Feedback control of piezoelectric tube scanners

Piezoelectric tube actuators commonly used in scanning probe microscopes display undesirable properties including hysteresis, creep, and varying voltage sensitivity. The effects of these nonlinearities must be counteracted to produce distortion-free images, especially for large scanning ranges. Methods implemented by previous researchers include calibration of the scanner, postimaging software image correction, and real-time correction via feedback control. This article focuses on the last of these approaches by describing the design and experimental results of two feedback controllers for scanner motion