Multicomponent force-torque sensor

• US 4,704,909 A
• Filed: 07/22/1985
• Issued: 11/10/1987
• Est. Priority Date: 07/22/1985
• Status: Expired due to Term

• Current Assignee: Bonneville Scientific Incorporated
• Original Assignee: Allen R. Grahn, Lynn Astle
• Inventors: Astle, Lynn, Grahn, Allen R.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/757,360
• Time in Patent Office: 841 Days
• Field of Search: 73/862.04, 73/862.05, 73/862.06, 73/DIG. 4, 73/703, 73/189, 33/125 W, 367/99, 367/107, 367/114
• US Class Current: 73/862.043
• CPC Class Codes: G01L 1/24 by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
• CPC Class Codes: G01L 1/255 using acoustic waves, or acoustic emission G01L1/10 and G01L1/16 take precedence
• CPC Class Codes: G01L 5/16 for measuring several components of force
• CPC Class Codes: G01L 5/166 using photoelectric means
• CPC Class Codes: Y10S 73/04 Piezoelectric

Abstract

An apparatus and process for detecting and quantifying force-torque components applied to a loadable means. The apparatus includes a plurality of signal-transmission means, a plurality of signal-reflection means, a plurality of signal-detection means and a deformable means which is deformable in response to the application of force-torque components to the loadable means. Application of a force-torque component to the loadable means results in the alteration of the distance traveled by a signal from signal-transmission means to signal detection means. The apparatus further includes a means for utilizing the detected signals to determine force-torque components.

Claims

1. A multicomponent force-torque sensor comprising:

(a) a loadable means to which at least two force-torque components can be applied;

(b) a plurality of signal-transmission means for transmitting signals;

(c) a plurality of signal-reflection means for reflecting said transmitted signals;

(d) a plurality of signal-detection means for detecting said reflected signals;

(e) at least one medium through which said signals can travel;

(f) a deformable means which is deformable in response to the application of force-torque components to said loadable means; and

(g) a means for utilizing said detected signals to determine a plurality of force-torque components;

wherein (a), (b), (c), (d), (e) and (f) are adapted and arranged such that the application of a force-torque component to said loadable means results in the alteration of the distance traveled from signal-transmission means to signal-detection means by each of at least two of said signals.

2. A sensor in accordance with claim 1 wherein said loadable means is a surface of said deformable means.

3. A sensor in accordance with claim 1 wherein (g) is comprised of an electronic circuitry means for determining the transit time of each of said signals and for using said signal transit times to determine said plurality of force-torque components.

4. A sensor in accordance with claim 1 wherein said signal-reflection means are affixed to said loadable means.

5. A sensor in accordance with claim 1 wherein said signal-transmission means are ultrasonic transducers capable of transmitting an ultrasonic signal;

and wherein said ultrasonic transducers also serve as said signal-detection means.

6. A sensor in accordance with claim 1 wherein said deformable means is an elastomeric material.

7. A sensor in accordance with claim 6 wherein said deformable means has a cylindrical shape.

8. A sensor in accordance with claim 1 further comprising (h) a substrate which supports said signal-transmission means and signal-detection means and which provides a reference position from which differences in signal transit time can be determined.

9. A sensor in accordance with claim 1 wherein said loadable means is a cover plate;

and wherein said signal-transmission means are ultrasonic transducers;

wherein said ultrasonic transducers also serve as said signal-detection means;

wherein said signal-reflection means are affixed to said cover plate;

wherein (g) is comprised of an electronic circuitry means for determining the transit time of each of said signals and for using said signal transit times to determine said plurality of force-torque components.

10. A sensor in accordance with claim 9 wherein said deformable means is an elastomeric material.

11. A multicomponent force-torque sensor comprising:

(a) a cover plate;

(b) a substrate;

(c) a plurality of ultrasonic transducers capable of transmitting and detecting ultrasonic signals;

(d) a pluraltiy of reflectors capable of reflecting said ultrasonic signals and positioned to reflect said ultrasonic signals back to said transducers;

(e) a deformable means which is deformable in response to the application of force-torque components to said cover plate;

(f) at least one medium through which ultrasonic signals transmitted from said ultrasonic transducer can travel; and

(g) an electronic circuitry means for determining the transit time of said ultrasonic signals and for using said signal transit times to determine a plurality of force-torque components;

wherein (a), (b), (c), (d), (e) and (f) are adapted and arranged such that the application of a force-torque component to said cover plate results in the alteration of the transit time of at least one of said signals; and

wherein said substrate provides support to said ultrasonic transducers and provides a reference position from which differences in signal transit time can be determined.

