Active Vibration Isolation Control Of Piezoelectric Stack For Beam-plate Structure

As the core branch of intelligent manufacturing industry,the development of precision instruments and equipment is also exceptionally rapid,showing the trend of intellectualization,integration and refinement.It has huge potential demand in aerospace,civil engineering,rail transit,marine engineering and other fields.However,due to the high requirements of the service environment of precision instruments,the platform is required to have excellent vibration isolation performance.Once the environmental vibration exceeds its allowable value,it will lead to such problems as processing accuracy decline,test error,product failure,and even damage to instruments and equipment,with unpredictable consequences.Therefore,the piezoelectric active vibration isolation device based on the principle of piezoelectric stack actuation is designed in this paper.On this basis,a simulation precision vibration isolation test system is developed to test and analyze the vibration acceleration transmission rate.The main contents of this paper are as follows:(1)The piezoelectric stack is composed of multi-layer micron-scale PZT sheets laminated along the polar axis.Considering the d33 effect in the direction of polarization thickness,a one-dimensional piezoelectric equation is derived.The influence factors of the output displacement of the piezoelectric stack are verified by finite element simulation.The equivalent stiffness of piezoelectric stack is calculated by output analysis under no-load state and constraint state,and the mechanical model of piezoelectric stack under static/dynamic load is studied.(2)Selecting appropriate elements in ANSYS finite element modeling can initially simplify the model and reduce the number of model elements and degrees of freedom while ensuring the accuracy of analysis.Guyan reduction method is used to eliminate the structural pair degrees of freedom to achieve model condensation.The H2 norm is used to further reduce the order of the model,and the model is reduced according to the contribution of the corresponding modes to the mode shapes.By comparing the amplitude-frequency response curves and vibration response time-history curves before and after order reduction,and modal test of steel plate structure,the correctness of finite element modeling and order reduction is verified.(3)The MCS algorithm is compiled based on MATLAB/Simulink,and the state observer is constructed to observe the whole state of the structure in response to the fixed position of the clearance.The state control is realized and the global asymptotic stability of the MCS algorithm is verified.The tracking performance of MCS control algorithm is studied under 10-100 Hz sinusoidal excitation and white noise excitation to show that the MCS control system has good tracking and robustness,and achieves good vibration isolation effect.(4)A piezoelectric active vibration isolation device for precise vibration isolation is developed.Based on this,software and hardware are developed.A simulation precise vibration isolation test system with dSPACE as the control core is built.The experimental study of rigid support,passive vibration isolation and active vibration isolation proves that the acceleration amplitude of piezoelectric stack active vibration isolation controlled by MCS can be effectively attenuated.