| 摘要 |
PROBLEM TO BE SOLVED: To prevent startup failure from occurring by abnormal oscillation generated in forming the driving circuit of an ultrasonic motor out of a self- oscillation circuit. SOLUTION: This ultrasonic motor 1 is capable of restarting by forming a motor operation determining command means 14 for comparing the frequency of an oscillation signal generated from a driving circuit with a reference frequency range, or a voltage amplitude value with a reference voltage value, and generating a stop signal for stopping the oscillation circuit when the frequency deviates from the reference frequency range, or the voltage less than or equal to the reference voltage value is obtained, and a restart signal generating means 15 for generating a signal restarting the oscillation circuit. By adjusting the phase of a phase adjusting circuit 16, startup failure can be prevented more positively. By setting the timing when the voltage amplitude value exceeds the reference voltage value in the motor operation determining command means 14 to the reference of the drive startup of the ultrasonic motor or another object to be controlled, the motor operation determining command means 14 can control the actual movement. |
