Tactile sensor

1. A tactile sensor comprising:

a contact-portion unit composed of a flexible material;

a contact-portion housing unit which surrounds and houses the contact-portion unit in a removable state while forming a posture so that a top portion of the contact-portion unit may project;

an injection tube projecting through the contact-portion housing unit to permit injection of unhardened flexible material into the contact-portion unit; and

a strain sensing element or a pressure sensing element embedded into the contact-portion housing unit.

2. The tactile sensor according to claim 1 , wherein the contact-portion housing unit houses a plurality of contact-portion units.

3. The tactile sensor according to claim 1 , wherein the flexible material of the contact-portion unit is a silicone material.

4. The tactile sensor according to claim 1 , wherein the flexible material comprises at least one of silicone and urethane.

5. The tactile sensor according to claim 1 , wherein the top portion of the contact portion unit has a convex surface that projects from the contact portion housing unit.

6. The tactile sensor according to claim 1 , wherein the top portion defines a surface central portion about one millimeter to about two millimeters from the strain sensing element or the pressure sensing element.

7. The tactile sensor according to claim 1 , wherein the injection tube projects through a bottom of the contact-portion housing unit.

8. The tactile sensor according to claim 1 , wherein the injection tube is a first injection tube and the unhardened flexible material includes a base resin, and further comprising:

a second injection tube projecting through the contact-portion housing unit to permit injection of a sub-resin into the contact-portion unit.

9. The tactile sensor according to claim 1 , further comprising:

an optical fiber extending into at least a portion of the contact portion unit to receive light propagating toward or through the contact portion unit;

an optical sensor operably coupled to the optical fiber to detect the light received by the optical fiber; and

a processor communicatively coupled to the optical sensor to determine a thickness of the contact portion unit based on light detected by the optical sensor.

10. The tactile sensor according to claim 1 , wherein the tactile sensor is disposed on a manipulating member of a robot.

11. A tactile sensor comprising:

a contact-portion unit composed of a silicone material;

a contact-portion housing unit which surrounds and houses the contact-portion unit while forming a posture so that a top portion of the contact-portion unit may project; and

a strain sensing element or a pressure sensing element embedded into the contact-portion housing unit,

wherein the silicone material is a two-liquid type of a silicone base-resin and a sub-resin that hardens the material by being mixed therein, an injection tube for injecting the silicone base-resin into the bottom of the contact-portion unit from the bottom of the contact-portion housing unit is provided, and re-injection of the silicone base-resin is enabled through the injection tube.

12. The tactile sensor according to claim 11 , wherein the silicone material is a heat-hardened type which is replaced with the two-liquid type, an injection tube for injecting an unhardened silicone into the bottom of the contact-portion unit from the bottom of the contact-portion housing unit is provided, and re-injection of the unhardened silicone is enabled through the injection tube.

13. The tactile sensor according to claim 11 , wherein the contact-portion housing unit houses a plurality of contact-portion units.

14. A method of providing a tactile sensor comprising a contact-portion unit made of flexible material and disposed within a contact-portion housing unit, at least a portion of the contact-portion unit projecting from the contact-portion housing unit, the method comprising:

injecting unhardened flexible material into the contact-portion housing unit via an injection tube projecting through the contact-portion housing unit; and

curing the unhardened flexible material to form the flexible material.

15. The method according to claim 14 , wherein the flexible material comprises at least one of silicone and urethane.

16. The method according to claim 14 , wherein the unhardened flexible material comprises a base resin, and further comprising:

injecting a sub-resin into the contact-portion housing unit via another injection tube projecting through the contact-portion housing unit.

17. The method according to claim 14 , wherein the unhardened flexible material comprises a base resin, and further comprising:

injecting a sub-resin into the contact-portion housing unit via the at least a portion of the contact-portion unit projecting from the contact-portion housing unit.

18. The method according to claim 14 , further comprising:

detecting light transmitted toward or through at least a portion of the contact-portion unit;

determining a thickness of the contact-portion unit based on the detected light; and

determining an amount of unhardened flexible material to inject into the contact-portion housing unit based on the thickness of the contact-portion unit.

19. The method according to claim 14 , further comprising:

placing the at least a portion of the contact-portion unit in contact with an object.

20. The method according to claim 14 , further comprising:

sensing a strain or pressure on the contact-portion unit.