]
[[File:微信图片 20260618100040.jpg|center|thumb|607x607px|motor system]]

== 1. Mechanical Goals ==
The mechanical system has five main goals:

# '''Keep the vehicle stable on uneven ground''' so the prototype can drive without tipping or excessive body movement.
# '''Reduce vibration from the road''' to protect the rider model, frame, and internal components.
# '''Keep the wheels in contact with the ground''' so steering and traction stay consistent.
# '''Transfer motor torque to the wheels efficiently''' using a reliable gear/chain drive.
# '''xChoose a gear ratio that balances speed and torque''' instead of only maximizing top speed.

== 2. Design Constraints from the Project ==
The design must stay within the main project limits:
{| class="wikitable"
!Constraint
!Mechanical meaning
|-
|Width <= 240 mm
|The frame, wheels, steering linkage, and suspension arms must stay within the allowed width.
|-
|Fit within a 430 x 279 mm footprint
|The full prototype layout must be compact, especially the wheelbase and rear drive area.
|-
|Accommodate a 360 mm mannequin
|The chassis and upper frame must support the rider model without blocking steering or drivetrain parts.
|-
|Power limit: 9.6 V, 2.8 A
|The drivetrain should reduce losses and provide enough starting torque within limited motor power.
|-
|Complete straight driving and figure-8 path
|Steering geometry, wheel alignment, and traction must be stable during both straight and turning motion.
|}

== 3. Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.
[[File:微信图片 20260605021854.jpg|center|thumb|Early sketch for a simple solid-axle layout.]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.
[[File:微信图片 20260618101427.jpg|center|thumb|Selected mechanical layout sketch: independent front motion with a simpler rear drive axle.]]

== 4. Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:Team3 mech red frame link.jpg|center|thumb|Example CAD part for a red frame or linkage component.]]

== 5. Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.
[[File:微信图片 20260618102518.jpg|center|thumb|Gear design used as a drivetrain reference for the mechanical prototype.]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.
[[File:微信图片 20260618102344.jpg|center|thumb|solidwork single gear system]]

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.

== 6. Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== 7. Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}

== 8. Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

Sandbox:Team 3 Mechanical sub-team

2026-06-18T02:31:31Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou || Zehao Zhao || Zhihao Yin

== Project Context ==
This mechanical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The mechanical sub-team focuses on the parts that physically support motion: chassis layout, suspension, steering clearance, wheel contact, and the gear/chain drive.
[[File:Team3_mech_axle_wheel_assembly.png|center|thumb|689x689px|Prototype axle and wheel assembly concept used for the mechanical layout.]]'''Real look'''
[[File:微信图片 20260618095939.jpg|center|thumb|586x586px|The whole car before inserting the basis]]
[[File:微信图片 20260618100040.jpg|center|thumb|607x607px|motor system]]

== 1. Mechanical Goals ==
The mechanical system has five main goals:

# '''Keep the vehicle stable on uneven ground''' so the prototype can drive without tipping or excessive body movement.
# '''Reduce vibration from the road''' to protect the rider model, frame, and internal components.
# '''Keep the wheels in contact with the ground''' so steering and traction stay consistent.
# '''Transfer motor torque to the wheels efficiently''' using a reliable gear/chain drive.
# '''xChoose a gear ratio that balances speed and torque''' instead of only maximizing top speed.

== 2. Design Constraints from the Project ==
The design must stay within the main project limits:
{| class="wikitable"
!Constraint
!Mechanical meaning
|-
|Width <= 240 mm
|The frame, wheels, steering linkage, and suspension arms must stay within the allowed width.
|-
|Fit within a 430 x 279 mm footprint
|The full prototype layout must be compact, especially the wheelbase and rear drive area.
|-
|Accommodate a 360 mm mannequin
|The chassis and upper frame must support the rider model without blocking steering or drivetrain parts.
|-
|Power limit: 9.6 V, 2.8 A
|The drivetrain should reduce losses and provide enough starting torque within limited motor power.
|-
|Complete straight driving and figure-8 path
|Steering geometry, wheel alignment, and traction must be stable during both straight and turning motion.
|}

== 3. Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.

