ENCODER HOME POSITION SENSING METHOD AND SYSTEM.

摘要

An encoder home position sensing system and method is disclosed, which includes the use of an analog quadrature encoder reader and either a code wheel or a code strip. The code wheel possesses an optical track comprised of annular ring patterns, the thickness of which can be modulated by a sinusoidal function about the code wheel circumference, with one cycle of a sine wave corresponding to one encoder cycle. In one region of the optical track the amplitude of the sine function is changed to imbed an absolute reference home position. This region of the optical track can be sensed and used to determine an absolute system position. The linear code strip is similarly constructed with lines along the direction of motion, the thickness of which are modulated with a sine function, with one cycle of the sine wave corresponding to one encoder cycle, and the amplitude of the sine wave function changed to imbed an absolute reference home position in the optical track.