ENGS 89/90 Reports

Year of Graduation

2025

Project Advisor

Mike Kokko

Instructor

Solomon Diamond

Document Type

Report

Publication Date

2025

Abstract

This project developed a reliable wheel slip detection system for Dartmouth Formula Racing's (DFR) electric racecar, the first step for implementing traction control. The existing wheel speed sensors on DFR's vehicle ("Cherri") were not producing reliable or readable data. This limits the team's ability to implement effective traction control. Our solution includes a comprehensive hardware and software package that accurately measures, filters, and processes wheel speed data to calculate slip ratio - a key parameter for implementing traction control. The system utilizes high-resolution rotary encoders mounted on the front wheels that sample at 5-20ms intervals, runs hardware based quadrature decoders to process encoder signals, and infinite impulse response (IIR) filters to reduce noise. This data, along with rear wheel speed measurements from the vehicle's motor inverter, is transmitted over the car's Central Area Network (CAN) bus to the Central Vehicle Controller (CVC), where the slip ratio is calculated in real-time. Through extensive testing and validation, we demonstrated the system's ability to detect slip ratios as low as 1% and maintain wheel speed measurements within 5% of ground truth across the vehicle's full operating range, including top speeds of approximately 120 MPH. The project also delivered comprehensive documentation, a new front sensor board schematic, and training materials to ensure knowledge transfer to future DFR team members. This wheel slip detection system provides the foundation for future traction control implementations that will enhance the vehicle's acceleration performance, improve energy efficiency, and increase safety by preventing loss of traction during competitive driving scenarios.

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