| 摘要 |
PURPOSE:To raise the accuracy of an estimated value in a non-detection period of a pulse by deriving an estimated value of a rotating speed and a speed from acceleration in a no-pulse period, and an estimated value of a speed when the number of pulses is '1' in a unit operation period, and setting a smaller value as the rotating speed. CONSTITUTION:A CPU 21 stores a constant alpha derived from a radius R of a rotating body 11 and the number Z of magnets 12, and the maximum value PM of a continuous rotation P for discontinuing an estimating operation by considering the rotating body 11 to have stopped, when a unit operation period of no-pulse has continued, in a memory 25. In the case of the operation period of no-pulse, for instance, P<PM, and when a pulse exists in the previous opera tion period, an estimated value is calculated by a speed V=alpha/(t0-T1) by using an elapsed time T extending from the previous detection time t2 to the end time t0 of the present operation period. Also, from a rotating speed Vc and acceleration A which have been calculated in the previous operation period, an estimated value of a speed is calculated by V=VC+A.TM.(P+1), and a smaller one of the values which have been derived by both the equation is selected as a speed of this period. |
