Research On Control Method Of Semi-Active Vehicle Suspension System Based On Magnetorheological Damper

With the rapid development of national economy in recent years,automobiles have become an indispensable transportation in daily life.Meanwhile,people have proposed higher requirement to the comfort and safety of vehicles.Semi-active suspension with magnetorheological damper(MRD)can be real-time controlled according to the road condition and has high stability,low power consumption,which has become a hotspot in the field of intelligent suspension.In this paper,modeling and control of MRD,suspension dynamic characteristics,control strategy of semiactive suspension and the realization of asymmetric damping characteristic are systematically studied.The main contributions of this paper are as follows.Mechanics performance of MRD is tested,Bingham model,Tanh model and simplified Tanh model are established based on test data.The models above are compared to provide the evidence for the study of MRD control.Simplified Tanh model is easy to invert and has a good accuracy.A feedforward-PID control is proposed,which combines the advantages of the controlers above and has a better effect.Model of quarter-car suspension is established and the variations of suspension system's response under different system parameters and road input are researched to lay the basis for the study of semi-active suspension control.The skyhook control,skyhook-PID control and LQG strategy are adopted to design the system controller and are compared by control effect and realizability.The result shows that LQG control has the best control effect,but it is also hard to realize.Skyhook-PID control has a low realization difficulty and a good control effect as well.Asymmetric control algorithm is proposed to realize the asymmetrical damping characteristics in semi-active suspension.The influences of asymmetric damping characteristics on the semi-active suspension are studied by simulation.It can be observed that asymmetric semi-active suspension has a better comfort than symmetric semi-active suspension under the condition of adopting the same control strategy.Therefore,semi-active susnpension system's performance which takes the riding comfort a priority can be further improved by applying asymmetric algorithm.