Single bar type vibrating element angular rate sensor system
DCFirst Claim
1. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
- a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, said angular rate sensor system further comprising a third outer electrode, the third outer electrode being disposed on the first side of the vibratory sensing element and oriented generally parallel with the plane, and a fourth outer electrode, the fourth outer electrode being disposed on the second side of the vibratory sensing element and oriented generally parallel with the plane,whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals.
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Abstract
An angular rate sensor system [10] comprising a vibratory sensing element [12] and signal processing circuit [14]. The element [12] is preferably a polymorphic rectangular bar fabricated from two layers of piezoceramic material [26, 28] divided by a thin center electrode [Ec ], and a plurality of electrodes [E1 -E4 ] scored onto the planar conductive surfaces [30, 32]. The element [12] is suspended at its acoustic nodes [N, N'"'"'] to vibrate in one direction [V] normal to the physical plane of the electrodes [Ec, E1 -E4 ] using any suitable mounting structure such as parallel crossed filaments [34] or inwardly angled support arms [64] that provide predetermined degrees of lateral [S'"'"'] and longitudinal [S] stiffness. The circuit [14] may optionally constitute totally shared [FIG. 7], partially shared [FIG. 8], or totally isolated [FIG. 9] driving and sensing functions, the corresponding element [12] being configured with dual-pair, single-pair, or single-triple outer electrodes [E1 -E4 ], respectively. The circuit [14] typically utilizes an automatic gain control and two operational amplifiers, and may include various signal conditioning components and a separate tuning module.
162 Citations
74 Claims
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1. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
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a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, said angular rate sensor system further comprising a third outer electrode, the third outer electrode being disposed on the first side of the vibratory sensing element and oriented generally parallel with the plane, and a fourth outer electrode, the fourth outer electrode being disposed on the second side of the vibratory sensing element and oriented generally parallel with the plane, whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals. - 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, 35, 36, 37, 38, 39, 40, 41, 42)
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43. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
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a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, said system further comprising; a third outer electrode, the third outer electrode being disposed on the second side of the vibratory sensing element, whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 58)
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54. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
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a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, said system further comprising; a third outer electrode and a fourth outer electrode, the third outer electrode and fourth outer electrode each being disposed on the second side of the vibratory sensing element, whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals. - View Dependent Claims (55, 56, 57, 59, 60, 61, 62, 63, 64, 65, 66)
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67. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
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a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals; wherein the vibratory sensing dement has a first acoustic node and a second acoustic node spaced apart from the first acoustic node, the angular rate sensor system further comprising; a mounting structure, the mounting structure being attached to the vibratory sensing element proximate to each of the first acoustic node and the second acoustic node, the vibratory sensing element being suspended on the mounting structure so as to vibrate in the direction of vibration, wherein the mounting structure comprises; a frame member defining an opening within which the vibratory sensing element is received, the opening having a first edge and a second edge; a first pair of filaments; and a second pair of filaments, each of the first pair of filaments and the second pair of filaments being connected to and extending from the first edge to the second edge and receiving the vibratory sensing element therebetween, the first pair of filaments being generally aligned along and parallel with the first acoustic node, the second pair of filaments being generally aligned along and parallel with the second acoustic node. - View Dependent Claims (68)
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69. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
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a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode being oriented generally parallel with a plane, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals; wherein the vibratory sensing element has a first acoustic node and a second acoustic node spaced apart from the first acoustic node, the angular rate sensor system further comprising; a mounting structure, the mounting structure being attached to the vibratory sensing element proximate to each of the first acoustic node and the second acoustic node, the vibratory sensing element being suspended on the mounting structure so as to vibrate in the direction of vibration, wherein the mounting structure further comprises; a first plate member spaced apart from and disposed on a first side of the vibratory sensing element and defining a first pair of support arms extending inwardly toward the vibratory sensing element; and a second plate member spaced apart from and disposed on a second side of the vibratory sensing element opposing the first side and defining a second pair of support arms extending inwardly toward the vibratory sensing element, the first pair of support arms being connected to the vibratory sensing element proximate to the first acoustic node, and the second pair of support arms being connected to the vibratory sensing element proximate to the second acoustic node. - View Dependent Claims (70, 71)
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72. An angular rate sensor system which may be used with a signal processing circuit to discriminate an angular rate, the angular rate sensor system comprising:
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a vibratory sensing element including a base electrode, at least two layers of piezoelectric material each disposed on opposing sides of the base electrode, a first outer electrode disposed on a first side of the vibratory sensing element, and a second outer electrode disposed on a second side of the vibratory sensing element opposing the first side, the first outer electrode and the second outer electrode begins oriented generally parallel with a plate, the vibratory sensing element defining a pair of acoustic nodes when vibrated in a direction of vibration oriented generally perpendicular to the plane, the vibratory sensing element being suspended proximate to the pair of natural acoustic nodes, whereby the vibratory sensing element vibrates in the direction of vibration oriented generally perpendicular to the plane when either the first electrode or the second electrode are excited by a drive signal, and further whereby the first electrode or the second electrode produce sensing signals responsive and proportional to the angular rate of the vibratory sensing element, the signal processing circuit discriminating the angular rate from the sensing signals; wherein the vibratory sensing element has a first acoustic node and a second acoustic node spaced apart from the first acoustic node, the angular rate sensor system further comprising; a mounting structure, the mounting structure being attached to the vibratory sensing element proximate to each of the first acoustic node and the second acoustic node, the vibratory sensing element being suspended on the mounting structure so as to vibrate in the direction of vibration, wherein the vibratory sensing element has a length, a width, and a thickness, the length being generally greater than the width, and further wherein the mounting structure has a first stiffness in a longitudinal direction parallel with the length of the vibratory sensing element, and the mounting structure has a second stiffness in a lateral direction parallel with the width of the vibratory sensing element. - View Dependent Claims (73, 74)
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Specification