Research On Control Strategy Of Magnetorheological Semi-active Suspension

With the improvement of people’s requirements for comfort,the development of automobiles has shifted from a single pursuit of mechanical performance to the pursuit of comprehensive performance of intelligence,comfort and safety.Suspension system is one of the most critical components that determine the comprehensive performance of vehicles.At present,intelligent suspension is widely used.Compared with traditional passive suspension,intelligent suspension has the advantages of simple structure,fast response speed and adjustable damping force,so it is of great research significance to study intelligent suspension.This paper takes magnetorheological semi-active suspension as the research object.At present,scholars at home and abroad have made some achievements on the ride comfort of MR semi-active suspension,but there is little research on the finite frequency output feedback control of MR semi-active suspension control strategy.Therefore,this paper proposes a finite frequency domain output feedback control mode,which can improve vehicle performance and ride comfort by feedback control of semi-active suspension of Magneto-rheological damper,MRD).The main work is as follows:First,the magneto-rheological damper is selected as the main research object,which is a hot research topic in the field of semi-active suspension and can effectively improve the performance of semi-active suspension.Semi-active suspension,as the suspension type with the highest comprehensive performance and moderate price,has received widespread attention.The application of smart materials such as magneto-rheological fluids has made the development level of magneto-rheological dampers relatively high,which has a good effect on improving vehicle stability and ride comfort.Based on the structure and mechanical properties of the magneto-rheological damper,combined with the research proposed in this paper,the Bouc-Wen model is ultimately selected,which can well reflect the hysteresis characteristics of magneto-rheology.The mathematical model of the damper is established,and the completeness of its performance is verified through mechanical property experiments,which can support the subsequent research.The parameters of the damper mathematical model are identified to obtain an accurate model of the damper.Then,the system is theoretically studied and modeled.The dynamic motion equation of the 1/4 semi-active suspension is established according to the characteristics of semi-active suspension.In order to more comprehensively and realistically simulate the real road conditions,white noise random road and bump road are selected for simulation,and the road model is established in the Carsim software and combined with MATLAB/Simulink for joint simulation.Combining the driving characteristics of the vehicle on the road and the sensitivity of the human body to vibration frequencies of4-8Hz,a limited frequency domain output feedback control is proposed for fixed frequency control,and the system is simulated in a fixed frequency interval.Finally,the entire system is simulated,and the results obtained from different control methods are compared to draw conclusions.The results show that when driving on a bump road,the control method proposed in this paper can effectively attenuate vehicle vibration and reduce the response peak value of the vehicle.When the road is excited by white noise,compared with passive suspension,the improvement rates of the root mean square and peak value of vehicle vertical acceleration by this control method are 19.45% and 24.67%,respectively,and the improvement rates of the root mean square and peak value of suspension spring deflection are 10.79% and 22.21%,respectively.The improvement rates of the root mean square and peak value of tire load are 0.17% and 1.18%,respectively,which effectively improves vehicle performance and ride comfort.