Method for controlling piezoelectric driving apparatus, piezoelectric driving apparatus, and robot

{
  "publication_number": "US11751479B2",
  "country": "US",
  "kind": "B2",
  "title": "Method for controlling piezoelectric driving apparatus, piezoelectric driving apparatus, and robot",
  "abstract": "A piezoelectric vibrator has a first frequency region where the phase difference between a pickup signal representing the vibration of the piezoelectric vibrator and a drive signal that drives the piezoelectric vibrator does not monotonously change in accordance with the frequency of the drive signal and a second frequency region where the phase difference monotonously changes in accordance with the frequency of the drive signal. A method for controlling a piezoelectric driving apparatus including the piezoelectric vibrator controls the frequency of the drive signal in such a way that pickup voltage representing the amplitude of the pickup signal is fixed in the first frequency region and controls the frequency of the drive signal in such a way the pickup voltage is fixed with the phase difference maintained smaller than or equal to a prespecified value in the second frequency region.",
  "claims": [
    "1. A method for controlling a piezoelectric driving apparatus including a piezoelectric vibrator, the piezoelectric vibrator having a first frequency region where a phase difference between a pickup signal representing vibration of the piezoelectric vibrator and a drive signal that drives the piezoelectric vibrator does not monotonously change in accordance with a frequency of the drive signal and a second frequency region where the phase difference monotonously changes in accordance with the frequency of the drive signal, the method comprising: controlling the frequency of the drive signal in such a way that pickup voltage representing an amplitude of the pickup signal is fixed in the first frequency region; and controlling the frequency of the drive signal in such a way the pickup voltage is fixed with the phase difference maintained smaller than or equal to a prespecified value in the second frequency region.",
    "2. The method for controlling a piezoelectric driving apparatus according to claim 1, wherein the first frequency region is a region where the frequency is higher than the frequency in the second frequency region.",
    "3. The method for controlling a piezoelectric driving apparatus according to claim 1, wherein the prespecified value is 90°.",
    "4. The method for controlling a piezoelectric driving apparatus according to claim 1, wherein the piezoelectric vibrator undergoes longitudinal vibration and bending vibration to drive a driven section, and the pickup signal is a signal representing the longitudinal vibration.",
    "5. A piezoelectric driving apparatus that drives a driven section, the apparatus comprising: a piezoelectric vibrator that drives the driven section; and a controller, wherein the piezoelectric vibrator has a first frequency region where a phase difference between a pickup signal representing vibration of the piezoelectric vibrator and a drive signal that drives the piezoelectric vibrator does not monotonously change in accordance with a frequency of the drive signal and a second frequency region where the phase difference monotonously changes in accordance with the frequency of the drive signal, and the controller controls the frequency of the drive signal in such a way that pickup voltage representing an amplitude of the pickup signal is fixed in the first frequency region, and controls the frequency of the drive signal in such a way the pickup voltage is fixed with the phase difference maintained smaller than or equal to a prespecified value in the second frequency region.",
    "6. A robot comprising the piezoelectric driving apparatus according to claim 5."
  ],
  "description_excerpt": "The present application is based on, and claims priority from JP Application Serial Number 2019-230206, filed Dec. 20, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.\n\nThe present disclosure relates to a method for controlling a piezoelectric driving apparatus, the piezoelectric driving apparatus, and a robot.\n\nAs for a method for controlling a piezoelectric driving apparatus, for example, JP-A-2008-160913 discloses a method for controlling an ultrasonic motor formed of a vibrator and an annular rotor. JP-A-2008-160913 discloses a control method using a phase different between a vibration detection signal detected from the driven vibrator and a drive control signal that drives the vibrator. In the control method described in JP-A-2008-160913, the frequency at which the vibrator is driven is so controlled that the phase difference is a predetermined value when the vibrator is driven.\n\nDepending on the frequency region within which the vibrator is driven, however, no stable vibration detection signal is generated, and it is therefore difficult to detect the phase difference, resulting in possible inappropriate control of the driving frequency.\n\nAccording to a first aspect of the present disclosure, a method for controlling a piezoelectric driving apparatus including a piezoelectric vibrator is provided.",
  "cpc": [
    "H10N 30/2023",
    "B25J 9/12",
    "B25J 9/123",
    "H02N 2/004",
    "H02N 2/008",
    "H02N 2/02",
    "H02N 2/04",
    "H02N 2/062",
    "H02N 2/103",
    "H02N 2/14",
    "H10N 30/802"
  ],
  "ipc": [
    "B25J 9/12",
    "H02N 2/00",
    "H10N 30/20",
    "H10N 30/80"
  ],
  "assignees": [
    "Seiko Epson Corp"
  ],
  "inventors": [
    "Hidetoshi Saito"
  ],
  "filing_date": "2020-12-18",
  "publication_date": "2023-09-05",
  "grant_date": "2023-09-05",
  "priority_date": "2019-12-20",
  "application_number": "US-202017126048-A",
  "family_id": "76383533",
  "cited_by_count": 0,
  "citations": [
    "JPH1118456A",
    "JP2007074829A",
    "US20080150393A1",
    "JP2008160913A",
    "US11482661B2"
  ]
}