Time-delayed Feedback Control Of 1/4 Nonlinear Vehicle Active Suspension System And Its Parameter Optimization

The vibration control effect of the vehicle suspension system is a key factor affecting the ride comfort,handling stability and safety of the vehicle.In recent years,the active vibration control effect of the vehicle suspension system has become the focus of research at home and abroad through active control and optimization strategies.However,the time delay phenomenon inevitably exists in vehicle active suspension systems.Time delay may reduce the control effect and even cause system instability.Initially,time-delayed elimination techniques were used to reduce or eliminate the negative effects of time delay on the control system.Later,as the research progressed,it was discovered that the introduction of an appropriate amount of active time delay can improve the control effect and system stability.In recent years,people have done a lot of research on vehicle active suspension systems under time-delayed feedback control,and have achieved many results.However,the following two aspects need to be further explored.On the one hand,the optimization of control parameters in time-delayed feedback control is mostly performed at a single frequency,and there is less research on optimization of control parameters in a limited frequency band;On the other hand,the research objects are mostly linear vehicle suspension systems,and the research on nonlinear vehicle suspension systems is relatively rare.To this end,this paper introduces the time-delayed feedback control into the linear and nonlinear vehicle suspension systems respectively,and studies the time-delayed feedback control and parameter optimization of the 1/4 vehicle suspension system from the following three aspects.(?)The single-objective optimization problem of control parameters is studied with the 1/4 linear vehicle suspension system controlled by time-delayed feedback.Firstly,the dynamic model of the system is established,and the amplitude-frequency response of the body and the wheel is derived theoretically.Secondly,the stability of the system is analyzed according to the eigenvalue method,and the stability partition map of the system on the two-parameter plane with time delay and feedback gain coefficient is obtained.again,with time delay and feedback gain coefficient as control parameters,and with the minimum body acceleration amplitude as the optimization objective,single objective optimization of control parameters is carried out in single frequency and limited frequency bands respectively,and the verification of the optimization results is given.(?)The multi-objective optimization problem of control parameters is studied based on the 1/4 linear vehicle suspension system with time-delayed feedback control.Based on the single optimization objective function,the feedback control force amplitude is considered,and the linear weighted combination of the vehicle body acceleration and the feedback control force amplitude is taken as the new objective function.The multi-objective control parameters are carried out in the single frequency band and the finite frequency band respectively,and the numerical verification of the optimization results is given.(?)With the 1/4 nonlinear vehicle suspension system controlled by time-delayed feedback,the single-objective and multi-objective optimization problems of control parameters are studied.Firstly,the dynamic model of the system is established,and the acceleration amplitude of the body and the wheel is obtained by the harmonic balance method.Secondly,the single-objective and multi-objective optimization of the control parameters are carried out.Finally,the vibration control effects of linear and nonlinear vehicle suspension systems under optimal control parameters are analyzed and compared.The results show that,compared with the linear vehicle suspension system,the vibration control effect of the nonlinear vehicle suspension system under the optimal control parameters is significantly improved,and that provides a theoretical basis and evidence for the application of time-delayed feedback control in vehicle suspension systems.