| 摘要 |
PURPOSE:To improve constant speed control of a motor by providing means for relatively increasing the phase difference control component in a feedback control signal of the motor when a judgment is made that the rotational speed of motor is reached to a steady region. CONSTITUTION:When the rising detecting circuit 131 at an encoder signal input section detects rising edge of a speed detection pulse, count in a free running counter 133 is read in then it is subjected to phase comparison and stored. Then, a phase reference is calculated and stored. Thereafter, phase difference is calculated and stored. The operation is repeated. Since the ratio of the phase difference control component due to a control signal increases relatively, a stable constant speed control having excellent follow-up performance to variation of load can be realized. |
