High speed nanopositioning with force feedback

In this work a new method for feedback control of nanopositioning systems is proposed. A measurement of the force applied to the moving platform by the actuator is utilized as a feedback variable for both tracking and damping control. Excellent tracking and damping performance can be achieved with a simple integral controller. Other outstanding characteristics include guaranteed stability and insensitivity to changes in resonance frequency. Experimental results on a high-speed nanopositioner demonstrate an increase in closed-loop bandwidth from 210 Hz (with an integral controller) to 2.07 kHz (with force feedback control). Gain-margin is simultaneously improved from 5 dB to infinity.