Methods and apparatus for layer jamming

• US 20150107233A1
• Filed: 10/16/2014
• Published: 04/23/2015
• Est. Priority Date: 10/19/2013
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Ou, Jifei, Yao, Lining, Ishii, Hiroshi, Tauber, Daniel
• Granted Patent: US 9,664,210 B2
• Time in Patent Office: Days
• US Class Current: 60/327
• CPC Class Codes: F15B 15/10 the motor being of diaphragm type
• CPC Class Codes: F15B 2211/705 characterised by the type of output members or actuators
• CPC Class Codes: F15B 2211/7107 the output members being mechanically linked
• CPC Class Codes: F15B 2211/78 Control of multiple output members
• CPC Class Codes: F15B 2211/89 Control specific for achieving vacuum or "negative pressure"
• CPC Class Codes: F16J 3/02 Diaphragms

Abstract

In some implementations, bending or other shape changes of a device are actuated by inflating or deflating a bladder in the device. Then, once the desired new shape is achieved by this actuation, another bladder in the device is layer-jammed, to make the device rigid in the new shape. In some cases, sheets in the layer-jamming bladder are coated with abrasive particles. In some cases, layer jamming bladders are interwoven to form a woven device. The rigidity of the woven device can be anisotropically controlled. Layer jamming some, but not all, of the bladders in the woven device causes the woven device to have a rigidity that varies by direction. In some cases, a layer-jamming bladder includes a solid layer with a crease in it. As a result, the bladder can easily bend at the crease.

Claims

1. Apparatus comprising a first set of bladders and a second set of bladders, wherein:

(a) at least one cavity exists within each respective bladder in the first and second sets of bladders, within which cavity are located

(i) fluid, which fluid has a pressure, and

(ii) two or more sheets, which sheets have a rigidity that is adjustable by adjustment of the pressure of the fluid; and

(b) the first and second sets of bladders are interwoven with each other, such that;

(i) each respective bladder in the first set of bladders (A) goes over at least two bladders in the second set of bladders and under at least one bladder in the second set of bladders, or (B) goes under at least two bladders in the second set of bladders and over at least one bladder in the second set of bladders, and

(ii) each respective bladder in the second set of bladders (A) goes over at least two bladders in the first set of bladders and under at least one bladder in the first set of bladders, or (B) goes under at least two bladders in the first set of bladders and over at least one bladder in the first set of bladders.

2. The apparatus of claim 1, wherein the sheets, taken together, have a tensile strength in a direction, which tensile strength is adjustable by adjustment of the pressure of the fluid.

3. The apparatus of claim 1, wherein the fluid is a liquid.

4. The apparatus of claim 1, wherein the fluid is a gas.

5. The apparatus of claim 1, wherein two or more of the sheets comprise sandpaper.

6. The apparatus of claim 1, wherein, in each respective bladder, abrasive particles are bonded to a surface of each of the sheets.

7. The apparatus of claim 1, further comprising a pump system, which pump system includes:

(a) one or more pumps;

(b) tubing that connects the first set of bladders to at least one pump and connects the second set of bladders to at least one pump; and

(c) one or more valves;

wherein fluid flow within the tubing is controllable by opening or closing of the valves.

8. The apparatus of claim 7, wherein a first fluid pressure within the first set of bladders and a second fluid pressure within the second set of bladders are each separately adjustable by the pump system.

9. The apparatus of claim 7, further comprising one or more computers that are programmed to control the one or more pumps and one or more valves.

10. The apparatus of claim 1, wherein:

(a) two or more bladders, in the first set of bladders, together comprise a single integral structure; and

(b) two or more bladders, in the second set of bladders, together comprise a single integral structure.

11. The apparatus of claim 1, wherein:

(a) a portion of the first cavity is located within each bladder in the first set of bladders; and

(b) a portion of the second cavity is located within each bladder in the second set of bladders.

12. The apparatus of claim 1, wherein the apparatus further comprises one or more additional sets of bladders, each of which additional sets of bladders is interwoven with the first or second sets of bladders.

13. The apparatus of claim 1, wherein bladders are interwoven at angles, relative to each other, that are not substantially perpendicular.

14. A method that comprises using a pump system:

(a) to change a first fluid pressure of a fluid in a first bladder, and thereby to adjust stiffness of sheets that are in the first bladder by layer jamming; and

(b) to change a second fluid pressure of a fluid in a second bladder, and thereby to cause the second bladder to undergo inflation or deflation, which inflation or deflation changes the shape of the first and second bladders;

wherein

(i) the first bladder is connected to the second bladder, such that inflation or deflation of the second bladder causes mechanical forces to be transmitted to the first bladder; and

(ii) the pump system comprises one or more pumps connected by tubing to the first and second set of bladders.

15. The method of claim 14, wherein:

(a) the sheets in the first bladder are stiffer when the first fluid pressure is below a first value than when the first fluid pressure is above the first value;

(b) the second bladder is less inflated when the second fluid pressure is below a second value than when the second fluid pressure is above the second value; and

(c) the method includes the steps of using the pump system

(i) to increase the second fluid pressure above the second value, while the first fluid value remains above the first value, thereby at least partially inflating the second bladder and causing at least a portion of the first and second bladders to undergo bending, and

(ii) then to decrease the first fluid pressure below the first value, thereby increasing the stiffness of the sheets in the first bladder.

16. The method of claim 15, further comprising an additional step that:

(a) occurs after step (c)(ii) of claim 15; and

(b) comprises using the pump system (1) to increase the first fluid pressure above the first value, thereby decreasing the stiffness of the sheets in the first bladder, and (2) to decrease the second fluid pressure below the second value, thereby at least partially deflating the second bladder.

17. The method of claim 14, wherein the device includes a solid layer that is creased by a crease and that is more flexible at the crease than in another region of the layer.

18. Apparatus comprising:

(a) a first bladder, which first bladder is inflatable, such that the shape of the apparatus is adjustable by inflation or deflation of the first bladder; and

(b) a second bladder that has a rigidity that is adjustable by layer jamming;

wherein the first and second bladders are connected, such that inflation or deflation of the first bladder causes mechanical forces to be transmitted to the second bladder.

19. The apparatus of claim 18, further comprising one or more pumps connected by tubing to the first and second bladders.

20. The apparatus of claim 18, further comprising a solid layer that:

(a) is creased by a crease; and

(b) has an angle of bending at the crease, which angle is adjustable by inflation or deflation of the first bladder.