Abstract: A gyroscopic apparatus includes two gyro sensors having substantially the same structure. The two gyro sensors are arranged on first and second major surfaces, respectively, of a mounting base so that the gyro sensors have an approximately 180-degree rotation symmetry about a virtual rotation axis penetrating the mounting base substantially parallel thereto in the same direction as rotation detecting axes. The outputs of the two gyro sensors are added, and the sum is output. Thus, the output of the gyroscopic apparatus is much less susceptible to impact from a specific direction, and a high detection accuracy can be maintained.

Abstract: A rotation-type decoupled MEMS gyroscope including a drive body movable about the X-axis, a sensing body movable about the Z-axis, a medium body moving together with the drive body about the X-axis and the sensing body about the Z-axis. The drive body is fixed on a substrate by a first torsion spring torsion-deformed about the X-axis, and the medium body is connected to the drive body by a first bending spring bending-deformed about the Z-axis. The sensing body is connected to the medium body by a second torsion spring torsion-deformed about the X-axis and fixed to the substrate by a second bending spring bending-deformed about the Z-axis. If angular velocity is applied relative to the Y-axis while the drive body vibrates in a certain range about the X-axis by a driving electrode, the sensing body rotates about the Z-axis by the Coriolis force and a sensing electrode senses the rotation.

Abstract: A balanced resonant micro electromechanical system angular rate sensor includes a feedback control loop that generates a null signal to rebalance the sense element to cancel any a Coriolis force induced displacement of the proof mass. The null signal is proportional to the Coriolis force and is used as the sensor output signal. A test signal is injected into the null signal feedback control loop. The resulting sensor output signal is a function of the test signal. If there is no change in the output signal following the injection of the test signal or if the output signal resulting from the test signal exceeds a predetermined threshold, the sensor is defective. Because the test signal is used to cancel the proof mass displacement, the test verifies operation of the sensor element.

Abstract: By applying a first value of voltage to a first side of a MEMS gyroscope and applying a second value of voltage to a second side of the MEMS gyroscope, the start time of the MEMS gyroscope may be improved. The first and second value of voltage may be provided by a bias power source, such as a battery or a super capacitor. The first value of voltage may be substantially equal in magnitude to and opposite in polarity to the second value of voltage. The bias power source may also be applied to drive electronics connected to the MEMS gyroscope. The bias power source may prevent amplifiers within the drive electronics from saturating during the start time.

Abstract: In a method for producing a micromechanical rotation rate sensor, a wafer stack arrangement is used wherein a substrate wafer arrangement (12, 16) is connected to a structural wafer arrangement (14, 18) by means of an insulating connecting layer (15). The required thickness of the structural wafer arrangement (14, 18) is adjusted by thinning it out, where-upon the structural wafer arrangement is structured so as to define at least one seismic mass (20), a suspension (24) and a spring means (22a, 22b) which connects the seismic mass to the suspension. The connecting layer acts as an etch stop for a dry-etching method in which the structural wafer arrangement is structured. In a subsequent further dry-etching step, the connecting layer is selectively removed in such a way that the seismic mass can carry out an excitation oscillation and the seismic mass or parts thereof can carry out a detection oscillation on the basis of a Coriolis force relative to the substrate wafer arrangement.

Abstract: A microgyroscope having a suspended vertical post uses the Coriolis force to detect the rotation rate. The microgyroscope consists of a single vertical post which is the rotation rate sensing element. The vertical post is formed from the same silicon wafers as the rest of the microgyroscope. A first portion of the vertical post and the clover-leaf structure are made from a first silicon wafer. A second portion of the vertical post and the baseplate are made from a second silicon wafer. The two portions are then bonded together to from the clover-leaf gyroscope with an integrated post structure.

Abstract: A vehicle is provided, including a vehicle body; at least one vehicle element pivotally mounted to the vehicle, the vehicle element configured to pivot through an angle not more than 360 degrees; and a measuring arrangement configured to measure an angular velocity of the at least one vehicle element.

Abstract: An inertia force sensor with a damper. The damper includes a cantilever for a movable part disposed in a movable electrode protruding therefrom, and a cantilever for a fixed part disposed in a support portion for the movable part or a support portion for the fixed part and protruding therefrom. The damper allows the cantilever for the movable part and the cantilever for the fixed part to contact each other before the movable electrode contacts the support portion for the movable part and the support portion for the fixed part. As a result, it is possible to prevent a stopper from being damaged and to improve the reliability of the sensor.

