Position sensor having compact arrangement of coils
First Claim
Patent Images
1. An apparatus for use in a position encoder comprising:
- a first plurality of conductor tracks arranged along a measurement path;
a second plurality of conductor tracks arranged along said measurement path;
wherein the first and second pluralities of conductor tracks are superimposed on each other to define (i) a first circuit having at least two series connected loops arranged along the measurement path; and
(ii) a second circuit having at least one loop which extends along said measurement path;
characterised in that the conductor tracks of said first plurality of conductor tracks which form part of said first circuit are arranged in first and second groups which are transversely spaced relative to said measurement path;
the conductor tracks of said second plurality of conductor tracks which form part of said first circuit are arranged for connecting conductor tracks in the first group with conductor tracks in the second group; and
the conductor track or tracks of said first plurality of conductor tracks which form said at least one loop of said second circuit are located between and electrically separate from said first and second groups of conductor tracks.
1 Assignment
0 Petitions
Accused Products
Abstract
A transducer is provided for use in a position sensor which senses the position of two relatively movable members. In one form, the transducer has a plurality of sensor windings having a number of loops arranged in succession and connected in series so that signals induced in adjacent loops by a common electromagnetic field oppose each other and an excitation winding having at least one loop super-imposed on but electrically isolated from the loops of the sensor windings.
-
Citations
50 Claims
-
1. An apparatus for use in a position encoder comprising:
-
a first plurality of conductor tracks arranged along a measurement path;
a second plurality of conductor tracks arranged along said measurement path;
wherein the first and second pluralities of conductor tracks are superimposed on each other to define (i) a first circuit having at least two series connected loops arranged along the measurement path; and
(ii) a second circuit having at least one loop which extends along said measurement path;
characterised in that the conductor tracks of said first plurality of conductor tracks which form part of said first circuit are arranged in first and second groups which are transversely spaced relative to said measurement path;
the conductor tracks of said second plurality of conductor tracks which form part of said first circuit are arranged for connecting conductor tracks in the first group with conductor tracks in the second group; and
the conductor track or tracks of said first plurality of conductor tracks which form said at least one loop of said second circuit are located between and electrically separate from said first and second groups of conductor tracks. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
first and second members which are relatively moveable along a measurement path;
said first member comprising an apparatus according to claim 1; and
said second member comprising means for interacting with said circuits on said apparatus such that in response to an input driving signal applied to one of said circuits, there is induced in the other said circuit an output signal which varies as a function of the relative position between said first and second members along said measurement path.
-
-
18. A sensor according to claim 17, wherein said interacting means comprises an electromagnetic field generator.
-
19. A sensor according to claim 17, wherein said interacting means comprises at least one of:
- an electromagnetic resonant device, a short circuit coil, a conductive screen or a ferrite pole piece.
-
20. A sensor according to claim 17, wherein said interacting means and said at least two loops of said first circuit are arranged so that said output signal continuously varies as a function of the relative position of said first and second members along said measurement path.
-
21. A sensor according to claim 20, wherein said output signal varies periodically as a function of the relative position between said interacting means and said at least two loops.
-
22. A sensor according to claim 21, wherein said periodic variation is substantially sinusoidal.
-
23. A sensor according to any of claims 17, further comprising drive means for applying said input driving signal to one of said first and second circuits and processing means for processing the signal generated in said other circuit and for providing an indication therefrom of the relative position of said first and second members.
-
24. A sensor according to claim 23, wherein said processing means comprises a demodulator which is matched to the phase of the signal generated in said other circuit by said interacting means.
-
25. A sensor according to claim 24, wherein said demodulator is operable to demodulate said signal using a 90°
- phase shifted version of the excitation signal.
-
26. A sensor according to claims 23, wherein said apparatus comprises two or more of said first circuits, wherein the loops of the respective first circuits are spatially separated along said measurement path and wherein said processing circuit is operable to perform a trigonometric ratio calculation of the signals generated in said two or more first circuits.
-
27. A sensor according to any of claims 23, wherein said output signal generated in said other circuit varies sinusoidally as a function of the position along said path of said interacting means relative to said at least two loops, and wherein one period of said sinusoidal variation corresponds to a relative movement along the measurement path of the extent of two of said series connected loops.
-
28. A sensor according to any of claims 23, wherein said first and second circuits are mounted on a circuit board, and wherein said drive means and/or said processing means is mounted on said circuit board.
-
29. A sensor according to any of claims 17, wherein said first and second circuits are formed on substantially planar surfaces.
-
30. A sensor according to claim 29, wherein said interacting means comprises a coil and wherein the axis of the coil is generally perpendicular to said planar surface.
-
31. A sensor according to claim 30, wherein the first and second circuits lie in substantially the same plane, and wherein said coil is movable relative to said first and second circuits in a plane which is substantially parallel to the plane in which said first and second circuits lie.
-
32. A sensor according to any of claims 17, wherein said first member is fixed and wherein said second member is movable with respect to said first member.
-
33. A method of detecting the position of first and second members which are relatively moveable along a measurement path, the method comprising the steps of:
-
providing a position sensor according to claim 17;
applying a drive signal to one of the circuits on said apparatus; and
detecting the signal generated in said other circuit and deriving therefrom the relative position of said first and second members.
-
-
34. A method according to claim 33, wherein said driving signal comprises an alternating signal having a frequency in the range of 10 KHz to 10 MHz.
