Model-less inversion-based iterative control for output tracking: Piezo actuator example

In this article, we propose a model-less inversion- based iterative control (MIIC) approach for high-speed output tracking in repetitive applications such as the lateral scanning during atomic force microscope (AFM) imaging. The MIIC algorithm extends the inversion-based iterative control (IIC) technique and the enhanced inversion-based iterative control (EIIC) technique. The main contribution of this article is the development of the MIIC algorithm to eliminate the modeling process while further enhancing the output tracking performance. We explicitly consider the disturbance and/or measurement noise effect in the convergence analysis of the MIIC algorithm. It is shown that convergence can be reached in one iteration step if the noise/disturbance effect is negligible; Or, the input error can be quantified by the disturbance/noise to signal ratio (NSR, relative to the desired trajectory). The MIIC is applied to a piezo scanner on an atomic force microscope, and experimental results are presented to demonstrate the efficacy of the MIIC technique.