Vertical Vibration Control Problems Of Semi-active Suspension Of Passenger Vehicle

Based on the theory of vehicle dynamics, in order to improve vehicle ride comfort,several key problems of semi-active suspension system control of passenger vehicle arestudied in this paper. According to the characteristics of the semi-active suspension system,a quarter vehicle model, half vehicle model and the whole vehicle model are established.The road random excitation model is established according to the national standards.Incentives are simulated by white noise as the input of models. As the same time, grade A,B, C level road excitations are simulated. In order to thoroughly study the semi-activesuspension characteristics, based on passive suspension system, the invariance of thesuspension system is studied. It can be found that body displacement transfer function hasfour invariant points and suspension dynamic travel function has two invariant points. Inthese invariant points, there are three points which have nothing to do with the suspensionstiffness, which is of extraordinary significance to suspension design.In order to improve the ride comfort, sky-hook two states damper control, sky-hooklinear approximation damper control, acceleration driven damper control, power drivendamper control and mixed control are mainly studied. In order to make the intelligentsemi-active suspension, the genetic optimization LQR, PSO optimization PID, fuzzycontrol and neural-fuzzy control are thoroughly studied. There are two methods to evaluatethe performance of suspension, one is the value of root mean square, the other is specialused in semi-active suspension. For example, compared to passive suspension,neural-fuzzy net control make body acceleration improve6.709%, make suspension travelimprove2.985%, make wheel dynamic load improve20.02%. A real vehicle experimentresearch is carried on, which was found that as the test speed increasing, the body vibrationis sensitive to it. The same result can be achieved in the simulation.