[[File:Team3_mech_steering_sketch_option_a.jpeg|center|thumb|650x650px|[[File:微信图片 20260605021854.jpg|center|thumb]]Early sketch for a simple solid-axle layout.]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

[[File:Team3_mech_suspension_sketch_option_b.jpeg|center|thumb|650x650px|Early sketch for a more complex independent suspension concept.]]

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.

[[File:Team3_mech_selected_layout_sketch.jpeg|center|thumb|650x650px|Selected mechanical layout sketch: independent front motion with a simpler rear drive axle.]]

== 4. Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:Team3_mech_red_frame_link.jpeg|center|thumb|600x600px|[[File:Team3 mech red frame link.jpg|center|thumb]]Example CAD part for a red frame or linkage component.]]

== 5. Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.

[[File:Team3_mech_gear_design.png|center|thumb|600x600px|[[File:微信图片 20260618102518.jpg|center|thumb]]Gear design used as a drivetrain reference for the mechanical prototype.]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.
[[File:微信图片 20260618102344.jpg|center|thumb|solidwork single gear system]]

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.

== 6. Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== 7. Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}

== 8. Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

Sandbox:Team 3 Mechanical sub-team

2026-06-18T02:30:26Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou || Zehao Zhao || Zhihao Yin

== Project Context ==
This mechanical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The mechanical sub-team focuses on the parts that physically support motion: chassis layout, suspension, steering clearance, wheel contact, and the gear/chain drive.
[[File:Team3_mech_axle_wheel_assembly.png|center|thumb|689x689px|Prototype axle and wheel assembly concept used for the mechanical layout.]]'''Real look'''
[[File:微信图片 20260618095939.jpg|center|thumb|586x586px|The whole car before inserting the basis]]
[[File:微信图片 20260618100040.jpg|center|thumb|607x607px|motor system]]

== 1. Mechanical Goals ==
The mechanical system has five main goals:

# '''Keep the vehicle stable on uneven ground''' so the prototype can drive without tipping or excessive body movement.
# '''Reduce vibration from the road''' to protect the rider model, frame, and internal components.
# '''Keep the wheels in contact with the ground''' so steering and traction stay consistent.
# '''Transfer motor torque to the wheels efficiently''' using a reliable gear/chain drive.
# '''xChoose a gear ratio that balances speed and torque''' instead of only maximizing top speed.

== 2. Design Constraints from the Project ==
The design must stay within the main project limits:
{| class="wikitable"
!Constraint
!Mechanical meaning
|-
|Width <= 240 mm
|The frame, wheels, steering linkage, and suspension arms must stay within the allowed width.
|-
|Fit within a 430 x 279 mm footprint
|The full prototype layout must be compact, especially the wheelbase and rear drive area.
|-
|Accommodate a 360 mm mannequin
|The chassis and upper frame must support the rider model without blocking steering or drivetrain parts.
|-
|Power limit: 9.6 V, 2.8 A
|The drivetrain should reduce losses and provide enough starting torque within limited motor power.
|-
|Complete straight driving and figure-8 path
|Steering geometry, wheel alignment, and traction must be stable during both straight and turning motion.
|}

== 3. Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.

[[File:Team3_mech_steering_sketch_option_a.jpeg|center|thumb|650x650px|[[File:微信图片 20260605021854.jpg|center|thumb]]Early sketch for a simple solid-axle layout.]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

[[File:Team3_mech_suspension_sketch_option_b.jpeg|center|thumb|650x650px|Early sketch for a more complex independent suspension concept.]]

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.

[[File:Team3_mech_selected_layout_sketch.jpeg|center|thumb|650x650px|[[File:微信图片 20260618101427.jpg|center|thumb]]Selected mechanical layout sketch: independent front motion with a simpler rear drive axle.]]

