Research On Dynamic Characteristics And Control Method Of Magnetorheological Dampers Used In Whole-Spacecraft Vibration Isolation

In the rocket launch process, satellite or spacecraft experience of dynamic environment is very bad, the excitation is not only from the random excitation when the rocket engines working, but also the pneumatic incentive and the transient shock from the separation of rockets. In order to reduce the vibration and impact from satellite or aircraft launched by rocket, a reliable and effective platform is urgently needed. A semi-active vibration isolation platform has huge potential in the carrier rockets star isolation,which is based on the isolation of magnetorheological damper(MR damper) with its fast reaction (ms), high reliability (even the control system failured, it still can work as a passive isolation system), strong adaptability (very close to the control effect), low energy consumption, etc.Beginning with MR damper which used for Whole-spacecraft Isolation and according to the structure of MR damper high-frequency decoupling partment and its working characteristics, a modified damper model was proposed, which is based on intensive study of several basic mechanical model of MR damper and uses the Bouc-Wen model as the foundation model. For further studies in the MR damper dynamic characteristics, a dynamic characteristics of the damper experiment has been taken, and the damper force and the dependence of displacement on the current changes were obtained. Besides, According to the experimental data and using particle swarm optimization algorithm, the dynamic model of damper parameters were optimized, then the practical calculation model of damper was obtained.According to the practical calculation model of damper, two kinds of damper control algorithm were simuliated and compared by Matlab/Simulink. It is showed that the control effect of the modified Sigmoid function controller is better than that of Sign function controller. Finally a reconfigurates forced vibration system was established, and a semi-active control simulation was taken by the damper simulation model and the controller model. It is showed that, at the step and sine excitation, the MR damper mechanical model and semi-active control system based on the Sigmoid function controller has good effect on vibration control.This paper theoretically analysis the MR damper ,establish the mechanical model for real, and optimized the model parameters and the dynamics of the real damper .It is of prevalent meaning of guidance for MR damper modeling. Furthermore, based on the MR damp simulation model and modified controller model, the semi-active control simulation was taken for two degrees of forced vibration system, the results not only verifies the validity of the model but also shows that the vibration of the semi-active control is effective.