Research On Modeling And Control Of Vehicle Active Suspension

With the development of modern technology and the continuous improvement of the level of science and technology,the technical development of the automobile industry has also been a rapid break through.The traditional passive suspension can not meet the needs of people.Because of its superior performance,the active suspension has greatly improved its performance in riding comfort and handling stability,and gradually replaced the passive suspension.According to the current research status and development trend of active suspension,this paper presents a new method to design the controller of active suspension with the electric actuator as the actuator and the robust control method.Firstly,the evaluation index of suspension system is given,and two representative road models,random road model and convex road model,are established.According to the simplified model of suspension system,differential equation and state equation are established.Then,the working principle and structure of the electric actuator are described.Through the force analysis of the actuator and the relative relationship between the ball and the lead screw,different signal elements and mechanical elements are selected in AMESim software to build the physical model of the electric actuator,and the simulation verification is carried out under different input signals to study and analyze the dynamic characteristics of the actuator.For the controller design of active suspension,this paper uses robustH₂/H_∞control method to design the controller of active suspension.The vertical acceleration of the vehicle body is taken as theH₂ performance output of the suspension system,and the dynamic travel of the suspension and the dynamic load of the tire are taken as the H_∞time domain hard constraint output of the suspension system.By combining theH₂ performance and H_∞performance,the vehicle can safely drive under the condition that the vertical acceleration of the vehicle body is minimized.Finally,according to the actuator of the active suspension built in AMESim software,the joint simulation is carried out with the robust controller designed in Matlab,and the random road surface and convex road surface are used as the interference input.In order to verify the influence of the designed active suspension controller on the parameter perturbation,the optimal guaranteed cost control law of the suspension system is designed based on the robust controller.The simulation results show that the vehicle body vertical acceleration,suspension dynamic travel and tire dynamic load of the active suspension with the robust controller are much smaller than those of the traditional passive suspension,and the ride comfort of the vehicle is significantly improved;for the suspension system with the stiffness coefficient and damping coefficient perturbed,the evaluation indexes of the active suspension with the optimal guaranteed performance controller are the standard is better than the active suspension and passive suspension with robust controller.Therefore,in the case of parameter perturbation,the suspension system still has good robustness and meets the design requirements.