A control system for stopping a spindle at a predetermined rotational position.

摘要

A control system for stopping a spindle 202 at a predetermined rotational position, for driving a spindle 202 in such a manner that a positional deviation signal between the present rotational position of a specified point on the spindle 202 and a predetermined rotational position at which the specified point is to be stopped, is reduced to zero, thereby to stop the specified point on the spindle at the predetermined rotational position. First and second rotational position sensors 204, 205 are attached to the spindle 202 at first and second specified points thereof, the position at which at least the first rotational position sensor 204 is attached being adjustable. Further provided are changeover means 209 and an orientation control circuit 210. The first position sensor 204 produces a rotational position deviation signal when a tool is inserted into and withdrawn from a workpiece at the time of a boring operation, and the second position sensor 205 produces a rotational position deviation signal when tools are changed. These deviation signals are applied to the orientation control circuit 210 selectively by the changeover means 209. As a result, the orientation control circuit 210 controls the rotation of the spindle 202 so as to reduce to zero the difference between an average speed signal, which conforms to the actual rotational speed of the spindle 202, and each of the deviation signals, whereby a specified point on the spindle 202 is stopped at a predetermined rotational position.