-
35. An apparatus for use in a position encoder comprising:
-
an insulator base defining first and second surfaces which extend along a measurement path;
a first plurality of conductor tracks arranged on said first surface along said measurement path;
a second plurality of conductor tracks arranged on said second surface along said measurement path;
wherein the insulator base comprises a plurality of via holes for connecting the conductor tracks on the first surface to the conductor tracks on the second surface to define (i) a first circuit having at least two series connected loops arranged along the measurement path; and
(ii) a second circuit having at least one loop which extends along said measurement path;
characterised in that the first and second plurality of conductor tracks and said via holes are arranged so that the at least one loop of said second circuit extends across the at least two loops of said first circuit.
-
-
36. An apparatus for use in a position encoder comprising:
-
an insulator base defining first and second surfaces which extend along a measurement path;
a first plurality of conductor tracks arranged on said first surface along said measurement path;
a second plurality of conductor tracks arranged on said second surface along said measurement path;
wherein the insulator base comprises a plurality of via holes for connecting the conductor tracks on the first surface to the conductor tracks on the second surface to define (i) a first circuit having at least two series connected loops arranged along the measurement path; and
(ii) a second circuit having at least one loop which extends along said measurement path;
characterised in that;
the conductor tracks on said first surface which form part of said first circuit are arranged in first and second groups which are transversely spaced relative to said measurement path;
the conductor tracks on said second surface which form part of said first circuit are arranged for connecting conductor tracks in the first group with conductor tracks in the second group; and
the conductor track or tracks which form said at least one loop of said second circuit are carried by said first surface between said first and second groups.
-
-
37. An apparatus for use in a position sensor, comprising:
-
two layers of conductor tracks insulated, at least at any crossovers, by an insulator, the conductor tracks being arranged so as to define (i) a first circuit having at least two loops of opposite sense which extend along a measurement path, said loops being connected in series and being arranged so that signals generated in said at least two loops by a common electromagnetic field oppose each other; and
(ii) a second circuit having at least one loop which extends along said measurement path and which is superimposed on but electrically isolated from said at least two loops of said first circuit;
wherein an electromagnetic coupling area between the at least one loop of said second circuit and one or more loops of one sense of said first circuit is varied to oppose the effect of a variation in coupling between the at least one loop of said second circuit and a loop of the other sense of said first circuit caused by an arrangement of connector tracks to said second circuit. - View Dependent Claims (38, 39, 40, 41)
-
-
42. An apparatus for use in a position encoder comprising:
-
an insulator base defining first and second surfaces which extend along a measurement path;
a first plurality of conductor tracks arranged on said first surface along said measurement path;
a second plurality of conductor tracks arranged on said second surface along said measurement path;
wherein the insulator base comprises a plurality of via holes for connecting the conductor tracks on the first surface to the conductor tracks on the second surface to define (i) a first circuit having at least two loops along the measurement path, said loops being connected in series and being arranged so that signals generated in said at least two loops by a common electromagnetic field oppose each other; and
(ii) a second circuit having at least one loop which extends along said measurement path and which is superimposed on but electrically isolated from said at least two loops of said first circuit;
wherein an electromagnetic coupling area between the at least one loop of said second circuit and one or more loops of one sense of said first circuit is varied to oppose the effect of a variation in coupling between the at least one loop of said second circuit and a loop of the other sense of said first circuit caused by an arrangement of connector tracks to said second circuit.
-
-
43. An apparatus for use in a position sensor comprising:
-
a first plurality of conductor tracks arranged in a first layer along a measurement path;
a second plurality of conductor tracks arranged in a second layer along said measurement path;
wherein the first and second pluralities of conductor tracks are superimposed on each other and connected together to define first and second circuits;
wherein the conductor tracks in said first layer which form part of said first circuit are arranged in first and second groups which are transversely spaced relative to said measurement path;
wherein the conductor tracks in said second layer which form part of said first circuit are arranged for connecting conductor tracks in the first group with conductor tracks in the second group; and
wherein the conductor track or tracks which form said second circuit are arranged in said first layer between said first and second groups of conductor tracks. - View Dependent Claims (44, 45, 46)
-
-
47. An apparatus for use in a position sensor comprising:
-
an insulator base defining first and second surfaces which extend along a measurement path;
a first plurality of conductor tracks arranged on said first surface along said measurement path;
a second plurality of conductor tracks arranged on said second surface along said measurement path;
wherein the insulator base comprises a plurality of via holes for connecting the conductor tracks on the first surface to the conductor tracks on the second surface, the conductor tracks on said first surface and the conductor tracks on said second surface being arranged so that when connected together through said vias, they define first and second circuits;
wherein the conductor tracks on said first surface which form part of said first circuit are arranged in first and second groups which are transversely spaced relative to said measurement path;
wherein the conductor tracks on said second surface which form part of said first circuit are arranged for connecting conductor tracks in the first group with conductor tracks in the second group; and
wherein the conductor track or tracks which form said second circuit are carried by said first surface between said first and second groups.
-
-
48. An apparatus for use in a position encoder comprising:
-
a first plurality of conductor tracks arranged in a first layer along a measurement path;
a second plurality of conductor tracks arranged in a second layer along said measurement path;
wherein the first and second pluralities of conductor tracks are superimposed on each other to define first and second circuits;
wherein the conductor tracks in said first layer which form part of said first circuit are arranged in first and second groups which are transversely spaced relative to said measurement path;
the conductor tracks in said second layer which form part of said first circuit are arranged for connecting conductor tracks in the first group with conductor tracks in the second group; and
the conductor track or tracks which form said second circuit are arranged in said first layer between said first and second groups of conductor tracks. - View Dependent Claims (49, 50)
-
Specification