Vibration Suppression Of Semi-active Suspension System For High-speed Train

In recent years, the development of high-speed rail technology, related to dynamicstheory, control theory and other disciplines, are getting much attention. As it isdeveloping faster and faster, high-speed rail has already become an important way forrailway transportation.The time lag problem is inevitable in the vibration control system of high-speedtrain, which can increase the vehicle vibration, deteriorate the vibration control effect,reduce the ride comfort; therefore it is very necessary to research.Most of thetime-delayed research of suspension system both home and aboard, then treated thetime-delayed as a fixed parameter, and compensated by the control rule or method, inorder to weaken the influence of deterioration effect. But researches have shown that thetime-delayed is a dynamic parameter, so the influence to the vehicle vibration is notfixed. There may be advantaged time-delayed damping vibration sections, so treatedtime-delayed as a fixed parameter is a fallacy of traditional time-delayed research.This paper bases on engineering practice, takes the time-delay as a adjustablevariable and uses the time-delayed feedback control of speed to control the vibration ofthe suspension system, and obtains advantaged time-delayed damping vibration sectionsof train control. The theoretical analysis and simulation results with WIPP software arein good agreement. The briefly work and results of this paper are as follows:1) Research on the transverse linear model of semi-active suspension system withtwo degrees of freedom. Through the study on the frequency-response curve of passivesuspension system without time-delayed condition, use time-delayed feedback controlin somewhere the amplitude is larger than others to achieve the purpose of damping,and using the direct method and Routh-Hurwit criteria for assessment the stability ofsystem. Compared between the amplitude of damping and passive condition, analysisand numerical simulation results show that damping range can be50%, proved thesuperiority of vibration suppression by time-delayed.2) Research on a nonlinear vertical suspension system with single degree offreedom, in order to introduce the three nonlinear of stiffness. The method of multiplescales is adopted to get the second the second-order approximate analytical solution of the main system, and studied the primary resonance of the system state and stability,and analyses the influence of time-delay and nonlinear stiffness to body’s curve ofamplitude and frequency, and the stability boundary of the system is also given. Theresults shows that the reasonable time-delay and damping coefficient can effectivelysuppress the vibration of system, even lead to damage the system.3) Extends the three nonlinear of stiffness to secondary suspension system,research on nonlinear vertical nonlinear suspension system model with two degrees offreedom. To convert the vibration differential equation of the suspension system tomodal coordinates, get the average equations when1:3internal resonance and1:1resonance exist at the same time by using multiple scales method, then obtained theapproximate analytical solution of the average equation by numerical method. Studieshave shown that appropriate adjusting the volume of feedback gain coefficients andtime-delay can suppress the vibration to a certain extent; the amplitude of body canreduce20%, it’s improved the ride comfort significantly. However, when the feedbackgain coefficient and delay are improper, the system vibration will increase.This paper studies the time-delay and nonlinear problem of suspension system, andthe research methods and theories have to be innovative. The study will help to improvethe control theory of the vibration of vehicle suspension system and the nonlineardynamics theory of time-delayed, not only has scientific significance but also haspractical application value.