With the continuous development of automobile technology, vehicle handling performance and safety have become increasingly critical research areas. The active rear-wheel (ARW) steering system, a technology that significantly enhances vehicle dynamics and driving stability, has garnered widespread attention. By coordinating front-wheel steering with rear-wheel angle adjustments, ARW improves handling flexibility and stability, particularly during high-speed driving and under extreme conditions. Therefore, designing an efficient ARW control algorithm and optimizing its performance are vital to enhancing a vehicle's overall handling capability.
This study delves into the control algorithm design and performance optimization of ARW. First, a comprehensive vehicle dynamics model is constructed to provide a solid theoretical basis for developing control algorithms. Next, optimal control theory is applied to regulate the rear-wheel steering angle, and an LQR control strategy with variable weight coefficients is proposed to address the linear and nonlinear characteristics of tire lateral slip. Finally, comparative simulation verification is conducted using CarSim software, referencing a conventional front wheel steering (2WS) vehicle, a proportional steering control strategy for front and rear wheels, and a proportional feedforward plus yaw rate feedback control strategy. The results demonstrate that under conditions such as angle step inputs, double-lane change maneuvers, and limit double-lane changes on low-friction roads, the vehicle equipped with the LQR control strategy with variable coefficients achieves excellent control performance. The algorithm enhances stability and active safety, meeting all control objectives with objective and quantitative evaluation criteria.