SYNCHRONIZED MASS GYROSCOPE WITH FULL SYMMETRY AND ROTATION

Description

CLAIM OF PRIORITY

[0001] This application claims priority to U.S. Provisional Application Serial No. 63 / 357,861, filed July 1, 2022.FIELD OF THE DISCLOSURE

[0002] This document pertains generally, but not by way of limitation, to sensors that are micro-electromechanical systems (MEMS), and more particularly, to MEMS gyroscope sensors.

[0003] Document US 2022 / 057208 A1 discloses a microelectromechanical systems (MEMS) device wherein one or more components of the MEMS device exhibit attenuated motion relative to one or more other moving components.SUMMARY OF THE DISCLOSURE

[0004] The solution is provided by the features of the independent claims. Variations are as described by the features of the dependent claims.

[0005] MEMS include small mechanical devices performing electrical and mechanical functions that are fabricated using photo-lithography techniques similar to techniques used to fabricate integrated circuits. Some MEMS devices are sensors that can detect motion such as an accelerometer or detect angular rate or rotation rate such as a gyroscope. A capacitive MEMS gyroscope undergoes a change in capacitance in response to a change in rotation rate. However, MEMS gyroscopes can be susceptible to errors such as quadrature error and offset error.

[0006] MEMS gyroscopes have a movable proof mass that moves in response to an electrical drive signal. The drive motion is along a drive axis (e.g., an X axis) of the proof mass. When the moving proof mass experiences rotation, a Coriolis force causes movement in a sense axis direction orthogonal to the drive axis (e.g., a Y axis). The drive axis and sense axis can be any axes that are mutually orthogonal. Movement of the proof mass in the sense axis direction causes a detectable change in capacitance representative of the rotation of the proof mass. The vibration pattern can be at any angle not necessarily the X axis or Y axis. For instance, by applying forces equally along X and Y axes, the vibration pattern angle will be at 45 degrees.

[0007] In general, MEMS gyroscopes are asymmetric between the drive axis direction and the sense axis direction because the amplitude of motion of the Coriolis mode vibration is thousands of times less than the amplitude of motion of the drive mode vibration. The axial symmetry, however, is beneficial for reduction of cross-axis damping errors, minimizing mass and momentum imbalance - all of which contribute to gyroscope output drift. The present inventors have recognized, among other things, that use of an MEMS gyroscope with axial symmetry provides advantages due to its intrinsic self-calibration properties.

[0008] In one approach, a gyroscope includes a substrate and a proof mass coupled to the substrate and configured to move in direction of a first axis (e.g., an X axis) and in direction of a second axis orthogonal to the first axis (e.g., a Y axis). The gyroscope includes a first axis shuttle structure or axis shuttle, to selectively drive the proof mass along the first axis as a drive axis, or to selectively sense movement of the proof mass under rotation (e.g., Coriolis sensing) along the first axis as a sense axis in response to the proof mass being driven along the second axis as the drive axis. The gyroscope also includes a second axis shuttle to selectively sense movement of the proof mass along the second axis as a sense axis in response to the proof mass driven along the first axis, or to selectively drive the proof mass along the second axis as the drive axis. The first axis shuttle is symmetric to the second axis shuttle along a diagonal axis that is diagonal to both the first axis and the second axis.

[0009] In another aspect of the present subject matter, a method of operating an MEMS gyroscope includes driving the MEMS gyroscope along a first axis of the MEMS gyroscope as a drive axis, sensing a response of the MEMS gyroscope along a second axis orthogonal to the first axis as a sense axis, and turning the MEMS gyroscope and changing the drive axis to the second axis changing the sense axis to the first axis.

[0010] This summary is intended to provide an overview of subject matter of the present patent application. It is not intended to provide an exclusive or exhaustive explanation of the invention. The detailed description is included to provide further information about the present patent application.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document. FIG. 1 is an example of a mode match micro-electromechanical system (MEMS) gyroscope. FIG. 2 is another example of a mode match MEMS gyroscope. FIG. 3 is a portion of the MEMS gyroscope of FIG. 2. FIG. 4 is another example of a portion of a mode match MEMS gyroscope. FIG. 5 is an example of cross quadrant routing of tuning signals in the mode match MEM gyroscope of FIG. 1. FIG. 6 an example of cross quadrant routing for X axis pickoff electrodes in the mode match MEM gyroscope of FIG. 1. FIG. 7 an example of cross quadrant routing for Y axis pickoff electrodes in the mode match MEM gyroscope of FIG. 1. FIG. 8 is a block diagram of a control circuit for open loop control of turning and mode switching of a mode match MEMS gyroscope. FIG. 9 is an example of an axis shuttle of a MEMS gyroscope. DETAILED DESCRIPTION

