Patent EP0638960A2 successfully refreshed from Google Patents.
Patent EP0226716A2 successfully refreshed from Google Patents.
EP0226716A2
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EP
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Capacitive position transducer system
Assignee: HP Inc
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Filing: 1986-09-05
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Granted: —
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Expires: 2006-09-05
Abstract
Abstract A transducer comprises a drive member (24) and a sense rotor (22) having confronting capacitively coupled electrode faces, each face of which comprises a circular pattern of electrodes (38,44) relatively rotatably mounted in concentric relationship. Either the drive member or the sense rotor, or both, are provided with a set of curved electrodes (38,44) which are slanted or swept back with respect to one direction of rotation. The electrodes (38) of the drive member (24) are completely interdigitated using a plurality of successively phase shifted, time varying drive voltages, coupled (at 5,6,7,8) individually to a corresponding plurality of drive member electrodes (38). Pickup signal errors are minimized by a three dimensional sense rotor (22) in which the sense electrodes (44) are coupled to an isolated pickup electrode (48) disposed adjacent the axial face of the sense rotor opposite that of the sense electrode face. The drive electrodes (38) and the sense electrodes (44) are configured to provide capacitive coupling between a single drive electrode and a single sense electrode that closely approaches a pure sine wave as a function of the angular displacement of the sense rotor (22) with respect to the drive member (24). The sensed phase angle is used to provide an accurate digital indication of position which can be read by a microprocessor or other controller.
Inventors
- 👤 Tammy Herr
- 👤 Michael L. Hoggatt
- 👤 Howard L. Merrill
- 👤 Arthur K. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:40
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/12; G01D5/14; G01D5/24; G01D5/241; G01D5/2412; G01D5/2415
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
96 words
A position transducer system responsive to angular displacement, characterized by: means including two relatively angularly displaceable members (22,24; 56,60) having confronting capacitively coupled electrode faces; and a set of electrodes (44,38;58,62) on each of said electrode faces comprising a plurality of electrodes disposed in outwardly radiating positions in a repeating circular pattern, the set of electrodes of at least one (56) of said members comprising curved electrodes (58) having curved opposite edges which are curved in substantially the same direction, for providing an essentially sinusoidal capacitance versus angle function for the purpose of minimizing transducer errors.
Claim 2
Dependent Claim
96 words
A position transducer system responsive to angular displacement, characterized by: means including two relatively angularly displaceable members (22,24; 56,60) having confronting capacitively coupled electrode faces; and a set of electrodes (44,38;58,62) on each of said electrode faces comprising a plurality of electrodes disposed in outwardly radiating positions in a repeating circular pattern, the set of electrodes of at least one (56) of said members comprising curved electrodes (58) having curved opposite edges which are curved in substantially the same direction, for providing an essentially sinusoidal capacitance versus angle function for the purpose of minimizing transducer errors.
Claim 3
Dependent Claim
37 words
A position transducer system according to claim l, characterized in that the curved opposite side edges of said electrodes (44;58) are swept back with respect to one direction of rotation of that member (22; 56) which rotates.
Claim 4
Dependent Claim
28 words
A position transducer system according to claim l or 2, characterized in that said curved opposite side edges of said electrodes are substantially or precisely spiral curved edges.
Claim 5
Dependent Claim
27 words
A position transducer system according to claim l or 2, characterized in that said curved opposite side edges of said electrodes (58) are arcs of a circle.
Claim 6
Dependent Claim
39 words
A position transducer system according to claim 4, characterized in that said arcs of a circle are substantially of the same radius (A) as the outer diameter of the circular pattern of said electrodes (58) of said one member.
Claim 7
Dependent Claim
53 words
A position transducer system according to claim 5, characterized in that the centers of said arcs of a circle defining the curved opposite side edges of each electrode of said one member are circumferentially spaced (about C) substantially on a circle concentric with the circular pattern of said one set of electrodes (58).
Claim 8
Dependent Claim
31 words
A position transducer system according to one of claims l to 6, characterized in that the member having said curved electrodes (58) is the rotatable member (56) or the non-rotatable member.
