Development of Active Rear Wheel Steering and Evaluation of Steering Feel

Abstract: In the last few years, with the development of sensor and actuator technology along with increased computation power available on-board of vehicles, the automotive industry is em-ploying more and more mechatronic systems for Advanced Driver Assistance Systems (ADAS) and Autonomous Driving (AD). Driver Assistance Systems are being used to increase safety (eg. Electronic stability program, lane keep assist etc.), reduce drive fatigue (eg. Electronic power steering) and of increasing vehicle performance and handling (eg. torque vectoring).‚is thesis explores one such driver assistance system, the Active Rear Wheel steering (ARWS) system, which is capable of increase the stability and handling of the vehicle at high speeds and reduce driver fatigue at very low speeds (such as parking manoeuvre). ‚e thesis starts by discussing the history and present state of art of ARWS systems and the control algorithms used for it. ‚en, e‡ort is put in to develop tests and objective metrics to evaluate the per-formance of the system compared to a passive vehicle. ‚ese metrics are of importance in situations where subjective driver feedback is either not available at all (such as computer simulations) or when data is needed to back up the driver feedback (inexperienced drivers).‚ese objective metrics can help the design engineer to evaluate and even predict vehicle’s performance during the design and tuning phase.‚e thesis then deÿnes how the ARWS system should beneÿt the handling of the vehicle along with certain undesired behaviour that may arise due to ARWS and should be avoided.‚is was done based upon feedback from experienced drivers and engineers along with inputs from various literature.‚e Sliding Mode Control (SMC) algorithm is chosen for the control of ARWS system due to it relative simplicity and robust performance. ‚e SMC theory is presented and then the con-troller is developed along with the reference model. ‚e controller is then put in a So›ware-in-Loop environment with IPG CarMaker and put through various test scenarios for tuning and evaluation purposes. ‚e results suggest that the system improves the vehicle’s handling.‚e last part of the thesis looks into the steering feel and its objectiÿcation along with how the AWRS system in…uences the steering feel compared to that of a passive vehicle.