Abstract: An angular velocity sensor is disclosed having a sensing element and a pair of driven mass drive elements. The driven mass drive elements have a support structure which defines at least one vibrational node. the driven mass drive element drive elements are coupled to the sensing element at the node so as to allow the driven mass drive elements to oscillate about an axis to generate Coriolis forces, which are measured by the sensing element.

Abstract: An apparatus for controlling an amplitude of a signal generated from a digitized sinusoid of rapidly and widely varying amplitude is described herein. The apparatus includes a two stage gain adjuster which produces a gain adjusted signal, a phase shifter which converts the gain adjusted signal into two gain adjusted output signals separated in phase by 90 degrees, a power estimation unit to estimate the power of the gain adjusted signal, and an adjusting unit to adjust a gain of the gain adjuster according to a power estimate from the power estimation unit and a desired output signal power.

Abstract: A MEMS gyroscope may be coupled to drive electronics that provide a pulse width modulation drive signal to the MEMS gyroscope. The pulse width modulation drive signal may be generated by comparing a pickoff signal and/or input signal to a direct current threshold level.

Abstract: A method for reduces the sticking of proof masses in micro-electromechanical systems (MEMS) devices to sense plates in the MEMS device due to acceleration forces to which the MEMS device is subjected. The method includes determining a beginning of acceleration events which would cause proof masses to contact sense plates, reducing sense bias voltages to the sense plates, determining an end of the acceleration event, and increasing sense bias voltages to their former levels.

Abstract: For a decoupled to gyro to have high sensitivity to angular rate, it is necessary to have the design flexibility to achieve all the critical frequencies in the design. The geometry of the gyro is first estimated and is followed by a performance analysis to maximize the gyro sensitivity. If the performance requirements cannot be met, the next iteration is started by a new estimate of the geometry. For a given design iteration, the desired modal response is implemented with a predetermined or given gyro flexure system. The flexure system disclosed here has enough independent design parameters to allow the desired modal response required for high gyro performance to be selected by independent design choice of the available geometric and configurational design parameters of the gyroscope.

Abstract: A micro-gyroscope having electronic alignment by performing an electronic coordinate transformation on control voltages (VTX, VTy) through an attenuator network thereby canceling first and second harmonic signals from the output (Vthx, Vthy). The micro-gyroscope is tuned by automatic electronic compensation based on quadrature error that is applied to correct for variations in the gyroscope.

Abstract: A vibrating gyroscope includes a vibrator having a driving electrode and a sensor electrode, a driving circuit for applying a driving voltage to the driving electrode, a detection circuit which receives, from the sensor electrode, a signal corresponding to a bending displacement of the vibrator, a signal processing circuit for processing a signal input from the detection circuit to detect an angular velocity, a power supply circuit, and a diagnostic circuit for examining whether or not the detection circuit, the driving circuit, the signal processing circuit, and the power supply circuit are all functioning normally.

Abstract: A method of mapping diagonal rows and columns of two-dimensional grid elements to rectangular rows and columns of two-dimensional grid elements. The method is of particular use with a spatial light modulator in optical equalization application.

Abstract: A gyroscopic sensor comprising: a sensing element (1) associated with detection and excitation electrodes (8); conductive rods (6) connected in particular to said electrodes (8); a protective housing (3, 4) enclosing the sensing element (1) and the electrode (8) and having insulating feed-throughs (7) for the conductive rods (6); and support means interposed between the housing (3, 4) and the sensing element (1) with the electrodes (8); the sensor being characterized in that said support means are constituted by the conductive rods (6) themselves, which are made so as to be elastically deformable.

Abstract: The present invention discloses a gyroscope comprising an isolated resonator including a post proof mass and counterbalancing plate. One or more double beam flexures each interconnect the counterbalancing plate and the proof mass with a first and a second beam attached to the post proof mass and a third and a fourth beam attached to the counterbalancing plate. A baseplate is affixed to the resonator by the double beam flexures. The counterbalancing plate and the proof mass transfer substantially no net momentum to the baseplate when the resonator is excited.

Abstract: A MEMS gyroscope may be coupled to drive electronics that provide a pulse width modulation drive signal to the MEMS gyroscope. The pulse width modulation drive signal may be generated by comparing a pickoff signal and/or input signal to a direct current threshold level.

