Study Of Hybrid Piezoelectric Vibration Isolator

Micro vibration isolation platform in military field needs wide vibration isolation frequency band and high vibration isolation efficiency.Because of piezoelectric stack actuator has small driving power and fast response,rubber vibration isolator has simple structure and large damping ratio,a hybrid piezoelectric vibration isolator which uses an actuator in series with a passive rubber isolator is developed in this paper,and a multi degree of freedom vibration isolation platform is builded.On the basis of the hybrid piezoelectric vibration isolator,theoretical analysis,simulation and experimental research have been carried on,and the main work is as follows:According to specific vibration isolation requirements of the vibration isolation object,design,parameter calculation and processing of the piezoelectric stack actuator and rubber vibration isolator are conducted.In process of design of the piezoelectric stack actuator,the electromechanical conversion principle of piezoelectric material is analyzed.The expressions of output displacement and force are deduced.Output displacement,output force and mode characteristics of the piezoelectric stack are analyzed through APDL language.The dynamics modeling of vibration isolation system consist of the load and hybrid piezoelectric vibration isolator is builded.Simulation research of the isolation system including feed forward control and feedback control is conducted through MATLAB simulation software.The way of series combination of the piezoelectric stack actuator and rubber vibration isolator is discussed and the corresponding isolation effect is analyzed.A multi degree of freedom vibration isolation platform made up of hybrid piezoelectric vibration isolators is builded.Mathematical modeling of the platform is conducted,and the mathematical expression of force transmissibility is obtained.Besides,vibration performance of the bench system is analyzed through finite element simulation and experiment research.Passive vibration isolation experiment of the platform is conducted.Experiment results show that the passive system component has a very high level of vibration isolation in high frequency.But in low frequency,the passive system component is ineffective.Finally,active isolation experiments of the platform are conducted to verify performance of the piezoelectric stack actuator and isolation effect of the hybrid piezoelectric isolator.Experiment results show that the piezoelectric stack actuator works well and it is able to be used to active vibration control.For single frequency and dual frequency excitation,the hybrid piezoelectric isolator achieves 18.1dB~21.0dB vibration isolation with an addition mass on the upper plate of the platform to approximate the vibration isolation object.