Driving control device for vibration wave motor

A control device for an ultrasonic vibration motor in which vibrations are generated on an elastic body by at least a pair of alternating voltages applied to an electromechanical transducer provided on the elastic body, said alternating voltages being out of phase to each other, comprising:

• a power supply circuit electrically connected to said electromechanical transducer, which applies said at least a pair of alternating voltages to said electromechanical transducer;
• and
• a voltage control system including a state judgement circuit and a voltage control circuit;
• wherein said state judgement circuit is electrically connected to said motor and is constructed to judge whether the motor is in an abnormal operating state in which said motor may stop operating, said motor being constructed so that it operates in a normal operating state corresponding to a first frequency characteristic curve and in the abnormal operating state corresponding to a second frequency characteristic curve having frequencies in common with said first frequency characteristic curve so that said motor can operate in either said normal operating state or said abnormal operating state at the same frequency, a predetermined portion of said first frequency characteristic curve defining a normal operating frequency range of said motor,
• wherein said voltage control circuit is electrically connected to said power supply circuit and increases the voltage magnitude of said at least a pair of alternating voltages when said state judgement circuit judges the abnormal operating state in order to place said motor in said normal operating state,
• wherein said state judgement circuit includes a detecting circuit which detects a monitor voltage generated in response to a deformation of said electromechanical transducer, and a comparing circuit which compares a phase difference between the monitor voltage and said at least a pair of alternating voltages with a reference valve, and
• wherein said state judgement circuit includes a circuit which generates a pulse output with a duty ratio, which, when the phase difference is in a predetermined range, is different from a duty ratio when the phase difference is out of the predetermined range, and said voltage control circuit determines the voltage magnitude of said at least a pair of said alternating voltages based on the duty ratio of the pulse output.

A control device for an ultrasonic vibration motor in which vibrations are generated on an elastic body by at least a pair of alternating voltages applied to an electromechanical transducer provided on the elastic body, said alternating voltages being out of phase to each other, comprising:

• a power supply circuit electrically connected to said electromechanical transducer, which applies said at least a pair of alternating voltages to said electromechanical transducer;
• and
• a voltage control system including state judgement means and voltage control means;
• wherein said state judgement means judges whether the motor is in an abnormal operating state, said motor being constructed so that it operates in a normal operating state corresponding to a first frequency characteristic curve and in the abnormal operating state corresponding to a second frequency characteristic curve having frequencies in common with said first frequency characteristic curve so that said motor can operate in either said normal operating state or said abnormal operating state at the same frequency, a predetermined portion of said first frequency characteristic curve defining a normal operating frequency range of said motor,
• and wherein said voltage control means is electrically connected to said power supply circuit and increases the voltage magnitude of said at least a pair of alternating voltages when said state judgement means judges the abnormal operating state.

A vibration motor in which vibrations are generated on an elastic body by an electromechanical transducer provided on the elastic body, comprising:

• a power supply circuit electrically connected to said electromechanical transducer, which applies at least a pair of alternating voltages to said electromechanical transducer;
• and
• a voltage control system including a state judgement means and voltage control means;
• wherein said state judgement means judges whether the motor is in an abnormal operating state, said motor being constructed so that it operates in a normal operating state corresponding to a first frequency characteristic curve and in the abnormal operating state corresponding to a second frequency characteristic curve having frequencies in common with said first frequency characteristic curve so that said motor can operate in either said normal operating state or said abnormal operating state at the same frequency, a predetermined portion of said first frequency characteristic curve defining a normal operating frequency range of said motor,
• and wherein said voltage control means is electrically connected to said power supply circuit and increases the voltage magnitude of said at least a pair of alternating voltages when said state judgement means judges the abnormal operating state.

An ultrasonic vibration motor having a stator and a moving member, in which vibrations are generated on an elastic body by at least a pair of alternating voltages applied to an electromechanical transducer provided on the elastic body, said alternating voltages being out of phase to each other, comprising:

• a power supply circuit electrically connected to said electromechanical transducer, which applies said at least a pair of alternating voltages to said electromechanical transducer;
• and
• a voltage control system including state judgement means and voltage control means;
• wherein said state judgement means judges whether the motor is in an abnormal operating state, said motor being constructed so that it operates in a normal operating state corresponding to a first frequency characteristic curve and in the abnormal operating state corresponding to a second frequency characteristic curve having frequencies in common with said first frequency characteristic curve so that said motor can operate in either said normal operating state or said abnormal operating state at the same frequency, a predetermined portion of said first frequency characteristic curve defining a normal operating frequency range of said motor,
• and wherein said voltage control means is electrically connected to said power supply circuit and increases the voltage magnitude of said at least a pair of alternating voltages when said state judgement means judges the abnormal operating state.