Triaxial normal and shear force sensor
First Claim
1. A sensor for use in determining shear and normal components of a force applied thereto, comprising:
- a substantially rigid support member carrying a compliant structure;
at least one target for reflecting ultrasonic waves supported by said compliant structure;
at least two ultrasonic transducers aimed at said target, each of said transducers adapted to emit and detect ultrasonic signals, said transducers being laterally and vertically offset from said at least one target; and
a substantially acoustically-transparent, substantially acoustically-nonrefractive medium disposed between said transducers and said at least one target.
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Accused Products
Abstract
A triaxial force sensor using a hemispherical target supported by a compliant element such as a spring or an elastomer supported by a rigid support member. The sensor includes a plurality of ultrasonic transducers disposed in a plane at equal intervals about the target and vertically and laterally offset from the target. The transducers are oriented at an oblique angle to the plane, and aimed at the target in its rest position. The target is displaced by sufficient force applied to elastically deform the compliant element, which displacement alters the transit times of ultrasonic signals from the transducers which are reflected from the target. If at least three sensor units are employed non-colinearly, the six force-torque components, Fx, Fy, Fz, Mx, My, Mz, can be determined from the pulse transit times, the speed-of-sound in the medium or media between the transducers and the target, the deformation response of the compliant element, and the known geometry and spacing of the transducers. Pairs of transducers may be rotationally offset from each other to determine different force-torque components. A plurality of sensors as described may be employed together in a multi-sensor array. An alternative embodiment employing both the amplitude and the transit time of an ultrasonic pulse is also disclosed.
36 Citations
76 Claims
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1. A sensor for use in determining shear and normal components of a force applied thereto, comprising:
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a substantially rigid support member carrying a compliant structure;
at least one target for reflecting ultrasonic waves supported by said compliant structure;
at least two ultrasonic transducers aimed at said target, each of said transducers adapted to emit and detect ultrasonic signals, said transducers being laterally and vertically offset from said at least one target; and
a substantially acoustically-transparent, substantially acoustically-nonrefractive medium disposed between said transducers and said at least one target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A multi-sensor array for use in determining shear and normal components of a force applied thereto, comprising:
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a substantially rigid support member carrying a plurality of laterally separated compliant structures located at predetermined intervals;
a plurality of targets for reflecting ultrasonic waves, each of said targets being supported by one of said compliant structures;
each of said targets having associated therewith at least a pair of ultrasonic transducers adapted to emit and receive ultrasonic signals, said transducers of each pair being aimed at said target with which said transducers are associated and horizontally and vertically offset therefrom; and
a substantially acoustically-transparent, substantially acoustically-nonrefractive medium disposed between said transducers and said targets. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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- 38. A sensor for use in determining shear and normal components of a force applied thereto, comprising:
- 55. A multi-sensor array for use in determining shear and normal components of a force applied thereto, comprising:
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73. A method of determining shear and normal components of a force, comprising:
positioning at least one acoustically-reflective target;
- View Dependent Claims (74, 75, 76)
Specification