Abstract: A microelectromechanical (MEMS) gyroscope has one or more proof masses mechanically coupled to a substrate by springs. A motor force drives the proof masses at their resonant frequency in one direction, 180 degrees out of phase with each other in the case of a dual proof mass gyroscope. Sense electrodes sense motion of the proof masses in response to a Coriolis force. The motion caused by the Coriolis force is perpendicular to the motion caused by the motor force. An AC pump voltage at twice the motor frequency is applied to the sense electrodes to provide parametric amplification of the Coriolis force. The AC pump voltage alters the mechanical and electrical gain of the gyroscope.

Abstract: MEMS-Integrated IMUs are possible based on a common substrate that provides a common oscillatory drive for the operation of the gyroscopes and accelerometers. The common substrate becomes the stable member utilized in conventional IMUs. The advantages of the embodiments are smallest size, flexibility in how IMUs are configured, reduced electronics and a single package. MEMS integration also reduces uncertainties due to separately developed instruments based on different fabrication processes, materials, assembly and alignment.

Abstract: A MEMS gyroscope system and method for increasing a dynamic range of the MEMS gyroscope is provided. By adjusting a scale factor of the MEMS gyroscope, the highest sensed rate will be increased, which increases the dynamic range. The scale factor may be adjusted by using a variable sense bias and/or an automatic gain control loop in sense electronics.

Abstract: The present invention discloses a resonator gyroscope including an isolated resonator. One or more flexures support the isolated resonator and a baseplate is affixed to the resonator by the flexures. Drive and sense elements are affixed to the baseplate and used to excite the resonator and sense movement of the gyroscope. In addition, at least one secondary element (e.g., another electrode) is affixed to the baseplate and used for trimming isolation of the resonator. The resonator operates such that it transfers substantially no net momentum to the baseplate when the resonator is excited. Typically, the isolated resonator comprises a proof mass and a counterbalancing plate.

Abstract: The present invention discloses a resonator gyroscope comprising a resonator including two bodies, each with a center of mass and transverse inertia symmetry about an axis that are substantially coincident and each supported by one or more elastic elements and wherein the bodies together forming two differential rocking modes of vibration transverse to the axis with substantially equal frequencies and wherein the two bodies transfer substantially no net momentum to the baseplate when the resonator is excited. The gyroscope further includes a baseplate affixed to the resonator by the one or more elastic elements and sense and drive elements each affixed to the resonator and baseplate.

Abstract: Quadrature error occurs in Corolis based vibrating rate sensors because of manufacturing flaws that permit the sensing element to oscillate either linearly along or angularly about an axis that is not orthogonal to the output axis. This creates an oscillation along or about the output axis that is a component of the sensing element's vibration acceleration. This output axis oscillation is in phase with the driven acceleration of the sensing element and is called quadrature error since it is ninety degrees out of phase with the angular rate induced Coriolis acceleration. Rather than applying forces that reorient the axis of the driven vibration to be orthogonal to the output axis to eliminate the output axis oscillation, the present invention applies sinusoidal forces to the sensing element by means of a quadrature servo to cancel the output oscillation.

Abstract: A yaw-rate sensor is proposed having a first and a second Coriolis element (100, 200) which are arranged side-by-side above a surface (1) of a substrate. The Coriolis elements (100, 200) are induced to oscillate parallel to a first axis. Due to a Coriolis force, the Coriolis elements (100, 200) are deflected in a second axis which is perpendicular to the first axis. The first and second Coriolis elements (100, 200) are coupled by a spring (52) which is designed to be yielding in the first and in the second axis. Thus, the frequencies of the oscillations in the two axes are developed differently for the in-phase and antiphase oscillation.

Abstract: A yaw-rate sensor is proposed having a first and a second Coriolis element (100, 200) which are arranged side-by-side above a surface (1) of a substrate. The Coriolis elements (100, 200) are induced to oscillate parallel to a first axis Y. Due to a Coriolis force, the Coriolis elements (100, 200) are deflected in a second axis X which is perpendicular to the first axis Y. The oscillations of the first and second Coriolis elements (100, 200) take place in phase opposition to each other on paths which, without the effect of a Coriolis force, are two straight lines parallel to each other.