Claim 9
Dependent Claim
59 words
A position transducer system according to claims l to 6, characterized in that the set of electrodes of the other (24) of said members comprises curved electrodes (38) having curved opposite side edges , the electrodes (38,44) of both said members (24; 22) preferably being curved in the same direction when said electrode faces are disposed in confronting relationship.
Claim 10
Dependent Claim
97 words
A position transducer system according to claim 8, characterized in that the curved opposite side edges of the electrodes of the other of said members are arcs of a circle of a lesser radius than the radius of the curved opposite side edges of the electrodes of said one of said members, the centers of said arcs of a circle being preferably circumferentially spaced on a circle of lesser radius than the outer radius of the circular pattern of electrodes and concentric with the circular pattern of the set of electrodes of said other of said members.
Claim 11
Dependent Claim
37 words
l0.A position transducer system according to one of the preceding claims, characterized in that the number of electrodes of the other of said members is an even multiple of the number of electrodes of said one member.
Claim 12
Dependent Claim
35 words
ll.A position transducer system according to one of the preceding claims, characterized in that each member (22,24; 56,60) comprises a flat plate substrate of electrical insulating material upon which said electrodes (44,38; 56,62) are mounted.
Claim 13
Dependent Claim
194 words
l2.A position transducer system according to claim ll, characterized by: a central electrode (59) on the flat plate substrate (57) of said one member (56) and coupled to said curved electrodes (58), said one member being a rotatable member; a central electrode (63) on the flat plate substrate of the other of said members electrically insulated from the electrodes (62) on said other (60) of said members, said other of said members being a stationary member; electrical connections (40) at the outer ends of a first selected even submultiple number of electrodes (62) on said stationary member (60) for coupling phase shifted time varying electrical energy to said first selected even submultiple number of electrodes; individual circuits (66 to 72) on the side of said stationary member (60) opposite said electrodes and extending through said substrate, coupling each outer end of each electrode to the inner end of each corresponding electrode of an adjacent selected even multiple number of electrodes removed in the same direction around said circular patterns, said individual circuits preferably being curved; and means for establishing an electrical connection with the central electrode (63) on said other (60) of said members.
Claim 14
Dependent Claim
72 words
A position transducer system according to one of claims l to ll, characterized in that said rotatable member (22) is three dimensional and has opposite axial faces, one axial face comprising said curved electrodes (44) and the opposite axial face comprising a pickup face electrically coupled to said curved electrodes; and in that a pickup electrode (48) is capacitively coupled to said pickup face for establishing a connection to an external circuit.
Claim 15
Dependent Claim
58 words
A position transducer system according to claim l3, characterized in that said rotatable member (22) comprises a body portion of electrical insulating material having said curved electrodes (44) on said one axial face, or in that said rota tablemember comprises a body portion of electrical conducting material, said curved electrodes (44) being integral projections of said body portion.
Claim 16
Dependent Claim
166 words
l5.A positon transducer system according to one of the preceding claims, having integral circuit and electrode connections, characterized in that one (24; 60) of said members is a stationary member and comprises a circuit board of electrical insulating material having said set of electrodes (38) disposed on said electrode face; a group of circuits (66 to 80) on the opposite side of said circuit board from said electrode face is individually coupled through said circuit board to individual electrodes of a first group of electrodes of said set of electrodes; each outer end of each electrode (38) is connected through said circuit board via a circuit on said opposite face to the inner end of a corresponding electrode in an adjacent group of electrodes in said circular pattern, corresponding to said first group of electrodes, providing individual continuous circuits including corresponding electrodes of each group; and means are provided for coupling individual, time varying successively phase shifted voltages to individual circuits of said group of circuits.
Claim 17
Dependent Claim
21 words
l6.A position transducer system according to claim l5, characterized in that said time varying voltages are phase modulated, rectangular wave voltages.
Claim 18
Dependent Claim
20 words
A position transducer system according to claim l5 or l6, characterized in that said group of circuits comprises four circuits.
