Theoretical Research Of Semi-active Control System In Structural Vibration

ABSTRACT The semi-active control is a main research field at present, and it creates a newway to suppress dynamical response of structures. As one method in the structurevibration control, semi-active control combine active control and passive control, andit can approach to the control effectiveness of active control with only little energy.However, as a kind of strong nonlinear control, semi-active control is a kind ofparameter control in essence, many certainties have varying influence control systemcharacteristics such as robust ability and time delay. In recent years, since all kinds ofintelligent materials and intelligent control algorithm have been introduced intosemi-active control system, many superior semi-active control devices are put forwardand produce favorable values in engineering. So in the background, main researchcontent of this paper is as followed: 1. Two kinds of popular semi-active control systems at present are analyzed andcompared, and their application and characters are pointed, then based on the STMDsystem, this paper propose a strategy which can adjust control force on-linecontinuously. This control strategy depends on active control algorithm and thecontinuity of MR fluid. Moreover, AVS/D system is simply and easy to be realizedand little on-line calculation, so the structure control strategy is also one of mostpromising semi-active control devices. 2. Put forward an H∞ control scheme of uncertain nonlinear systems based onartificial neural networks (ANNs) adaptive method, based on the fact that there arealways uncertainty external disturbance, the perturbation of parameters often appearsand the damping performance of damper is controlled continuously. The strategydivides the uncertainty in vibration into two parts, on part is solved by H∞ the other ,solved by neural networks. 3. For solving the problem of sensor invalidation in vibration control, this paperpresent robust reliable control strategy. The method is demonstrated with an 3degree-of-freedom structure. Results show that the method has a good stability,precision and robustness. 4. Above all, this paper recommend the fundamental principle and mechanicalbehavior of several intelligent materials, such as shape memory alloy, piezoelectricceramics, ER fluids and MR fluids etc, then the application of SMA and MR in thesemi-active control system are discussed and the existing problems in the applicationand research are presented. The future development of the intelligent material systemsand structures are prospected and some proposals are put forward.