1. Dynamic Traction Control By: Thiago Avila, Mike Sinclair & Jeffrey McLarty

2. Motivation Drastically improve vehicle performance and safety by maintaining optimal wheel traction in all road conditions

3. Motivation

4. Needs Assessment FSAE car is currently traction limited and would benefit from the use of a traction control system System must follow FSAE guidelines Minimal cost solution should be pursued

5. Design Criteria and Constraints ◦Meet FSAE Guidelines ◦Predict slip with enough time to adjust engine output ◦Reduced FSAE 75m acceleration times ◦Improve FSAE skid pad testing results

6. Problem Formulation The traction control system is required to prevent driver error from overloading any of the four wheels and causing slip, through either throttle or brake application

7. Abstraction Physics model sensors ◦3-axis Accelerometer ◦Linear Potentiometer Cost & Complexity Engine Power Control ◦Cutting Spark Difficult to Predict Power ◦Limiting Fuel Improper Fuel Ratio ◦Drive by wire throttle Infringes FSAE rules ◦Electronic Air Restrictor

8. Proposed Solution Breakdown Slip Model ◦Vehicle Dynamics and Sensing Vehicle Control ◦Electronic Restrictor

9. Proposed Solution Slip Model ◦Dynamic Physics Model ◦Dynamic Coefficient of Friction ◦Understeer Detection

10. Design Layout Physics Model (Saturator) ECU RPM Throttle Pos. Driver Pedal Slip Angle Radius External Sensors X/Y/Z Acceleration + - CBR 600 F4i Engine Wheels Wheel Slip Detector μs/μkμs/μk

11. Physics Model

12. Torque Map

13. Interpolation Interpolate Between Four Points on Torque Map Interpolate between Engine Speeds at Throttle 1

14. Interpolation Interpolate Between Four Points on Torque Map Interpolate between Engine Speeds at Throttle 1 Interpolate between Engine Speeds at Throttle 2

15. Interpolation Interpolate Between Four Points on the Torque Map Interpolate between Engine Speeds at Throttle 1 Interpolate between Engine Speeds at Throttle 2 Interpolate between results at different Throttles

16. Interpolation Interpolate Between Four Points on the Torque Map Interpolate between Engine Speeds at Throttle 1 Interpolate between Engine Speeds at Throttle 2 Interpolate between results at different Throttles

17. Interpolation Interpolate Between Four Points on the Torque Map Interpolate between Engine Speeds at Throttle 1 Interpolate between Engine Speeds at Throttle 2 Interpolate between results at different Throttles Engine Power from 4 point Interpolation = Done

18. Physics Model

19. Data Acquisition Installed Sensors ◦Steering Wheel Angle ◦2-D Acceleration ◦Suspension Deflection ◦Wheel Velocity ◦Brake Pressure ◦Engine RPM ◦Throttle Position ◦Air Mass Flow Rate

20. Physics Model Simulation

21. Model Validation – FL Tire

22. Slip Condition

23. Dynamic Coefficient of Friction Calculator Slip Detected Calculate Engine Torque @ T(0) Calculate Vertical Force @ T(0) Calculate Coefficient of Friction and Update Model μ s Calculate Coefficient of Friction and Update Model μ s

24. Optimize Performance No Slip Detected Is μ s at the limit? No Slip Detected Is μ s at the limit? Maintain current μ s Increase μ s Yes No New Limit Initial Value Calculated Values

25. Understeer Detection Turning Radius: ◦Desired vs. Actual Major Factor: ◦Wheel Slip Angle

26. Slip Angle

27. Proposed Solution Vehicle Control ◦Electronic Restrictor ◦Brake Pressure Controller

28. Electronic Restrictor

35. Servo Rotary Potentiometer Gears Butter -Fly- Valve

36. Electronic Restrictor

37. Patents Physics Model (Saturator) ECU RPM Throttle Pos. Driver Pedal Slip Angle Radius External Sensors X/Y/Z Acceleration + - CBR 600 F4i Engine Wheels Wheel Slip Detector μs/μkμs/μk

38. Patents Physics Model (Saturator) ECU RPM Throttle Pos. Driver Pedal Slip Angle Radius External Sensors X/Y/Z Acceleration + - CBR 600 F4i Engine Wheels Wheel Slip Detector μs/μkμs/μk Possibly patentable: Continuously Improving Predictive Traction Control

39. 1 day 2 weeks 1 week 2.5 weeks 4 weeks Commissioning The Plan Start Create Controller based on Design Criterion Finish Install Restrictor Order Parts & Materials Build Restrictor Test & Optimize Critical Path ~10 weeks 3.5 weeks Program PSoC with Physics Model & Interpolation

40. Questions? Comments?

41. The End Thank you!