Quartz resonant gyroscope or quartz resonant tuning fork gyroscope
First Claim
1. A quartz material tuning fork rate sensor comprising:
- at least one elongated quartz member projecting from a body and vibrationally responsive to electrical stimulation;
first and second regions of said member located at different distances from said body;
a set of drive electrodes in said first region and having at least one first drive electrode spaced from at least one second drive electrode through said quartz material;
a drive circuit adapted for oscillation at a frequency determined by piezoelectric resonant properties of said first region of said member;
electrical drive leads coupling said at least one first and second drive electrodes to said drive circuit, said at least one first and second drive electrodes exciting vibration of said member in a plane having said member;
a set of sense electrodes in said second region and having at least one first sense electrode spaced apart from at least one second sense electrode on said quartz material, said at least one first and second sense electrodes positioned to receive current piezoelectrically induced therein in response to a rotation rate about said member; and
a sense circuit coupled to said sense electrodes by electrical sense leads for detecting current piezoelectrically induced in said sense electrodes, said sense circuit including a differential input, having respective inputs connected to a first and second pairs of electrodes, balanced with respect to said drive circuit and providing common mode rejection at said sense circuit,said electrical drive leads disposed, on said member, along lines of minimal field strength in a field piezoelectrically induced from vibration of said member for coupling said drive electrodes to said drive circuit, andsaid electrical sense leads disposed, on said member, along lines of minimal field strength in an electric field induced by said drive electrodes for coupling said sense electrodes to said sense circuit.
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Accused Products
Abstract
A resonantly vibrating or tuning fork rate sensor in which a quartz beam is instrumented with electrodes in first and second regions forming respective sense and drive electrodes wherein the piezoelectric resonance affect of the quartz material between the drive electrodes is used as a tuning element for an oscillator circuit. The electrodes are driven in a balanced voltage mode and sensed in a common mode rejection differential amplifier while leads running to the electrodes along the quartz beam are placed at positions of minimal field strength for improving the signal to noise ratio of the device. The rate sensor utilizes a multi-electrode pattern in order to make such lead placement possible. The sense pattern and drive pattern may be either in one orientation with the drive electrodes proximate to the body of the quartz resonator or in a second pattern with the sense electrodes proximate to the body. Both the drive electrodes and the sense electrodes operate on the piezoelectric principal, utilizing constriction to induce vibration from the drive electrodes and sensing the current generated from piezoelectric effect resulting from the vibrational compression which occurs out of the plane of vibration during inertial rate input. Alternatively, a capacitive electrode structure may be utilized as a pick-off.
54 Citations
25 Claims
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1. A quartz material tuning fork rate sensor comprising:
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at least one elongated quartz member projecting from a body and vibrationally responsive to electrical stimulation; first and second regions of said member located at different distances from said body; a set of drive electrodes in said first region and having at least one first drive electrode spaced from at least one second drive electrode through said quartz material; a drive circuit adapted for oscillation at a frequency determined by piezoelectric resonant properties of said first region of said member; electrical drive leads coupling said at least one first and second drive electrodes to said drive circuit, said at least one first and second drive electrodes exciting vibration of said member in a plane having said member; a set of sense electrodes in said second region and having at least one first sense electrode spaced apart from at least one second sense electrode on said quartz material, said at least one first and second sense electrodes positioned to receive current piezoelectrically induced therein in response to a rotation rate about said member; and a sense circuit coupled to said sense electrodes by electrical sense leads for detecting current piezoelectrically induced in said sense electrodes, said sense circuit including a differential input, having respective inputs connected to a first and second pairs of electrodes, balanced with respect to said drive circuit and providing common mode rejection at said sense circuit, said electrical drive leads disposed, on said member, along lines of minimal field strength in a field piezoelectrically induced from vibration of said member for coupling said drive electrodes to said drive circuit, and said electrical sense leads disposed, on said member, along lines of minimal field strength in an electric field induced by said drive electrodes for coupling said sense electrodes to said sense circuit. - View Dependent Claims (2, 3, 4, 5, 21, 22, 23, 24, 25)
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6. A quartz material tuning fork rate sensor comprising:
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at least one elongated quartz member projecting from a body and vibrationally responsive to electrical stimulation; first and second regions of said member located at different distances from said body; a set of drive electrodes in said first region and having first and second drive electrodes of a first polarity facing each other along a first axis across said material and bordered by third and fourth drive electrodes of a second polarity facing each other across an orthogonal, second axis through said material; a drive circuit adapted for oscillation at a frequency; electrical drive leads coupling said first and second polarity drive electrodes to said drive circuit to excite vibration of said member at said frequency in a plane having said member; a set of sense electrodes in said second region and having at least one first sense electrode spaced apart from at least one second sense electrode through said quartz material, said at least one first and second sense electrodes positioned to receive current piezoelectrically induced therein in response to a rotation rate about said member; and a sense circuit coupled to said sense electrodes by electrical sense leads for detecting current piezoelectrically induced in said sense electrodes, said sense circuit including a differential input, having respective inputs connected to a first and second pairs of electrodes, balanced with respect to said drive circuit and providing common mode rejection at said sense circuit, said electrical drive leads disposed, on said member, along lines of minimal field strength in a field piezoelectrically induced from vibration of said member for coupling said drive electrodes to said circuit, and said electrical sense leads disposed, on said member, along lines of minimal field strength in an electric field induced by said drive electrodes for coupling said sense electrodes to said sense circuit. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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13. A quartz material tuning fork rate sensor comprising:
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at least one elongated quartz member projecting from a body; first and second regions of said member located at different distances from said body; a set of drive electrodes in said first region and having at least one first, first polarity drive electrode spaced from at least one second, opposite polarity drive electrode through said quartz material; an oscillator circuit adapted for oscillation at a frequency; electrical drive leads coupling said first and second drive electrodes to said oscillator circuit causing vibration of said member in a plane having said member; a set of sense electrodes in said second region and having at least one first sense electrode spaced apart from at least one second sense electrode through said quartz material, said at least one first and second sense electrodes positioned to receive current piezoelectrically induced therein in response to a rotation rate about said member; a sense circuit coupled to said sense electrodes by electrical sense leads for detecting current piezoelectrically induced in said sense electrodes; and means providing a common mode rejection input for said sense circuit, said electrical drive leads disposed, on said member, along lines of minimal field strength in a field piezoelectrically induced from vibration of said member for coupling said drive electrodes to said oscillator circuit, and said electrical sense leads disposed, on said member, along lines of minimal field strength in an electric field induced by said drive electrodes for coupling said sense electrodes to said sense circuit. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification