Research On Vehicle Magnetorheological Semi-Aactive Suspension Vibration Control

Along with the rapid development of economy, automobiles have become more widely available. The consumers put forward higher requirements on riding comfort and handing stability. In the complicated vehicle vibration system, passive suspension system can not effectively improve the strength of vibration transmitting and the attaching condition between wheel and road, with the limited structure of itself, Semi-active suspension or active suspension systems become in effective control. The Magneto-Rheological(MR)technology has received great attentions in recent years, the MR damper utilized the MR fluid has shown superior performance in vibration control. In addition, the MR damper is applied to suspension system for dissipating the main vibration energy generated by road exciting. As a result, the comfort of riding is improved.This dissertation took the semi-active suspension based on MR damper as research object, by summarizing the research situation of home and abroad suspension and comparative analyzing different semi-active control strategies. According to the inherent and high nonlinearity of the MR damper, its inverse dynamics could be emulated applying to the neural network, that is to say, it is available to forecast the input voltage by giving the displacement of MR damper and ideal force. Then the inverse dynamic model can be used to connect with the LQR active control algorithm to form a closed-loop feedback control for semi-active suspension. The results of numerical simulations show that the reverse model can obtain continuous controlling voltage for MR damper, the resistance force of MR dampers can also be adjusted continuously, this strategy is feasible, the vibration reduction effect is obviously improved compared with passive suspension.The integrated system included semi-active suspension and electric power steering system(EPS)is established. Considering the coupling relationship between the subsystems, a layered coordination control method is proposed, meanwhile a LQR controller of SAS based on MR damper’s inverse dynamic model and a PID controller of EPS are designed respectively. Then aiming at the optimization of the whole vehicle, the upper coordination controller is made. The results of simulation show that the layered coordination control can improve vehicle’s comprehensive performance effectively, and coordinate the riding comfort and handing stability.