Patent ID: 6965188

Claim:
An ultrasonic-actuator driving apparatus comprising: an ultrasonic actuator including a transducer and a driven body that is in contact with the transducer, the transducer to which a frequency signal is applied friction-driving the driven body; an original-signal outputting unit for outputting an original signal on which the frequency of the frequency signal depends; a waveform averaging unit for averaging the original signals during a predetermined period to calculate average-waveform data; a position detecting unit for detecting an absolute position of the driven body with respect to the transducer; a position averaging unit for averaging the absolute positions during a predetermined period to calculate average-position data; a control-signal calculating unit that generates a control signal for controlling the frequency of the original signal based on the average-waveform data and the average-position data and supplies the generated control signal to the original-signal outputting unit; and a driving unit for generating the frequency signal based on the original signal and applying the generated frequency signal to the transducer.