Robustness Assessment of Feedback Self-Tuning Controller for Steering Feel in Steer-by-Wire Systems through Numerical Simulation Approach

This study introduces a novel and highly applicable torque tracking algorithm as a controller to develop a realistic steering feel in a front steer-by-wire (SbW) architecture. The objective of this study was to propose a self-tuning PI-based controller using a gain scheduling method to mimic the torque generated by a rack and pinion system through the torque produced by a DC motor. To provide the foundation for the torque tracking control strategy, a full car model with 14 degrees of freedom was developed to assess the efficacy of the proposed control scheme in generating the steering feel. Based on the Newton’s second law, the SbW model was developed and verified using a step input signal in two extreme conditions. The performance of the proposed controller and its robustness were validated through two vehicle dynamic tests based on ISO standard, the Double Lane Change (DLC) and Slalom (SL) tests under varying vehicle speeds and extreme maneuvers. This robustness assessment demonstrates that the gain-scheduling proportional-integral (GS-PI) controller performs significantly well in tracking the desired steering wheel torque, compared to the results from the CarSim software, which served as a benchmark. Additionally, the results indicated that the proposed controller was capable of replicating the steering feel of a conventional steering system with a mean absolute error (MAE) of less than 1.90. This study prepares a platform for practical applications in developing realistic steering feel in future SbW systems. Furthermore, the control proposed in this study provides a practical control system approach suitable for hardware implementation.