Patent ID: 6998808
Filing Date: 2006-02-14
Classification: G05B,H02P

Abstract:
1. A positioning apparatus comprising: a brushless motor having a plurality of magneto-sensitive elements and a plurality of fixed coils; a positioning mechanism to position a movable member within a predetermined movable range in accordance with rotation of the brushless motor; and a motor control circuit to rotate a rotor of the brushless motor by sequentially supplying driving pulses to said fixed coils; wherein the motor control circuit comprises: driving pulse generating means to generate the driving pulse, present stage number detecting means to detect a present stage number to which a current angular position of the rotor belongs in accordance with output signals from said magneto-sensitive elements, initialization means to move the movable member to at least a forward traveling limit or a backward traveling limit within the movable range so as to set the detected present stage number as a forward traveling limit stage number or a backward traveling limit stage number when the movable member reaches the forward traveling limit or the backward traveling limit, and speed reduction means to reduce a rotating speed of the rotor by reducing power carried by the driving pulses when the detected present stage number is equal to either one of the forward traveling limit stage number and the backward traveling limit stage number.