Conceptual Design and Trajectory Planning of a Precision Repetitive-Scanning Stage With Separated Drive Unit for Energy Saving

Precision repetitive-scanning stages, which exist in lithographic reticle systems, scanning probe microscopes, and scanning electrodischarge machines, have been widely used in modern precision industry. To design such stages, energy consumption has become one of the most important criteria due to energy crisis and practical heat-reduction request. Considering the motion characteristics of such stages, it would lead to an energy-saving nature if the accelerated and constant-speed motions are driven by two separated drive units (SDUs). Inspired by this thought, we propose a novel concept of precision repetitive-scanning stage especially equipped with a separate permanent-magnet drive unit for accelerated motion. In order to exploit the function of SDUs for achieving high energy-saving performance, a modified repetitive-scanning trajectory is proposed. For this trajectory, complete analytic formulas allowing real-time planning are provided to match the permanent-magnet drive force, which results in a sufficient utilization of the SDUs’ drive ability. Finally, a precision repetitive-scanning stage prototype is set up. Comparative experimental results demonstrate that the proposed structural concept and its matched trajectory can significantly save energy without any motion accuracy deterioration. Essentially speaking, the proposed conceptual design and trajectory planning strategy provide a good guidance for precision repetitive-scanning system on energy saving, which could be applied to industry of semiconductor manufacturing, precision detection, microfabrication, and so on.