An improved controller design for reducing errors in AFM imaging

In this article, the design and implementation of a multi-input multi-output (MIMO) model predictive control (MPC) framework for reducing errors in images scanned by an atomic force microscope (AFM) is presented. To improve the damping capability of the proposed control framework, it is augmented with a damping compensator. The MIMO form of this control framework compensates the tilted natures of the scanned images by compensating the cross-coupling effect while its augmented damping compensator reduces the vibration effect by improving damping in the resonant mode of the AFM's piezoelectric tube scanner (PTS). Experimental results using the existing AFM proportional integral (PI) controller and single-input single-output (SISO) MPC are also presented to show the effectiveness of the MIMO MPC controller. This paper is an extension of an authors' earlier published work.