[0012] MEMS gyroscopes can be susceptible to errors such as quadrature error and common mode offset error. Quadrature error can be caused by the vibrating direction of the proof mass not being fully in line with the driving direction, resulting in an undesired vibration component perpendicular to, or in quadrature with, the driving direction. Common mode offset error can be caused by unequal damping of the proof mass in the two mutually orthogonal directions.

[0013] A MEMS gyroscope that is symmetric has intrinsic self-calibration properties that can improve performance by several orders of magnitude. Self-calibration of the gyroscope involves periodically switching an axis of the gyroscope from a Coriolis sensing mode to a resonator drive mode. This periodic switching requires axial symmetry of features of the gyroscope and equal electrode gaps in axis shuttle structures of the two mutually orthogonal axes. This symmetry allows the drive axis and the sense axis of the gyroscope to be interchanged when the orientation of the gyroscope is turned ninety degrees. This "mode turnability" between resonator mode and Coriolis mode of the axes cancels out many common mode offset error terms and quadrature error terms that change sign by the turning of the gyroscope. This causes the error term to average out over time.

[0014] FIG.1 is an example of a mode match MEMS gyroscope 102. The gyroscope 102 includes four identical quadrants each including a moveable proof mass 106A - 106 D coupled to a substrate. Each proof mass is movable in the direction of two mutually orthogonal axes. The axes in the example are a horizontal axis and a vertical axis labeled the X axis and the Y axis respectively, as an example, but the axes can be any mutually orthogonal axes. The first axis can be aligned to any in-plane or out-of-plane angle in three-dimensional (3D) space and the second axis is orthogonal to the first axis. Multiple gyroscopes can be assembled on surfaces with different angles. In an example intended to be illustrative and non-limiting, the multiple gyroscopes can be mounted on a foursided pyramid with 45-degree surfaces to realize 3-axis sensing. In another example, multiple gyroscopes can be mounted on vertical or horizontal boards for 3-axis sensing.

[0015] FIG. 2 is an example of a mode match MEMS gyroscope 104 that is one quadrant or one-fourth of the MEMS gyroscope of FIG. 1. The gyroscope 104 includes one proof mass 106B coupled to the substrate. The gyroscope 104 also includes box linkage 208, outer couplers 210, and stress relieved anchors 212. The gyroscope 104 also includes shuttle structures or shuttle frames that can be referred to as "shuttles." The MEMS gyroscope 104 includes two shuttles 214 for the X axis and two shuttles 216 for the Y axis. The shuttles 214, 216 are coupled to the substrate by stress relieved frame anchors 218 and to the proof mass 106B with the box linkage 208 and a lever having a pivot point around frame anchors 218.

[0016] A shuttle 214, 216 is both a drive structure that causes the proof mass 106B to move in response to an electrical signal, and a sense structure that produces an electrical signal representative of movement of the proof mass 106B. The Y axis shuttles 216 include Y Force electrodes 220, Y sense or Y pickoff electrodes 222, and one or more Y frequency tuning electrodes 224. The X axis shuttles 214 include X Force electrodes 226, X pickoff electrodes 228, and one or more X frequency tuning electrodes 230. The gyroscope 104 also includes quadrature electrodes 232 used for trimming to reduce quadrature error.

[0017] An X axis shuttle 214 and a Y axis shuttle 216 can be used interchangeably in either a drive mode to drive the proof mass 106B or a sense mode to sense a Coriolis effect on the proof mass 106B. As an example, if the Y axis is the sense axis and is in a Coriolis sense mode and the X axis is the drive axis and is in a drive mode, the Y force electrodes 220 are Coriolis force electrodes, the pickoff electrodes 222 are Coriolis pickoff electrodes, and the tuning electrodes 224 are Coriolis tuning electrodes. The X force electrodes 226 are drive electrodes, the X pickoff electrodes 228 are velocity pickoff electrodes, and the X tuning electrodes 230 are resonant frequency tuning electrodes. Similarly, if the Y axis is the drive axis and the X axis is the sense axis, the Y force electrodes 220 are drive electrodes, the pickoff electrodes 222 are velocity pickoff electrodes, and the tuning electrodes 224 are resonant frequency tuning electrodes. The X force electrodes 226 are Coriolis force electrodes, the X pickoff electrodes 228 are Coriolis pickoff electrodes, and the X tuning electrodes 230 are Coriolis tuning electrodes. To facilitate this mode match of the axes, several structures of the gyroscope 104 are symmetric.

