Spatial-Temporal Trajectory Redesign for Dual-Stage Nanopositioning Systems with Application in AFM

This article focuses on trajectory redesign for dual-stage nanopositioning systems, where speed, range, and resolution are considered. Dual-stage nanopositioning systems are becoming increasingly popular due to their unique ability to achieve long-range and high-speed operation. Conventional trajectory assignment methods for dual-stage systems commonly consider frequency characteristics of the actuators, a process that can inappropriately allocate short-range, low-frequency components of a reference signal. A new systematic range-and-temporal-based trajectory-redesign process is presented, where the desired trajectory is first split based on achievable positioning bandwidth, and then, split spatially based on the achievable range and positioning resolution. Inversion-based feedforward control techniques are then used to compensate for the dynamic and hysteretic behaviors of a piezo-based prototype dual-stage positioner; this control architecture is selected to emphasize improvements achieved through the new trajectory-redesign method, as well as allow for implementation onto platforms with minimal sensing capabilities. Simulations and atomic force microscope experiments are included to demonstrate the success of this redesign procedure compared to approaches that consider frequency or range alone.