Control system for stopping spindle at predetermined rotational position
AssigneeFujitsu Fanuc Limited
InventorsYoshinori Kohzai, Yoshiki Fujioka, Naoto Ota
Life of this patent
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Abstract
A control system for stopping a spindle at a prescribed rotational position having a position control loop for driving a spindle so that a positional deviation between the present rotational position of a specified point on the spindle and a predetermined rotational position at which the specified point is to be stopped, is reduced to zero to stop the specified point on the spindle at the predetermined rotational position. Fine and coarse voltage signals are utilized for the final positioning process.
Claims9
A control system for stopping a spindle at a predetermined rotational position, which comprises:
- a position control loop for driving the spindle, for reducing to zero a positional deviation between the present rotational position of a specified point on the spindle and the predetermined rotational position, and for stopping the spindle at the specified point on the spindle at the predetermined rotational position, comprising:
- a sensor operatively connected to the spindle and to the position control loop, for producing a predetermined voltage signal level, in response to the specified point on the spindle being at the predetermined rotational position, for producing positive or negative voltage signals with respect to said predetermined voltage signal level in response to the specified point on the spindle being to the left or right of the vicinity of the predetermined rotational position, and for producing a fine position deviation voltage varying about said predetermined voltage signal level;
- coarse positioning means for generating a coarse position deviation voltage in accordance with the positional deviation between the present rotational position of the specified point on the spindle and the predetermined rotational position;
- and
- position deviation signal generating means for selectively providing one of the coarse position deviation voltage and the fine position deviation voltage as, a position deviation signal, in accordance with the specified point on the spindle being outside the vicinity of the predetermined rotational position or the specified point on the spindle being in the vicinity of the predetermined rotational position, respectively;
- wherein the position control loop drives the spindle in accordance with the coarse position deviation voltage until the specified point on the spindle reaches the vicinity of the predetermined rotational position, and then drives the spindle such that the fine position deviation voltage is reduced to zero after the specified point on the spindle has reached the area in the vicinity of the predetermined rotational position, thereby stopping the specified point at the predetermined rotational position.
Dependencies are inferred from the claim text.