Research On Active Control Of Vibration For Complex Vibration Isolation System

Along with the active control technology of vibration 's development,the active control of power flow transfer in flexible system have already acaused high value in china and abroad.With the power flow for performance index,to investigate each of the active control strategy of the flexible isloation system is one of the leading reserch issue in the field of vibration and noise control. Combining the foreback-feedback control theories and methods,this thesis descriped detailly for the the active control strategy of the flexible isolation system and floating raft.In the aspect of the flexible effect of foundation to the dynamic respond of engine supporting system ,when the foundation is rigidity,use predigest model to analyse the system,we can find the difference between the low frequency and high frequency by the force transfer-ratio curve;when it is flexible,by analysing the system combining the theory of power flow,we can get the power flow curve,we also analyse some influent factors. The results shows that reducing the length of the foundation and increasing the foundation's modulusofelasticity can reduce the power flow transferrin-g to the foundation.Firstly,it is analyzed detailly about the excellence and localization of the classic monolayer and two-double isolation system.Floating raft is applied for it's reducing vibration and yawp.Aim at the problem that the passive control can't resolve,it implement the active control for the monolayer isolation system which foundation is flexible combining the foreback theories.On this condition,it is discussed three control methods about the rigid floating raft system. The executor and absorber's location has some influence for the isolation effect of the flotating raft.The results shows that the foreback control can restrain vibration transfer from low to high frequency,the higer the frequency,the well the isolation effect.Further more, the displacement,velocity and acceleration feedback control are carried out for reducing vibration transfer to the machine. for the system that foundation move,it is necessary to execute the relative displacement, velocity, acceleration and force feedback control.It is adopted the force feedback control to the monolayer isolation system which foundation is flexible,collocating the compensator is also necessary.The results shows that the velocity feedback and relative relocity can reduce vibration in all frequence fields,it also has the best stability.