GB2156512A - Pressure or touch sensor - Google Patents

Pressure or touch sensor Download PDF

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Publication number
GB2156512A
GB2156512A GB08407679A GB8407679A GB2156512A GB 2156512 A GB2156512 A GB 2156512A GB 08407679 A GB08407679 A GB 08407679A GB 8407679 A GB8407679 A GB 8407679A GB 2156512 A GB2156512 A GB 2156512A
Authority
GB
United Kingdom
Prior art keywords
cavity
load
light
sensor
detector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08407679A
Other versions
GB8407679D0 (en
GB2156512B (en
Inventor
Mohammad Barkhordar
James Marcus Nightingale
Denis Ronald William May
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JE Hanger and Co Ltd
Original Assignee
JE Hanger and Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JE Hanger and Co Ltd filed Critical JE Hanger and Co Ltd
Priority to GB08407679A priority Critical patent/GB2156512B/en
Publication of GB8407679D0 publication Critical patent/GB8407679D0/en
Publication of GB2156512A publication Critical patent/GB2156512A/en
Application granted granted Critical
Publication of GB2156512B publication Critical patent/GB2156512B/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
    • G01L11/02—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00 by optical means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/24—Measuring force or stress, in general by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/12—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof structurally associated with, e.g. formed in or on a common substrate with, one or more electric light sources, e.g. electroluminescent light sources, and electrically or optically coupled thereto
    • H01L31/16—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof structurally associated with, e.g. formed in or on a common substrate with, one or more electric light sources, e.g. electroluminescent light sources, and electrically or optically coupled thereto the semiconductor device sensitive to radiation being controlled by the light source or sources
    • H01L31/167—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof structurally associated with, e.g. formed in or on a common substrate with, one or more electric light sources, e.g. electroluminescent light sources, and electrically or optically coupled thereto the semiconductor device sensitive to radiation being controlled by the light source or sources the light sources and the devices sensitive to radiation all being semiconductor devices characterised by potential barriers
    • H01L31/173—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof structurally associated with, e.g. formed in or on a common substrate with, one or more electric light sources, e.g. electroluminescent light sources, and electrically or optically coupled thereto the semiconductor device sensitive to radiation being controlled by the light source or sources the light sources and the devices sensitive to radiation all being semiconductor devices characterised by potential barriers formed in, or on, a common substrate

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Prostheses (AREA)

Abstract

A load sensor for use in a powered hand or arm comprises a light source e.g. an LED 15 and a light detector e.g. a phototransistor 10 in an enclosed cavity 14 defined in a body of opaque resilient material. Deformation of the cavity material under load varies the proportion of the omitted light that is received by the detector 16 in a manner that varies monotonically with applied load. The cavity 14 may also be connected via a conduit 22 to microphone 24 connected via an amplifier and filter 24, 26 to a sound detector 30 that detects stick-slip motion of an object being gripped. The cavity 14 may further be connected to pressure transducer 22. <IMAGE>

Description

SPECIFICATION Pressure or touch sensor The present invention relates to a pressure or touch sensor particularly, though not exclusively intended for use on a finger of a powered hand or arm such as a prosthetic hand and which is operable either to give an ON-OFF touch signal or to give a signal proportional to applied force.
Broadly stated, the invention provides, in a first aspect a load sensor comprising a light source and a light detector located in an enclosed cavity defined in a body of opaque reslient material such that the deformation of the cavity material under load varies the proportion of the emitted light that is received by the detector in a manner that varies monotonically with applied load.
The sensor is particularly appropriate for burying in a cosmesis material of a prosthetic hand or the like and associated control circuits are adjustable for loss of sensitivity on application of another layer of material (e.g. a plastic cover layer) over the cosmesis. The sensor, can be located near the surface of the cosmesis where it is more sensitive to applied load. It has the further advantage that it can "float" in the cosmesis and need not be rigidly connected to the endoskeleton of the hand.
The above sensor may advantageously be, but is not necessarily, combined with a load slip sensor for detecting travel of a load in stick-slip motion along a surface of a deformable material comprises means defining an enclosed cavity underneath the surface of the deformable material, a microphone, a conduit communicating the microphone with the cavity and detector means selectively responsive to pressure waves resulting from the stick slip motion. It is a particular advantage of the above sensor that by selective timing a high response is obtainable to pressure waves from stickslip motion whilst a far lesser response occurs for ambient sound e.g. speech or music or shock impact.
Advantageously, the cavity may be gas tight in which case a second conduit may lead to a pressure sensor operable to give a signal in response to a pressure rise in the cavity with applied load.
An embodiment of the invention will now be described by way of example, only with reference to the accompanying drawing which shows a touch sensor according to the invention.
A light emitting diode 10 powered via resistor 12 provides a continuous light output and is located to one side of a gas-containing cavity 14 of a rubber or plastics material within a body of otherwise light opaque resilient material. To the other side of the cavity is provided phototransistor 16 that receives light reflected from walls of the cavity and direct light from the diode 10 and in the rest state will provide a constant voltage when the power to diode 10 remains unchanged. But when a load is applied having a component orthogonal to the light beam the cavity is compressed to a degree depending upon the mechanical properties of the surrounding resilient material and also on the increased pressure of the gas entrapped in the cavity.
The result is to vary the voltage output of phototransistor 16 in monotonic relationship to the applied load.
The voltage output derived by potentiometer or resistor 18 may be amplified by amplifier 19 and then applied to a potentiometer or an A/D converter for digitisation. The ambient output value may be compared with a known rest value which may be set zero by varying the value of potentiometer 18, a change from the rest value denoting contact of the material about the sensor with an object.
The path between the light emitter and detector need not be straight, but can be generally arcuate, light being transmitted by internal reflection. It is also to be understood that the light source need not be operated continuously but may be pulsed by the action of a control circuit with a minimum duration and frequency dependant on the particular light emitters and detector used.
From the same cavity a conduit 22 leads to a microphone 24 connected via amplifier 26 to an appropriate filter 28 and detector 30.
The filter selectively passes frequencies associated with stick-slip motion of different textured objects e.g. to be gripped by a prosthetic hand or other gripper device and the detector 30 detects the onset or cessation of slip as signals occuring above a defined threshold. The fact that the cavity 14 is wholly within the resilient material means that it selectively collects vibrations transmitted within the resilient material and attenuates external vibrations.
Also, connected to the cavity 14 via tube 31 is a pressure sensor 32 responsive to changes in gas pressure in cavity 14 due to applied load. The signal from sensor 32 is amplified by amplifier 33 and digitised. By this means large forces may be detected whilst the optical sensor 10, 16 detects very low contact forces.
It will be appreciated that various modifications may be made to the invention without departing from the invention the scope of which is defined in the appended claims.

