WO1989008820A1 - Angular displacement sensor - Google Patents
Angular displacement sensor Download PDFInfo
- Publication number
- WO1989008820A1 WO1989008820A1 PCT/GB1989/000273 GB8900273W WO8908820A1 WO 1989008820 A1 WO1989008820 A1 WO 1989008820A1 GB 8900273 W GB8900273 W GB 8900273W WO 8908820 A1 WO8908820 A1 WO 8908820A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- transducer
- component
- path
- portions
- displacement sensor
- Prior art date
Links
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
- G01D5/12—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 using electric or magnetic means
- G01D5/14—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 using electric or magnetic means influencing the magnitude of a current or voltage
-
- 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
- G01D5/12—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 using electric or magnetic means
- G01D5/14—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 using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/16—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 using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance
- G01D5/165—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 using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance by relative movement of a point of contact or actuation and a resistive track
- G01D5/1655—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 using electric or magnetic means influencing the magnitude of a current or voltage by varying resistance by relative movement of a point of contact or actuation and a resistive track more than one point of contact or actuation on one or more tracks
-
- 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
- G01D5/12—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 using electric or magnetic means
- G01D5/14—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 using electric or magnetic means influencing the magnitude of a current or voltage
- G01D5/24—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 using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance
- G01D5/241—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 using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes
- G01D5/2412—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 using electric or magnetic means influencing the magnitude of a current or voltage by varying capacitance by relative movement of capacitor electrodes by varying overlap
Definitions
- the present invention relates to an angula displacement sensor comprising an electrical device fo providing a signal relating to angular displacement, e.g For use as a shaft angle transducer. It particularl relates to sensors responsive over a full 360° of rotatio and/or continuous rotation. Such a sensor, i gravitationally biased, can be used as an inclinometer. Summary of the Invention
- the present invention provides an angular displacemen sensor comprising an electrical device for providing signal relating to angular displacement, said electrica device comprising first and second angular displacemen transducers each having a first component that is rotatabl relative to a second component; means coupling rsaid firs components of the first and second transducers together s that their angular displacements are synchronised; eac said transducer having a respective electrical paramete that varies with said angular displacement; each of sai transducers having electrical output means for deriving fo each transducer an electrical signal indicative of said parameter; the arrangement being such that for the first component of the first transducer the path of relative angular displacement has a plurality of successive like portions in each of which the parameter varies substantially uniformly over the same range; and for the first component of the second transducer the path of relative angular displaement has a like plurality of successive portions in each of which the associated electrical parameter has a characteristic value or range, the synchronisation of
- the second transducer may also have successive like path portions in each of which its parameter varies substantially uniformly over the same range, the two first components being mutually out of phas such that when one is at the start of a portion, the othe is in the middle of a portion.
- each path has two portions.
- th first transducer there may be two portions in each of whic the parameter varies from a maximum positive value to maximum negative value. (This may be relative to a arbitrary baseline.)
- the second transducer's parameter ma show the same variation overall but, since it is out o phase, for one portion (corresponding to one portion of th first transducer's path) it is always negative, while fo the other portion it is always positive.
- it serves t provide a logic signal for telling whether a given value of the output of the first transducer represents a position on the first path portion or on the second path portion.
- the second transducer can have a respective characteristic constant value of its parameter for each path portion.
- the displacement path is preferably a complete revolution, and the path portions may be of 180° or other integral fraction of 360°.
- the parameters may be voltage, capacitance, or inductance (and may be different for the two transducers).
- the variation over each path portion (of the first transducer and also of the second when this has variation within path portions) is preferably substantially linear with displacement.
- the transducers may share a single path-defining element as their second components, the element being acted on by both of the first components.
- the second component may be an annular resistor, and the two first components may be coaxial rotors having wipers that each run on the same track.
- there may be different paths for the two transducers e.g. provided by two resistors which may be axially spaced along a shaft whose displacement is to be monitored.
- a capacitance-based sensor may employ a pair of differential capacitors whose moving parts are mechanically linked.
- An inductance-based sensor may use a transducer having a coil portion and a relatively rotatable core portion whose permeability to magnetic flux from the coil portion varies over its angular extent.
- the coil portion may extend over 180°.
- the core portion may extend over 360°, with two 180° portions of different permeabilities.
