Pump-integrated flexible actuator

• US 20020157388A1
• Filed: 11/20/2001
• Published: 10/31/2002
• Est. Priority Date: 03/28/2000
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Takagi, Kunihiko, Seto, Takeshi
• Granted Patent: US 6,718,766 B2
• Time in Patent Office: Days
• US Class Current: 60/325
• CPC Class Codes: B25J 15/12 with flexible finger members
• CPC Class Codes: B25J 9/142 comprising inflatable bodies
• CPC Class Codes: F15B 15/103 using inflatable bodies that contract when fluid pressure is applied, e.g. pneumatic artificial muscles or McKibben-type actuators
• CPC Class Codes: F15B 15/18 Combined units comprising both motor and pump

Abstract

A pair of flexible actuators (4) according to the present invention is supported by a fixture (2) made of a hard rubber at base ends of the flexible actuators (4). Each flexible actuator (4) includes a movable unit (6) capable of bending, a pump unit (8) integrally connected to the movable unit (6) at an end thereof, for controlling transfer of work fluid sealed in the movable unit, and a pump driver (10) for controlling driving of the pump unit (8). The movable unit (6) includes two long and narrow tubes (12) and (14) each having an accordion wall, a core (16) maintaining the tubes in parallel to each other, and a thin-film-bag-like cover (18) covering the tubes (12) and (14). The tube (12), which comes into contact with a subject (B), is made of a soft material. The movable unit (6) provided with the tube (12) softly comes into contact with the subject at a plurality of plane-contact portions of action of the movable unit (6), thereby holding the subject without scratching the same.

Claims

1. A pump-integrated flexible actuator comprising:

a movable unit provided with a plurality of fluid chambers having fluid sealed therein, the movable unit being movable with the fluid chambers being deformed by a transfer of the fluid between the fluid chambers;

a pump unit integrated with the movable unit, for transferring the fluid between the plurality of fluid chambers; and

a pump driver for controlling driving of the pump unit.

2. A pump-integrated flexible actuator according to claim 1, wherein the plurality of fluid chambers having fluid sealed therein are disposed parallel to each other, the movable unit is deformed by the transfer of the fluid between the fluid chambers, the pump unit is integrated with the movable unit and transfers the fluid between the plurality of fluid chambers, and the pump driver controls driving of the pump unit.

3. A pump-integrated flexible actuator according to one of claims 1 and 2, wherein the movable unit is provided with at least one long and narrow deformable tube forming the plurality of fluid chambers having fluid sealed therein, and a flexible core disposed parallel to the tube, for restricting expansion of the tube in a longitudinal direction thereof.

4. A pump-integrated flexible actuator according to one of claims 1 and 2, wherein the movable unit is provided with at least two long and narrow tubes, which are capable of expansion and contraction, disposed parallel to each other, each tube forming the fluid chamber, and a flexible core disposed between the tubes, for restricting expansion of each tube in a longitudinal direction thereof.

5. A pump-integrated flexible actuator according to one of claims 1 to 4, wherein the tube, which is disposed at a side of the movable unit to be brought into contact with a subject when a pressing force and a holding force of the movable unit act on the subject, is made of a soft and elastic material.

6. A pump-integrated flexible actuator according to one of claims 1 to 5, wherein a soft member covers the pump unit.

7. A pump-integrated flexible actuator according to one of claims 1 to 6, wherein the fluid sealed in the fluid chambers is a liquid, and an outer cover having a liquid-absorbing function covers the movable unit at the periphery thereof.

8. A pump-integrated flexible actuator according to one of claims 1 to 7 further comprising a depressurization mechanism which reduces inner pressure of one of the plurality of fluid chambers by having the plurality of fluid chambers communicate with each other when the inner pressure of the one of the plurality of fluid chambers increases to an abnormal level.

9. A pump-integrated flexible actuator according to one of claims 3 to 8, wherein the core is formed with a signal wire or an electrical wire connected between the pump unit and the pump driver.

