GB2151774A - Measuring displacement - Google Patents
Measuring displacement Download PDFInfo
- Publication number
- GB2151774A GB2151774A GB08333604A GB8333604A GB2151774A GB 2151774 A GB2151774 A GB 2151774A GB 08333604 A GB08333604 A GB 08333604A GB 8333604 A GB8333604 A GB 8333604A GB 2151774 A GB2151774 A GB 2151774A
- Authority
- GB
- United Kingdom
- Prior art keywords
- source
- displacement
- sensor
- radiation
- 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.)
- Withdrawn
Links
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 33
- 230000005855 radiation Effects 0.000 claims abstract description 16
- 230000008859 change Effects 0.000 claims abstract description 5
- 230000001419 dependent effect Effects 0.000 claims abstract description 4
- 238000000034 method Methods 0.000 claims description 9
- 238000005286 illumination Methods 0.000 description 4
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 4
- 239000010937 tungsten Substances 0.000 description 4
- 229910052721 tungsten Inorganic materials 0.000 description 4
- 238000011088 calibration curve Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 230000001133 acceleration Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
Displacement of a body 14 is measured by placing the body between a radiation source 11 and a sensor 12 and sensing over a range the change in radiation received by the sensor from the source dependent on the displacement of the body. The displacement may be radial, axial or rotational. The source and sensor may be displaceable and the relative displacement between the body and the source and sensor is sensed. A control box 30 is provided for source and sensor. The device can detect rotational instabilities. <IMAGE>
Description
SPECIFICATION
Improvements in or relating to apparatus and methods for measuring displacement
This invention relates to apparatus and methods for measuring displacement.
One form of such displacement is vibration.
It is known to use a photo-electric source and radiation sensor to indicate, on an on/off basis, when a moving object has reached a predetermined position.
According to one aspect of the invention a method for measuring displacement of a body comprises placing the body between a radiation source and a sensorforthe radiation, and sensing, over a range, change in the radiation received by the sensor from the source dependent on displacement of the body.
This is to be contrasted with the on/off arrangement mentioned above.
The source and sensor may be mounted so as to be displaceable, and the method may comprise sensing the relative displacement between the body and the source and sensor.
According to another aspect of the invention apparatus for measuring displacement of a body comprises a radiation source, a sensor for said radiation, means for mounting the body so that displacement of the body changes, over a range, the radiation received by the sensor from the source, and means responsive to said change for producing an indication of the displacement.
The body may be mounted for radial displacement.
The body may be mounted for axial displacement.
The body may be mounted for rotational movement.
The source and sensor may be mounted for displacement and said responsive means may be responsive to the relative displacement between the body and the source and sensor.
The invention may be performed in various ways and some specific embodiments with possible modifications will now be described by way of example with reference to the accompanying drawings, in which:
Figure I is a side view of a movement sensor apparatus;
Figure 2 is a view of the line A-A of Figure 1;
Figure 3A is a side of another arrangement;
Figure 3B is a plan view of Figure 2A;
Figure 4 is a circuit of a control unit;
Figure 5 is an output/displacement curve;
Figures 6A, 6B are similar to Figures 3A, 3B of another arrangement; and
Figure 7 is an output/displacement curve for the arrangement of Figure 6.
Figures 1 a and 1 b show the general principle.
A support frame 10 carries a light source 11, for example, a uniform rectangular tungsten filament source, confronting a photo detector 12, the frame being fixed to a stationary support 13. If an obstacle 14 enters the field between the dotted lines, there is a reduction in light or radiation received by the detector from the source 11 and a proportional reduction in output voltage of the detector.
The detector is connected to a control box (not shown) by wires 15 and the source is connected to the control box by wires 16.
Displacement of the obstacle 14 in the directions of the arrows can thus be determined from a measure of the detector output voltage or from an output voltage of the control box.
Figures 3a and 3b show application of this method to vibration in a support column 20 of a rig or structure for rotating a hollow cylinder to investigate hoop stresses in such a cylinder.
A blackened plate 21 is fixed to the column 20 via clamp 22 and acts as the obstacle 14. The plate 22 is horizontal and any movement of the plate 22 in this plane as indicated by the arrows produces a corresponding output voltage of the appropriate sign. For optimum range and linearity the plate 22 is positioned so that when stationary it intercepts about half the light from the source going to the detector. An electronic control unit 30 Figure 4 is adjusted to produce zero output voltage at this stationary central position ofthe plate.
