Dynamic Load And Yaw Stability Coordination Control Of Semi-active Suspension Vehicles

Automobile suspension is usually used to improve the comfort and handling ability of vehicle.It is limited by the small adjustment range of the passive suspension,and there is little research on the integrated control of suspension and lateral dynamics.The semi-active suspension has the characteristics of transient damping adjustment,which comes to a new vehicle coordination control idea to improve the lateral characteristics of the vehicle by controlling the suspension damping.In this paper,from the perspective of yaw stability and steering stability,the steering characteristics of the vehicle are improved by the method of suspension damping adjustment and traditional yaw moment control.The coupling characteristics of vertical and lateral dynamics of the vehicle are studied in this paper.The control problem is divided into two parts:suspension control and yaw stability control.The study of the suspension section is mainly the coordination between the vertical correction of the steering characteristics and the handling stability caused by the suspension roll motion during steering.For the study of the yaw part,the influence of suspension roll motion on the lateral dynamics is mainly considered,to solve the yaw stability control problem under the influence of the internal perturbation parameters.The article is elaborated from three aspects:vehicle vertical and lateral coupling dynamics analysis,suspension dynamic load optimization control and yaw robust gain scheduled control.To solve the problem of complicated coupling relationship between vertical and lateral motion,this paper establishes a magnetorheological damper fitting model that ignores hysteresis characteristics from the actual working condition simulation.On the basis of this,combined with the simulation results of the coupling characteristic and vehicle dynamics analysis,the effective vehicle dynamic characteristics under steering condition are explored,then the relationship between the suspension motion and the yaw motion is analyzed and work out the dynamic expression considering the coupling relationship.Aiming at the conflict between the handling stability and the steering optimization characteristics under suspension control,this paper starts with the study of dynamic load transfer function that considering coupling dynamics,then explores and verifies the relationship between dynamic tire load transfer and suspension damping through the pole-zero analysis.For the established transfer function function,the Particle Swarm Optimization algorithm with constraint parallel optimization is used to optimize the steering correction and suspension maneuver for different weights under different conditions,which obtains the optimal current under different conditions as the open-loop optimization control strategy.And the vehicle state adjusts the output current as a method of coordinated control.To solve the parameter varying problem of the lateral force of the tire,the variation of the lateral stiffness of the tire model is fitted by the dynamic load transfer,and the whole lateral dynamic model is transformed into a standard LPV system for analysis.The controller with robust gain scheduled control is used to design the controller that satisfies the H_? performance.The controller output can be adjusted according to the variable parameters to ensure the stability of the yaw under different dynamic load transfer conditon.The simulation result of the integrated controller verifies the mutual promotion effect of the coordinated control strategy,and provides a new idea and reference for the research of suspension and steering coordination control.