== 4. Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:Team3_mech_red_frame_link.jpeg|center|thumb|600x600px|[[File:Team3 mech red frame link.jpg|center|thumb]]Example CAD part for a red frame or linkage component.]]

== 5. Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.

[[File:Team3_mech_gear_design.png|center|thumb|600x600px|[[File:微信图片 20260618102518.jpg|center|thumb]]Gear design used as a drivetrain reference for the mechanical prototype.]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.
[[File:微信图片 20260618102344.jpg|center|thumb|solidwork single gear system]]

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.

== 6. Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== 7. Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}

== 8. Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

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Sandbox:Team 3 Mechanical sub-team

2026-06-16T18:43:55Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou || Zehao Zhao || Zhihao Yin

== Project Context ==
This mechanical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The mechanical sub-team focuses on the parts that physically support motion: chassis layout, suspension, steering clearance, wheel contact, and the gear/chain drive.
[[File:Team3_mech_axle_wheel_assembly.png|center|thumb|689x689px|Prototype axle and wheel assembly concept used for the mechanical layout.]]

== 1. Mechanical Goals ==
The mechanical system has five main goals:

# '''Keep the vehicle stable on uneven ground''' so the prototype can drive without tipping or excessive body movement.
# '''Reduce vibration from the road''' to protect the rider model, frame, and internal components.
# '''Keep the wheels in contact with the ground''' so steering and traction stay consistent.
# '''Transfer motor torque to the wheels efficiently''' using a reliable gear/chain drive.
# '''xChoose a gear ratio that balances speed and torque''' instead of only maximizing top speed.

== 2. Design Constraints from the Project ==
The design must stay within the main project limits:
{| class="wikitable"
!Constraint
!Mechanical meaning
|-
|Width <= 240 mm
|The frame, wheels, steering linkage, and suspension arms must stay within the allowed width.
|-
|Fit within a 430 x 279 mm footprint
|The full prototype layout must be compact, especially the wheelbase and rear drive area.
|-
|Accommodate a 360 mm mannequin
|The chassis and upper frame must support the rider model without blocking steering or drivetrain parts.
|-
|Power limit: 9.6 V, 2.8 A
|The drivetrain should reduce losses and provide enough starting torque within limited motor power.
|-
|Complete straight driving and figure-8 path
|Steering geometry, wheel alignment, and traction must be stable during both straight and turning motion.
|}

== 3. Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.

[[File:Team3_mech_steering_sketch_option_a.jpeg|center|thumb|650x650px|Early sketch for a simple solid-axle layout.]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

[[File:Team3_mech_suspension_sketch_option_b.jpeg|center|thumb|650x650px|Early sketch for a more complex independent suspension concept.]]

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.

[[File:Team3_mech_selected_layout_sketch.jpeg|center|thumb|650x650px|Selected mechanical layout sketch: independent front motion with a simpler rear drive axle.]]

== 4. Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:Team3_mech_red_frame_link.jpeg|center|thumb|600x600px|Example CAD part for a red frame or linkage component.]]

== 5. Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.

[[File:Team3_mech_gear_design.png|center|thumb|600x600px|Gear design used as a drivetrain reference for the mechanical prototype.]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.

== 6. Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== 7. Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}

== 8. Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

Sandbox:Team 3 Mechanical sub-team

2026-06-16T18:33:46Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou || Zehao Zhao || Zhihao Yin

== Project Context ==
This mechanical plan is for the VANT151 / VD2 Team 3 e-cycle engineering project. The project uses a 1:5 scale prototype to demonstrate a practical electric cycle concept that improves rider protection, comfort, and commuting convenience.

The mechanical sub-team focuses on the parts that physically support motion: chassis layout, suspension, steering clearance, wheel contact, and the gear/chain drive.
[[File:Team3_mech_axle_wheel_assembly.png|center|thumb|689x689px|Prototype axle and wheel assembly concept used for the mechanical layout.]]

