| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain high-peed movement and to improve stoppage precision, while the cost of linear scale is reduced. <P>SOLUTION: A position sensor reads graduations of the linear scale and generates first position information. A magnetic sensor detects a magnetic field generated from a moving member or a stator. A sine wave-like signal and a cosine wave-like signal, which have a phase difference of 90° are outputted. A position detecting means generates second position information, based on the sine wave-like signal and the cosine wave-like signal. Either the linear scale or the position sensor moves with the moving member. The other side of the linear scale or the position sensor is arranged so that the position sensor can read the gradation of the linear scale, only in a partial range of a range where the moving member can move. A controller uses second position information, when the position of the moving member goes out of the partial range, and first position information, if the moving member is stopped in the range, when the position of the moving member lies within the partial range for control of current flowing into a coil. <P>COPYRIGHT: (C)2010,JPO&INPIT |