Figure 4 shows the circuit of one control unit. A photodiode with integral amplifier 40 has a temperature compensated reference voltage VR, obtained using temperature compensated zener diodes 41, which can be adjusted by continuously variable resistor 42. The voltage output VR of the diode 40 is kl-VR where k is the responsivity over the whole spectrum of illumination and I is the visible light illumination in watts.
A switched gain control 44 is provided for Vo, in which R2 < R3 < R4, in association with a fairly low drift operational amplifier 45.
The output voltage at 46 is
Rf (kl-VR).
RI The supply to tungsten filament lamp 11 can be varied by resistor RC to vary the illumination level.
A continuously variable gain control could be used. The photodiode 40 has good temperature stability, adequate time response, satisfactory spectral matching with selected light sources, and good responsivity.
The separation between source and detector can be varied dependent on source intensity and expected extent of movement of the obstacle 14.
In one example the separation is 5.0cm using a 12v tungsten lamp and 1.8cm x 1.2cm diffused plastic lens to provide uniform illumination. Figure 5 shows a calibration curve to this and the curve is linear over a range of about 0.5cm.
For measurement ofvibration amplitude also in a vertical plane a similar arrangement is used appropriately orientated.
Figures 6a and 6b illustrate use of the method in respect of radial movement or wobble of shaft 60.
An annular aluminium disc 61, 64mm diameter by 1cm thick is bolted on to the shaft 60 with the peripheral edge 62 of the disc 61 lying between source and detector and midway between them and separated from them by about 0.5cm.
Again about half the light is intercepted in the datum stationary position. Movement in an orthogonal direction can be sensed using another source/detector pair 11', 12'.
In one case the reference frame to which source and detector are fixed in Figures 6A, 6B instead of being stationary was selected to be the column 20 and in this case differential movement between the source and detector (column 20) and the shaft 60 is measured, but light emitting diodes replace the tungsten source because of the high accelerations involved. A current-limiting resistor is added to the control unit circuit to protect the LEDS.
In another arrangement the shaft 60 forms the obstacle 14 in an arrangement as in Figure 1 with detector 13.0cm from the shaft and the source 5.0cm from the shaft. Figure 7 shows a typical calibration curve for this, the voltages being generated by the control unit; this shows a sensitivity of 0.36v per 0.1cm of shaft movement over the linear region (0.2 to 0.9cm).
With this apparatus potentially damaging instabilities at certain rotation speeds can be detected.
Claims (9)
1. A method of measuring displacement of a body comprising placing the body between a radiation source and a sensor for the radiation, and sensing, over a range, change in the radiation received by the sensor from the source dependent on displacement of the body.
2. A method as claimed in claim 1, in which the source and sensor are mounted so as to be displaceable, and sensing relative displacement between the body and the source and sensor.
3. Apparatus for measuring displacement of a body comprising a radiation source, a sensor for said radiation, means for mounting the body so that displacement of the body changes, over a range, the radiation received by the sensor from the source, and means responsive to the change for producing an indication of the displacement.
4. Apparatus as claimed in claim 3, in which the body is mounted for radial displacement.
5. Apparatus as claimed in claim 3, in which the body is mounted for axial displacement.
6. Apparatus as claimed in claim 3, in which the body is mounted for rotation.
7. Apparatus as claimed in any of claims 3 to 6, in which the source and sensor are mounted for displacement, and the responsive means is responsive to the relative displacement between the body and the source and sensor.
