Research On Coordinated Control Of Vehicle Chassis Based On ESP And SAS

When the vehicle is turning too fast or driving in extreme conditions such as wet and slippery roads,the wheel sideslip causes the vehicle to have insufficient steering or excessive steering or even roll.Therefore,this paper studies the control of the Electronic Stability Program(ESP)based on particle swarm optimization fuzzy control to solve the problem of insufficient steering and excessive steering of vehicles.At the same time,the semi-active suspension system(SAS)control based on the PID algorithm is studied to solve the vehicle roll problem.Furthermore,considering the coupling effect between ESP and SAS,the control effect of ESP and SAS is weakened.The coordinated control of ESP-SAS based on compensation torque is studied.The specific contents are as follows:Aiming at the problem of oversteer and understeer in the steering process of the vehicle,an ESP control strategy based on particle swarm optimization fuzzy control is proposed.Firstly,by establishing a linear two-degree-of-freedom dynamic model,the expected values of the yaw rate and sideslip angle are calculated in real-time.Secondly,the difference between the expected value of the yaw rate and the actual value,the difference between the expected value of the sideslip angle and the actual value are taken as the input of fuzzy control,and the additional yaw moment is taken as the output of fuzzy control,to design the ESP controller based on fuzzy control.Then,considering the subjectivity of fuzzy controller parameter design,the membership function,scale factor,and quantization factor of the fuzzy controller are optimized by the particle swarm optimization algorithm.Finally,in the simulation experiment,the effectiveness and feasibility of the proposed control strategy are verified.Aiming at the problem of vehicle roll during steering,a SAS anti-roll control strategy based on the PID algorithm is proposed.Firstly,the lateral load transfer rate and ideal roll angle of the vehicle are solved by establishing a linear three-degree-of-freedom dynamic model of the vehicle.Secondly,the lateral load transfer rate is used as the roll risk index of the vehicle,and the difference between the ideal value and the actual value of the roll angle is used as the input of the PID algorithm.The antiroll torque of SAS is used as the output of the PID algorithm,and the solved anti-roll torque is distributed to each suspension through the torque distribution module.Finally,the effectiveness of the proposed anti-roll control strategy is verified in the simulation test.Aiming at the problem of coupling between ESP and SAS,an ESPSAS coordinated control strategy based on torque compensation is proposed.Firstly,by analyzing the vehicle state when ESP and SAS work at the same time,the controllers of ESP and SAS are designed respectively to solve the additional yaw moment of ESP and the anti-roll moment of SAS.Secondly,according to the relationship between the dynamic vertical load of the vehicle and the longitudinal acceleration and lateral acceleration,the ESP-SAS coordinated controller is designed to solve the compensation yaw moment and anti-roll moment of the vehicle.Then,the solved ESP additional yaw moment and compensation yaw moment,SAS anti-roll moment,and compensation anti-roll moment are applied to the vehicle system in the form of superposition.Finally,the simulation results show the effectiveness and feasibility of the proposed strategy.