Soft actuators and artificial muscles

• US 6,109,852 A
• Filed: 02/05/1999
• Issued: 08/29/2000
• Est. Priority Date: 01/18/1996
• Status: Expired due to Term

• Current Assignee: Science & Technology Corporation
• Original Assignee: The University of New Mexico
• Inventors: Mojarrad, Mehran, Shahinpoor, Mohsen
• Primary Examiner(s): DUDASH, DIANA L
• Application Number:
  US09/101,856
• Time in Patent Office: 571 Days
• Field of Search: 74/490.02, 74/490.05, 244/22, 244/11, 244/72, 244/75 R, 395/80, 395/84, 427/308, 427/316, 427/337, 427/341, 427/342, 427/379, 427/434.2, 427/443.1, 414/753, 414/730, 901/1, 901/14, 901/16, 901/36, 623/25, 623/64, 604/158, 604/171
• US Class Current: 414/1
• CPC Class Codes: A61F 2/08 Muscles; Tendons; Ligaments sutures A61B17/04
• CPC Class Codes: A61F 2002/0894 Muscles non-implantable A61F2002/5066
• CPC Class Codes: A61F 2002/5066 Muscles implantable A61F2002/0894
• CPC Class Codes: B25J 15/02 servo-actuated
• CPC Class Codes: B25J 18/06 flexible
• CPC Class Codes: B25J 9/1075 with muscles or tendons
• CPC Class Codes: B25J 9/1095 chemically actuated
• CPC Class Codes: B64C 2027/7266 actuated by actuators
• CPC Class Codes: B64C 27/72 Means acting on blades
• CPC Class Codes: B64C 9/00 Adjustable control surfaces or members, e.g. rudders trimming stabilising surfaces B64C5/10
• CPC Class Codes: F03G 7/005 Electro-chemical actuators; Actuators having a material for absorbing or desorbing gas, e.g. a metal hydride; Actuators using the difference in osmotic pressure between fluids; Actuators with elements stretchable when contacted with liquid rich in ions, with UV light, with a salt solution
• CPC Class Codes: Y02T 50/30 Wing lift efficiency
• CPC Class Codes: Y10T 74/20311 including power cable or connector

Abstract

A chemical (coating and reduction)/mechanical/electrical treatment of ion-exchange materials (preferably ion-exchange membranes) to convert them to artificial muscles. The figure is a perspective view of an actuator of the invention showing the treated membrane actuator (A) with electrodes (25 and 26) placed at one end of the membrane, the electrodes being further attached to a power source (35). Artificial muscles created by the inventive method are capable of undergoing electrically-controllable large deformations resembling the behavior of biological muscles. A typical flap muscle of 0.2-0.4 mm thickness, 2-5 mm width and 20 mm length manufactured by the inventive process can achieve a completely reversible maximum deflection of 12-15 mm under a maximum voltage of 2.0-2.5 volts.

Claims

1. A method of preparing an actuator comprising the steps of:

a) coating a bendable ion-exchange material with a substance which undergoes chemical reduction in the presence of a reducing agent;

b) reducing the coating on the ion-exchange material by exposing the ion-exchange material to a reducing agent; and

c) performing a secondary reduction by exposing the ion-exchange material simultaneously to a salt and a reducing agent.

2. An actuator comprising a treated ion-exchange material capable of a completely reversible deflection and means operably connected to said ion-exchange material for electrically driving the deflection of said ion-exchange material, wherein said actuator is capable of a maximum deflection of at least 15% of its length.

10. The actuator of claim 2 wherein said actuator is capable of a maximum deflection of at least 55% of its length.

11. The actuator of claim 2 wherein said actuator is capable of a maximum deflection of up to 75% of its length.

3. An actuator for use in a gripper mechanism comprising:

at least two actuators comprising an ion-exchange material positioned opposite to each other and being capable of bending in equal and opposing directions, and each of said actuators having a first end;

means for providing power to said actuators to drive the mechanical bending of said actuators in opposing directions;

means, operably attached to said first end of each of said actuators, for conducting electrical impulses across said actuators; and

wiring means, operably attached to said conducting means and to said means for providing power, for electrically connecting said actuators to said power source.

4. An actuator for providing three-dimensional movement, comprising:

three actuators comprising an ion-exchange material and comprising a hollow triangular tube having a longitudinal axis and a first end wherein each of said actuators of said tube comprises a face of said tube;

means, operably attached to said first end of each of said actuators, for conducting a signal across each of said faces of said tube, thereby stimulating each face of said tube at a phase angle apart from each adjacent face to produce a motion around said longitudinal axis of said tube; and

means for providing power to said signal conducting means; and

tube to said power means, attached to said signal conducting means, for operably connecting said tube to said power providing means.

5. An actuator for use as a wing flap, comprising:

at least two actuators comprising a bendable ion-exchange material sandwiched in series in a stack configuration, each of said actuators formed in a planar layer and capable of acting as a series resistor element and said stack having first and second ends, a top surface and a bottom surface;

means, operably attached to said stack at said first end and said top and bottom surfaces, for conducting power across said stack;

means for supplying power to said stack; and

means for connecting said power supplying means to said power conducting means.

6. An actuator for use as a robotic swimming structure, comprising:

at least two actuators formed in a bendable ion-exchange material having a first end, said ion-exchange material comprising a plurality of polymer gel fibers imprinted with means for conducting power through said ion-exchange material;

means, operably attached to said ion-exchange material at said first end, for conducting an alternating low voltage across said ion-exchange material;

means for providing power to said conducting means;

means for modulating speed of bending of said ion-exchange material varying the frequencies of the applied voltage; and

means for operably connecting said conducting means to said power providing means.

7. An actuator for use as a resonant flying machine, comprising:

at least one ion-exchange material actuator in the form of a planar layer having first and second ends, a top surface and a bottom surface;

means for conducting power across said ion-exchange material actuator, operably attached to said top and bottom surfaces of said ion-exchange material and along a central axis of said ion-exchange material equidistant from said first and second ends, whereby said ion-exchange material actuator is capable of reversibly bending in a flapping motion upon receiving power;

means for providing power to said conducting means; and

means for connecting said conducting means to said power providing means.

8. An actuator for use as a guide wire in medical applications, comprising:

at least one bendable ion-exchange material actuator formed in a strip;

means for providing power to said strip; and

means for connecting said strip to said power supply.

9. An actuator comprising:

a bendable ion-exchange material; and

a coating on said ion-exchange material which has undergone chemical reduction in the presence of a reducing agent and a secondary reduction in the simultaneous presence of a reducing agent and a salt.