Research On Steering Stability For Autonomous Vehicle With Distributed Drive-by-Wire Control

As a new type of chassis drive with multiple drive actuators serving automatic driving,distributed drive by wire brings more convenience to vehicle motion control,but also puts forward higher requirements for vehicle handling stability and safety.In this paper,a steering stability control algorithm and a torque allocation algorithm based on all wheel execution and single wheel failure conditions are proposed for distributed drive by wire vehicles,to improve the steering stability of distributed drive by wire vehicles.(1)Based on the dynamic analysis of distributed drive-by-wire vehicles,this paper establishes models such as vehicle dynamics model,tire mechanics model,drive-by-wire system model,and wheel dynamics model.Based on the models established in Matlab/Simulink and Carsim,simulation comparisons of partial parameter responses are conducted to verify the effectiveness of the model.(2)In this paper,a drive steering stability strategy architecture based on distributed drive by wire vehicles is proposed,and the controller involved in the architecture is specifically designed based on the actual driving situation of the vehicle.It includes a centroid sideslip angle observer based on extended Kalman filtering and a road adhesion coefficient observer,a longitudinal speed tracking controller based on PID control principle,and a yaw moment control controller based on adaptive fuzzy PID.(3)Aiming at the overdrive characteristic of distributed drive-by-wire vehicles,where the number of actuating mechanisms is greater than the controlled degrees of freedom of the vehicle,this paper optimizes the distribution control of the controlled variables of the drive steering stability control strategy-the target longitudinal force and the target yaw rate based on the quadratic programming principle.The optimal allocation considers two actuator states,the full wheel execution state and the single wheel failure state.Under this actuator state,three optimization objectives,namely,maximum tire adhesion margin,minimum energy consumption,and minimum longitudinal motion deviation,are considered to achieve the optimal allocation of control variables for drive-by-wire stability.The specific optimal allocation algorithm is designed.(4)In order to verify the effectiveness of the steering stability control strategy and the optimal allocation of stability control variables designed in this paper,a joint simulation model for driving steering stability control is constructed based on Matlab/Simulink and Carsim.The simulation results under linear drive,steering wheel angle sinusoidal input drive,and double shift drive conditions are compared and analyzed to compare the control effects of optimal allocation and rule allocation,as well as the vehicle response to failure free control and fault tolerant control.