== 1. Mechanical Goals ==
The mechanical system has five main goals:

# '''Keep the vehicle stable on uneven ground''' so the prototype can drive without tipping or excessive body movement.
# '''Reduce vibration from the road''' to protect the rider model, frame, and internal components.
# '''Keep the wheels in contact with the ground''' so steering and traction stay consistent.
# '''Transfer motor torque to the wheels efficiently''' using a reliable gear/chain drive.
# '''Choose a gear ratio that balances speed and torque''' instead of only maximizing top speed.

== 2. Design Constraints from the Project ==
The design must stay within the main project limits:
{| class="wikitable"
!Constraint
!Mechanical meaning
|-
|Width <= 240 mm
|The frame, wheels, steering linkage, and suspension arms must stay within the allowed width.
|-
|Fit within a 430 x 279 mm footprint
|The full prototype layout must be compact, especially the wheelbase and rear drive area.
|-
|Accommodate a 360 mm mannequin
|The chassis and upper frame must support the rider model without blocking steering or drivetrain parts.
|-
|Power limit: 9.6 V, 2.8 A
|The drivetrain should reduce losses and provide enough starting torque within limited motor power.
|-
|Complete straight driving and figure-8 path
|Steering geometry, wheel alignment, and traction must be stable during both straight and turning motion.
|}

== 3. Suspension Design Alternatives ==

=== Option A: Front and Rear Solid Axles ===
Front and rear wheels are connected by solid axles.

* '''Advantages:''' strong, simple, and easy to build.
* '''Reason not selected:''' front steering would be less smooth because the front wheels cannot move independently.

[[File:Team3_mech_steering_sketch_option_a.jpeg|center|thumb|650x650px|Early sketch for a simple solid-axle layout.]]

=== Option B: Full Independent Suspension ===
Each wheel moves separately with its own suspension parts.

* '''Advantages:''' best handling and stability.
* '''Reason not selected:''' too complex, heavy, and time-consuming for the first prototype.

[[File:Team3_mech_suspension_sketch_option_b.jpeg|center|thumb|650x650px|Early sketch for a more complex independent suspension concept.]]

=== Option C: Independent Front Suspension + Rigid Rear Axle ===
Front wheels use independent suspension for better steering. Rear wheels use a rigid axle for strength and simplicity.

* '''Advantages:''' balances performance, weight, and ease of construction.
* '''Reason selected:''' it gives better front steering than a full solid-axle layout while staying much easier to build than full independent suspension.

[[File:Team3_mech_selected_layout_sketch.jpeg|center|thumb|650x650px|Selected mechanical layout sketch: independent front motion with a simpler rear drive axle.]]

== 4. Selected Suspension System Plan ==

=== 4.1 Front Suspension Design ===
The front suspension should use a simplified double-arm or pivot-arm style layout.

Each front wheel should include:

* one lower control arm;
* one upper guide arm or support link;
* one steering knuckle;
* one spring, rubber band, or flexible shock element;
* one steering linkage rod.

The front suspension should let the wheel move slightly up and down while limiting sideways movement. This helps the vehicle keep wheel contact during small bumps and improves stability during steering.

=== 4.2 Rear Suspension and Drive Axle ===
The rear should use a solid axle suspension. Both rear wheels rotate with the axle, and the rear sprocket should be fixed tightly to the axle.

This approach is useful because:

* the rear axle is stronger and easier to align;
* the chain path can stay short and straight;
* the rear drive wheels receive torque together;
* fewer moving parts make the first prototype easier to test and repair.

=== 4.3 Suspension Materials ===
{| class="wikitable"
!Part
!Recommended material or component
|-
|Chassis
|Acrylic, plywood, or 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Shock element
|Small compression springs, rubber bands, or flexible printed arms
|-
|Fasteners
|M3 screws and nuts
|}
[[File:Team3_mech_red_frame_link.jpeg|center|thumb|600x600px|Example CAD part for a red frame or linkage component.]]

