Design And Implementation Of Control In Active Vibration Isolation Platform

Low frequency vibration is a key factor which affects the accuracy and performance of precision optical instruments or equipment. With the continuous improvement in the measuring accuracy of precision instruments or equipment, the demands for the precision active vibration isolation system are also increasing. Based on the national major projects, in view of the working environment of the scanning electron microscopes, scanning probe microscopes and other precision optical instruments, this thesis designs a controller of active vibration isolation platform that has good vibration isolation effect for 1-30 Hz low frequency vibration. Compared to conventional active feedback systems, the extraordinary platform can solve the problem that structural resonances peak between the payload and floor-induced vibration cannot be eliminated by adding feed-forward control.Firstly, based on analyzing the vibration isolation requirement of control system and referring to the existing isolation products, this thesis proposes the design requirements of control system and discourses the characteristics of the active vibration isolation platform about the whole mechanical structure and system components; on this basis, scheme of control system is proposed and control scheme modules are analyzed to finish the design of the entire isolation.Secondly, the controller hardware design about active vibration isolation platform is finished. The hardware design includes the low frequency extension circuit, analog-todigital conversion circuit, digital-to-analog conversion circuit, and communication interface circuit, control circuit based on DSP + CPLD architecture and drive circuit. Low frequency extension circuit and drive circuit are verified by simulation and experimental. Except for the design of hardware circuit, control circuit also including the realization of the function of control algorithm and diagnosis.At last but not least, an experimental platform is built to verify the diagnosis function and transmissibility about active vibration isolation platform. The bandwidth of the system lies in about 1-100 Hz, especially for 1-30 Hz low frequency vibration. The passive resonance peak is reduced by 29 d B when feed-forward control is active.