Tactile sensor

• US 5,014,224 A
• Filed: 07/13/1989
• Issued: 05/07/1991
• Est. Priority Date: 07/14/1988
• Status: Expired due to Fees

• Current Assignee: Blomberg Robotertechnik GmbH Voltastrasse 50 D-4730 Ahlen / FRG
• Original Assignee: Blomberg Robotertecknik GmbH
• Inventors: Hans, Richter
• Primary Examiner(s): Reynolds, Bruce A.
• Assistant Examiner(s): Lateef, Marvin
• Application Number:
  US07/379,211
• Time in Patent Office: 663 Days
• Field of Search: 338/99, 338/114, 338/71
• US Class Current: 338/99
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

In a tactile sensor, a first conductive path made of an electrically resistive material, which is elastic, is fixed to a foil-like base. At points of intersection with good electrically conducting conductive paths, which are fixed to a second elastic foil, the first conductive path has a uniformly curved convex surface. If pressure is exerted on the second flat foil, then the convex surface of the first conductive path is deformed in the area where the pressure is exerted so that, in this area, the first good electrically conducting conductive path presses against the first conductive path over a pressure-responsive longitudinal area, so that the total resistance of the first conductive path changes in a pressure-responsive manner. By measuring the total resistance and the potential of the good electrically conducting conductive paths, the pressure exertion can be determined as to location and amount of pressure.

Claims

1. A tactile sensor comprised of at least two parallel plates, at least one of the plates being elastic, the plates being formed into a number of pressure-sensitive measuring cells, each cell having a first conductive path on one plate and a second conductive path on the other plate, one of the two conductive paths being comprised of good electrically conducting material, the other conductive path being comprised of electrically resistive material, the two conductive paths of each cell extending in the same direction, at least one of the conductive paths being in the form of a uniformly curved surface, means for retaining the two conductive paths of a cell adjacent each other whereby when pressure is exerted resulting in deformation of the elastic material of the elastic plate the conductive paths come into contact with each other in a cell with the length of the contact being proportionate to the pressure, thus causing variation of the resistance of the other conductive path, allowing the pressure at the location at which the pressure is exerted to be determined by measurement of the resistance of said other conductive path.

2. A tactile sensor according to claim 1, in which the uniformly curved surface is convex.

3. A tactile sensor according to claim 1, in which each cell is formed of a convexly curved conductive path and of a flat conductive path, and at least one of the conductive paths being disposed on or is comprised of an elastic foil.

4. A tactile sensor according to claim 3, in which the convexly curved conductive path is comprised of an elastic resistive material and the flat conductive path is disposed on an elastic foil.

5. A tactile sensor according to claim 3, in which the convexly curved conductive path is comprised of a rigid resistive material and the flat conductive path is disposed on a plastic foil.

6. A tactile sensor according to claim 3, in which the convexly curved conductive path is comprised of an elastic, highly conductive material and is disposed on the convexly curved surface of an elastic foil.

7. A tactile sensor according to claim 5, in which the elastic foil is comprised of a rubber material which can be deformed.

8. A tactile sensor according to claim 5, in which a concavely curved conductive path is disposed on the side of the foil which is opposite the convexly curved conductive path and the foil is comprised of two wedge-shaped conductive paths on that side.

9. A tactile sensor according to one of the claims 1 to 8, in which the conductive paths comprised of a resistive material, of adjacent cells are situated in a row and are electrically connected in series.

10. A tactile sensor according to one of the claims 1 to 8, in which the conductive paths comprised of a resistive material, of the cells are attached to separate terminals.

11. A tactile sensor according to claim 8, in which the foil has a wire strain gauge connected between the concavely and convexly curved conductive paths.

12. A tactile sensor according to claim 4, in which several of said first conductive paths of several cells made from the elastic resistive material are disposed adjacent to one another and are in the form of strips which are convexly curved in each cell, the cells of adjacent conductive paths being crossed by strip-shaped second conductive paths made of a good electrically conducting material, which are disposed of the elastic foil.

13. A tactile sensor according to claim 5 or 8, in which the foil is held stretched over the convexly curved conductive path.

14. A tactile sensor according to one of claims 3 to 6, in which the conductive paths made from a good electrically conducting material are electrically separated from one another.

15. A tactile sensor according to claim 6 in which the flat conductive path made from a resistive material of a cell has several straight conducting elements, each of said elements being located adjacent a separate convexly curved surface of the elastic foil, the conductive path made from good electrically conducting material being disposed on this surface.

16. A tactile sensor according to claim 15, in which adjacent conducting elements extend at right angles to one another and the elastic foil has spacers surrounding the convexly curved surfaces, said spacers adjoining the surface of the foil having the flat conductive paths.

17. A tactile sensor according to claim 16, in which a nipple, which catches in a bore of a base having the flat conductive paths extends from the elastic foil, and is centred in relation to each of the four convexly curved surfaces of each cell.