High Q angular rate sensing gyroscope
AssigneeWatson Industries, Inc.
InventorWilliam S. Watson
Life of this patent
Estimating the term…
Abstract
A structure and arrangement for improving the accuracy and efficiency of an angular rate sensing gyroscope is herein disclosed. Voltage pick-off conductors are applied to an area of the surface of a resonating element of an angular rate sensing gyroscope that is subject to substantially zero stress when the gyroscope is rotationally stationary. Actuator conductors are similarly applied to a resonating element at a location bounded by areas of the resonating element subject to substantially uniform levels of stress when the gyroscope is rotationally stationary. A method for improving the voltage response of a piezoelectric resonating element is also disclosed.
Claims15
A gyroscope comprising:
- a) a resonating element arranged and constructed to oscillate at a resonant frequency;
- b) a voltage pick-off conductor applied to a predetermined area of said resonating element so as to sense net voltage signals proportional to a rate of rotation of said gyroscope when said gyroscope is rotated;
- and
- c) a voltage balancing conductor applied to a predetermined area of said resonating element and in conductive communication with said pick-off conductor, said balancing conductor being arranged and constructed to zero net voltage signals sensed by said voltage pick-off conductor when said gyroscope is rotationally stationary.
In a gyroscope comprising a ring suspended from a support structure in a magnetic field by a plurality of leg members and wherein said ring is capable of vibrating at a given resonant frequency defined by a plurality of vibratory nodes and anti-nodes located upon said ring, said ring being further provided with a plurality of pick-off conductors arranged to sense electrical currents indicative of rotation of the gyroscope and induced therein by movement of said pick-off conductor through said magnetic field when said ring is deflected by rotation of said gyroscope, and a plurality of actuator conductors arranged upon said ring so as to pass currents through said magnetic field, thereby causing deflection in said ring to induce said resonant vibrations in said ring, an improvement comprising:
- a) a plurality of pairs of leg members located adjacent to and symmetrically bracketing said nodes of said ring;
- b) a plurality of pick-off conductors, each pick-off conductor disposed down one of said leg members of said pair of leg members, across the portion of said ring intermediate said leg members of said pair of leg members, and up the remaining leg member of said pair of leg members, each of said portions of said pick-off conductors disposed upon said ring intermediate said legs of said pairs of leg members being arranged symmetrically about one of said nodes of said ring;
- c) a plurality of actuator conductors, each of said actuator conductors being disposed down a leg member of a first pair of leg members, across a portion of said ring intermediate said first pair of leg members and a second pair of leg members, and up a leg member of said second pair of leg members nearest the first pair of leg members, each of said portions of said actuator conductors disposed upon said ring intermediate said pairs of leg members being arranged symmetrically about one of said anti-nodes of said ring;
- and
- d) each of said plurality of pick-off and actuator conductors being arranged to form a conductor loop that passes through said magnetic field, each of said pick-off and actuator conductor loops being further electrically connected to circuit means for operating said gyroscope.
A method of improving the uniform voltage response of a piezoelectric resonating element at a predetermined location upon said resonating element, said resonating element having a first surface and a second, opposing surface, said resonating element being solid between said first and second surfaces, the method comprising the steps of:
- a) applying a first applied film conductor to the entire first surface of said resonating element;
- b) applying a second applied film conductor to the entire second surface of said resonating element;
- c) connecting said first and second thin film conductors to a DC voltage source;
- and
- d) applying a DC voltage of predetermined strength to said first and second applied film conductors so as to create a voltage differential between said first and second applied film conductors, said voltage differential uniformly modifying the voltage response of the piezoelectric material of the resonating element over substantially the entire area of the piezoelectric material located between the first and second thin film conductors.
In a gyroscope comprising an axisymmetrical resonating element having a plurality of applied film conductors applied to a surface of an upper portion of said resonating element, said upper portion being supported upon a base portion, said base portion being substantially vibration free, an improvement comprising:
- a) a plurality of applied film conductor leads, each of said plurality of conductor leads extending from one of said plurality of thin film conductors arranged upon said surface of said resonating element to said base portion of said element, each of said conductor leads being arranged to electrically connect said plurality of applied film conductors to circuitry for operating said gyroscope.
In an angular rate sensor comprising a tuning fork structure composed of vibrator components which include a pair of parallel piezoelectric drive elements;
- a pair of parallel piezoelectric sensing elements;
- said drive elements and said sensing elements being joined together into a tuning fork configuration, said drive and sensing elements lying in respectively orthogonal planes;
- a plurality of leads electrically connected to said drive and detection elements;
- and a plurality of lead terminals electrically connected to said leads for communicating said sensed voltage signals to circuitry which operates said gyroscope, an improvement comprising:
- a) voltage pick-off conductor on the surface of each said sensing element, said pick-off conductor being arranged and constructed to sense stress-induced voltage signals outputted by said sensing elements, said sensed voltage signals being applied to areas of the surface of said sensing elements that are subject to substantially zero stress when said angular rate sensor is rotationally stationary, said voltage pick-off conductor being interposed between said sensing elements and said leads and providing an electrical pathway from said sensing element to said lead.
In an angular rate sensing gyroscope comprising a resonating element having a polygonal cross-section defining a plurality of faces, the resonating element being supported above a base upon a plurality of support members secured respectively to said base, a plurality of conductive pads formed on the base, a plurality of conductive elements secured to a predetermined number of the plurality of faces of the resonating element and having a plurality of wires which connect the conductive elements to the conductive pads, an improvement comprising:
- a) arranging the predetermined number of said conductive elements so as to sense net voltage signals proportional to a rate of rotation of said element when said element is rotated, by applying said conductive elements to said predetermined number of faces of said resonating element at an area of said faces subjected to substantially symmetric stress when said angular rate sensing gyroscope is rotationally stationary.
Dependencies are inferred from the claim text.