Study On Control Technique For Vehicle Active Suspension System

In the vehicle engineering, people are paying more and more attention to the handling safety and the riding comfort of the vehicle. The suspension system is the key component to improve the riding comfort and the handling safety, and reduce the components' fatigue damage. Recently, the research and exploiture of the suspension and the vibration control system are the international foreland problem in field of vehicle dynamics. Many countries have successively done much research on both theory and experiment of active suspension in the suspension design since the concept of active suspension was brought firstly up. hi China, the semi-active suspension and active suspension have also been studied since 1980's. But a lot of control algorithms are brought up, few is verified by experiments. With the control algorithm being complicated gradually, it must influence its engineering application.The control theory and experiment for vehicle active suspension system are deeply studied. Some applied control methods of active suspension is put forward based on the practical requirement for the development of the vehicle. Through comprehensive experimental research on two-DOF model of suspension system, the simulation results from the theoretical study are validated.With the nonlinearity of vehicle suspension, simulation signal of suspension system is more practical by road exciting signal of time domain than frequency domain, furthermore, it is easy to get the results which are consistent with practical results. So the production of road signal is firstly studied. By virtue of the analysis and contrast of suspension performance, the acceleration of sprung mass, dynamic tyre load, suspension dynamic deflection and active control force are determined as the evaluation indexes of suspension performance.Energy consumption badly restricts the development and applied research of active suspension system. So the concept of compound suspension is put forward.The device consists of the passive shock absorber and an electromagnetic actuator.In order to apply the control algorithm to experimental research, the two-DOF suspension model is designed and developed. The LMS adaptive filter technology is applied in the vibration control of vehicle active suspension. For the problem in controlling active suspension, the LMS control method is studied deeply. The results show there are the coupling channel and error channel in control system of vibration. By decoupling filter and error compensation filter designed, the effects of the two key problems are minimized. So the new design method of vibration control for active suspension system is available.On the basis of the fuzzy logic control, the LMS adaptive filter technology is applied. A new LMS adaptive fuzzy control strategy of active suspension is brought up. According to actual condition of system, the rectification factor can be continuously adjusted so as to follow the control process in real time. The experimental results verified that the control strategy is effective on the control of active suspension.Multi-degree and multi-index vibration control technique is studied. Through simulation research, it is comfirmed that the LMS adaptive fuzzy control algorithm is not only desired, but also can remain stable with change of suspension parameter.