- the variation of the parameter associated with one transducer can be used to provide an analogue displacement signal, while the variation of the parameter of the second transducer can serve to provide a logic signal indicative of the path portion occupied by the first component of the first transducer.
- the provision of the second transducer enables a device to be constructed that can provide data about the complete range of displacement, i.e. in general a complete revolution.
- Fig. 1 is a schematic view of a first embodiment o the invention which is an angular displacement sensor usin resistance variation;
- Fig. 2 is a graph for use in explaining the operatio thereof; .
- Fig. 3 is a schematic view of a second embodiment o the invention which is an angular displacement sensor usin resistance variation;
- Fig. 4 is a schematic view of part of a third embodiment of the invention which is an angular displacement sensor using capacitance variation;
- Fig. 5 and 6 are plan and end elevational views of a third type of transducer which employs variable inductance.
- Fig. 7 is a graph showing variation of inductance of the third transducer.
- Fig. 1 shows a resistive transducer which comprises a 360° resistive toroid 1 which may be wirewound or of carbon film or other appropriate construction, the toroid being fed with a suitable voltage at diametrically opposed tapping points A and B.
- a contact wiper 2 is rotatable continuously around the toroid, and connected (via a slipring if for more than 360" rotation) to a terminal C.
- a second identical contact wiper 3 is mechanically coupled to the first with a displacement of 90°, and connected to terminal D, the two wipers being electrically insulated from each other.
- a plus/minus sign can be assigned to the analogue output to give full 360° data.
- This may be carried out by a signal processing and display unit P. While the illustration shows a single resistive element with two wipers displaced 90°, it would obviously be possible to use two identical such resistive elements with single wipers, coupled mechanically to give the required 90° displacement.
- Fig.3 shows a second resistive embodiment which again has a 360° resistive toroid 1 with diametrical taps A,B and a contact wiper 2 connected to a terminal C. There is a second contact wiper 3 which is rotationally coupled to the first wiper 2 and electrically connected to a terminal D. However, it does not run on the toroid 1.
- One contact 14 may be connected via a suitable resistor 6 to supply high voltage, the other similarly to supply low voltage.
- the output from the second contact wiper 3 will then be a square wave logic output 16 with continuous rotation.
- the phase relationship of the outputs from the two wipers 3,4 is such that this square wave signal 16 provides a plus/minus logic signal directly, for assigning the output of the first wiper 3 to the correct 180° sector.
- Fig. 4 shows in principle how a transducer of the differential capacitor type may be adapted to produce similar characteristics to the first embodiment.
- the transducer incorporates two stator surfaces 24 and 25, swept by a rotor 26 at a constant separation.
- the surface areas are configured so that capacitance differential between the rotor and the two stators can be used to derive a signal which rises and falls in a substantially linear manner with 180° rotation either side of a datum position.
- FIGs. 5 - 8 show an example of another form of transducer in which the variable parameter is inductance.
- a cylindrical half-stator 31 of suitable ferromagnetic material for a.c. magnetisation has a number of similar poles 41 which extend radially inwardly over 180°, each of which is wound with the same number of turns of wire 36 of alternate direction so that adjacent poles are of opposite polarity. All the poles are connected in series to terminals A and B, and energised with a.c. Concentric with this is a cylindrical rotor 32 on a shaft 35.
- the surface annulus of the rotor is divided into two sections of differing effective permeability to the magnetic flux from the stator, which loops into and out of the rotor as indicated by the broken lines.
- Section 33 is of high permeability
- section 34 of low permeability. This low effective permeability may be produced either by omitting ferromagnetic material, or by using a surface screen of high conductivity metal such as copper or aluminium, in which the magnetic flux produced by induced eddy currents opposes the stator flux.
- the interface between sections 33 and 34 is skewed by one pole as can be seen from Fig. 6.
- inductanc This is so as to produce a stepless increase in inductanc as the rotor is turned to present a high permeabilit path, rising from L Q to L ⁇ through 180° as shown in Fig. 7, returning to Lg as the full 360° is traversed.
- a simila stator-rotor assembly displaced 90° from this will produc a characteristic change of inductance displaced 90° as shown by the broken line in Fig. 7.