== 5. Gear / Chain Drive System Plan ==

=== 5.1 Recommended Drive Type ===
Use a '''chain drive system''' to transfer power from the motor to the rear wheels.

Chain drive is recommended because:

* it is more reliable than friction drive;
* it slips less than a belt drive;
* it can handle higher torque;
* the sprocket sizes can be changed to tune speed and torque.

[[File:Team3_mech_gear_design.png|center|thumb|600x600px|Gear design used as a drivetrain reference for the mechanical prototype.]]

=== 5.2 Gear Ratio Logic ===
For a chain drive:

<code>Wheel speed = Motor speed x (motor sprocket teeth / rear sprocket teeth)</code>

<code>Torque change is approximately proportional to (rear sprocket teeth / motor sprocket teeth)</code>

This means:

* '''smaller rear sprocket''' gives higher wheel speed but lower torque;
* '''larger rear sprocket''' gives lower wheel speed but higher torque.

=== 5.3 Gear Ratio Options ===
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Speed multiplier
!Expected result
|-
|22T
|10T
|2.20x
|Fastest option, but weakest starting torque
|-
|22T
|14T
|1.57x
|Balanced starting point
|-
|22T
|18T
|1.22x
|More torque, slower speed
|}
The first prototype should start with '''22T to 14T''' because it gives a better balance between speed and torque. If the vehicle cannot start smoothly or struggles under load, change to '''22T to 18T'''. If the vehicle has enough torque and needs more speed, test '''22T to 10T'''.

== 6. Mechanical Layout Recommendation ==
The recommended layout is:

* motor and drive sprocket near the rear axle;
* rear sprocket fixed to the rear axle;
* battery and heavier components low and near the center;
* front steering linkage kept clear of the chassis;
* left and right suspension arms kept symmetric.

This layout is good because the rear drive gives better traction, the chain can be shorter, the center of gravity stays low, and the front remains free for steering.

== 7. Build and Test Plan ==

=== Step 1: Build the chassis ===
Make a flat chassis plate first. Keep the total footprint within the project limit and leave clearance for the front wheels to steer.

=== Step 2: Build the rear axle ===
Install the rear axle rod, two rear wheels, rear sprocket, two bearings, and bearing holders. The rear wheels and sprocket should rotate together.

=== Step 3: Install the motor and chain ===
Place the motor close to the rear axle. The motor sprocket and rear sprocket must be aligned so the chain is straight. Chain tension should not be too loose or too tight.

=== Step 4: Build the front suspension ===
Make the left and right front suspension symmetric. Check that the wheels can move up and down and steer left and right without hitting the chassis.

=== Step 5: Test gear ratios ===
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

{| class="wikitable"
!Test result
!Mechanical adjustment
|-
|Car is too slow
|Use a smaller rear sprocket
|-
|Car cannot start smoothly
|Use a larger rear sprocket
|-
|Chain falls off
|Improve sprocket alignment and chain tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering is unstable
|Reduce speed, improve front alignment, or increase steering clearance
|}

== 8. Final Recommendation ==
For the first working prototype, use '''Option C: independent front suspension with a rigid rear axle''' and begin drivetrain testing with a '''22T motor sprocket and 14T rear sprocket'''.

This setup is not the most complex or the fastest option, but it is the best starting point because it balances stability, steering, torque transfer, weight, and build difficulty.

File:Team3 mech axle wheel assembly.png

2026-06-16T18:31:56Z

ZiruiDou: Uploaded own work with UploadWizard

=={{int:filedesc}}==
{{Information
|description={{en|1=english}}
|date=2026-06-17
|source={{own}}
|author=[[User:ZiruiDou|ZiruiDou]]
|permission=
|other versions=
}}

=={{int:license-header}}==
{{self|cc-by-sa-4.0}}

Sandbox:Team 3 Mechanical sub-team

2026-06-04T18:04:59Z

ZiruiDou:

= Team 3 Mechanical Sub-team Plan =
Zirui Dou||Zehao Zhao||Zhihao Yin

== Small Vehicle Suspension System and Gear System ==

== 1. Mechanical Goals ==
Our mechanical system has two main goals:

# '''Suspension system''' Keep the car stable when driving over uneven ground, reduce vibration, and prevent the wheels from losing contact with the ground.
# '''Gear / chain drive system''' Transfer torque from the motor to the wheels efficiently, while choosing a proper gear ratio between speed and climbing/starting torque.

