Double resonant controller for fast atomic force microscopy

This paper presents the design and implementation of a double resonant controller with an integral controller in the piezoelectric tube scanner (PTS) of an atomic force microscope (AFM) to damp the resonant mode of the scanner, increase the bandwidth of the overall closed-loop system, and improve the high speed imaging performance of the AFM. The X and Y axes of the PTS is treated as an independent single-input singleoutput system and the system is identified by using the measured open-loop data. In order to measure the performance of the proposed controller a comparison of the scanned images have been made by using the proposed controller and the built-in proportional-integral (PI) controller of the AFM. The comparison of the scanned images demonstrate the performance improvement achieved by the proposed controller.