Force sensor

Patent metadata

Field	Value
Publication number	US-11226245-B2
Application number	US-201716498437-A
Country	US
Kind code	B2
Filing date	Mar 31, 2017
Priority date	Mar 31, 2017
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

A force sensor includes a frame and an oscillation structure which has arms and can oscillate freely in the frame. The arms are fixed to suspension frame regions and run transverse to one another at least in sections. At least one conductor extends along at least two arms. An AC voltage can be applied to the at least one conductor to excite at least one oscillation mode of the oscillation structure with a resonant frequency using Lorentz force. The force sensor is designed such that the suspension regions are at least partially spatially displaced relative to one another when a force is applied to the frame, that the magnitude of the spatial displacement of the suspension regions depends on the magnitude of the force, and that the spatial displacement of the suspension regions causes detuning of the resonant frequency, the magnitude of which depends on the spatial displacement magnitude.

First claim

The invention claimed is:

1. A system comprising a force sensor, the force sensor comprising a frame as well as an oscillation structure, which has multiple arms and can oscillate freely in the frame,
wherein the arms are fixed in place on suspension regions of the frame and run transverse to one another, at least in certain sections,
wherein the force sensor is designed in such a manner that the suspension regions are displaced spatially relative to one another, at least in part, when the frame has a force applied to it, that the magnitude of the spatial displacement of the suspension regions depends on the magnitude of the force, that the spatial displacement of the suspension regions brings about detuning of a resonance frequency of at least one oscillation mode of the oscillation structure, and that the magnitude of the detuning depends on the magnitude of the spatial displacement of the suspension regions,
wherein at least one conducting means is provided, which extends along at least two arms, so as to allow a flow of current in the form of moving charge carriers at least between two suspension regions,
wherein the at least one conducting means can have an alternating voltage applied to it, so as to excite at least one oscillation mode of the oscillation structure with a resonance frequency, particularly in an unstressed state of the force sensor, making use of the Lorentz force, when the oscillation structure is situated in a magnetic field,
wherein the system further comprises read-out means for determination of the resonance frequency,
wherein a control unit is provided configured to cause an alternating voltage to be applied to the at least one conducting means, so as to excite the oscillation structure to cause the oscillation structure to oscillate, and
wherein the control unit is connected with the read-out means for determination of the resonance frequency,
wherein the control unit is designed for applying at least one pulse of alternating voltages to the at least one conducting means, so as to excite the oscillation structure to cause the oscillation structure to oscillate,
wherein the at least one pulse has a bandwidth of frequencies, which bandwidth comprises the resonance frequency of at least one oscillation mode of the oscillation structure, and
wherein the system comprises means for generation of the magnetic field.

2. The system according to claim 1 , wherein the suspension regions are disposed in the region of corners of the frame.

3. The system according to claim 1 , wherein four corners of the frame are provided, which are disposed in a plane of the frame.

4. The system according to claim 3 , wherein the four corners of the frame are disposed in a plane of the frame and form a rectangle.

5. The system according to claim 3 , wherein the four corners of the frame are disposed in a plane of the frame and form a square in the plane.

6. The system according to claim 1 , wherein the frame has at least one meander-shaped section.

7. The system according to claim 6 , wherein the at least one meander-shaped section is disposed between at least two suspension regions.

8. The system according to claim 1 , wherein the number of arms is a whole-number multiple of four.

9. The system according to claim 8 , wherein the number of arms is precisely four.

10. The system according to claim 1 , wherein the oscillation structure has a coupling element by means of which the arms are mechanically coupled with one another.

11. The system according to claim 10 , wherein the coupling element forms an edge around a surface.

12. The system according to claim 11 , wherein the coupling element is polygonal.

13. The system according to claim 12 , wherein each arm is fixed in place on the coupling element in the region of a corner point of the element.

14. The system according to claim 12 , wherein the coupling element is four-cornered.

15. The system according to claim 14 , wherein the coupling element is rectangular.

16. The system according to claim 14 , wherein the coupling element is square.

17. The system according to claim 10 , wherein each arm is fixed in place on the coupling element with one end.

18. The system according to claim 10 , wherein the coupling element forms an edge around a surface that lies in a plane of the frame.

19. The system according to claim 1 , wherein the arms are fixed in place on the respective suspension region, in each instance, by means of a temperature-compensation structure that is meander-shaped at least in certain sections.

20. The system according to claim 1 , wherein the frame and the oscillation structure are produced in one piece from silicon.

21. The system according to claim 20 , wherein the frame and the oscillation structure are produced in one piece from mono-crystalline silicon.

22. The system according to claim 1 , wherein at least two conducting means are provided and the control unit is designed for applying counter-phase alternating voltages to the at least two conducting means.

23. The system according to claim 1 , wherein the control unit is designed for application of multiple pulses of alternating voltages to the at least one conducting means, one after the other, wherein the different pulses comprise resonance frequencies of different oscillation modes of the oscillation structure.

24. The system according to claim 1 , wherein the system comprises at least one permanent magnet and/or at least one Helmholtz coil.

25. The system according to claim 1 , wherein the control unit is designed for excitation of oscillations of the oscillation structure in a plane of the frame.

26. A prosthesis comprising the system according to claim 1 .

Assignees

• Univ Wien Tech

Inventors

• Dabsch Alexander
• Keplinger Franz
• Rosenberg Christoph

Classifications

• G01L1/10

  by measuring variations of frequency of stressed vibrating elements, e.g. of stressed strings (using resistance strain gauges G01L1/22) · CPC title

• G01L1/103

  optical excitation or measuring of vibrations · CPC title

• G01L1/106 Primary

  Constructional details · CPC title

• G01L5/169

  using magnetic means · CPC title