Patent ID: 8841868

Claim:
A spherical ultrasonic motor comprising: a rotor having a curved surface part; a plurality of stators which are arranged at predetermined intervals in contact with surfaces of the rotor and to which two-phase drive signals are supplied to generate ultrasonic vibrations; a plurality of oscillation units which are provided corresponding to the plurality of stators and which generate two-phase drive signals of predetermined frequencies based on inputted frequency control signals; a plurality of phase control units which are provided corresponding to the plurality of stators and which adjust phase differences of two-phase drive signals generated at the plurality of oscillation units based on inputted phase control signals; and a control unit which outputs frequency control signals for adjusting frequencies of two-phase drive signals which are generated at the plurality of oscillation units to the target frequencies, to the plurality of oscillation units to cause the plurality of oscillation units to adjust frequencies of two-phase signals which are generated at the plurality of oscillation units to the target frequencies, and outputs phase control signals for adjusting phase differences of two-phase drive signals generated at the plurality of oscillation units to target phase differences, to the plurality of phase control units to cause the plurality of phase control units to adjust phase differences of two-phase drive signals which are generated at the plurality of oscillation units to the target phase differences, wherein two-phase drive signals whose frequencies have remained unchanged from initial frequencies and whose phase differences have been adjusted to target phase differences are supplied from respective phase control units of the plurality of phase control units to respective corresponding stators, and thereafter, two-phase drive signals whose phase differences have remained unchanged from initial phase differences and whose frequencies have been adjusted to target frequencies are supplied from respective phase control units of the plurality of phase control units to respective corresponding stators concurrently.