- the inductance can b measured by any suitable method familiar to the skilled, e variation of volt-drop with constant current passing, o variation in frequency if the winding forms part of a oscillator circuit.
- signal processing means of generally known type can be employed to process the dat from the two sets of terminals to provide data relating t angular displacement, as will be apparent to the ma skilled in the art.
- signal processing means of generally known type can be employed to process the dat from the two sets of terminals to provide data relating t angular displacement, as will be apparent to the ma skilled in the art.
- a singl capacitive transducer as shown in Fig. 4 could be used i conjunction with the contact-type resistive device 3,4,5 shown in Fig. 3 for providing a logic signal.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
A displacement sensor, particularly for monitoring angular displacement over 360°, uses two transducers (1, 2 and 1, 3; 1, 2 and 3, 14, 16; 24-26) whose moving parts (2, 3; 26) are coupled for synchronous displacement over respective paths. Each transducer has a measurable parameter. For the first transducer (1, 2; 24-26), the path has a plurality of equal portions (AB, BA) in each of which the parameter varies uniformly over the same range. For the second transducer, the values or ranges of its parameter are characteristic of the portions. Thus they can provide a logic signal for indicating the path portion so that the parameter value of the first transducer determines the displacement position uniquely. For example, the first transducer may be a rotary potentiometer (1, 2) with 180° taps (A, B). The second transducer (3, 14, 15) may employ two 180° contact plates (14, 15) held at high and low potential (respectively), and a sliding contact (3) rotationally fast with the contact (2) of the potentiometer.
Description
ANGULAR DISPLACEMENT SENSOR Background of the Invention
The present invention relates to an angula displacement sensor comprising an electrical device fo providing a signal relating to angular displacement, e.g For use as a shaft angle transducer. It particularl relates to sensors responsive over a full 360° of rotatio and/or continuous rotation. Such a sensor, i gravitationally biased, can be used as an inclinometer. Summary of the Invention
The present invention provides an angular displacemen sensor comprising an electrical device for providing signal relating to angular displacement, said electrica device comprising first and second angular displacemen transducers each having a first component that is rotatabl relative to a second component; means coupling rsaid firs components of the first and second transducers together s that their angular displacements are synchronised; eac said transducer having a respective electrical paramete that varies with said angular displacement; each of sai transducers having electrical output means for deriving fo each transducer an electrical signal indicative of said parameter; the arrangement being such that for the first component of the first transducer the path of relative angular displacement has a plurality of successive like portions in each of which the parameter varies
substantially uniformly over the same range; and for the first component of the second transducer the path of relative angular displaement has a like plurality of successive portions in each of which the associated electrical parameter has a characteristic value or range, the synchronisation of displacements being such that as the first component of the first transducer traverses any path portion, the first component of the second transducer traverses a respective path portion whereof the associated electrical parameter serves to distinguish between the like portions of the path of the first component of the first transducer.
For example, the second transducer may also have successive like path portions in each of which its parameter varies substantially uniformly over the same range, the two first components being mutually out of phas such that when one is at the start of a portion, the othe is in the middle of a portion.
Typically each path has two portions. Thus for th first transducer there may be two portions in each of whic the parameter varies from a maximum positive value to maximum negative value. (This may be relative to a arbitrary baseline.) The second transducer's parameter ma show the same variation overall but, since it is out o phase, for one portion (corresponding to one portion of th first transducer's path) it is always negative, while fo the other portion it is always positive. Thus it serves t
provide a logic signal for telling whether a given value of the output of the first transducer represents a position on the first path portion or on the second path portion.
Alternatively, the second transducer can have a respective characteristic constant value of its parameter for each path portion.
The displacement path is preferably a complete revolution, and the path portions may be of 180° or other integral fraction of 360°. The parameters may be voltage, capacitance, or inductance (and may be different for the two transducers). The variation over each path portion (of the first transducer and also of the second when this has variation within path portions) is preferably substantially linear with displacement. The transducers may share a single path-defining element as their second components, the element being acted on by both of the first components. For example the second component may be an annular resistor, and the two first components may be coaxial rotors having wipers that each run on the same track. Alternatively there may be different paths for the two transducers, e.g. provided by two resistors which may be axially spaced along a shaft whose displacement is to be monitored. A capacitance-based sensor may employ a pair of differential capacitors whose moving parts are mechanically linked.
