Control method for piezoelectric driving device, piezoelectric driving device, and robot

Patent metadata

Field	Value
Publication number	US-11476403-B2
Application number	US-202016857359-A
Country	US
Kind code	B2
Filing date	Apr 24, 2020
Priority date	Apr 26, 2019
Publication date	Oct 18, 2022
Grant date	Oct 18, 2022

Abstract

There is provided a control method for a piezoelectric driving device including a vibrating body including a piezoelectric element for driving and configured to vibrate when a driving signal is applied to the piezoelectric element for driving, a section to be driven that is driven by the vibration of the vibrating body, and a driving-signal generating section configured to generate the driving signal using a pulse signal generated based on a target pulse duty ratio. When the target pulse duty ratio is smaller than a predetermined value, the driving signal generated by the driving-signal generating section is an intermittently generated periodic signal.

First claim

What is claimed is:

1. A control method for a piezoelectric driving device comprising:
a vibrating body including a piezoelectric element for driving and configured to vibrate when a driving signal is applied to the piezoelectric element for driving;
a section to be driven that is driven by the vibration of the vibrating body; and
a driving-signal generating section configured to generate the driving signal using a pulse signal generated based on a target pulse duty ratio, wherein
when the target pulse duty ratio is smaller than a predetermined value, the driving signal generated by the driving-signal generating section is an intermittently generated periodic signal.

2. The control method for the piezoelectric driving device according to claim 1 , wherein, when a ratio of an output period to an intermittent cycle is represented as an intermittent duty ratio in the intermittently generated periodic signal, the intermittent duty ratio is switched based on the target pulse duty ratio.

3. The control method for the piezoelectric driving device according to claim 2 , wherein
the piezoelectric element for driving includes a stretching piezoelectric element that causes the vibrating body to stretching-vibrate and a bending piezoelectric element that causes the vibrating body to bending-vibrate,
the driving signal includes a bending driving signal applied to the bending piezoelectric element and a stretching driving signal applied to the stretching piezoelectric element, and
the intermittent duty ratio of the bending driving signal and the intermittent duty ratio of the stretching driving signal are different.

4. The control method for the piezoelectric driving device according to claim 3 , wherein, when the target pulse duty ratio used for the generation of the stretching driving signal is represented as a stretching driving target pulse duty ratio, the target pulse duty ratio used for the generation of the bending driving signal is represented as a bending driving target pulse duty ratio, the predetermined value for the stretching driving target pulse duty ratio is represented as a stretching driving predetermined value, and the predetermined value for the bending driving target pulse duty ratio is represented as a bending driving predetermined value, the bending driving predetermined value is larger than the stretching driving predetermined value.

5. The control method for the piezoelectric driving device according to claim 4 , wherein the stretching driving predetermined value is 0.

6. The control method for the piezoelectric driving device according to claim 1 , wherein, when a ratio of an output period to an intermittent cycle is represented as an intermittent duty ratio in the intermittently generated periodic signal, the driving-signal generating section calculates the intermittent duty ratio based on a conversion method for converting the target pulse duty ratio.

7. The control method for the piezoelectric driving device according to claim 1 , wherein, the predetermined value in a step of reducing the target pulse duty ratio is represented as a first predetermined value and the predetermined value in a step of increasing the target pulse duty ratio is represented as a second predetermined value, the first predetermined value and the second predetermined value are different.

8. A piezoelectric driving device comprising:
a vibrating body including a piezoelectric element for driving and configured to vibrate when a driving signal is applied to the piezoelectric element for driving;
a section to be driven that is driven by the vibration of the vibrating body; and
a voltage control section configured to apply the driving signal to the piezoelectric element for driving, wherein
the voltage control section includes:
a pulse-duty-ratio-signal generating section configured to generate a target pulse duty ratio signal based on an input target driving signal;
a pulse-signal generating section configured to generate a pulse signal having a target pulse duty ratio indicated by the target pulse duty ratio signal; and
a driving circuit configured to generate the driving signal using the pulse signal,

the pulse-signal generating section includes:
a comparing section configured to compare the target pulse duty ratio indicated by the target pulse duty ratio signal and a predetermined value and output a result of the comparison; and
an output section configured to make the pulse signal intermittent based on the comparison result and output the pulse signal, and

the driving circuit generates an intermittently generated periodic signal as the driving signal using the pulse signal made intermittent.

9. The piezoelectric driving device according to claim 8 , wherein the output section makes the pulse signal intermittent and outputs the pulse signal when the target pulse duty ratio is smaller than the predetermined value.

10. A robot comprising:
a first arm;
a second arm coupled to the first arm in a joint section; and
the piezoelectric driving device according to claim 8 disposed in the joint section.

Assignees

• Seiko Epson Corp

Inventors

• Saito Hidetoshi

Classifications

• H02N2/004

  Rectangular vibrators · CPC title

• B25J9/00

  Program-controlled manipulators · CPC title

• H02N2/103 Primary

  by pressing one or more vibrators against the rotor · CPC title

• H02N2/145

  Large signal circuits, e.g. final stages · CPC title

• H02N2/142

  Small signal circuits; Means for controlling position or derived quantities, e.g. speed, torque, starting, stopping, reversing · CPC title