Abstract: The present invention discloses a resonator gyroscope comprising a vibrationally isolated resonator including a proof mass, a counterbalancing plate having an extensive planar region, and one or more flexures interconnecting the proof mass and counterbalancing plate. A baseplate is affixed to the resonator by the one or more flexures and sense and drive electrodes are affixed to the baseplate proximate to the extensive planar region of the counterbalancing plate for exciting the resonator and sensing movement of the gyroscope. The isolated resonator transfers substantially no net momentum to the baseplate when the resonator is excited.

Abstract: A self-diagnosing circuit for a vibrating gyroscope for detecting a vibration due to a Coriolis force including a differential operating circuit for determining a difference between output signals outputted from a plurality of detecting electrodes which provided on the vibrator to detect the vibration due to the Coriolis force; and an offset signal source for superposing an offset signal on at least one of the signals outputted from said plurality of detecting electrodes such that the signals are offset with different signal levels.

Abstract: An acceleration-detecting type gyro apparatus of an electrostatic supporting type, in which displacements of a gyro rotor are actively made zero is proposed. The acceleration-detecting type gyro apparatus includes: a gyro case; a gyro rotor which is supported within the gyro case by electrostatic supporting forces such that the gyro rotor is not in contact with the gyro case; electrostatic supporting electrodes for generating the electrostatic supporting forces; a rotor drive system for rotating the gyro rotor around the spin axis at high speed; a displacement-detection system for detecting displacements of the gyro rotor; and a restraining system having a feedback loop for correcting control voltages applied to the electrostatic supporting electrodes so that displacements of the gyro rotor become zero, the gyro rotor is annular-shaped, and the electrostatic supporting electrodes are disposed in a manner of surrounding the gyro rotor.

Abstract: X type MEMS gyroscope has a first mass vertically vibrating on a substrate and a second mass horizontally vibrating on the substrate. A driving electrode is disposed on the same surface with the first mass. When the first mass vertically vibrates, the second mass vibrates vertically together with the first mass. When angular velocity that is at a right angle to a movement direction of the first mass and the second mass is applied while the first mass is vertically vibrating, the second mass moves as Coriolis force is added to the second mass in a horizontal direction, and a sensing electrode measures displacement of the second mass in the horizontal direction. All moving electrodes and stationary electrodes are disposed on the same surface, and all elements are manufactured by using one mask. Therefore, adhesion between the moving and stationary electrodes is prevented and the manufacturing process is simplified.

Abstract: A flexible substrate (110) having flexibility and a fixed substrate (120) disposed so as to oppose it are supported at their peripheral portions by a sensor casing (140). An oscillator (130) is fixed on the lower surface of the flexible substrate. Five lower electrode layers (F1 to F5: F1 and F2 are disposed at front and back of F5) are formed on the upper surface of the flexible substrate. Five upper electrode layers (E1 to E5) are formed on the lower surface of the fixed substrate so as to oppose the lower electrodes. In the case of detecting an angular velocity &ohgr; x about the X-axis, an a.c. voltage is applied across a predetermined pair of opposite electrode layers (E5, F5) to allow the oscillator to undergo oscillation Uz in the Z-axis direction. Thus, a Coriolis force Fy proportional to the angular velocity &ohgr;x is applied to the oscillator in the Y-axis. By this Coriolis force Fy, the oscillator is caused to undergo displacement in the Y-axis direction.

Abstract: A digital phase locked loop includes an automatic gain control that applies a gain to an input signal in order to provide a gain controlled signal. A 90° phase shifter applies a 90° phase shift to the gain controlled signal in order to provide a 90° phase shifted version of the gain controlled signal. A phase detector is driven by the gain controlled signal, by the 90° phase shifted version of the gain controlled signal, and by sinusoidal and co-sinusoidal signals. A loop filter integrates an output of the phase detector and provide servo equalization for the phase-locked loop. A digital dual frequency oscillator has a fundamental frequency controlled by an output signal from the loop filter. Also, the digital dual frequency oscillator generates the sinusoidal and co-sinusoidal signals.

Abstract: An optical switch that any vibration or oscillation transmitted to the optical switch from the outside is substantially prevented from being transmitted to a movable electrode is provided. In an optical switch comprising: a stationary electrode; a movable electrode opposed to the stationary electrode with a predetermined space therebetween; and a mirror mounted to the movable electrode, wherein the movable electrode and the mirror are moved together by applying a voltage between the stationary electrode and the movable electrode thereby to switch the path of an incident optical signal to the optical switch, a buffer member provided with a diaphragm is attached to the bottom of the stationary electrode, and a vibration or oscillation is substantially prevented from being transmitted to the movable electrode by the damping effects of the diaphragm and the space area formed above the diaphragm.

