A Study Of Low-frequency Active Isolation Of Small Vibration

For satisfying the demand of isolating the low-frequency vibration in precision process, this thesis conducts theoretical and experimental research on an active isolation system of small vibration based on piezoceramic actuator. The electromechanical integration system consists of piezoceramic material as the actuator and the disturbance source, a double-layered vibration isolation system as the controlled object. First, this paper studies the single-layered and double-layered passive vibration isolation system theoretically. As they aren't able to isolate the low-frequency vibration, the author does an emphatic research on the single-layered and double-layered active vibration isolation system. The author puts forward three kinds of method for improving the sensor's low-frequency function, also conducts emulating research on steady-state and transient responses with software MATLAB respectively. After designing the new-type high-voltage power amplifier, the static and dynamic responses of actuators made from piezoceramic material are studied experimentally, and introduced as actuating device used in active vibration isolation system. Making use of electronic technology, the author expands the velocity sensor's natural frequency from 4.5Hz to 0.2Hz successfully, and does an experimental research after it is introduced into the studied system. The experimental results show that the active vibration isolation system based on piezoceramic actuator has the good performance of isolating the low-frequency vibration. So, it can meet the demand of precision vibration isolation. Besides, to study the sensor's low-frequency performance, the author designs the hardware and software of digital control system based on TMS320F240, and conducts the research of expanded sensor's performance. The results show that the expanded sensor based on digital control technique has the advantage of withstanding the impact, also its transient process is very short. The research works for further studying are proposed in the last.