TW200600753A - A homocentric degree correcting apparatus and the method thereof - Google Patents

Abstract

This invention of a homocentric degree correcting apparatus and the method thereof, wherein the correcting apparatus is installed on a platform includes a rotary system, an image access system, a complement system and computer system. The controller is electrically connected to the computer system to make the computer system connect and control the controller so as to control the operation of the rotary system and the complement system. The rotary system is composed of a rotary motor installed under a base and a ring case fixed on the base. The ring supports a disc-shaped optical encoder and is fixed together with the base to prevent the ring case from being tilted due to the effect of torque. The image access system connects to a laser for instantly accessing image data of the disc type optical encoder such that the computer system controls the correction angle of the rotary system and the correction distance of the supplement system according to the accessed image data. The correction method corrects the eccentric value between the grating disc and the axis center body of the disc type optical encoder. In the method, by setting the circle center of the axis center body as the point A, the circle center of the grating disc as the point B, and the visual area as F.O.V, x is the shortest distance from point P, which is a fixed point chosen from the visual area. When the axis center body begins to revolve, x changes accordingly. When these three points A, B and P are on the same line, and the point B and P are on the same side as point A, value x has the maximum value x-max; when these three points A, B and P are on the same line, and the point A and P are on the same side as point B, value x has the minimum value x-min so the bias value d between center A and center B is equal to (xmax-xmin)/2. The bias value d can correspond to the angle between these collinear points A, B, P and the moving direction of the complement push-plate such that the axis center body can be rotated θ to make the collinear points A, B, P and the movement of the complement push-plate have the same direction. After the θ rotation, the complement push-plate is controlled to conduct the correction onto the bias value d. The present device and methods can be used to improve the correction quality and correction speed of the homocentric degree of disc-shaped optical encoder.