Claim 19
Dependent Claim
110 words
A position transducer system according to claim l7, characterized by: a first circuit (66,68) for producing a first phase modulated, rectangular wave voltage and its inverse voltage; a second circuit (66,70) for producing a second phase modulated, rectangular wave voltage, shifted in phase from said first phase modulated rectangular wave voltage by 90 electrical degrees, and its inverse voltage, and means for coupling said first phase modulated, rectangular wave voltage, said second phase modulated, rectangular wave voltage, the first inverse voltage and the second named inverse voltage, in the named sequence, to successive ones of said four circuits of said group of circuits, for energizing and electrically interdigitating said electrodes.
Claim 20
Dependent Claim
68 words
A position transducer system according to claim l8, characterized in that said first circuit comprises a counter (66) driven read only memory (68) for producing said first phase shifted, rectangular wave voltage, and said second circuit comprises a counter driven read only memory (70) for producing said second phase shifted, rectangular wave voltage shifted in phase by 90 electrical degrees from said first phase shifted, rectangular wave voltage.
Claim 21
Dependent Claim
138 words
A position transducer system according to one of claims l to ll, characterized in that one of said members is a rotatable member (22) and the other member is a stationary member (24); a pickup electrode electrode (48) is capacitively coupled to said rotatable member (22) for picking up position signals indicative of the angular position of said rotatable member relative to said stationary member (24); a sychronizing circuit (78) is provided; means for coupling said position signals to said sychronizing curcuits is provided; a counter (66) for producing count pulses is provided, and a digital position signal output circuit including a latch circuit (72) is coupled to said counter (66) for receiving count pulses and is coupled to and controlled by said sychronizing circuit (78) for receiving said count pulses under the control of said synchronizing circuit.
Claim 22
Dependent Claim
60 words
2l. A position transducer system according to claim 20, characterized in that said digital position output circuit comprises a buffer circuit (80) for controlling the selection of most significant or least significant bits in the digital output of said latch circuit (72) for use in determining the angular position of said rotatable member (22) relative to said stationary member (24).
Claim 23
Dependent Claim
118 words
A capacitive position transducer system, characterized by: a drive electrode assembly (24) having a plurality of drive electrodes (38) forming a drive electrode face; means (66 to 80) for coupling a plurality of successively phase shifted, time varying voltages individually to said plurality of drive electrodes; a three dimensional sense electrode assembly (22) having a plurality of sense electrodes (44) forming a sense electrode face confronting and capacitively coupled to said drive electrode face, and having a pickup face physically removed from but electrically coupled to said sense electrode face on a side of said three dimensional sense electrode assembly opposite said sense electrode. face; and a pickup electrode (48) confronting and capacitively coupled to said pickup face.
Claim 24
Dependent Claim
118 words
A capacitive position transducer system, characterized by: a drive electrode assembly (24) having a plurality of drive electrodes (38) forming a drive electrode face; means (66 to 80) for coupling a plurality of successively phase shifted, time varying voltages individually to said plurality of drive electrodes; a three dimensional sense electrode assembly (22) having a plurality of sense electrodes (44) forming a sense electrode face confronting and capacitively coupled to said drive electrode face, and having a pickup face physically removed from but electrically coupled to said sense electrode face on a side of said three dimensional sense electrode assembly opposite said sense electrode. face; and a pickup electrode (48) confronting and capacitively coupled to said pickup face.
Claim 25
Dependent Claim
80 words
A capacitive position transducer system, characterized by: relatively movable, capacitively coupled, drive and sense electrode assemblies (22,24), each having a plurality of individual electrodes; means (66 to 80) for coupling a plurality of successively phase shifted, phase modulated, rectangular wave voltages, individually to the electrodes of the drive electrode assembly; and means (48) coupled to the electrodes (44) of the sense electrode assembly (22) for providing an indication of the relative position of said drive and sense electrode assemblies (22,24).
Claim 26
Dependent Claim
80 words
A capacitive position transducer system, characterized by: relatively movable, capacitively coupled, drive and sense electrode assemblies (22,24), each having a plurality of individual electrodes; means (66 to 80) for coupling a plurality of successively phase shifted, phase modulated, rectangular wave voltages, individually to the electrodes of the drive electrode assembly; and means (48) coupled to the electrodes (44) of the sense electrode assembly (22) for providing an indication of the relative position of said drive and sense electrode assemblies (22,24).
References Cited (Backward Citations)
No citation records indexed.
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