10. A pump-integrated flexible actuator according to one of claims 1 to 9, wherein the pump driver is disposed in the movable unit which has liquid sealed therein so that the pump driver is in contact with the liquid.

11. A pump-integrated flexible actuator according to one of claims 1 to 10 further comprising a reservoir storing a predetermined amount of fluid, and supply means for controlling supply of the fluid stored in the reservoir to each fluid chamber of the movable unit.

12. A pump-integrated flexible actuator according to one of claims 1 to 11, wherein two pump units are integrated with the movable unit at respective longitudinal ends of the movable unit and the two pump units simultaneously operate to transfer fluid between the plurality of fluid chambers.

13. A pump-integrated flexible actuator according to claim 12, wherein each pump unit is provided with a detachable connecting part such that when a pair of the movable units are connected to each other in series, the movable unit is connected to the other movable unit at the pump unit of each movable unit.

14. A pump-integrated flexible actuator according to one of claims 1 to 13, wherein the pump unit comprises a diaphragm which defines a pump fluid chamber between an end of the movable unit.

15. A pump-integrated flexible actuator according to claim 14, wherein a piezoelectric element is laminated on the diaphragm.

16. A pump-integrated flexible actuator according to one of claims 1 to 15, wherein the pump unit is provided with a valve for setting a direction of the transfer of fluid between one tube forming the fluid chamber and another tube forming the other fluid chamber via the pump fluid chamber.

17. A pump-integrated flexible actuator according to one of claims 1 to 15, wherein the pump unit comprises the same number of unidirectional-flow-type pumps as the number of fluid chambers, each fluid chamber communicating with one unidirectional-flow-type pump which transfers fluid from said fluid chamber to another fluid chamber and another unidirectional-flow-type pump which transfers the fluid from another fluid chamber to said fluid chamber.

18. A pump-integrated flexible actuator according to one of claims 1 to 17, wherein the plurality of fluid chambers are each provided with a pressure sensor, and the pump driver computes an actual operational force of the movable unit according to determination by the pressure sensors and controls driving of the pump unit.

19. A pump-integrated flexible actuator according to one of claims 1 to 18, wherein the plurality of fluid chambers are each provided with an acoustic wave generator for generating acoustic waves and an acoustic wave sensor for sensing the acoustic waves, and the pump driver computes an actual amount of displacement of the movable unit according to determination by the acoustic wave sensors and controls driving of the pump unit.

20. A pump-integrated flexible actuator according to one of claims 1 to 19, wherein the pump unit comprises a diaphragm which defines a pump fluid chamber, variation in current generated when a pressure is applied to the diaphragm which has been applied with a voltage is inputted to the pump driver, and the pump driver computes an actual operational force of the movable unit according to determination of the variation in current for controlling driving of the pump unit.

21. A pump-integrated flexible actuator according to one of claims 1 to 20, wherein the pump unit comprises a diaphragm which defines a pump fluid chamber, a plurality of the fluid chambers are each provided with an acoustic wave sensor for sensing acoustic waves generated by the diaphragm, and the pump driver computes an actual amount of displacement of the movable unit according to determination by the acoustic wave sensors for controlling driving of the pump unit.

22. A pump-integrated flexible actuator according to one of claims 19 to 21, wherein the pump driver comprises a table for computing an operational force and displacement of the movable unit from the determined acoustic waves and pressure.

23. A pump-integrated flexible actuator according to one of claims 1 to 22, wherein the movable unit comprises a light generator and a light receiver opposing each other or a light generating/receiving member and a reflector opposing each other, and an actual operational force of the movable unit is computed in accordance with determination by either the light receiver or the light generating/receiving member so that drive of the pump unit is controlled.

24. A pump-integrated flexible actuator according to claim 23, wherein the pump driver comprises a table for computing an operational force and displacement of the movable unit from an amount of light which is determined by the light receiver or the light generating/receiving member.