Purpose

Design a function that optimizes 0–60 mph acceleration by adjusting torque output based on slip ratio.

• Optimal slip ratio ≈ 7% (commonly 5–10% depending on car).
• If slip ratio exceeds optimal → decrease torque
• If slip ratio falls below optimal → increase torque

Algorithm Overview

Initial Function

• Validate and reset PID gains and internal PID state.
• Obtain constants (max torque, optimal slip target).
• Initialize launch control button to false (inactive until pressed).

Update Function

1. Check button state

   • If not pressed → output driver torque normally.

2. Wheel speeds

   • Controlled speed: rear wheel with higher speed.
   • Free rolling speed: front wheel with lower speed.

3. Slip Ratio

   • slip = (controlledSpeed - freeRollingSpeed) / freeRollingSpeed

4. Torque Logic

• If slip < 0.05 → increase torque.
• If slip > 0.10 → decrease torque.

5. PID Correction

• Run at 100 Hz (dt = 0.01).
• Use PID::PID_Calculate() for correction.
• Add correction to driver torque.

6. Clamp Torque

• If corrected torque > max → clamp to maxTorque.
• If < 0 → clamp to 0 Nm.

Implementation Details

void launchControl_Init()

Initializes PID controller values for slip ratio correction.

void threadLaunchControl(void *pvParameters)

LAUNCH_STATE_ON

1. Obtain slower front wheel speed.
2. Convert rad/s → m/s using wheel radius.
3. Motor/rear speed used as controlled speed.
4. Compute slip.
5. PID applies torque correction.
6. Clamp torque within bounds.
7. If brakes are pressed → exit to LAUNCH_STATE_OFF.

LAUNCH_STATE_OFF

• Wait for:
• Front brake fully pressed
• Motor speed = 0
• Then activate launch control (FSAE requires button activation — must update logic).

FAULT State

• Triggered by irregular wheel speeds or invalid conditions.

TESTING PLAN

Method Signature:

threadLaunchControl(void *pvParameters)

Constants:

slipTarget = 0.7f

minTorque = 0.0f

maxTorque = 260.0f

wheelRadius = 0.35f