| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the rotational speed or the rotational angle of a detection target with high accuracy by improving an uneven-rotation suppression capability, while outputting an accurate correction waveform, by eliminating not only the error components accompanying the decentering and ovalization of a rotary member, but also the FM modulation errors. <P>SOLUTION: Two rotation sensors 40, arranged at an interval of 90° in the circumferential direction of a cord wheel 36 mounted to a motor respectively output signals, corresponding to the rotational speed of the cord wheel 36. When the cord wheel 36 is decentered with respect to an output shaft 26, an error component of one period is generated by a single rotation, and when it is deformed elliptically, an error component of two periods is generated by a single rotation. A first control means makes a single-period component of a calculation signal, which is half of the difference between output signals of each rotation sensor 40 for the single rotation of the cord wheel 36, is ma de to coincide with the amplitude and the phase of the single-period component of each output signal from each rotation sensor 40 and generates a correction output waveform so as to correct the FM modulation errors. <P>COPYRIGHT: (C)2009,JPO&INPIT |
