Application Of Vibration Reduction Control Technology In Railway Vehicle Systems

Six times of raising speed of railways has already been carried out in China. But with increase of speed, the vibration problem of the train becomes more serious, which affects the current-collection quality of pantograph and ride quality of the train. Since the catenary is composed of cables, the dynamic behavior of such a string structure is difficult to be simulated by a test facility. Therefore, most of the pantograph-catenary tests were carried out under field conditions. Some indoor experiments either were too complex to be executed, or were too simple to give expected results. The rapid progress in computer simulation techniques in recent years reveals the possibility of incorporating mathematical model of the catenary system with the physical model of the pantograph system to form a unified hybrid experimental system. In the hybrid simulation test system, the pantograph is real and its dynamic behavior can be tested. While the catenary is a theoretical model and its dynamic behavior is realized by a servo hydraulic system. Such a hybrid simulation test facility possesses the ability of not only simulating the running behavior of pantograph, but also analyzing the influence of different catenary on pantograph behavior. The ride quality of the train includes vertical and lateral directions. Good vertical ride quality is relatively not difficult to be achieved, but the lateral ride quality is always not satisfactory. The limitation of the passive suspension system turns to be more and more obvious. The use of active and semi-active suspension systems is an efficient way to improve the lateral ride quality.Referring to the pantograph/catenary dynamic behavior and lateral ride quality of the train, the following main work has been done in the thesis:(1) Research on the pantograph/catenary hybrid dynamic simulation system: The catenary theretical model is used to undertake the real time simulation, and in the mean time, the virtual catenary and the actual pantograph are combined together through the hydraulic actuator. Then the pantograph/catenary dynamic interactions and parameter optimization can be studied by using this hybrid system.(2) Research on active vibration control for pantograph-catenary system: An active vibration control method based on fuzzy technology is put forward in order to reduce the locomotive pantograph. According to the characteristic analysis of the pantograph/catenary system, a fuzzy controller is designed to undertake real time fuzzy inference and operation. The pantograph behavior of SS7 locomotive is tested in laboratory, and the results show that the pantograph contact force fluctuation is greatly reduced by using active control technology, which considerably improves the pantograph/catenary operation behavior.(3) On the basis of analyzing the traditional iterative method for track irregularity simulation, a new method is proposed based on the adaptive filters: By adopting multi-channel inverse control with adaptive finite impulse response filters and the realization method for adaptive filters, the system response of multi-channel vibration testing system can approach the expected signals. And the simulation results are given by using this method, which indicate that the test simulation system by using this method can accurately reproduce the desired response and meet the test demand.(4) Based on the analysis of the traditional active control stragtegy, a new duo-loop active control strategy with direct feedback of carbody lateral acceleration and force is put forward. This control method not only overcomes the diverge problem caused by the direct acceleration feedback, but also ensures the stablility and rapid response of the control system.(5) In consideration of the complexity, nonlinearity and time varying of the vehicle system, an control strategy combined with on line identification of carbody inertia parameters and fuzzy-PID algorithm is put forward, which can achieve the good results in vibration reduction under different condition.(6) Based on the realizability of using micro-controller technology, the concept of the damper with variable structure and the realization method are proposed. The realizable field and dynamic characteristics of the damper are studied. The simulation shows that the semi-active damper with variable structure obviously has better performance than the traditional passive damper.(7) The load control loop is added into the semi-active control system, which can overcome the effect of damper parameter variation on vibration reduction.(8) The software and hardware of the test system for the train lateral active and semi-active suspensions are designed and constructed. By utilizing the roller test rig in the Traction Power State Key Laboratory of Southwest Jiaotong University, the comparison tests for a test vehicle under different test cases of passive suspension, active and semi-active suspensions with different control strategies are undertaken.