Abstract: A microgyroscope having a suspended vertical post uses the Coriolis force to detect the rotation rate. The microgyroscope consists of a single vertical post which is the rotation rate sensing element. The vertical post is formed from the same silicon wafers as the rest of the microgyroscope. A first portion of the vertical post and the clover-leaf structure are made from a first silicon wafer. A second portion of the vertical post and the baseplate are made from a second silicon wafer. The two portions are then bonded together to from the clover-leaf gyroscope with an integrated post structure.

Abstract: A spin rate measurement device for rotating missiles. Preferably, three micromechanical spin rate sensors whose three spatial axes are aligned at right angles to one another, each of which is designed to be excited, read and reset capacitively, are arranged on a single platform that can be rotated by means of a servo loop for rotation decoupling. The spin rate measurement device is distinguished by high bias and scale factor stability that can be checked at any time.

Abstract: This invention discloses a method for electronically decreasing the sensitivity of thin film movable micromachined layers to vibrations, accelerations, or rotations that would result in part or all of the movable layer being displaced in the direction of the film thickness. In addition, the disclosed method can also be used to remove some of the curvature introduced into thin film movable structures due to vertical stress gradients. Electronic stiffening is achieved by using position sensing and force feedback at one or more points on the movable micromachined structure. Precise servo control of Z axis height makes it possible to dramatically decrease the spacing between the movable MEMS layer or layers and fixed electrodes, which can lead to a dramatic increase in sensitivity and/or actuation force.

Abstract: The angular speed sensor device includes a drive frame 11 and a detecting frame 12 which are supported on a silicon substrate 10 in a floating mode. The drive frame 11 and the detecting frame 12 are provided with an angular speed about the z-axis when the drive frame 11 and the detecting frame 12 are driven to vibrate in the x-direction, the resulting Corliolis force causing the detecting frame 12 to oscillate in the y-direction. Such a y-direction oscillation of the detecting frame 12 is detected as a displacement signal. On the basis of the displacement signal, the applied angular speed is calculated. The angular speed sensor device includes detecting electrodes 16a and 16b which drive the detecting frame 12 to vibrate in the y-direction when a drive signal is fed to each of the detecting electrodes 16a and 16b which changes the electrostatic capacitance between the detecting frame 12 and each of the detecting electrodes 16a and 16b.

Abstract: A method for testing a Coriolis transducer having a mass adapted vibrate along a vibratory direction in a resonant structure and undergo a displacement along a sensitive axis, perpendicular to the vibration, in response to an angular rate about a mutually perpendicular rate sensing axis. In the absence of an angular rate about the rate sensing axis, forces, FTEST VIBRATORY and FTEST SENSITIVE are applied on the mass along the direction of vibration and along the sensitive axis, respectively, in a predetermined ratio, N. The output VOUT TEST of the transducer is measured in response to the forces, FTEST VIBRATORY and FTEST SENSITIVE.

Abstract: A yaw rate motion sensor (10) that includes a driving element (12) having a first axis for oscillating generally in the direction of the first axis upon application of a driving voltage. The motion sensor (10) includes a sensing element (14) for sensing relative differences in capacitance occasioned from the driving element upon application of a Coriolis force induced by an angular rotation and linkage (16) between the driving element (12) and the sensing element (14).

Abstract: An inertial sensor includes a plurality of sense elements disposed upon a silicon wafer. Each of the sense elements senses a different inertia range. The sense elements are electrically connected to a common signal conditioning circuit that generates an output signal for each of the sense elements. The signal conditioning circuit has an output that is electrically connected to at least one control system and provides output signals in different ranges to the control system.

Abstract: A 3D angle measurement instrument includes a casing having a top and bottom with side walls extending therebetween. A gyroscope is positioned within the casing and electrically connected to a battery power source. The gyroscope is capable of measuring acceleration and deceleration velocities of the casing indicative of angular rotation thereof. A microprocessor is positioned within the casing and is electrically connected to the gyroscope and battery. The microprocessor receives an output signal from the gyroscope and is capable of calculating an angular displacement value using the output signal and a corresponding time factor. The angular displacement value is displayed on an electronic display in angular degrees from a reference point.