[0018] FIG. 3 shows the upper right one-fourth (1 / 4) portion of the gyroscope 104 of FIG. 2, or the upper right one-sixteenth (1 / 16) portion of the gyroscope 102 of FIG. 1. A diagonal axis 336 is drawn through the portion of the gyroscope and shows that box linkage 208, outer couplers 210, and springs 234 are symmetric about the diagonal axis. FIG. 3 shows a portion of a Y axis shuttle 216 and an X axis shuttle 214. Many features of the Y axis shuttle 216 are symmetric to the X axis shuttle 214 about the diagonal axis 336. The Y force electrodes 220 are symmetric with the X force electrodes 226, the Y pickoff electrodes 222 are symmetric with the X pickoff electrodes 228, and the Y tuning electrodes 224 are symmetric with the X tuning electrodes 230. Y axis shuttle springs 338 may or may not be symmetric with X axis shuttle springs 340.

[0019] In the example of FIG. 3, the quadrature electrodes 232 are not symmetric about the diagonal axis 336 but can be placed symmetrically along the diagonal axis 336. FIG. 2 shows that the quadrature electrodes 232 are symmetric about either of the X axis or Y axis. FIG. 4 is another example of a 1 / 16 portion of a gyroscope 404 where the quadrature electrodes 232 are symmetric about a diagonal axis 336 of the gyroscope 404.

[0020] Returning to FIG. 2, the symmetry of the MEMS gyroscope 104 allows mode switching each of the two mutually orthogonal axes between drive mode and sense mode. As part of the mode switching, the gyroscope 104 can be turned ninety degrees (90°). If the drive axis and the sense axis are the X-axis and Y-axis respectively, this turning or flipping changes sensitivity of the Coriolis effect from the positive Z-axis to the negative Z-axis. The turning together with the mode switching between the axes, cancels out common mode errors due to coupling between the X-axis and Y-axis. The error canceling can be viewed as self-calibration to reduce the offset and quadrature error sources, such as cross-axis damping and other errors common between X and Y axes. The error reduction reduces the offset and quadrature error of the gyroscopes that results in much smaller as-born error signals, drift in error over time, and environmental stresses than is possible without the mode switching.

[0021] The movement of the shuttles 214, 216 is substantially the same as the movement of the proof mass 106B. For example, if the proof mass 106B moves two micrometers (2µm), the frame of the shuttle moves 2µm. As explained previously herein, the shuttles 214, 216 include parallel plate pickoff electrodes 222, 228, that are used to sense the Coriolis effect or velocity depending on the mode of the corresponding axis of the shuttles. The movement of a shuttle changes the size of the capacitive gap space between the pickoff electrodes. It is desired to have the change in gap size to be large (e.g., thirty-percent (30%) or more of the movement of the proof mass) for mode turnability. However, this much of a change in the gap size can lead to nonlinearities in the movement of the shuttle springs 338, 340, when it is desired for the shuttle springs 338, 340, to move linearly. Previous approaches addressed the non-linearity by using an asymmetric gyroscope design in which the displacement of the sense axis was kept small and turnability of the axes was not possible.

[0022] To reduce or eliminate the nonlinearity due to the large displacement of the shuttle springs 338, 340, the box linkage 208 and stress relieved anchors 212 have minimal positive nonlinear stiffness. In addition, negative nonlinear stiffness (that can be referred to as spring softening) is generated in the pickoff electrodes 222, 228, to tune the gaps produced between the electrodes. Gaps are designed for a particular DC voltage to generate spring softening (negative cubic nonlinearity) that is equal to spring hardening (positive cubic nonlinearity) due to shuttle displacement. This spring softening using voltage cancels the positive nonlinear stiffness (or spring hardening). The overall effect is that the motion frequency of the gyroscope is linear over the full displacement of the gaps. Further tuning of frequencies (over process variations) is done by applying a DC voltage to the frequency tuning electrodes 224, 230 to adjust the voltage difference across the gaps. Moreover, a control loop for tuning electrodes maintains the mode match condition over time, temperature, and environmental stress effects.

