Six-axis force-torque sensor
| Title: | Six-axis force-torque sensor |
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| Patent Number: | 9,423,308 |
| Publication Date: | August 23, 2016 |
| Appl. No: | 14/371632 |
| Application Filed: | January 14, 2013 |
| Abstract: | A sensing device for measuring force and/or torque includes a top part with a top electrode structure, a bottom part with a bottom electrode structure, and a support structure. The support structure includes spring elements for supporting the top part on the bottom part with the top electrode structure parallel to and facing the bottom electrode structure. The spring elements provide a gap between the top and bottom electrode structures and allow displacement of the top part relative to the bottom part in three orthogonal directions two parallel and one perpendicular to the bottom plate, and for rotation of the top part relative to the bottom part around three orthogonal axes, corresponding with the two parallel and one perpendicular directions. The displacement and/or rotation induce a change in distance between and/or overlap area of the top and bottom electrodes and a corresponding change of capacitance. |
| Inventors: | Brookhuis, Robert Anton (Enschede, NL); Lammerink, Theodorus Simon Josef (Enschede, NL); Wiegerink, Remco John (Enschede, NL) |
| Assignees: | UNIVERSITEIT TWENTE (Enschede, NL), STICHTING VOOR DE TECHNISCHE WETENSCHAPPEN (Utrecht, NL) |
| Claim: | 1. A sensing device for measuring force and/or torque, comprising: a top part with a top electrode structure; a bottom part with a bottom electrode structure; and a support structure comprising spring elements for supporting the top part on the bottom part with the top electrode structure parallel to and facing the bottom electrode structure, the spring elements being configured to provide a gap between the top and bottom electrode structures, the spring elements being configured to allow displacement of the top part relative to the bottom part in three orthogonal directions—two parallel and one perpendicular—to the bottom part, and for rotation of the top part relative to the bottom part around three orthogonal axes, corresponding with said two parallel and one perpendicular directions, the top and bottom electrode structures being disposed in positions on the top and the bottom part, respectively, and positioned such that a change in distance between and/or a change in overlap area of the top and bottom electrodes and a corresponding change of capacitance are induced by the displacement and/or rotation of the top and bottom electrode structures relative to each other, wherein the top and bottom electrode structures comprise, for each of the three orthogonal directions, one or more pairs of top and bottom plate electrodes, with the plate electrodes in the top and bottom parts constituting a variable capacitor structure configured to measure change in capacitance due to a change of position of the electrode in the top part relative to the electrode in the bottom part, the change in position being one or more of a change in a gap distance and a change of the overlap area. |
| Claim: | 2. The sensing device according to claim 1 , wherein the force and/or torque range of the sensing device is adapted by the number of spring elements, and/or a shape and/or a stiffness of the spring elements and/or mechanical properties of the spring element material. |
| Claim: | 3. The sensing device according to claim 1 , wherein at least one electrode structure is arranged in electrode regions around an origin location in the sensing device. |
| Claim: | 4. The sensing device according to claim 1 , wherein the bottom top electrode structure comprises a plurality of bottom electrode regions around a center of the bottom electrode structure. |
| Claim: | 5. The sensing device according to claim 4 , wherein the bottom top electrode structure comprises four bottom electrode regions configured in quadrants. |
| Claim: | 6. The sensing device according to claim 4 , wherein top electrode region comprises a top comb structure at the outer edge of each quadrant, and each bottom electrode region comprises a bottom comb structure at the outer edge of the respective corresponding quadrant. |
| Claim: | 7. The sensing device according to claim 1 , wherein the spring elements comprise at least one pillar. |
| Claim: | 8. The sensing device according to claim 7 , wherein the at least one pillar comprises a hollow cylinder. |
| Claim: | 9. The sensing device according to claim 7 , wherein each pillar is arranged to be both longitudinally deformable and transversely flexible. |
| Claim: | 10. The sensing device according to claim 7 , wherein each pillar provides a mechanical coupling of the top part to the bottom part. |
