Investigation On Railway And Vehicles Semi-Active Suspension Control Strategy

With the rapid development of national economy, Chinese railway has been increased speed for five consecutive times. But with the speed increasing, the speeded-up locomotives have emerged in some new problems on dynamics performance. Stability, ride comfort and curve negotiation are the most important aspects of rolling stock dynamic performance, and reasonable active suspension can make them optimal. Semi-active suspension system has cheaper cost, simpler struction and higher running security, so it is more saving energy, stable and safe than active suspension, and it is a practical suspension form, which has important practical significance.However,the existing skyhook damper control strategy considers the ride comfort only,so when applying it to the rolling stock domain, it improves the vehicle running stability effectively, while the dynamic performances of the bogie and wheelsets change the difference, which is the disadvantage of semi-active suspension. So, the semi-active suspension control strategy is investigated systematically and the ride comfort, the dynamics performance of the bogies and wheelsets are considered synthetically by using optimal control method in this paper.Firstly, a 2DOF mathematical model of semi-active suspension locomotive is set up and the state equations are deduced; secondly, the acceleration of carbody and bogie are considered as the performance target using LQR method. At the same time, suitable Q and R are chosen in order to make the target minimize programming with Matlab language,and the simulation is carried out with Simulink; then,a 2DOF control model and a passive model were set up via Simpack in order to validate the availabity of this method, and the calculation is done as well; in addition, two control models and a passive model with the whole locomotive were set up via Simpack, and the dynamic performances of them were simulated and analyzed; lastly,another control model was set up,which the controllable dampers didn't replace the former ones,and the simulations were compared with the former.The analysis indicated that the semi-active suspension system based on optimal control can improve the disadvantage effectively. While it improves the vehicle running stability effectively, the dynamics performances of the bogie and wheelsets aren't worse. Thus the entire vehicle performances achieve optimization synthetically.