[0023] Multiple shuttle structures contribute to the total negative nonlinear stiffness K(-ve) including the pickoff electrodes 222, 228, the tuning electrodes and the quad electrodes or K − νe = K − νe , pickoffs + K − νe , tuning + K − νe , quad . The spring softness can be tuned so that the frequency of the drive mode for the X axis is the same as the frequency of the drive mode for the Y axis.

[0024] The axis shuttles 214, 216, in FIG. 2 include primary frequency tuning electrodes 224, 230. The axis shuttles 214, 216, also include minor tuning electrodes. FIG. 9 shows axis shuttle 216 with primary frequency tuning electrode 224 and minor tuning electrodes 942. The minor tuning electrodes 942 enable higher resolution tuning of the frequency for the same voltage difference after the tuning with the primary frequency tuning electrodes 224, 230 is completed. In some examples, tuning is applied to the shuttles of the axis that has the highest frequency. Primary tuning may be performed first by trimming a DC voltage applied to the primary frequency tuning electrodes 224, 230. After the primary trim, a continuous AC closed mode matching loop uses the minor tuning electrodes 942 to match the drive and sense frequencies of the axes while gyroscope is running.

[0025] Returning to FIG. 1, the mode match MEMS gyroscope 102 includes four proof masses 106A-D and four quadrants - one quadrant four each proof mass. The movement of the proof masses is cross quadrant. For example, proof masses 106A and 106C may move with similar phase and proof masses 106B and 106D with similar phase 180 degrees out of phase with proof masses 106A and 106C. The arrows 146 in FIG. 1 show an example of driving to move the proof masses in the X axis direction. The arrows 146 show that proof masses 106A and 106C move together in the X axis direction, and proof masses 106B and 106D move together in the X axis direction. The arrows 148 show an example of the Coriolis force sense direction in the Y axis direction. The arrows 148 show that proof masses 106A and 106C move together in the Y axis direction, and proof masses 106B and 106D move together in the Y axis direction.

[0026] The primary tuning and the minor tuning may be performed cross quadrant. The primary tuning electrodes of the upper left quadrant and the lower right quadrant may be electrically connected together. A cross diagonal tuning signal is provided to those cross quadrants and the cross quadrants are tuned together. Similarly, the primary tuning electrodes of the upper right quadrant and the lower left quadrant may be electrically connected together, and a cross diagonal tuning signal is provided to tune those cross quadrants together. FIG. 5 is an example of routing in the MEM gyroscope 102 to provide separate tuning signals to the upper left and lower right quadrants, and to the upper right and lower left quadrants.

[0027] Driving and sensing may be performed cross quadrant. For example, if the X axis is the drive axis for the mode match MEMS gyroscope 102, and the Y axis is the sense axis for the mode match MEMS gyroscope 102, the X axis pickoff electrodes for the upper left quadrant and the lower right quadrant may be electrically connected together, and those X axis pickoff electrodes provide a combined signal representing displacement of the proof masses 106A and 106C. The X axis pickoff electrodes for the upper right quadrant and the lower left quadrant may be electrically connected together, and those X axis pickoff electrodes provide a combined signal representing displacement of the proof masses 106B and 106D. FIG. 6 is an example of routing for the X axis pickoff electrodes.

[0028] Similarly, the Y axis pickoff electrodes for the upper left quadrant and the lower right quadrant may be electrically connected together, and those Y axis pickoff electrodes provide a combined signal for Coriolis force on the proof masses 106A and 106C. The Y axis pickoff electrodes for the upper right quadrant and the lower left quadrant may be electrically connected together and those Y-axis pickoff electrodes provide a combined signal for Coriolis force on the proof masses 106B and 106D. FIG. 7 is an example of routing for the Y axis pickoff electrodes.

[0029] The symmetry of the axis shuttles and the tunability of the axis shuttles 214, 216 allow for the turning and mode switching of the mode match MEMS gyroscope 102. The turning and mode switching periodically changes the axis of vibration from one axis (e.g., the X-axis) to the orthogonal axis (e.g., the Y-axis), which flips the sign of the scale factor of the sensed Coriolis signal so that errors (e.g., from cross-axis damping) are canceled. The turning and mode switching is performed periodically to change the principal axis of vibration (e.g., from the X-axis to the Y-axis) and back (from the Y-axis to the X-axis). The period of the turning should be faster than the time constant of bias instability of Allan Variance.

