PRESSURE-SENSITIVE SENSOR, AND GRIP APPARATUS AND ROBOT MANIPULATOR EQUIPPED WITH THE SAME

• US 20130145856A1
• Filed: 11/12/2012
• Published: 06/13/2013
• Est. Priority Date: 12/09/2011
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Sasajima, Kenta
• Granted Patent: US 8,875,584 B2
• Time in Patent Office: Days
• US Class Current: 73/774
• CPC Class Codes: G01L 1/005 by electrical means and not provided for in G01L1/06 - G01L1/22
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress

Abstract

A pressure-sensitive conductive rubber for reference is provided inside a housing in such a state that preload is imposed thereon. A pressure-sensitive conductive rubber for detection is also provided inside the housing in such a state that preload is imposed thereon and an external load acts thereon. A load detecting circuit applies voltage to the pressure-sensitive conductive rubbers to determine the external load based on a difference between a detected value corresponding to electric current flowing through the pressure-sensitive conductive rubber for reference and a detected value corresponding to electric current flowing through the pressure-sensitive conductive rubber for detection.

Claims

1. A pressure-sensitive sensor comprising:

a first pressure-sensitive conductive rubber provided inside a housing in such a state that preload is imposed thereon;

a second pressure-sensitive conductive rubber provided inside the housing in such a state that the preload is imposed thereon and an external load acts thereon; and

a load detecting portion for applying voltage to the first and second pressure-sensitive conductive rubbers to determine the external load based on a difference between a first detected value corresponding to electric current flowing through the first pressure-sensitive conductive rubber and a second detected value corresponding to electric current flowing through the second pressure-sensitive conductive rubber.

2. The pressure-sensitive sensor according to claim 1, further comprising

a biasing portion for pressing the first and second pressure-sensitive conductive rubbers integrally against an inner wall surface of the housing to impose the preload on the first and second pressure-sensitive conductive rubbers.

3. The pressure-sensitive sensor according to claim 2, wherein the biasing portion has a movable member provided inside the housing to be movable, and an elastic member for biasing the movable member in a direction in which the movable member is pressed against the first and second pressure-sensitive conductive rubbers.

4. The pressure-sensitive sensor according to claim 1, wherein

an opening portion is formed in the housing, and

an acting piece is provided on the second pressure-sensitive conductive rubber to project outside of the housing through the opening portion so that the external load will act on the second pressure-sensitive conductive rubber.

5. The pressure-sensitive sensor according to claim 4, wherein said acting piece is covered with a cover member.

6. A grip apparatus equipped with the pressure-sensitive sensor according to claim 1.

7. A robot manipulator equipped with the pressure-sensitive sensor according to claim 1.