Interferometer position sensor for precision machine tool

摘要

The interferometer position sensor is for monitoring a spindle on a worktable of a precision machine tool, and has a semiconductor laser source (21) for generating a light output. The wavelength is determined by the controller (22), and is stabilised against environmental change. An imposed change of wavelength gives rise to the increment and decrement values (Cx) for the interference flux wavelengths observed within a measurement path (Lx) and (Co), for a preset reference length (Lo), as revealed by the respective optical interference modules (23,24). An evaluation stage (25) uses this position data to determine the length (Lx) from the identity Lx = Lo (Cx/Co), and hence the absolute position (Pout) of a reflecting face of the monitored object.