----

= 2. Suspension System Plan =

== 2.1 Recommended Suspension Type ==
For this small vehicle, the best choice is:

== Simple independent front suspension + rigid rear axle ==
Why this is good:

* Front wheels need steering, so independent suspension helps steering stability.
* Rear wheels can use a simpler rigid axle because it is easier to build and stronger.
* It is lighter and easier than making full independent suspension on all four wheels.
* Good enough for a small project car.

----

== 2.2 Front Suspension Design ==
Use a '''double-arm style front suspension''' or simplified '''pivot arm suspension'''.

Each front wheel should have:

* One lower control arm
* One upper guide arm or support link
* One steering knuckle
* One spring or rubber band shock element
* One steering linkage rod

Simple structure:

The front suspension should allow the wheel to move slightly up and down, but not move sideways too much.
----

== 2.3 Rear Suspension Design ==
For the rear, use a '''solid axle suspension'''.

The rear axle carries both rear wheels together.

Structure:

Support the axle with two bearings on the chassis.

Add soft support using:

* Small springs, or
* Rubber bands, or
* Flexible plastic/printed arms

This makes the rear easier to build and stronger.
----

== 2.4 Suspension Materials ==
Recommended parts:
{| class="wikitable"
!Part
!Material
|-
|Chassis
|Acrylic / plywood / 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Springs
|Small compression springs / rubber bands
|-
|Fasteners
|M3 screws and nuts
|}
For your project, '''M3 screws''' are a good size.

== 2.5 Suspension Design Requirements ==
Important things to check:

# '''Wheel alignment''' The left and right wheels should be parallel when going straight.
# '''Suspension travel''' The wheel should move up and down about:

For a small car, this is enough.

# '''Low center of gravity''' Put heavy parts like motor and battery as low as possible.
# '''Symmetry''' Left and right suspension arms should have the same length.
# '''Steering clearance''' The front wheels must be able to turn without hitting the chassis.

----

= 3. Gear / Chain Drive System Plan =

== 3.1 Recommended Drive Type ==
Use a '''chain drive system'''.

Why chain drive is good:

* More reliable than friction drive.
* Easier to adjust gear ratio.
* Better for high torque.
* Less slipping than belt drive.

Basic layout:
----

== 3.2 Gear Ratio ==
Gear ratio formula:

Example:

If motor sprocket = 22 teeth

Rear sprocket = 10 teeth

This means the rear wheel spins faster than the motor sprocket, but torque becomes lower.

So:

* Smaller rear sprocket = higher speed, lower torque
* Larger rear sprocket = lower speed, higher torque

----

== 3.3 Recommended Gear Ratio Choice ==
For a small vehicle, do not only chase max speed. You need enough torque to start moving.

I recommend testing 3 options:
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Ratio
!Result
|-
|22T
|10T
|0.45
|Fast, but weak torque
|-
|22T
|14T
|0.64
|Balanced
|-
|22T
|18T
|0.82
|Stronger torque, slower
|}
Best starting choice:

This gives a better balance between speed and torque.

If the car cannot start smoothly or struggles under load, change to:

If the car is strong enough and you want more speed, try:
----

= 4. Wheel Speed Estimate =
If motor speed is about:

and the sprocket setup is:

Then rear wheel speed is approximately:

If rear wheel diameter is:

Wheel circumference:

Vehicle speed:

Convert to m/s:

So with 22T to 10T and 12 cm wheels:

This is not very fast, so if the motor really only has 14.6 rpm, the vehicle may need a larger speed-up ratio or larger wheels.
----

= 5. Mechanical Layout Recommendation =
Recommended layout:

This layout is good because:

* Rear drive gives better traction.
* Motor close to rear axle makes chain shorter.
* Battery in the middle balances weight.
* Front stays light for steering.