An inductance-based sensor may use a transducer having a coil portion and a relatively rotatable core portion
whose permeability to magnetic flux from the coil portion varies over its angular extent. The coil portion may extend over 180°. The core portion may extend over 360°, with two 180° portions of different permeabilities. The variation of the parameter associated with one transducer can be used to provide an analogue displacement signal, while the variation of the parameter of the second transducer can serve to provide a logic signal indicative of the path portion occupied by the first component of the first transducer. There may be signal processing means for deriving an output related to displacement.
The provision of the second transducer enables a device to be constructed that can provide data about the complete range of displacement, i.e. in general a complete revolution.
Brief Description of the Drawings
Some embodiments of the invention will now be described with reference to the accompanying drawings i which: Fig. 1 is a schematic view of a first embodiment o the invention which is an angular displacement sensor usin resistance variation;
Fig. 2 is a graph for use in explaining the operatio thereof; . Fig. 3 is a schematic view of a second embodiment o the invention which is an angular displacement sensor usin resistance variation;
Fig. 4 is a schematic view of part of a third embodiment of the invention which is an angular displacement sensor using capacitance variation;
Fig. 5 and 6 are plan and end elevational views of a third type of transducer which employs variable inductance; and
Fig. 7 is a graph showing variation of inductance of the third transducer.
Description of the Preferred Embodiments Fig. 1 shows a resistive transducer which comprises a 360° resistive toroid 1 which may be wirewound or of carbon film or other appropriate construction, the toroid being fed with a suitable voltage at diametrically opposed tapping points A and B. A contact wiper 2 is rotatable continuously around the toroid, and connected (via a slipring if for more than 360" rotation) to a terminal C. A second identical contact wiper 3 is mechanically coupled to the first with a displacement of 90°, and connected to terminal D, the two wipers being electrically insulated from each other.
If the voltages at terminals C and D are measured relative to either terminal A or B, as the rotor constituted by the two wiper assemblies is turned, the voltages will rise and fall in accordance with the Fig. 2 curves. That is, as a wiper moves from A to B, the voltage falls linearly with angular displacement to a minimum value. Continued rotation reverses the process. The two
wipers 2,3 give identical characteristics, but 90° out of phase. It will be apparent that, if voltage output C-B is used to give an analogue level corresponding with 180° rotation either side of a datum position, the level of output D-B will be high for 180° in one direction, and low for the other. By converting the high/low comparison into a logic signal, a plus/minus sign can be assigned to the analogue output to give full 360° data. This may be carried out by a signal processing and display unit P. While the illustration shows a single resistive element with two wipers displaced 90°, it would obviously be possible to use two identical such resistive elements with single wipers, coupled mechanically to give the required 90° displacement. Fig.3 shows a second resistive embodiment which again has a 360° resistive toroid 1 with diametrical taps A,B and a contact wiper 2 connected to a terminal C. There is a second contact wiper 3 which is rotationally coupled to the first wiper 2 and electrically connected to a terminal D. However, it does not run on the toroid 1. Instead it runs on a ring 10 of contact material split to form two semicircular fixed contacts 14,15 separated by minimal gaps 16, positioned so that the gaps occupy the 0° and 180° degree transition points of the analogue output channel. One contact 14 may be connected via a suitable resistor 6 to supply high voltage, the other similarly to supply low voltage. The output from the second contact wiper 3 will
then be a square wave logic output 16 with continuous rotation. The phase relationship of the outputs from the two wipers 3,4 is such that this square wave signal 16 provides a plus/minus logic signal directly, for assigning the output of the first wiper 3 to the correct 180° sector. Fig. 4 shows in principle how a transducer of the differential capacitor type may be adapted to produce similar characteristics to the first embodiment. The transducer incorporates two stator surfaces 24 and 25, swept by a rotor 26 at a constant separation. The surface areas are configured so that capacitance differential between the rotor and the two stators can be used to derive a signal which rises and falls in a substantially linear manner with 180° rotation either side of a datum position. By coupling two such transducers together displaced by 90° from each other, two signals following the general form of Fig. 2 may be derived, and from them an analogue plus logic signal for plus and minus 180° rotation. The surface configurations shown are schematic only, and not necessarily accurate representations of those required to produce the linear analogue characteristics of Fig. 2.