[0030] The output voltage of the MEMS gyroscope is converted to a rotation rate signal. During the flipping of the MEMS gyroscope 102, the gyroscope is turned off and the MEMS gyroscope 102 stops sensing. After flipping, the MEMS gyroscope 102 is turned on and the drive signal builds up the vibrations of the resonant movement to the desired displacement (e.g., 4µm). During the flipping time, rate information is not available and would normally be lost and information from the gyroscope would be interrupted.

[0031] Recovering the rotation rate information would allow uninterrupted operation of the MEMS gyroscope 102. The rotation rate information can be determined from the electrostatic force (F VIRT ) used to turn the MEM gyroscope 102 from 0° to 90°. The flipping of the MEMS gyroscope 102 can be performed under open loop or closed loop control.

[0032] In open loop control, the electrostatic force used to turn the MEMS gyroscope 102 is constant, and a different value of force turns the MEMS gyroscope at a different rate (e.g., in the range from 10 degrees per second (10° / sec) to 2000° / sec). The electrostatic force F VIRT acts as a virtual rotation rate Ω VIRT , Ω VIRT = F VIRT / 2 ω √ E , where ω is the frequency of oscillation and E is energy. The turn time of the MEMS gyroscope is determined from the virtual rate. As an example, for a virtual rate of 2000° / sec, the turn time from 0° to 90° is 90 / 2000 or 45 milliseconds (45ms), which corresponds to the gyroscope bandwidth of 22 Hertz. The physical rotation rate is obtained by subtracting the applied virtual slewing rate (in this example 2000° / sec).

[0033] In closed loop control, the electrostatic force F VIRT varies. For example, the control loop may be a Proportional-Integral-Derivative (PID) loop that changes the angle from 0° to 90° using a varying F VIRT . For example, the PID angle control loop may change F VIRT to start at a fast rate at first (e.g., 10,000° / sec) and then a slow rate as it nears 90° for accuracy. The profile of the electrostatic force and the virtual rate are known. The virtual rate can be subtracted from the gyroscope output to get the physical rotation rate information.

[0034] FIG. 8 is a block diagram of a control circuit for open loop control. The frequency of oscillations ω is controlled by a phased-locked loop (PLL) loop that tracks the gyro motion at any arbitrary pattern angle. With the PLL loop enabled, the Gyro Model extracts the slow-varying variables: energy (E), quadrature error (Q), and a pattern angle (θ). A set of PID controllers regulate the following: energy E (amplitude E) by the command voltage E PID , quadrature null action Q PID , and a feedforward control F VIRT that continuously rotates the pattern angle (θ) at the rate Ω VIRT . The control forces fx, fy are applied along the pattern angle θ, which is accomplished by the coordinate transform followed by modulation of the command voltages at PLL frequency ω.

[0035] The following forces were applied to X and Y electrodes: E PID to control amplitude, Q PID to null quadrature, and F VIRT to set virtual rate Ω VIRT : fx = E PID sinωsinθ + Q PID cosωtcosθ + F VIRT sinωtcosθ , fx = E PID sinωcosθ + Q PID cosωtsinθ + F VIRT sinωtsinθ .

[0036] The forces for applying virtual rates are the same as the forces to operate the gyroscope in a rate mode if the virtual rate is controlled to operate the gyroscope at a fixed angle (either 0° or 90 °).

[0037] The systems and methods described provide a MEMS gyroscope that is symmetric. The symmetry allows the drive axis and the sense axis of the gyroscope to be interchanged when the orientation of the gyroscope is turned ninety degrees. This "mode turnability" between resonator mode and Coriolis mode of the axes cancels out many common mode offset error terms and quadrature error terms that change sign by the turning of the gyroscope. This causes the error term to average out over time, allowing much smaller signals to be read from the MEMS gyroscope and improving performance by several orders of magnitude.

