Evaluation of positioning performance of a fine-coarse 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 with guaranteeing positioning accuracy. A conventional speed reducer unit is utilized to cope with this problem in this study. The combination of reducer and overdrive enables to position the end effector with accurate and rapid. This fine-coarse motion of the developed system is realized by only commercial-release parts consisted of two stepping motors and speed reducer aligned in an axis. The main advantage of this mechanism is that there is no stroke limitation in fine and coarse motions compared with the conventional fine-coarse motion stage by usage of PZT device. The basic performances are evaluated by adopting the feedback positioning control in this report. The developed positioning system demonstrates the efficient performance with accurate and rapid positioning.