Research On Mechanical Modeling Of Magnetorheological Damper And Vibration Control Of Simi-active Suspension

The performance of the suspension system directly affects the ride comfort and handling performance of vehicles.The semi-active suspension has the advantages of simple structure,less energy input and lower manufacturing cost.Its dynamic characteristics can be changed and controlled by electrical parameters,which can significantly improve the damping performance of vehicles,therefore it has attracted much attention.The magnetorheological damper(MRD)is a kind of smart semi-active control device,which has the characteristics of rapid response,low energy consumption,simple structure and control and failure safety,and so on.Its application in civil structure,automobile and rail vehicle has attracted considerable interest.The semi-active suspension system based on MR damper can control the output damping force to improve the automobile’s ride comfort according to the road condition.Due to the nonlinear hysteretic characteristics of MR damper,it is difficult to establish an accurate model to describe its mechanical behavior.In addition,an excellent control strategy has a great impact on the performance of semi-active suspension.The research on the accurate modeling and intelligent control strategy of MR semi-active suspension has become the focus of scholars civil and abroad.Hence,the mechanical modeling of MR damper and the control strategy of MR semi-active suspension are studied in this research.The main researches are as follows:1.The mechanical properties test of the squeeze mode MR damper is carried out and a novel parametric model based on arc tangent function is proposed.This model can not only accurately describe the hysteretic behavior of the squeeze mode MR damper but also has its own features,such as less parameters,simple structure and explicit physical meaning.An improved differential evolution(DE)algorithm,which can avoid the shortage of being easily trapped in a local extremum,is applied to identify the parameters of the model.It has laid the foundation for the establishment of accurate mechanical model.2.A shear-valve mode MR damper with a double rod structure is manufactured to improve the vibration suppression in vehicle suspension systems.Based on the mechanical properties of the MR device,an improved model based on tan-sigmoid function is proposed.The estimated and measured responses from the proposed model are in good agreement,which confirms the effectiveness of the proposed model.The damping force error of proposed model is compared with the Bouc-Wen model and the polynomial model which indicates the proposed model has the characteristics of high precision,simple structure and less parameters.This work lays a foundation for designing more effective control strategy of semi-active suspension.3.A fuzzy control algorithm with a correction factor is adopted to control the input current of the damper and obtain better control performance of the suspension system.The control simulation of suspension system is carried out under random road excitation,and the results show that the vibration reduction of improved fuzzy controller is better than fuzzy controller and passive suspension and has better adaptability.In addition,an efficient variable universe fuzzy proportional integral derivative control strategy optimized by a hybrid genetic algorithm is proposed.In this strategy,the hybrid genetic algorithm is used to optimize control parameters of fuzzy PID controller,and the contraction–expansion factors realizes real-time optimization of the controller of fuzzy variables,which improves the control precision of the system.The simulation test is carried out under random road excitation,and the effectiveness of this control strategy is verified,which compared with the performance indexes of passive control and fuzzy PID control semi-active suspension system.4.A 2-DOF MR semi-active suspension system test platform is established to experimentally evaluate the damping performance of MR semi-active suspension.The results show that the MR suspension can improve vehicle dynamic performance under the random road excitation and has better practical value.