8. A method of measuring displacement of a body substantially as hereinbefore described.
9. Apparatus for measuring displacement of a body substantially as hereinbefore described.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08333604A GB2151774A (en) | 1983-12-16 | 1983-12-16 | Measuring displacement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08333604A GB2151774A (en) | 1983-12-16 | 1983-12-16 | Measuring displacement |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8333604D0 GB8333604D0 (en) | 1984-02-15 |
| GB2151774A true GB2151774A (en) | 1985-07-24 |
Family
ID=10553414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08333604A Withdrawn GB2151774A (en) | 1983-12-16 | 1983-12-16 | Measuring displacement |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2151774A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4808000A (en) * | 1986-10-15 | 1989-02-28 | Union Oil Company Of California | Positioning device and method |
| EP0423104A1 (en) * | 1989-10-13 | 1991-04-17 | Claude Poulain | Method of detecting the attainment of a specific position of a needle indicator, and electronic apparatus for carrying out this method |
| US5024527A (en) * | 1986-02-12 | 1991-06-18 | British Aerospace Public Limited Company | Method and apparatus for remote position sensing using edge diffraction |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1024473A (en) * | ||||
| GB888927A (en) * | 1958-06-11 | 1962-02-07 | United Steel Companies Ltd | Improvements relating to apparatus for controlling the continuous casting of metals |
| GB1030205A (en) * | 1963-04-23 | 1966-05-18 | Elliott Brothers London Ltd | Improvements relating to measuring or indicating apparatus |
| GB1044695A (en) * | 1964-05-25 | 1966-10-05 | Ibm | Torqueless shaft coupling system |
| GB1103799A (en) * | 1964-12-28 | 1968-02-21 | Gen Electric | Improvements in optical readout systems |
| GB1249905A (en) * | 1968-03-07 | 1971-10-13 | Plasser Bahnbaumasch Franz | Mobile railway track levelling machine |
| GB1557441A (en) * | 1976-05-10 | 1979-12-12 | Dresser Ind | Optical position sensor |
| EP0005798A1 (en) * | 1978-06-02 | 1979-12-12 | Asea Ab | Stabilized fibre-optical measuring apparatus |
| GB2077421A (en) * | 1980-05-31 | 1981-12-16 | Rolls Royce | Displacement sensing |
| EP0062192A2 (en) * | 1981-03-26 | 1982-10-13 | Fraunhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E.V. | Method of optically measuring a distance |
| GB2114733A (en) * | 1982-02-12 | 1983-08-24 | Atomic Energy Authority Uk | Measuring strain |
| GB2122760A (en) * | 1982-06-04 | 1984-01-18 | Philips Nv | Measuring torque on cassette player spindles |
-
1983
- 1983-12-16 GB GB08333604A patent/GB2151774A/en not_active Withdrawn
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1024473A (en) * | ||||
| GB888927A (en) * | 1958-06-11 | 1962-02-07 | United Steel Companies Ltd | Improvements relating to apparatus for controlling the continuous casting of metals |
| GB1030205A (en) * | 1963-04-23 | 1966-05-18 | Elliott Brothers London Ltd | Improvements relating to measuring or indicating apparatus |
| GB1044695A (en) * | 1964-05-25 | 1966-10-05 | Ibm | Torqueless shaft coupling system |
| GB1103799A (en) * | 1964-12-28 | 1968-02-21 | Gen Electric | Improvements in optical readout systems |
| GB1249905A (en) * | 1968-03-07 | 1971-10-13 | Plasser Bahnbaumasch Franz | Mobile railway track levelling machine |
| GB1557441A (en) * | 1976-05-10 | 1979-12-12 | Dresser Ind | Optical position sensor |
| EP0005798A1 (en) * | 1978-06-02 | 1979-12-12 | Asea Ab | Stabilized fibre-optical measuring apparatus |
| GB2077421A (en) * | 1980-05-31 | 1981-12-16 | Rolls Royce | Displacement sensing |
| EP0062192A2 (en) * | 1981-03-26 | 1982-10-13 | Fraunhofer-Gesellschaft Zur Förderung Der Angewandten Forschung E.V. | Method of optically measuring a distance |
| GB2114733A (en) * | 1982-02-12 | 1983-08-24 | Atomic Energy Authority Uk | Measuring strain |
| GB2122760A (en) * | 1982-06-04 | 1984-01-18 | Philips Nv | Measuring torque on cassette player spindles |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5024527A (en) * | 1986-02-12 | 1991-06-18 | British Aerospace Public Limited Company | Method and apparatus for remote position sensing using edge diffraction |
| US4808000A (en) * | 1986-10-15 | 1989-02-28 | Union Oil Company Of California | Positioning device and method |
| EP0423104A1 (en) * | 1989-10-13 | 1991-04-17 | Claude Poulain | Method of detecting the attainment of a specific position of a needle indicator, and electronic apparatus for carrying out this method |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8333604D0 (en) | 1984-02-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |