Study On State Estimation And Control Strategy Of Vehicle Suspension System While Its Vertical & Lateral Motion Characteristics Are Considered

With the development of intelligent,energy-saving and securitization for automobile technology is increasing.As the the application of controllable suspension,due to the structure nonlinear and working complexity of vehicle,the design of nonlinear state estimation and control alogirithm for vehicle integrated performace have become the challenging.Based on the problem of the dynamic performance optimization of multi-degree-of-freedom nonlinear vertical and lateral dynamics under complex driving conditions,using the method of state observer and nonlinear control theory,combining with adjustable magnetorheological semi-active suspension damping properties,dynamic modeling,state observation and optimization control of suspension and vehicle systems are studied respectively.The simulations and tests verifies the effectiveness and feasibility of the nonlinear observer.The main research contents are as follows in this paper:(1)To describe accurately the motion characteristics between the vertical and lateral dynamics of vehicle and suspension system under complex driving conditions,the model of vertical and lateral dynamics model of vehicle,the linear and nonlinear model of Mc Pherson suspension and the road excitation model are established,and dynamics software Car Sim~?is used to verify the accuracy of vehicle vertical and lateral dynamics model.Based on the analysis above,the problem of accurate modeling of vertical and lateral dynamics of vehicles is solved.(2)To solve the influence of different vehicle parameters on the vertical and lateral response of vehicle system under different road excitation and steering wheel angle complex input conditions,global sensitivity analysis(GSA)method is the firstly used to analyzed the influence of twelve critical system parameters on vehicle coupling response under complex driving conditions is analyzed comprehensively and quantitatively.The simulation results show that the steering wheel Angle has significant influence on the vertical and lateral response of the vehicle system,and the influence factors of the roll response of the vehicle system are relatively fixed and the correlation of the influence factors of the vertical response is relatively high.Based on the above analysis,the problem of the state of vehicle and suspension system under uncertain external excitation and system parameters is solved.(3)To achieve accurately the state of vehicle and suspension system under complex driving conditions,the method of adaptive Kalman Filter(AKF)and adaptive unscented Kalman Filter(AUKF)based road level classification theory are design.The minimum model error algorithm and Kalman Filter(KF)is used to develop minimum model error kalman filter(MME-KF).Due to the nonlinear performance of tire force,fuzzy model(T-S)fuzzy observer is design based fuzzy theory and bayesian theory.The simulation data shows that AKF,AUKF and MME-KF algorithms can effectively improve the accuracy of system state observation caused by disturbance noise,and T-S fuzzy observer has higher observation precision than AUKF algorithm.Based on the above observer study,the problem of the state of the vehicle and suspension system under uncertain external excitation and system parameter influence factors is solved.(4)To improve the control problem of the comprehensive performance of the vehicle under the complex driving conditions based on magnetorheological semi-active suspension system,a nonlinear feedback controller(PPC)for vehicle and suspension system is designed to guaranteed the optimal performance of vehicle roll dynamics response.To furthur validate the effective of PPC algorithm,the modified model predictive control(MPC)algorithm is proposed to compare the simulation data under J-turn and Fishhook test conditions.Simulation results show that the correctness and feasibility of proposed PPC algorithm is validated,and the PPC algorithm can effectively reduce the vehicle caused by vehicle transient and steady-state incentive roll,which greatly improve the vehicle's roll performance.(5)A quarter test and vehicle test platform test system are designed to validate the state observer of road profile and vehicle state under various disturbance excitation conditions.The experimental results show that the linear and nonlinear observer methods proposed in this paper can accurately estimate the state of the system,and have certain engineering practical value.