| 摘要 |
PROBLEM TO BE SOLVED: To stably drive a rotation display device by a vibration wave motor by performing the initializing operation for storing the control value at a start time and the control value corresponding to an objective speed within a drivable range. SOLUTION: The actual rotational speed of a rotation display device 11 is calculated by operating the count value of pulses per a unit time counted by a counter 19 by utilizing the output of a pulse encoder 16. When position data, that is, data showing whether the display part of the rotation display device 11 is stopped at a predetermined stop position is inputted to the microcomputer 12 from a host computer 20, the driving of a vibration wave motor 14 is stopped according to predetermined speed data corresponding to the count value counted by the counter 19. In the microcomputer 12, the variable range min. frequency-max. frequency corresponding to the used vibration wave motor is set so as to contain the drive frequency-start frequency at the actual max. operation speed and the drive frequency and start frequency at the stored actual max. operation speed are renewed. |