Claims

1. A gyroscope (102), comprising: a substrate; a proof mass (106B) coupled to the substrate and configured to move in direction of an X axis and in direction of a Y axis orthogonal to the X axis; an X axis shuttle (214) to selectively drive the proof mass along the X axis as a drive axis or sense movement of the proof mass along the X axis as a sense axis in response to the proof mass driven along the Y axis as the drive axis; a Y axis shuttle (216) to selectively sense movement of the proof mass along the Y axis as a sense axis in response to the proof mass driven along the X axis or drive the proof mass along the Y axis as the drive axis; and wherein the X axis shuttle is symmetric to the Y axis shuttle along a diagonal axis (336) that is diagonal to both the X axis and the Y axis, wherein the X axis shuttle includes drive-or-sense (drive / sense) electrodes (226, 228) symmetrical about the diagonal axis to drive / sense electrodes (220, 222) of the Y axis shuttle, and wherein the gyroscope further comprises: springs (234) coupled to the proof mass; a gap space between the drive / sense electrodes of the X axis shuttle and Y axis shuttle, wherein displacement of the X and Y axis shuttles changes the gap space between the drive / sense electrodes; and characterized in that a predetermined DC voltage applied to the gap space causes motion frequency of the proof mass to be linear over full displacement of the X and Y axis shuttles and over a full change of the gap space due to the displacement of the X and Y axis shuttles.

2. The gyroscope of claim 1, wherein driving the proof mass along a selected one of the X axis or Y axis causes the proof mass to vibrate in the direction of the selected axis, and movement of the proof mass along the other axis is representative of a Coriolis force on the proof mass.

3. The gyroscope of any preceding claim, wherein the X axis shuttle includes a frequency tuning electrode (230) symmetrical about the diagonal axis to a frequency tuning electrode (224) of the Y axis shuttle; and wherein applying a voltage to the frequency tuning electrode of the X axis shuttle or the Y axis shuttle changes a frequency of movement in the corresponding X axis or Y axis direction.

4. The gyroscope of any preceding claim, including multiple quadrature trimming electrodes (232), wherein the quadrature trimming electrodes are arranged in a pattern symmetrical about the diagonal axis and / or wherein the quadrature trimming electrodes are arranged in a pattern symmetrical about both of the X axis and the Y axis.

5. The gyroscope of any preceding claim, wherein the X axis shuttle includes one or more springs (340), and wherein the Y axis shuttle includes one or more springs (338) asymmetrical about the diagonal axis to the springs of the X axis shuttle and / or wherein the Y axis shuttle includes one or more springs symmetrical about the diagonal axis to the springs of the X axis shuttle.

6. The gyroscope of any preceding claim, wherein the gyroscope is a four-quadrant gyroscope including: four proof masses (106A, 106B, 106C, 106D) coupled to the substrate and each proof mass is included in one quadrant of the four quadrant gyroscope, an X axis shuttle and a Y axis shuttle in each quadrant of the four-quadrant gyroscope.

7. The gyroscope of claim 6, wherein the Y axis shuttle of each quadrant includes drive / sense electrodes; and wherein the X axis shuttle drive / sense electrodes of cross quadrants of the four quadrants are electrically connected together, and the Y axis shuttle drive / sense electrodes of cross quadrants of the four quadrants are electrically connected together.

8. The gyroscope of claim 6 or 7, further comprising a control circuit configured to mode switch the four quadrant gyroscope between driving along the X axis and sensing along the Y axis, and driving along the Y axis and sensing along the X axis.

9. A method of operating a gyroscope (102) according to any preceding claim, the method including: driving the gyroscope along the X axis of the gyroscope as the drive axis; sensing a response of the gyroscope along the Y axis orthogonal to the X axis as the sense axis; turning the gyroscope and changing the drive axis to the Y axis and changing the sense axis to the X axis; and applying a predetermined DC voltage to the gap space between the drive / sense electrodes of the X axis shuttle and Y axis shuttle.

10. The method of claim 9, wherein driving the gyroscope includes applying a drive signal to the X axis shuttle (214) to cause the proof mass (106B) of the gyroscope to vibrate in the X axis direction; wherein sensing the response includes sensing displacement of the Y axis shuttle (216) to sense a Coriolis effect movement of the proof mass; and wherein turning the gyroscope includes turning the gyroscope, driving the gyroscope along the Y axis to cause the proof mass to resonate in the Y axis direction, and sensing the Coriolis effect movement of the proof mass along the X axis.

11. The method of claim 9 or 10, including determining sensed rotation rate information during the turning of the gyroscope.

12. The method of any of claims 9 to 11, including one or both of: applying a voltage to the frequency tuning electrode (230) of the X axis shuttle (214) to change a frequency of movement in the X axis direction; and applying a voltage to the frequency tuning electrode (224) of the Y axis shuttle (216) to change a frequency of movement in the Y axis direction.