Figs. 5 - 8 show an example of another form of transducer in which the variable parameter is inductance. A cylindrical half-stator 31 of suitable ferromagnetic material for a.c. magnetisation has a number of similar poles 41 which extend radially inwardly over 180°, each of which is wound with the same number of turns of wire 36 of
alternate direction so that adjacent poles are of opposite polarity. All the poles are connected in series to terminals A and B, and energised with a.c. Concentric with this is a cylindrical rotor 32 on a shaft 35. The surface annulus of the rotor is divided into two sections of differing effective permeability to the magnetic flux from the stator, which loops into and out of the rotor as indicated by the broken lines. Section 33 is of high permeability, and section 34 of low permeability. This low effective permeability may be produced either by omitting ferromagnetic material, or by using a surface screen of high conductivity metal such as copper or aluminium, in which the magnetic flux produced by induced eddy currents opposes the stator flux. The interface between sections 33 and 34 is skewed by one pole as can be seen from Fig. 6. This is so as to produce a stepless increase in inductanc as the rotor is turned to present a high permeabilit path, rising from LQ to L^ through 180° as shown in Fig. 7, returning to Lg as the full 360° is traversed. A simila stator-rotor assembly displaced 90° from this will produc a characteristic change of inductance displaced 90° as shown by the broken line in Fig. 7. The inductance can b measured by any suitable method familiar to the skilled, e variation of volt-drop with constant current passing, o variation in frequency if the winding forms part of a oscillator circuit.
With any embodiment, signal processing means of
generally known type can be employed to process the dat from the two sets of terminals to provide data relating t angular displacement, as will be apparent to the ma skilled in the art. Of course, much variation is possibl within the scope of the invention. For example, a singl capacitive transducer as shown in Fig. 4 could be used i conjunction with the contact-type resistive device 3,4,5 shown in Fig. 3 for providing a logic signal.
Claims
1. An angular displacement sensor comprising an electrical device for providing a signal relating to angular displacement, said electrical device comprising first and second angular displacement transducers (1;1,3,10;24-26;31-41) each having a first component (2;3;26;32) that is rotatable relative to a second component (1;1,14,15;24,25;31); means coupling, said first components of the first and second transducers together so that their angular displacements are synchronised; each said transducer having a respective electrical parameter that varies with said angular displacement; each of said transducers having electrical output means (A,B,C,D) for deriving for each transducer an electrical signal indicative of said parameter; the arrangement being such that for the first component of the first transducer the path of relative angular displacement has a plurality of successive like portions (AB,BA) in each of which the parameter varies substantially uniformly over the same range; and for the first component (3) of the second transducer the path of relative angular displacement has a like plurality of successive portions (14,15) in each of which the associated electrical parameter has a characteristic value or range, the synchronisation of displacements being such that as the first component of the first transducer traverses any path portion the first component of the second transducer traverses a respective path portion, whereof the associated electrical paramete serves to distinguish between the like portions of the pat of the first component of the first transducer.
2. A displacement sensor according to Claim 1 in whic said first component of the second transducer has a pat with successive like portions (AB,BA) in each of which th parameter varies substantially uniformly over the sam range, said successive like portions being out of phas with said path portions (AB,BA) of the first component (2 of the first transducer, such that when one is at the star of a portion, the other is in the middle of a portion.
3. A displacement sensor according to Claim 1 in whic said first component (3) of the second transducer has respective characteristic constant value of its paramete for each path portion (14,15).
4. A displacement sensor according to Claim 1 wherein eac path is divided into only two 180° portions (A,B;14,15).
5. A displacement sensor according to Claim 4 wherein th path of the first component of the first transducer has tw portions (A,B) in each of which the parameter varies from maximum positive value to a maximum negative value relativ to an intermediate baseline value.
6. A displacement sensor according to Claim 5 wherein th path of the first component of the second transducer ha two portions (A,B) in each of which the parameter varie from a maximum positive value to a maximum negative value, but these path portions of the second transducer are out o phase with the path portions of the first transducer such that for one of the path portions of the first transducer the second transducer's parameter is always above the baseline while for the other one of the path portions of 5 the first transducer the second transducer's parameter is always below the baseline.
7. A displacement sensor according to Claim 1 wherein the displacement path for each transducer is a complete revolution and the path portions each correspond to an 0 integral fraction of 360°.
8. A displacement sensor according to Claim 1 wherein the second component of at least one transducer comprises an elongate resistor (1) and the first component of at least the first transducer comprises a variable contact (2) 5 displaceable relative to said elongate resistor.
9. A displacement sensor according to Claim 8 wherein the first components of both transducers comprise respective variable contacts (2,3) which are displaceable relative to the same said elongate resistor (1)„
20 10. A displacement sensor according to Claim 1 wherein at least one of the first and second transducers is a differential capacitor.
11. A displacement sensor according to Claim 1 wherein at least one of the first and second transducers is a a
25 variable inductor (31-41).
12. A displacement sensor according to Claim 11 wherein the variable inductor comprises a coil component (31,36,41) and a relatively rotatable core component (32,33,34) said core component having portions (33,34) of different permeability to magnetic flux arranged so that the inductance of the coil component is dependent on the relative configuration of the coil component.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB8806098 | 1988-03-15 | ||
GB888806098A GB8806098D0 (en) | 1988-03-15 | 1988-03-15 | Displacement sensor |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1989008820A1 true WO1989008820A1 (en) | 1989-09-21 |
Family
ID=10633443
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1989/000273 WO1989008820A1 (en) | 1988-03-15 | 1989-03-15 | Angular displacement sensor |
Country Status (2)
Country | Link |
---|---|
GB (1) | GB8806098D0 (en) |
WO (1) | WO1989008820A1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5133417A (en) * | 1990-06-18 | 1992-07-28 | The Charles Machine Works, Inc. | Angle sensor using thermal conductivity for a steerable boring tool |
FR2684758A1 (en) * | 1991-12-09 | 1993-06-11 | Alcatel Satmam | CLOSED CONTINUOUS RESISTIVE TRACK ANGLE POSITION SENSOR AND CORRESPONDING MEASUREMENT METHOD. |
DE4320176A1 (en) * | 1993-06-18 | 1994-12-22 | Bayerische Motoren Werke Ag | Circuit arrangement for detecting the position of a movable component in motor vehicles |
DE4408050A1 (en) * | 1994-03-10 | 1995-09-14 | Thomson Brandt Gmbh | Device for converting a mechanical to an electrical variable |
WO2000063652A1 (en) * | 1999-04-16 | 2000-10-26 | Vishay Limited | A position encoder |
CN102865218A (en) * | 2012-09-14 | 2013-01-09 | 山推楚天工程机械有限公司 | Accurate measuring method and equipment for coaxiality of concrete mechanical pumping system |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB870158A (en) * | 1959-10-20 | 1961-06-14 | Marconi Wireless Telegraph Co | Improvements in or relating to electro-mechanical translating devices |
GB870157A (en) * | 1958-05-08 | 1961-06-14 | Marconi Wireless Telegraph Co | Improvements in or relating to electro-mechanical translating devices |
JPS593212A (en) * | 1982-06-30 | 1984-01-09 | Kato Seisakusho:Kk | Rotary position detecting device for rotary body |
JPS59216201A (en) * | 1983-05-25 | 1984-12-06 | Sony Corp | Presettable control circuit |
EP0211477A2 (en) * | 1985-06-03 | 1987-02-25 | Honeywell Inc. | Angular position to linear voltage converter |
-
1988
- 1988-03-15 GB GB888806098A patent/GB8806098D0/en active Pending
-
1989
- 1989-03-15 WO PCT/GB1989/000273 patent/WO1989008820A1/en unknown
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB870157A (en) * | 1958-05-08 | 1961-06-14 | Marconi Wireless Telegraph Co | Improvements in or relating to electro-mechanical translating devices |
GB870158A (en) * | 1959-10-20 | 1961-06-14 | Marconi Wireless Telegraph Co | Improvements in or relating to electro-mechanical translating devices |
JPS593212A (en) * | 1982-06-30 | 1984-01-09 | Kato Seisakusho:Kk | Rotary position detecting device for rotary body |
