Research On Dynamics Cooperation Control For AWID Vehicles

The AWID/AWIS(All Wheel Independent Driving/Steering) vehicle,for which all wheels are driven and steered independently,is a new kind of vehicles which possess more flexibility of steering and driving combinations and can provide more motion modes(such as zero-radius turning,crab-moving and transversely shifting),thus having excellent power output,maneuvering capability and active safety ability.The AWID/AWIS vehicle is the frontier and important direction of the advanced vehicle research.Chassis manipulating control is one of the key technologies of AWID/AWIS vehicles,in which,the FSC(Front-wheel Steering Control) of AWID vehicle is an important research direction.In this thesis,the FSC of AWID vehicle is investigated and a novel control algorithm is developed and simulated.This thesis consists mainly of four parts:In the first part,the main idea of vehicle dynamics cooperation control is presented and the structure of the control system is constructed.The AWID vehicle is treated as a mobile agent with driving redundancy and the features of redundant system is analyzed.Based on this,the structure of a hybrid vehicle dynamics control system is designed,the function of each part is discussed,and the method of vehicle dynamics cooperation control is given.In the second part,the vehicle stabilizing control is investigated.First,the vehicle dynamic mode is constructed and the main factors that can affect the vehicle stability are analyzed.Then,a new control algorithm is developed based on the "feed-forward + optimal state feedback" strategy.In the third part,the optimal allocation algorithm of tire force is considered. Three kinds of tire force optimal allocation algorithms with multi-object and restriction are developed based on the Gradient Projection Algorithm,Bases Sequence Algorithm and Lemek Algorithm,respectively.The error between the expected and real total driving force/moment is analyzed.The three algorithms are compared in terms of force/moment matching accuracy,which is used as the main performance criterion.Then,the algorithm with best performance is pointed out.In the fourth part,the developed cooperation control method based on tire force optimal allocation is simulated and validated.The control effects under different conditions are compared and analyzed.The results of this thesis not only provide a new solution to the dynamic control of AWID/AWIS vehicles,but can also be extended to the dynamic control and active safety control of non-AWID/AWIS vehicles.