Pneumatic controlled soft gripper, manufacturing method thereof and article transport method using soft gripper

1. A pneumatic controlled soft gripper comprising:

a chamber having a negative-pressure action space defined therein and having an opening communicating with the negative-pressure action space;

a sucker extending radially outwardly from the opening of the chamber and having an annular contact surface;

an expandable and contractible protuberance protruding from a top face of the negative-pressure action space opposite to the opening, wherein the protuberance is received in the negative-pressure action space, and has a gas pocket defined therein; and

a gas channel extending from an outer face of the chamber into the gas pocket,

wherein the pneumatic controlled soft gripper is configured to flow gas into the gas pocket through the gas channel to expand the protuberance in the negative-pressure action space of the chamber, and flow gas out of the gas pocket through the gas channel to contract the protuberance.

2. The pneumatic controlled soft gripper of claim 1 , wherein the chamber has an inner wall disposed between the sucker and the protuberance and having a curved shape convex into the negative-pressure action space.

3. The pneumatic controlled soft gripper of claim 2 , wherein the gripper is able to work in an underwater environment.

4. The pneumatic controlled soft gripper of claim 1 , wherein the protuberance has a hemisphere shape.

5. The pneumatic controlled soft gripper of claim 1 , wherein the gripper further comprises projections on a surface of the sucker.

6. The pneumatic controlled soft gripper of claim 1 , wherein the pneumatic controlled soft gripper is made of a material selected from a group consisting of polydimethylsiloxane, polyurethane acrylate, polystyrene, polyvinyl alcohol, polyurethane, polyethylene glycol, and combinations thereof.

7. A method for manufacturing the pneumatic gripper of claim 1 , the method comprising:

preparing a first mold having:

a first polymer receiving groove in a three-dimensional shape corresponding to a combination of outer shapes of the chamber and the sucker; and

a second polymer receiving groove located in a central upper portion of the first polymer receiving groove;

preparing a second mold having:

a cover;

a gas channel forming portion having a pillar shape extending from a center of the cover; and

a protuberance forming portion coupled to a distal end of the pillar shape and having a shape corresponding to an outer shape of the second polymer receiving groove;

injecting a polymer material into the first polymer receiving groove and the second polymer receiving groove;

disposing the second mold on top of the first mold such that the protuberance forming portion is received in the second polymer receiving groove;

curing the first mold in a high temperature environment for a predefined period of time;

separating the second mold from first mold; and

withdrawing a soft gripper formed in the first mold out of the first mold.

8. The method of claim 7 , wherein the method further comprises, after preparing the second mold, surface-treating the first mold and the second mold.

9. The method of claim 8 , wherein the surface treatment of the first mold and the second mold includes:

immersing the first mold and the second mold in a self-assembled monolayer (SAM) solution for 50 to 70 minutes;

withdrawing the first mold and the second mold out of the solution; and

curing the first mold and the second mold in an oven of 50 to 70° C. for 11 to 13 hours.

10. The method of claim 7 , wherein the polymer material includes a material selected from a group consisting of polydimethylsiloxane, polyurethane acrylate, polystyrene, polyvinyl alcohol, polyurethane, polyethylene glycol, and combinations thereof.

11. A method for transferring an object using the pneumatic gripper of claim 1 , the method comprising:

providing the pneumatic gripper of claim 1 ;

bringing the sucker into close contact with a surface of the object;

creating a negative-pressure in the negative-pressure action space;

transferring the object to a target position; and

removing the negative-pressure in the negative-pressure action space,

wherein creating the negative-pressure includes supplying gas into the gas pocket through the gas channel to expand the protuberance to create the negative-pressure in the negative-pressure action space, and

wherein removing the negative-pressure includes inhaling gas from the gas pocket through the gas channel to contract the protuberance to remove the negative-pressure in the negative-pressure action space.

12. A pneumatic controlled soft gripper comprising:

a chamber having a negative-pressure action space defined therein and having an opening communicating with the negative-pressure action space;

a sucker extending radially outwardly from the opening of the chamber and having an annular contact surface;

an expandable and contractible protuberance protruding from a top face of the negative-pressure action space opposite to the opening, wherein the protuberance is received in the negative-pressure action space, and has a gas pocket defined therein; and

a gas channel extending from an outer face of the chamber into the gas pocket,

wherein gas flows into and out of the gas pocket through the gas channel, and

wherein the chamber has an inner wall disposed between the sucker and the protuberance, a curved shape convex into the negative-pressure action space, and a partially spherical shape.