JPS59216201A (en) * | 1983-05-25 | 1984-12-06 | Sony Corp | Presettable control circuit |
EP0211477A2 (en) * | 1985-06-03 | 1987-02-25 | Honeywell Inc. | Angular position to linear voltage converter |
Non-Patent Citations (2)
Title |
---|
Patent Abstracts of Japan, vol. 8, no. 86 (P-269)(1523), 19 April 1984 & JP-A-59003212 (KATOU SEISAKUSHO K.K.) 9 January 1984 * |
Patents Abstracts of Japan, vol. 9, no. 86 (P-349)(1809), 16 April 1985 & JP-A-59216201 (SONY K.K.) 6 December 1984 * |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5133417A (en) * | 1990-06-18 | 1992-07-28 | The Charles Machine Works, Inc. | Angle sensor using thermal conductivity for a steerable boring tool |
FR2684758A1 (en) * | 1991-12-09 | 1993-06-11 | Alcatel Satmam | CLOSED CONTINUOUS RESISTIVE TRACK ANGLE POSITION SENSOR AND CORRESPONDING MEASUREMENT METHOD. |
EP0546907A1 (en) * | 1991-12-09 | 1993-06-16 | Neopost Industrie | Angular position sensor with continuous closed resistive track and measuring method therefore |
US5399981A (en) * | 1991-12-09 | 1995-03-21 | Neopost Industrie | Closed continuous resistive track angular position sensor and measurement method |
DE4320176A1 (en) * | 1993-06-18 | 1994-12-22 | Bayerische Motoren Werke Ag | Circuit arrangement for detecting the position of a movable component in motor vehicles |
DE4408050A1 (en) * | 1994-03-10 | 1995-09-14 | Thomson Brandt Gmbh | Device for converting a mechanical to an electrical variable |
US5986585A (en) * | 1994-03-10 | 1999-11-16 | Deutsche Thomson-Brandt Gmbh | Device for converting a mechanical variable into an electrical variable |
WO2000063652A1 (en) * | 1999-04-16 | 2000-10-26 | Vishay Limited | A position encoder |
CN102865218A (en) * | 2012-09-14 | 2013-01-09 | 山推楚天工程机械有限公司 | Accurate measuring method and equipment for coaxiality of concrete mechanical pumping system |
CN102865218B (en) * | 2012-09-14 | 2014-12-31 | 山推楚天工程机械有限公司 | Accurate measuring method and equipment for coaxiality of concrete mechanical pumping system |
Also Published As
Publication number | Publication date |
---|---|
GB8806098D0 (en) | 1988-04-13 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US4991301A (en) | Inductive displacement sensors | |
US4853604A (en) | Position and speed sensors | |
US4682104A (en) | Angular displacement pickup, particularly for the detection of torque in power steering | |
US4238781A (en) | Capacitive angular displacement transducer for remote meter reading | |
US2674729A (en) | Measuring apparatus | |
US3845377A (en) | Rotational angle transducer | |
US3961318A (en) | Electrostatic position-measuring transducer | |
EP1898185B1 (en) | Position sensor | |
US5929631A (en) | Method of position sensing utilizing giant magneto resistance elements and solid state switch array | |
CN107407577B (en) | Induction type movable sensor | |
US7196527B2 (en) | Redundant compact encoders | |
US5872408A (en) | Capacitive sensor for indicating position | |
JPH03500204A (en) | Measuring device for rotation angle and/or torque | |
JPS6122888B2 (en) | ||
EP0438490B1 (en) | Homopolar inductive displacement sensor | |
US5637997A (en) | Angular displacement sensor with movable inductance affecting component | |
Brasseur | A robust capacitive angular position sensor | |
WO2002021081A1 (en) | Angle transducer | |
WO1997039312A1 (en) | Displacement sensors | |
US3729728A (en) | Capacitive switching device | |
JP3556949B2 (en) | Potentiometer | |
US5521494A (en) | Inductive displacement sensor including an autotransformer and an inductance effecting means extending between 90 and 180 electrical degrees | |
WO1989008820A1 (en) | Angular displacement sensor | |
US6922051B2 (en) | Displacement and/or angle sensor with a meander-shaped measuring winding | |
US20020158627A1 (en) | Analog sensor for contact-free angular offset sensing |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): GB JP US |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): AT BE CH DE FR GB IT LU NL SE |