Evaluation of Angular Error of Fine-coarse Motion Driving Mechanism

A new positioning system has been developed to realize both the fine motion and the coarse motion independently and/or simultaneously to reduce the positioning time under the limitation of guaranteeing the positioning accuracy. To cope with this problem, a new combination of positioning methods been proposed. The fine-coarse motion of the developed system is realized by only commercial-release parts consisted of two stepping motors and harmonic drive reducer aligned in an axis. The main characteristic is that there are no stroke limitations in the fine and coarse motions with respect to the conventional fine-coarse motion stage by usage of PZT device. The basic performances were evaluated by adopting the open loop positioning and the feedback positioning. The developed positioning system demonstrates the efficient performance of the accurate and rapid positioning