Research On Design And Control Of Active/Semi-active Combined Vibration Isolator

For different vibration isolation requirements,intelligent hybrid vibration isolation device can achieve intelligent control and high-efficiency vibration isolation,which has potential research value.However,due to the characteristics of large volume,complex structure and difficult control of hybrid micro vibration isolation device,there is little research on it at present.The purpose of this paper is to design an active / semi-active hybrid vibration isolator with magnetorheological elastomer and giant magnetostrictive materials as the core materials,design a mechanical structure that meets the requirements of vibration isolation and magnetic field,and simulate and optimize its magnetic field.Based on this structure,a frequency adaptive control method is designed to achieve high-efficiency vibration isolation for 0Hz-100 Hz vibration.Specific work are as follows:（1）According to active vibration isolation principle,semi-active vibration isolation principle and hybrid vibration isolation principle,device configuration and design idea of vibration isolation strategy are proposed.Linear working interval is selected according to the expansion coefficient curve of giant magnetostrictive material.The magneto-compressive stiffness is calculated by using the magneto-rheological elastomer micro-mechanical model.（2）The size parameters of the two materials are determined according to the design objectives and material properties,and the device structure is designed.The magnetic circuit is calculated according to Kirchhoff’s Law and Ohm’s Law and checked by ANSOFT Maxwell Software to determine its rationality and accuracy.The magnetic shield structure is designed and dimensionally optimized to ensure that the two parts of the magnetic field are free of interference.The device structure is fabricated and assembled.（3）Design LQR optimal controller and switching controller.Amplitude-frequency characteristic curves of semi-active vibration isolation part of magnetorheological elastomer under different current excitation are obtained through material properties,and switching control threshold is defined.The working modes of the hybrid insulator in different frequency ranges are preserved.Particle Swarm Optimization（PSO）is used to optimize the weight combination of LQR optimal controller under different working conditions.The results show that the corresponding vibration isolator can achieve effective vibration isolation under different conditions.（4）Taking displacement attenuation as performance index of hybrid vibration isolator,frequency adaptive control system is designed.Mathematical modeling of hybrid vibration isolator and control system is carried out by MATLAB/Simulink software to test the vibration isolation performance.The results show that the designed hybrid vibration isolator can realize automatic switching of vibration isolation mode and has good vibration isolation effect for different excitation conditions.Finally,the vibration isolator performance test system is built.This design provides a new idea for the design and control method of broadband vibration isolation device.