----

= 6. Design Steps =

== Step 1: Build the chassis ==
Make a flat chassis plate first.

Suggested size:

Since your box limit is about 45.6 cm, keep the total car length under:
----

== Step 2: Design the rear axle ==
Parts needed:

* Rear axle rod
* Two rear wheels
* Rear sprocket
* Two bearings
* Bearing holders

Make sure the rear sprocket is fixed tightly to the axle.

The rear wheels and sprocket should rotate together.
----

== Step 3: Install the motor ==
Place the motor close to the rear axle.

Important:

* Motor sprocket and rear sprocket must be aligned.
* Chain should be straight.
* Chain should not be too loose or too tight.

Good chain tension:
----

== Step 4: Build the front suspension ==
Make left and right front suspension symmetric.

Check:

* Wheel can move up and down.
* Wheel can turn left and right.
* Steering rod does not hit the chassis.
* M3 screws are not too tight, so the joints can rotate.

----

== Step 5: Test gear ratios ==
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

Choose based on result:
{| class="wikitable"
!Problem
!Solution
|-
|Car is too slow
|Use smaller rear sprocket
|-
|Car cannot start
|Use larger rear sprocket
|-
|Chain falls off
|Improve alignment and tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering unstable
|Reduce speed or improve front alignment
|}
----

= 7. Final Recommendation =
For the first prototype, use:

This setup is not the fastest, but it is the safest and easiest to build successfully.

Sandbox:Team 3 Mechanical sub-team

2026-06-04T18:03:24Z

ZiruiDou: Team 3 Mech

= Team 3 Mechanical Sub-team Plan =

== Small Vehicle Suspension System and Gear System ==

== 1. Mechanical Goals ==
Our mechanical system has two main goals:

# '''Suspension system''' Keep the car stable when driving over uneven ground, reduce vibration, and prevent the wheels from losing contact with the ground.
# '''Gear / chain drive system''' Transfer torque from the motor to the wheels efficiently, while choosing a proper gear ratio between speed and climbing/starting torque.

----

= 2. Suspension System Plan =

== 2.1 Recommended Suspension Type ==
For this small vehicle, the best choice is:

== Simple independent front suspension + rigid rear axle ==
Why this is good:

* Front wheels need steering, so independent suspension helps steering stability.
* Rear wheels can use a simpler rigid axle because it is easier to build and stronger.
* It is lighter and easier than making full independent suspension on all four wheels.
* Good enough for a small project car.

----

== 2.2 Front Suspension Design ==
Use a '''double-arm style front suspension''' or simplified '''pivot arm suspension'''.

Each front wheel should have:

* One lower control arm
* One upper guide arm or support link
* One steering knuckle
* One spring or rubber band shock element
* One steering linkage rod

Simple structure:

The front suspension should allow the wheel to move slightly up and down, but not move sideways too much.
----

== 2.3 Rear Suspension Design ==
For the rear, use a '''solid axle suspension'''.

The rear axle carries both rear wheels together.

Structure:

Support the axle with two bearings on the chassis.

Add soft support using:

* Small springs, or
* Rubber bands, or
* Flexible plastic/printed arms

This makes the rear easier to build and stronger.
----

== 2.4 Suspension Materials ==
Recommended parts:
{| class="wikitable"
!Part
!Material
|-
|Chassis
|Acrylic / plywood / 3D printed plate
|-
|Suspension arms
|3D printed plastic or aluminum strip
|-
|Axle
|Steel rod
|-
|Bearing support
|3D printed bracket
|-
|Springs
|Small compression springs / rubber bands
|-
|Fasteners
|M3 screws and nuts
|}
For your project, '''M3 screws''' are a good size.

