The Extension Coordinated Control Of Yaw Moment Control And Differential Drive Assisted Steering For Vehicle

The electric vehicles driven by in-wheel motor has many advantages,such as high efficiency,energy saving,large space,flexible control and so on.Therefore,according to the feature that the torque of each in-wheel motors is independently controllable,the thesis focuses on the differential drive assisted steering system and the yaw moment control system of the electric vehicle driven by in-wheel motor.Firstly,according to the driving feature of each wheel for the electric vehicle driven by in-wheel motor,the Carsim/Simulink was utilized to establish the dynamical model of the electric vehicle driven by in-wheel motor.Then,based on the theory of extension,the stability control of the electric vehicle driven by in-wheel motor was studied.According to the different states of vehicle in classical domain,extension domain and non-domain,the correlation function was used to realize the switching control between yaw rate and side slip angle.Then the yawing moment controller was established,the effectiveness of which was verified through the hook experiment and sine input experiments.In addition,the working principle of steering assisted drive aldifferenti system was introduced.Steering wheel torque direct control strategy based on incomplete differential PID was used to establish the differential drive assisted steering controller,and its power-assisted and return-to-center performance were simulated and analyzed.Considering the steering assisted drive aldifferenti system has an influence on vehicle stability,a two-layer stability control system was designed for differential drive assisted steering based on the yawing moment extension coordinated control.In the upper-layer controller,according to vehicle driving conditions,the extension coordination controller was established.The extension set was obtained,so as to solve the correlation function to determine the controllers' output weights.In the lower-layer controller,the yaw moment controller and the differential drive assisted steering controller determined the outputs based on the respective weights.Next,the optimal drive torque of four wheels was distributed based on quadratic programming and three different constraint conditions were selected according to different domains.The Carsim and Matlab/Simulink were utilized to carry out the simulation under the double lane conditions with different road friction coefficient.The results simulation show that the control system can improve the vehicle ' s road tracking ability andhandling stability.Thus the driving safety was improved.Finally,the performance of the in-wheel motor was analyzed by using the in-wheel motor test bench,and the hardware-in-the-loop experiment was carried out by using Carsim and LabVIEW to verify the designed control strategy.