基於前輪側向力跟隨之車輛橫擺運動控制

Abstract

本研究考慮主動式轉向系統，針對前輪轉向、後輪驅動的車輛提出了基於前輪側向合力跟隨的運動控制法則。整體控制系統架構包含上層控制器以及下層控制器，在駕駛者下達轉向命令後，上層控制器會計算車輛運動時所需要的前輪側向合力的參考訊號以控制橫擺角速度。下層控制器包含了轉向控制以及扭矩控制，轉向控制中考慮了輪胎的非線性特性以及模型不準確性並控制估測所得的前輪側向合力，計算出正確的前輪轉向角，另外，即時且準確的估測輪胎的前輪側向合力也提高了控制器的控制效果；扭矩控制則提供車輛維持等速時所需要的輪胎扭矩。最後藉由模擬驗證了控制策略的效能。

This thesis presents an active steering control scheme of vehicle’s yaw motion based on the front-wheel lateral force tracking method. The proposed control system consists of an upper controller and a lower controller. When the driver gives a steering command, the upper controller computes the reference signal of the front-wheel lateral force to control the vehicle’s yaw rate. The lower controller includes steering control and wheel torque control. The steering controller, taking into account the non-linear characteristic of the tire and the tire model uncertainty, calculates the required steering angle to follow the lateral force command. Besides, the accurate estimation of the front-wheel lateral force improves the performance of the steering controller. On the other hand, wheel torque controller provides the wheel torque needed for the vehicle to maintain a constant longitudinal velocity. Finally, the simulations are carried out to verify the effectiveness of the proposed control strategy.