Based On Piezoelectric Actuators For Active Vibration Isolation System Theory And Simulation Study

In recent years, the technology of active vibration control which combines intelligent material structure, control theories, signal processing technology and computer technology with mechanical vibration theories has become one of the most active research fields as its important application value in real engineering. In this dissertation, a vibration isolation system with piezo-ceramic actuators carrying out the controlling order is built up based on the vibration isolation requirements of a precise instrument in spacecraft. The dynamic equations of the system are founded as well as its state space model, followed by the theoretical study and numerical simulation study. The simulation results show that the active vibration isolation system studied in the dissertation has much better isolating performance against conventional passive isolation system in a very broad frequency range.The main research jobs are listed as follows:1. Both the basic concept and the general developing and studying situation of intelligent material structure are intruced, followed by the summarization of the controlling method and active vibration isolation technology;the development directions of intelligent actuators are indicated, and the application situation of intelligent actuators is also introduced.2. One and two dimentional piezoelectric equations are deduced, which are used to obtain driving force or displacement of the piezoelectric actuator;then the configuration of the actuator is designed.3. The dynamic model and formulations of one-degree-of-freedom vibration isolation systems are built up, then the influence of different frequency ratio to isolation effect is analyzed;the dynamic model of a specific precise instrument in spacecraft is established and an active vibration isolation system based on piezoelectric actuators is constructed.4. The principle and design method of PID controller are expatiated;the expression of the LQ optimal control force when the sysem is subjected to regular interference is deduced as well as the LQG optimal control force when subjected to random interference.5. The numerical simulations of the isolation system using Matlab scripts and its Simulink tool are done;the simulation results show that the active isolation systems has good isolation effects and the isolation effects of PID control are better than those of the common passive isolation system but worse than those of optimal control, and that the weighting matrices have important influence on the isolation effects.