| 摘要 |
PURPOSE:To rotate a plurality of ultrasonic motors as if they are driven simultaneously by a method wherein the title device is constituted of a driving means, driving a plurality of ultrasonic motors sequentially at every predetermined times, a tracking means, a memory means and a driving frequency commanding means. CONSTITUTION:An ultrasonic motor 31 is provided with electrodes A, B, C, D while another ultrasonic motor 32 is provided with electrodes A', B', C', D'. In the ultrasonic motors 31, 32, a signal voltage is impressed on one electrode group B, B' at all times while a voltage to be impressed on the other electrode group A, A' is impressed thereon by switching the voltage by a switching circuit 22. A CPU 20 drives the ultrasonic motors 31, 32 alternately at every predetermined times while the feedback control of the driving frequency of the motors is effected so that the driving frequency is approached to the resonance frequencies of the ultrasonic motors 31, 32 during the driving period of the same motors 31, 32. |