Claims (7)

1. A load sensor comprising a light source and a light detector located in an enclosed cavity defined in a body of opaque reslient material such that deformation of the cavity material under load varies the proportion of the emitted light that is received by the detec tor in a manner that varies monotonically with applied load.
2. A load sensor according to claim 1 wherein the light source is a light (including infra red) emitting diode and the light detector is a phototransistor.
3. A load sensor located at the end of a finger of a powered hand or arm or manipulator.
4. A load sensor according to any preceding claim wherein the material in which the cavity is defined is a plastics material.
5. A load sensor substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
6. A load slip sensor for detecting travel of a load in stick-slip motion along a surface of a deformable material comprising means defining an enclosed cavity underneath the surface of the deformable material, a microphone, a conduit communicating the microphone with the cavity and detector means selectively responsive to pressure waves resulting from the stick-slip motion.
7. A load slip sensor according to claim 6 wherein the cavity is gas tight and a second conduit leads to a pressure sensor operable to give a signal in response to a pressure rise in the cavity on applied load.
GB08407679A 1984-03-23 1984-03-23 Pressure or touch sensor Expired GB2156512B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08407679A GB2156512B (en) 1984-03-23 1984-03-23 Pressure or touch sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08407679A GB2156512B (en) 1984-03-23 1984-03-23 Pressure or touch sensor

Publications (3)

Publication Number Publication Date
GB8407679D0 GB8407679D0 (en) 1984-05-02
GB2156512A true GB2156512A (en) 1985-10-09
GB2156512B GB2156512B (en) 1988-06-02

Family

ID=10558615

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08407679A Expired GB2156512B (en) 1984-03-23 1984-03-23 Pressure or touch sensor

Country Status (1)

Country Link
GB (1) GB2156512B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109310188A (en) * 2016-04-19 2019-02-05 卡恩移动公司 Running gear and its cradle with intelligent characteristic

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1246295A (en) * 1968-12-19 1971-09-15 International Standard Electric Corp. Manual switch
GB2087070A (en) * 1980-11-05 1982-05-19 Standgrove Ltd Safety device
EP0093545A2 (en) * 1982-04-21 1983-11-09 University of Strathclyde Displacement sensitive transducers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1246295A (en) * 1968-12-19 1971-09-15 International Standard Electric Corp. Manual switch
GB2087070A (en) * 1980-11-05 1982-05-19 Standgrove Ltd Safety device
EP0093545A2 (en) * 1982-04-21 1983-11-09 University of Strathclyde Displacement sensitive transducers

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109310188A (en) * 2016-04-19 2019-02-05 卡恩移动公司 Running gear and its cradle with intelligent characteristic
US11071361B2 (en) 2016-04-19 2021-07-27 Can Mobilities, Inc. Mobility devices having smart features and charging mounts for same
CN109310188B (en) * 2016-04-19 2021-08-13 卡恩移动公司 Mobile device with intelligent characteristic and charging seat thereof

Also Published As

Publication number Publication date
GB8407679D0 (en) 1984-05-02
GB2156512B (en) 1988-06-02

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