Patent ID: 7183691

Claim:
A control apparatus for a vibration type actuator, which excites vibration in an elastic member to relatively drive the elastic member and a contact member which is in contact with the elastic member by applying a periodic signal to an electromechanical energy conversion element, the control apparatus comprising: a signal generation unit adapted to generate the periodic signal; a vibration detection unit adapted to detect a vibration state of the elastic member; a phase difference detection unit adapted to detect a phase difference between the periodic signal generated by the signal generation unit and an output signal from the vibration detection unit; a speed detection unit adapted to detect a drive speed of the contact member; and a control unit adapted to control a frequency and a voltage of the periodic signal generated by the signal generation unit, wherein the control unit decreases the frequency of the periodic signal without varying the voltage of the periodic signal so that the drive speed of the contact member approaches a target speed, in a case that the speed of the contact member detected by the speed detection unit is less than the target speed, and increases the voltage of the periodic signal without varying the frequency of the periodic signal, in a case that the phase difference detected by the phase difference detection unit reaches a first phase difference before the drive speed of the contact member reaches the target speed by the decreasing of the frequency of the periodic signal.