== 2.5 Suspension Design Requirements ==
Important things to check:

# '''Wheel alignment''' The left and right wheels should be parallel when going straight.
# '''Suspension travel''' The wheel should move up and down about:

For a small car, this is enough.

# '''Low center of gravity''' Put heavy parts like motor and battery as low as possible.
# '''Symmetry''' Left and right suspension arms should have the same length.
# '''Steering clearance''' The front wheels must be able to turn without hitting the chassis.

----

= 3. Gear / Chain Drive System Plan =

== 3.1 Recommended Drive Type ==
Use a '''chain drive system'''.

Why chain drive is good:

* More reliable than friction drive.
* Easier to adjust gear ratio.
* Better for high torque.
* Less slipping than belt drive.

Basic layout:
----

== 3.2 Gear Ratio ==
Gear ratio formula:

Example:

If motor sprocket = 22 teeth

Rear sprocket = 10 teeth

This means the rear wheel spins faster than the motor sprocket, but torque becomes lower.

So:

* Smaller rear sprocket = higher speed, lower torque
* Larger rear sprocket = lower speed, higher torque

----

== 3.3 Recommended Gear Ratio Choice ==
For a small vehicle, do not only chase max speed. You need enough torque to start moving.

I recommend testing 3 options:
{| class="wikitable"
!Motor sprocket
!Rear sprocket
!Ratio
!Result
|-
|22T
|10T
|0.45
|Fast, but weak torque
|-
|22T
|14T
|0.64
|Balanced
|-
|22T
|18T
|0.82
|Stronger torque, slower
|}
Best starting choice:

This gives a better balance between speed and torque.

If the car cannot start smoothly or struggles under load, change to:

If the car is strong enough and you want more speed, try:
----

= 4. Wheel Speed Estimate =
If motor speed is about:

and the sprocket setup is:

Then rear wheel speed is approximately:

If rear wheel diameter is:

Wheel circumference:

Vehicle speed:

Convert to m/s:

So with 22T to 10T and 12 cm wheels:

This is not very fast, so if the motor really only has 14.6 rpm, the vehicle may need a larger speed-up ratio or larger wheels.
----

= 5. Mechanical Layout Recommendation =
Recommended layout:

This layout is good because:

* Rear drive gives better traction.
* Motor close to rear axle makes chain shorter.
* Battery in the middle balances weight.
* Front stays light for steering.

----

= 6. Design Steps =

== Step 1: Build the chassis ==
Make a flat chassis plate first.

Suggested size:

Since your box limit is about 45.6 cm, keep the total car length under:
----

== Step 2: Design the rear axle ==
Parts needed:

* Rear axle rod
* Two rear wheels
* Rear sprocket
* Two bearings
* Bearing holders

Make sure the rear sprocket is fixed tightly to the axle.

The rear wheels and sprocket should rotate together.
----

== Step 3: Install the motor ==
Place the motor close to the rear axle.

Important:

* Motor sprocket and rear sprocket must be aligned.
* Chain should be straight.
* Chain should not be too loose or too tight.

Good chain tension:
----

== Step 4: Build the front suspension ==
Make left and right front suspension symmetric.

Check:

* Wheel can move up and down.
* Wheel can turn left and right.
* Steering rod does not hit the chassis.
* M3 screws are not too tight, so the joints can rotate.

----

== Step 5: Test gear ratios ==
Test in this order:

# 22T to 14T
# 22T to 18T
# 22T to 10T

Choose based on result:
{| class="wikitable"
!Problem
!Solution
|-
|Car is too slow
|Use smaller rear sprocket
|-
|Car cannot start
|Use larger rear sprocket
|-
|Chain falls off
|Improve alignment and tension
|-
|Wheels slip
|Add weight over rear axle or use softer tires
|-
|Steering unstable
|Reduce speed or improve front alignment
|}
----

= 7. Final Recommendation =
For the first prototype, use:

This setup is not the fastest, but it is the safest and easiest to build successfully.