Project

Technical Report: System-Level Simulation of an All-Terrain Vehicle (ATV)

1.Aim
To prepare a technical report on the simulation of a BAJA All-Terrain Vehicle (ATV) under different conditions.

2.Objective
To conduct a system-level simulation of an all-terrain vehicle and prepare a technical report explaining the model properties and commenting on the results. The specific objectives include:

1. Studying the BAJA ATV model without a dashboard.
2. Studying the BAJA ATV model with a dashboard.
3. Analyzing the vehicle’s performance with and without a dashboard.
4. Evaluating the simulation results under different input conditions.

3.Introduction
A transmission system transmits power from the engine to the wheels through shafts. It primarily consists of four types:

1. Manual Transmission – Requires manual gear shifting.
2. Continuously Variable Transmission (CVT) – Provides seamless gear ratio transitions.
3. Semi-Automatic Transmission – Uses automated clutch engagement while shifting gears manually.
4. Automatic Transmission – Changes gears automatically without driver intervention.

An all-terrain vehicle (ATV) is a motorized off-highway vehicle designed to travel on four low-pressure tires. It has a seat designed for the operator and handlebars for steering control.

4.SimulationStudies
The ATV simulation model consists of multiple subsystems, including:

• CVT Subsystem: Handles power transmission from the engine using variable gear ratios.
• Vehicle Body Subsystem: Includes mass, suspension, and interaction with terrain.
• Tire Model: Simulates traction and ground contact.
• Braking System: Regulates deceleration and vehicle control.
• Control System: Adjusts throttle and brake inputs.

Study 1: BAJA ATV Model without Dashboard

The CVT model in Simulink consists of various components such as a signal builder, generic engine, motion sensors, vehicle body, vehicle transmission, and system configuration blocks. The CVT subsystem includes transmission blocks, input and output shaft inertia, and motion sensors. The vehicle body subsystem consists of the vehicle body block, double drum brake, and tires. The vehicle has a mass of 250 kg and two axles connecting four wheels.

• CVT Subsystem Model – Represents power transmission components.
• Vehicle Body Subsystem Model – Captures the ATV's dynamics.
• Signal Builder Input – Defines throttle and braking profiles.
• Outputs: CVT output speed, CVT shaft speed, CVT ratio, engine torque speed.

Study 2: BAJA ATV Model with Dashboard

This model includes a dashboard with throttle and brake input meters instead of a signal builder. The user can manually adjust the brake and throttle values in real time to observe velocity and speed variations. The gear ratio is dynamically maintained.

• CVT Model with Dashboard – Allows real-time parameter adjustments.
• Observations: The vehicle's response to varying throttle and brake inputs can be analyzed interactively.

Study 3: BAJA ATV Model without Dashboard (Lookup Table Integration)

This version integrates lookup tables to refine CVT behavior. A lookup table is a data array that maps input values to output values, enabling interpolation or rounding where necessary.

• CVT Subsystem – Uses lookup tables for ratio optimization.
• Vehicle Body Subsystem – Simulates realistic vehicle dynamics.
• Outputs: CVT ratio, CVT shaft speed.
• Observations: Lookup tables help define input-throttle dependencies, improving accuracy in performance analysis.

Study 4: BAJA ATV Model with Dashboard (Lookup Table Integration)

This model combines dashboard interactivity with lookup tables to enhance simulation accuracy. It allows real-time manipulation of brake and throttle inputs while ensuring accurate transmission behavior through predefined lookup data.

• Outputs: CVT ratio, CVT shaft speed.
• Observations:
• The dashboard allows real-time speed and torque monitoring.
• As the gear ratio changes, torque varies proportionally.
• At maximum torque, vehicle speed and velocity decrease.

5.Results&Discussion
Key insights from the simulations include:

• The CVT dynamically adjusts the gear ratio to optimize power delivery.
• The suspension system ensures vehicle stability across rough terrains.
• Real-time dashboard input provides better control over vehicle response.
• Lookup tables improve simulation accuracy by mapping input values more efficiently.
• Torque and speed adjustments contribute to consistent vehicle performance.

6.Conclusion
Through system-level simulation, we analyzed the performance of a BAJA ATV with and without a dashboard, as well as the effects of lookup tables on powertrain behavior. The study highlights the effectiveness of CVT in optimizing power transfer and vehicle stability across varying terrains. Future enhancements could include real-world validation of simulation results.