整合差動式煞車與再生式煞車於車輛運動控制

Abstract

近年來越來越多的汽車大廠紛紛投入電動車的發展，可預期在未來電動車將成為主要的交通載具，電動車除了有環保節能的效益外，亦可提供不同的車輛驅動方式以及車輛操控架構，例如四輪獨立驅動與四輪獨立轉向。基於電動車所提供的驅動方式與操控架構，可應用更先進的運動控制技術來提升車輛的安全性與操控性。 本研究針對前輪驅動與前輪轉向車輛，將運動控制架構分為上、下層控制器，上層控制器計算路徑跟隨所需的縱向合力、側向合力與橫擺力矩總和，分配出四個輪胎的縱向摩擦力，使車輛的動態跟隨給定的參考軌跡；下層控制器則控制車輛的縱向滑動比，計算輪內馬達所需的轉速與轉矩，產生上層控制器所分配的輪胎縱向力，使車輛在運動過程中可保持穩定，且煞車過程中輪內馬達對電池充電，達到能量回收的目的。 最後透過模擬驗證在一般常見之轉向與變換車道駕駛情況下控制器控制的結果，結果顯示在此控制架構下，對於車輛的縱向速度、車身側滑角與橫擺角速度均有良好的控制效果，並能透過煞車來回收能量，增加電動車可行駛的距離。

In this paper, the proposed vehicle motion control structure is separated into the upper controller and the lower controller. Sliding mode control technique is used in the upper controller to calculate the amount of total longitudinal force, lateral force and yaw moment such that the vehicle can track a given reference trajectory and maintain stable. Then the tire force distribution algorithm determines the longitudinal forces of each tire. In the lower controller, a nonlinear inverse Dugoff tire model is considered to convert the longitudinal forces into the corresponding tire slip ratio. Sliding mode control technique is used to generate the assigned tire slip ratio by controlling the speed and torque of the in-wheel motor. The simulation results indicate that the proposed structure can guarantee the handling performance and stability of vehicle motion. While vehicle is braking, the proposed structure restores the energy to increase the driving distance.