Identification of Excitation Forces in Precision Equipments Driven by Stepping Motors

摘要

In many precision equipments, excitation forces generated by driving motors and ground vibrations are the major two disturbances which may deteriorate the precision. Traditionally, ground vibrations are considered to be far more influential and, hence, emphasis is mostly put on base isolation. As the level of precision requirement becomes higher and higher, however, for example, in micro- or nano-equipment, excitation forces generated mechanically or electromagnetically in the driving motors also need to be investigated carefully. In this paper, internal excitations in an x-y stage driven by stepping motors are estimated in terms of equivalent forces by measuring transmission forces at the stage mounting points and vibrations of the stage. A method is presented and confirmed. Furthermore, relative displacement between two specific points due to the internal excitations is investigated.