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Vibration type actuator drive controller and method of controlling drive speed of vibration type actuator

  • US 20050046363A1
  • Filed: 08/27/2004
  • Published: 03/03/2005
  • Est. Priority Date: 09/01/2003
  • Status: Active Grant
First Claim
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1. A vibration type actuator drive controller for controlling a drive speed of a vibration type actuator adapted to excite a vibration member by applying an A.C. signal to an electromechanical energy transducer to obtain a drive force, comprising:

  • an encoder which outputs a pulse signal having a period adapted to change in correspondence to the drive speed of the vibration type actuator;

    a counter which carries out up-count from a first value to a second value larger than the first value at predetermined time intervals while the vibration type actuator is accelerated;

    clock output unit which outputs a clock signal having a frequency corresponding to a count value of the counter;

    measurement unit which measures the period of the pulse signal outputted from the encoder by counting clock pulses of the clock signal outputted from the clock output unit; and

    control unit which controls the drive speed of the vibration type actuator such that the period of the pulse signal measured by the measurement unit becomes a predetermined target value.

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