Enhancing fixed-point control robustness for experimental non-contact scans with the Transverse-dynamic Force Microscope

Kaiqiang Zhang, Toshiaki Hatano, Guido Herrmann, Massimo Antognozzi, Christopher Edwards, Stuart Burgess, Thang Nguyen Tien, Mervyn Miles

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)

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Abstract

The Transverse Dynamic Force Microscope (TDFM) is unique as it uses a vertical cantilever, and genuinely permits scans without physical interaction with a specimen. Recently, we suggested a simple control scheme for true noncontact scans using the TDFM. This control scheme implemented in FPGA-systems (Field-Programmable Gate Arrays) was developed for a non-contact control task at specific points above a given specimen, but dynamic specimen placement requirements in the horizontal plane through an x-y stage were neglected. Considering the large range of the specimen, a practical approach has been developed which reconfigures the fixed-point-arithmetic control implementation and permits a dynamic scan in true non-contact mode. For this, an off-line numerical optimization has been developed which establishes the most suitable fixed-point ranges of the control algorithm, avoiding algorithm overflow. This creates an implementation robust to plant and sensor non-linearities and dynamic changes during non-contact scans. Experimental non-contact scanning results, for nano-spheres in water, demonstrate the imaging capacity of the TDFM.
Original languageEnglish
Title of host publicationAmerican Control Conference 2018 (ACC 2018)
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Number of pages6
ISBN (Electronic)978-1-5386-5428-6
ISBN (Print)978-1-5386-5429-3
Publication statusE-pub ahead of print - 16 Aug 2018

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    Zhang, K., Hatano, T., Herrmann, G., Antognozzi, M., Edwards, C., Burgess, S., Nguyen Tien, T., & Miles, M. (2018). Enhancing fixed-point control robustness for experimental non-contact scans with the Transverse-dynamic Force Microscope. In American Control Conference 2018 (ACC 2018) Institute of Electrical and Electronics Engineers (IEEE).