Study Of Active Isolation Vibration On Scanning Probe Microscope

With the development of science and technology and the progress of human society, people control vibration isolation in all kinds of high and precise fields more strictly. Series of vibration with unknown frequencies and amplitudes limit the process of excellent high and precise instruments to a great extent, such as scanning probe microscope (SPM), and encountering in various detective fields of high resolution and high and precise machining processes particularly. Therefore, it is very meaningful in theory and useful value to develop vibration isolation technology for super precise instruments.The research theme of this dissertation is from the National Natural Science Foundation of China--Study on elastic float lapping technology and diamond application (No.50675037) and the Science and Technology Program of Guangdong Province --Development of super micro gene injection device (No.2003B 12002), aimed to improve the performance of scanning probe microscope avoiding disturbance in ordinary laboratory as a tool for nanometer machining and detection. Meanwhile, learning new theory and technology at home and abroad as well as deep research of active isolation vibration on improvement of precise detection and anti-disturbance has been done from the point of view which is theory, experiment and computer simulation.In the dissertation the background and significance of the research are introduced, and the development trend and the current research situations are proposed as well, combined with lots of literatures at home and abroad. It is considered it's very meaningful combining passive vibration isolation with active vibration isolation. At the same time, the main contents are introduced briefly in this dissertation. Taking the CSPM4000 as the research object, which was made in benyuan nano instruments CO. LTD, the vibration isolation system and its dynamics model are built based on the principle of SPM and active vibration isolation. It is presented that combining active vibration isolation with passive vibration isolation for vibration isolation about low frequency disturbance according to the performance of disturbance in the ordinary laboratory.According to the performance of low frequency and considering with the cost of active vibration isolation, a vibration isolation system is present and produced consists of three parts, which are signal induction, control system and actuator. And the signal induction is achieved that vibration signal is induced by the magneto-electric sensor, control system concludes signal A/D (D/A) transform, low pass filtering, signal amplifying, FFT processing, and A/D (D/A) conversion is actualized by the acoustic card in PC, the other processing is achieved by MATLAB software with analyzing and computing with adding control policy. To so many control policies of active vibration isolation and taking their advantages and disadvantages, digital PID control policy, fuzzy control are chose to investigate in active vibration isolation. Studying vibration isolation effect for different frequencies via computer simulation in MATLAB with different control policies, results are analyzed and compared. Finally, PID control policy is adopted. Investigating under several conditions separately, they are working with passive vibration isolation, or with active vibration isolation, and comparing the results of experiments, it is gained from the result analyzed that it can achieve good performance of isolation combining active isolation with passive isolation.