Analog implementation of a damping and tracking controller for a high-speed X-Y nanopositioner

摘要

An analog implementation of a damping and tracking control algorithm is presented in this paper. Integral resonant control complemented with a high gain integral action is implemented using analog circuitry. Field programmable analog array (FPAA) is used for implementing the high bandwidth Integral Resonant Control (IRC) scheme while analog integrator is used to implement the high gain integral action on the lateral axis of the high-speed nanopositioner. In this paper, the controller is designed to accommodate systems with time delay arising due to capacitive sensing. The improvement in the lateral scanning bandwidth of a high-speed flexure based scanner for a commercial scanning probe microscope is presented. It is shown that by damping the resonant modes of the lateral axis, the scanning speed can be increased from 65 Hz to 200 Hz. The high gain integral feedback improves the tracking performance of nanopositioner and overcomes the hysteresis. Open loop and closed loop scanning performances are compared up to 200 Hz line rates. Limitations and suggestions for improvement of the nanopositioner performance are discussed.