Asymmetric Hysteresis Modeling and Compensation Approach for Nanomanipulation System Motion Control Considering Working-Range Effect

Atomic force microscope (AFM) has been defined as the one of the most powerful instruments to explore micro/nanoworld in various fields. To lower imaging noise, AFMs are commonly equipped with open-loop nanopositioners (scanners). However, the hysteretic effect of the AFM positioners is a dominate factor that increases the position error during AFM-based manipulations. To reduce hysteresis, inverse compensation approach is an effective solution. Normally, one compensator is designed for the manipulation task with maximum working range, which may not be efficient enough for maintaining uniform accuracy for tasks with different working ranges. The objective of this study is to develop a working-range adapted compensator to tackle this challenge. First, a generalized method that can precisely model various types of hysteresis is required. To fulfill this, a flexible Prandtl-Ishlinskii (PI) type model, named extended unparallel PI model, is employed. Based on this model, an implicit hysteresis compensation approach is developed, and its stability condition and control gain optimization approach are proposed. Combining the modeling and compensation approaches, a working-range adapted hysteresis compensator is finally established. Experimental results demonstrate that the mean control errors of the compensator are uniformly below $5\%$ in different working ranges.