Abstract: A method for testing a Coriolis transducer having a mass adapted vibrate along a vibratory direction in a resonant structure and undergo a displacement along a sensitive axis, perpendicular to the vibration, in response to an angular rate about a mutually perpendicular rate sensing axis. In the absence of an angular rate about the rate sensing axis, forces, FTEST VIBRATORY and FTEST SENSITIVE, are applied on the mass along the direction of vibration and along the sensitive axis, respectively, in a predetermined ratio, N. The output VOUT TEST of the transducer is measured in response to the forces, FTEST VIBRATORY and FTEST SENSITIVE.

Abstract: A gyroscopic sensor comprising: a sensing element (1) associated with detection and excitation electrodes (8); conductive rods (6) connected in particular to said electrodes (8); a protective housing (3, 4) enclosing the sensing element (1) and the electrode (8) and having insulating feed-throughs (7) for the conductive rods (6); and support means interposed between the housing (3, 4) and the sensing element (1) with the electrodes (8); the sensor being characterized in that said support means are constituted by the conductive rods (6) themselves, which are made so as to be elastically deformable.

Abstract: For a decoupled to gyro to have high sensitivity to angular rate, it is necessary to have the design flexibility to achieve all the critical frequencies in the design. The geometry of the gyro is first estimated and is followed by a performance analysis to maximize the gyro sensitivity. If the performance requirements cannot be met, the next iteration is started by a new estimate of the geometry. For a given design iteration, the desired modal response is implemented with a predetermined or given gyro flexure system. The flexure system disclosed here has enough independent design parameters to allow the desired modal response required for high gyro performance to be selected by independent design choice of the available geometric and configurational design parameters of the gyroscope.

Abstract: A method of determining an orientation of a body. The method includes the steps of measuring an acceleration of the body in a first direction, measuring an acceleration of the body in a second direction different from the first direction, the first direction and the second direction defining a plane. Measuring an acceleration perpendicular to the plane in a coordinate system rotating about an axis perpendicular to the plane, and inferring the orientation of the body from the three measurements.

Abstract: A balanced resonant micro electromechanical system angular rate sensor includes a feedback control loop that generates a null signal to rebalance the sense element to cancel any a Coriolis force induced displacement of the proof mass. The null signal is proportional to the Coriolis force and is used as the sensor output signal. A test signal is injected into the null signal feedback control loop. The resulting sensor output signal is a function of the test signal. If there is no change in the output signal following the injection of the test signal or if the output signal resulting from the test signal exceeds a predetermined threshold, the sensor is defective. Because the test signal is used to cancel the proof mass displacement, the test verifies operation of the sensor element.

Abstract: A microgyroscope having a suspended vertical post uses the Coriolis force to detect the rotation rate. The microgyroscope consists of a single vertical post which is the rotation rate sensing element. The vertical post is formed from the same silicon wafers as the rest of the microgyroscope. A first portion of the vertical post and the clover-leaf structure are made from a first silicon wafer. A second portion of the vertical post and the baseplate are made from a second silicon wafer. The two portions are then bonded together to from the clover-leaf gyroscope with an integrated post structure.

Abstract: This invention describes the addition of mechanical reference members (MRM) to MEMS gyroscopes and accelerometers in order to enable the measurement of their scale factor and bias characteristics. The measurements can be made prior to or during operation of the instruments. This approach is attractive since MEMS devices are subject to drift of these characteristics with time, with the environment and with application conditions. The mechanical reference members are used to provide a rotation rate reference for the gyroscopes and an acceleration reference for the accelerometers.

Abstract: Disclosed is a Coriolis Oscillating Gyroscopic instrument, comprising: a Double Ended Tuning Fork (DETF) having two stems and two tines; a Torque Summing Member (TSM) rigidly coupled to the DETF stems; drives located at least partially on the TSM for vibrating the tines sinusoidally in opposition along a first axis, the tines' motion having a constant amplitude, a frequency and a phase; a case; a plurality of flexures connecting the TSM to the case, to allow the TSM and the DETF to rotationally oscillate together relative to the case about a second axis transverse to the first axis; and a sensor and associated instrumentation for resolving rotation of the TSM relative to the case.