Research On The Performance Of Vehicle Semi-active Suspension System With Magnetorheological Damper

In recent years,the development of automobile industry is particularly rapid,which also makes people's requirements for vehicle comfort and safety continue to improve,while the traditional passive suspension system can not meet people's requirements because of its poor response effect and slow response speed.Therefore,it is very important to find a new suspension system.The vehicle suspension can greatly reduce the vibration.MR damper has many advantages,such as low energy consumption,large damping force can be obtained by only a few amperes of current,controlled by electromagnetic field,fast response,convenient control,and integration with vehicle electronic control system without complex mechanical structure.Therefore,a Semi-active suspension system with adjustable damping can be designed by using MR damper to improve vehicle ride performance Sitting comfort and safety.The damping force of MR damper is mainly obtained from the rheological response of MR fluid,and the rheological property is mainly controlled by the electromagnetic field generated by the excitation current.Therefore,a reasonable control strategy can greatly improve the response speed and damping performance of the seat suspension.In this paper,LQG control strategy and PID control strategy are used to control the vehicle body suspension and seat suspension respectively.The specific research work is as follows:(1)Establishment of mechanical model and parameter identification of MR damperFirstly,according to the damping force characteristic curve of different MR damper mechanical model,the most suitable MR damper mechanical model is selected,and the response data of MR damper collected by tensile testing machine is used to identify the parameters of the selected damper model by genetic algorithm,and then the parametric model which can accurately reflect the mechanical characteristics of the damper is obtained.At the same time,the neural network algorithm is used to train the damper to get the inverse model,and the current value is obtained according to the required damping force,so as to prepare for the subsequent research.(2)Establishment of vehicle model and road modelThe vehicle model uses one.half of the vehicle model,and obtains the vehicle suspension system equations through the mechanical balance equation to represent the current driving state of the vehicle.The suspension of seat is equivalent to seven models with mass and stiffness.The road model adopts the random excitation and trapezoid deceleration strip model obtained by filtering and transforming Gaussian white noise.(3)Control strategy design of Semi-active suspension systemLQG control algorithm has good stability and robustness.Composite genetic algorithm adjusts its weight matrix,which reduces the error of manual selection of weight and the development time to maximize the advantage of the algorithm.For the seat suspension,because the excitation it receives is weakened by the body suspension system,a simple PID control algorithm and particle swarm optimization algorithm are used to realize the Semi-active control.(4)Simulation experiment verificationThe road model,vehicle model,magnetorheological damper model and seat suspension model were built by MATLAB/ Simulink simulation toolbox,and the designed control algorithm was verified by simulation experiments.