A new robust damping and tracking controller for SPM positioning stages

Andrew J. Fleming, Sumeet S. Aphale, S. O.Reza Moheimani

Research output: Chapter in Book/Report/Conference proceedingPublished conference contribution

8 Citations (Scopus)


This paper demonstrates a simple second-order controller that eliminates scan-induced oscillation and provides integral tracking action. The controller can be retrofitted to any scanning probe microscope with position sensors by implementing a simple digital controller or op-amp circuit. The controller is demonstrated to improve the tracking bandwidth of an NT-MDT scanning probe microscope from 15 Hz (with an integral controller) to 490 Hz while simultaneously improving gain-margin from 2 dB to 7 dB. The penalty on sensor induced positioning noise is minimal. For the Scanning Probe Microscope considered in this paper, the noise is marginally increased from 0.30 nm RMS to 0.39 nm RMS. Open- and closed-loop experimental images of a calibration standard are reported at speeds of 1 and 10 lines per second (with a scanner resonance frequency of 290 Hz). Compared to traditional integral or PID controllers, the proposed controller provides a bandwidth improvement of approximately ten times. This allows faster imaging and less tracking lag at low speeds.

Original languageEnglish
Title of host publication2009 American Control Conference, ACC 2009
PublisherIEEE Explore
Number of pages6
ISBN (Print)9781424445240
Publication statusPublished - 24 Nov 2009
Event2009 American Control Conference, ACC 2009 - St. Louis, MO, United States
Duration: 10 Jun 200912 Jun 2009


Conference2009 American Control Conference, ACC 2009
Country/TerritoryUnited States
CitySt. Louis, MO


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