Patent ID: 6229245
Filing Date: 2001-05-08
Classification: H02N

Abstract:
A control apparatus for a vibration wave motor, in which a plurality of frequency signals respectively are applied to predetermined electro-mechanical energy conversion element parts arranged on a vibration member of the vibration wave motor, thereby to generate vibration in the vibration member, and whereby vibration generated in the vibration member provides a driving force that causes a contact member in contact with the vibration member to move relative to the vibration member, said control apparatus comprising:a driving circuit operable in a normal operation mode, in which said driving circuit sets a frequency of an applied frequency signal to a first frequency as a start frequency, and sweeps the frequency of the applied frequency signal from the first frequency to a lower frequency so as to start a driving operation of the vibration wave motor, and operable in a non-normal operation mode, in which said driving circuit sets, as the start frequency, a second frequency higher than the first frequency, and sweeps the frequency of the applied frequency signal from the second frequency to a lower frequency; anda mode changing circuit which changes the operation mode of said driving circuit from the normal operation mode to the non-normal operation mode when the vibration wave motor does not achieve a normal driving state in the normal operation mode.