12. A sensor in accordance with claim 11 wherein said cover plate, said deformable means and said substrate form a cavity;

and wherein said cavity contains a coupling agent which serves as a medium through which said ultrasonic signals can travel.

13. A sensor in accordance with claim 12 wherein said deformable means also serves as a medium through which said ultrasonic signals can travel.

14. A sensor in accordance with claim 13 further comprising:

(h) a post to which at least one of said ultrasonic transducers is affixed.

15. A sensor in accordance with claim 13 further comprising:

(h) a reflector post having at least one reflecting surface for reflecting at least one of said ultrasonic signals to its reflector and back to the ultrasonic transducer from which it was transmitted.

16. A sensor in accordance with claim 11 wherein said ultrasonic transducers are mounted on said substrate.

17. A sensor in accordance with claim 11 wherein said deformable means is in a cylindrical shape.

18. A process for determining a plurality of force-torque components comprising:

(a) subjecting a loadable means to a plurality of force-torque components;

(b) transmitting signals from a signal-transmission means;

(c) reflecting said transmitted signals with a signal-reflection means;

(d) detecting said reflected signals with a signal-detection means; and

(e) determining the transit times of said signals to determine a plurality of force-torque components;

wherein the signal transit times are altered in response to the force-torque components to which said loadable means is subjected.

19. A process in accordance with claim 18 wherein said transit times and said force-torque components are determined utilizing an electronic circuitry means.

20. A process in accordance with claim 19 wherein said signal-transmission means and said signal-detection means are ultrasonic transducers.

21. A force-torque sensor comprising:

(a) a loadable means having a contact surface to which at least one force-torque component selected from F_x, F_y, M_x, M_y and M_z can be applied;

(b) a plurality of signal-transmission means for transmitting signals;

(c) a plurality of signal-reflection means for reflecting said transmitted signals;

(d) a plurality of signal-detection means for detecting said reflected signals;

(e) at least one medium through which said signals can travel;

(f) a deformable means which is deformable in response to the application of said force-torque component to said loadable means; and

(g) a means for utilizing said detected signals to determine said force-torque component;

wherein (a), (b), (c), (d), (e) and (f) are adapted and arranged such that the application of said force-torque component to said loadable means results in the alteration of the distance traveled from signal-transmission means to signal-detection means by each of at least two of

said signals;

wherein said loadable means is oriented with respect to F_x, F_y, M_x, M_y, and M_z in a frame of reference such that the Z-axis of said frame of reference is normal to said contact surface of said loadable means.

22. A sensor in accordance with claim 21 wherein (g) is comprised of an electronic circuitry means for determining the transit time of each of said signals and for using said signal transit times to determine said force-torque component.

23. A sensor in accordance with claim 21 wherein said signal-reflection means are affixed to said loadable means.

24. A sensor in accordance with claim 21 wherein said signal-transmission means are ultrasonic transducers capable of transmitting an ultrasonic signal;

and wherein said ultrasonic transducers also serve as said signal-detection means.

25. A sensor in accordance with claim 21 further comprising (h) a substrate which provides support to signal-transmission means and signal-detection means and which provides a reference position from which differences in signal transit time can be determined.

26. A sensor in accordance with claim 25 wherein said loadable means is a cover plate;

wherein said signal-transmission means are ultrasonic transducers;

wherein said ultrasonic transducers also serve as said signal-detection means;

wherein said signal-reflection means are affixed to said cover plate; and

wherein (g) is comprised of an electronic circuitry means for determining the transit time of each of said signals and for using said signal transit times to determine said force-torque component.

27. A sensor in accordance with claim 26 wherein said deformable means is an elastomeric material in a cylindrical shape.

28. A sensor in accordance with claim 21 wherein said force-torque component is selected from M_x, M_y and M_z.