| Claim: | 11. The sensing device according to claim 7 , wherein the pillars form part of either the top part or the bottom part or both parts and extend above or below the electrode structure in the respective part. |
| Claim: | 12. The sensing device according to claim 1 wherein the sensing device comprises an enclosing part surrounding one of the top part and the bottom part and being attached to the other of the top part and the bottom part, and one or more additional spring elements is coupled between said enclosing part and said one of the top and the bottom part in order to provide additional support. |
| Claim: | 13. The sensing device according to claim 12 , wherein the one or more additional spring elements comprises a plurality of arbitrary shaped elements, each additional spring element being longitudinally deformable and transversely flexible. |
| Claim: | 14. The sensing device according to claim 12 , wherein the one or more additional spring elements comprise a membrane between said enclosing part and said one of the top and the bottom part, the membrane being longitudinally deformable and transversely flexible. |
| Claim: | 15. The sensing device according to claim 14 , wherein the membrane is corrugated. |
| Claim: | 16. The sensing device according to claim 1 , wherein the top part is a conductor-based plate and the bottom part is a second conductor-based bottom plate. |
| Claim: | 17. The sensing device according to claim 16 , wherein the top part and/or the bottom part is a semiconductor-based plate. |
| Claim: | 18. The sensing device according to claim 17 , wherein the top part is a doped silicon plate. |
| Claim: | 19. The sensing device according to claim 17 , wherein the bottom part is a doped silicon-on-insulator plate. |
| Claim: | 20. The sensing device according to claim 19 , wherein the top part is a doped silicon plate, the pillars are silicon based, form part of either the top part or bottom part or both, and couple the top part and the bottom part. |
| Claim: | 21. The sensing device according to claim 16 , wherein the top electrode structure comprises a metal pattern. |
| Claim: | 22. The sensing device according to claim 16 , wherein the bottom electrode structure comprises a metal pattern. |
| Claim: | 23. The sensing device according to claim 21 , wherein the top part and/or the bottom part comprises an insulating support layer supporting the top electrode and the bottom electrode structure, respectively. |
| Claim: | 24. The sensing device according to claim 14 , wherein the enclosing part and the additional spring elements or membrane consist of the same material as said one of the top part and the bottom part. |
| Claim: | 25. The sensing device according to claim 1 , wherein the bottom electrode regions configured around the center of the electrode structure comprise circular segment shaped electrodes, each region comprises an inner segment with first circular segment shaped electrodes and an outer segment with second circular segment shaped electrodes, and within each segment, the electrodes are interdigitated and connected to separate terminals. |
| Claim: | 26. The sensing device according to claim 1 , wherein the bottom electrode regions configured around the center of the electrode structure comprise elongated substantially straight electrodes running from the center of the electrode structure to a periphery of the electrode structure, wherein each region comprises an inner segment with first elongated electrodes and an outer segment with second elongated electrodes; within each segment the electrodes are interdigitated and connected to separate terminals. |
| Claim: | 27. The sensing device according to claim 2 , wherein the sensing device comprises an enclosing part surrounding one of the top part and the bottom part and being attached to the other of the top part and the bottom part, and one or more additional spring elements is coupled between said enclosing part and said one of the top and the bottom part in order to provide additional support, and the force and/or torque range of the sensing device is further adapted by the mechanical properties of the one or more additional spring elements. |
| Patent References Cited: | 4585082 April 1986 Harrington 6820493 November 2004 Bonin 2003/0094914 May 2003 Yanagita 2004/0187593 September 2004 Okada 2004/0221650 November 2004 Lehtonen 2005/0061082 March 2005 Dallenbach 2007/0058238 March 2007 Mala 2010/0268121 October 2010 Kilborn 2011/0005338 January 2011 Okada 2014/0208849 July 2014 Zhang 2010/223953 October 2010 2011/128096 June 2011 |
| Other References: | International Search Report, dated Sep. 19, 2013, from corresponding PCT application. cited by applicant |
| Primary Examiner: | Noori, Max |
| Attorney, Agent or Firm: | Young & Thompson |
| Accession Number: | edspgr.09423308 |
| Database: | USPTO Patent Grants |
| Language: | English |
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