Abstract
This paper presents a new methodology, employing a super-twisting sliding mode observer, to reconstruct un-measureable atomic-forces at nano-Newton precision in a Vertically Oriented Probe Microscope (VOPM). The VOPM senses the deflection of a vertically oriented cantilever, caused by shear-force interaction with a confined water layer above the sample-substrate. The paper describes the development of a model and the subsequent experimental process for computing its parameters. This forms the basis for the design of a super-twisting observer to estimate the unknown shear-forces. The reconstructed force can be decomposed into elastic and viscous components, which are important in biological research.
Original language | English |
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Article number | 104191 |
Journal | Control Engineering Practice |
Volume | 94 |
Early online date | 15 Nov 2019 |
DOIs | |
Publication status | Published - 1 Jan 2020 |
Keywords
- probe microscope
- shear force
- elastic and dissipative force
- sliding mode control
- super-twisting observer