Research On The Influences Of The Active Suspension Vibration Suppression Based On The Time-Delay Feedback Control

Suspension system is an important component of the vehicle chassis system,whose quality of its performance not only directly affects the vehicle smoothness and ride comfort on the road,but also play a critical role in the features of vehicle handling and steering stability.With the rapid development of the Mechatronics and the Control technique,the theoretical investigation on vehicle active suspension system was derived from extensive research by scholars.There exists inevitably certain phenomenon of time-delay,which occurs in the control processes of active suspension,such as signal acquisition and transmission of transducer,processor calculations and the Electromagnetic actuator implementation,etc.Nevertheless,the key to this problem is that the factor of time-delay potentially transforms the behavior of dynamical control system,according to the correlation research on time delayed system in the control field.And yet the intrinsic factor of timedelay factors in the suspension dynamic control modeling is usually neglected by most researchers,or compensate the given specific time-delay for the suspension control system.Accordingly,the research on the active suspension vibration suppression or even the field of vibration control have a significant effect on theoretical value and engineering application.Time-delay Control Theory is applied into the vehicle suspension control and discuss the influences of the time-delay feedback control on the active suspension vibration suppressing.⑴ Based on the theory of time-delay dynamical system applying in vehicle active suspension control and the theory of Time Delayed Dynamic Vibration Absorber,the delayed tire or body feedback control is applied to 1/4 vehicle active suspension,whose two-degree dynamical model is built,and the different state feedback control that have effect on the body and suspension vibration suppression is discussed when the harmonic excitation with body resonance frequency is selected as road irregularity.Routh-Hurwitz,Stability Switch Method and the stability criterion of retarded system with time delay is developed to analysis active suspension stability of each one of delayed state feedback control and attempt to access the stability and instability region.The optimum unified object function is established,which gain the optimum delayed control parameters by using Particle Swarm Optimization(PSO),and simulation is compared with the different delayed state feedback control.The results by simulation show that the method of tire delayed displacement feedback control can get the best performance of body vibration absorption,the time-delay body displacement feedback,time-delay body acceleration feedback and time-delay tire velocity feedback can get efficiency vibration suppression,but time-delay tire acceleration feedback control does not be applied to delayed vibration suppression of active suspension because of delay control region is unstable.⑵ A vehicle semi-active suspension control method based on the dual-delayed feedback optimum control was proposed for the 4-degree semi-car vehicle suspension model.On the basis of the mechanism of delayed vibration absorber introduced by the delayed control suppression technology and the System Amplitude-Frequency Characteristic,the unified-object function built on the body acceleration and pitch angle acceleration is established,and the delay feedback control parameters is optimized by the PSO(particle swarm optimization).The simulation results show that the vehicle suspension model with time delay control improve the modeling accuracy,and dual-delay feedback can get the better suppression performance which can provide good ride smoothness.The paper demonstrated that the influences of the different time-delay state feedback control on the active suspension vibration suppression is discussed and the optimal state feedback control is analyzed and obtained by comparing vibration suppression performance for each one of state control.The method optimum modelling theory of active suspension and provide a theoretical basis for the design of semi-suspension system,which is of theoretical and practical reference values.