Gyroscope with electrodes for tuning cross-axis sensitivity

Abstract

To provide gyroscopes with electrodes for tuning cross-axis sensitivity.SOLUTION: Gyroscopes with electrodes for tuning cross-axis sensitivity are disclosed. In certain embodiments, a microelectromechanical systems (MEMS) gyroscope includes a resonator mass that moves in a first direction (e.g., x-direction), a sensing structure that detects a Coriolis effect in a second direction (e.g., y-direction), and a plurality of electrodes that control a cross-axis stiffness of the MEMS gyroscope by controlling motion of the resonator mass in a third direction (e.g., z-direction). For example, the electrodes can be used to reduce or eliminate cross-axis sensitivity arising from cross-axis stiffnesses, such as kxz (resonator-to-orthogonal) and / or kyz (Coriolis-to-orthogonal).SELECTED DRAWING: None

Description

[Technical Field]

[0001] Embodiments of the present invention relate to electronic devices, and more specifically to micro-electromechanical systems (MEMS) gyroscopes. [Background technology]

[0002] A gyroscope is used to measure angular velocity using Coriolis acceleration. MEMS gyroscopes offer a compact form factor that enables accurate angular velocity and / or rotational velocity measurement even in the presence of shock and vibration. Exemplary applications of gyroscopes include, but are not limited to, inertial sensing and navigation. [Overview of the project]

[0003] A gyroscope is disclosed that includes electrodes for tuning cross-axis sensitivity. In certain embodiments, the MEMS gyroscope includes a resonator mass moving in a first direction (e.g., the x-direction), a sensing structure for detecting the Coriolis effect in a second direction (e.g., the y-direction), and a plurality of electrodes that control the cross-axis stiffness of the MEMS gyroscope by controlling the motion of the resonator mass in a third direction (e.g., the z-direction). For example, the electrodes are k xz (Orthogonal to the resonator) and / or k yz It can be used to reduce or eliminate cross-axis sensitivity arising from cross-axis stiffness (such as from Coriolis to orthogonal).

[0004] In one embodiment, a micro-electromechanical system (MEMS) gyroscope includes a resonator mass configured to move in a first direction, a sensing structure configured to detect the Coriolis effect on the resonator mass in a second direction, and a plurality of electrodes configured to control the cross-axis stiffness of the MEMS gyroscope by controlling the motion of the resonator mass in a third direction. The first, second, and third directions are orthogonal to each other.

[0005] In another embodiment, a method for tuning the cross-axis sensitivity in a MEMS gyroscope is disclosed. This method includes controlling the cross-axis stiffness of the MEMS gyroscope by moving the resonator mass in a first direction, detecting the Coriolis effect on the resonator mass in a second direction using a sensing structure, and controlling the motion of the resonator mass in a third direction using a plurality of electrodes. The first, second, and third directions are orthogonal to each other. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram of one embodiment of a MEMS gyroscope. [Figure 2A] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 2B] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 3A] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 3B] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 3C] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 3D] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 3E] This is a schematic diagram of another embodiment of a MEMS gyroscope. [Figure 4A] This is a schematic diagram of one embodiment of the x-axis side wall for a MEMS gyroscope. [Figure 4B] This is a schematic diagram of the x-axis side wall of Figure 4A in response to x-axis motion. [Figure 4C] This is a schematic diagram illustrating the z-axis reaction motion due to x-axis motion. [Figure 5A] This is a schematic diagram of one embodiment of the y-axis side wall for a MEMS gyroscope. [Figure 5B] This is a schematic diagram of the y-axis side wall of Figure 5A in response to z-axis motion. [Figure 5C]It is a schematic diagram depicting the y-axis reaction movement due to the z-axis movement. [Figure 6] It is a schematic diagram of another embodiment of the MEMS gyroscope. [Figure 7] It is a schematic diagram of one embodiment of a cross-axis sensitivity tuning circuit for a MEMS gyroscope. **[Embodiments for Carrying Out the Invention]**

[0007] The following detailed description of the embodiments presents various descriptions of specific embodiments of the present invention. However, the present invention can be embodied in many different ways. In this description, reference is made to the drawings, in which like reference numerals may indicate the same or functionally similar elements. It should be understood that the elements illustrated in the figures are not necessarily drawn to scale. In addition, it should be understood that a particular embodiment can include more elements and / or a subset of the elements illustrated in the drawings than are illustrated. Furthermore, some embodiments can incorporate any suitable combination of features from two or more of the drawings.

[0008] FIG. 1 is a schematic diagram of one embodiment of a MEMS gyroscope 10. The MEMS gyroscope 10 includes a resonator mass 3, a spring 4, an x-axis electrode 5, a y-axis electrode 6, and an anchor 9.

[0009] In the illustrated embodiment, the spring 4 couples the resonator mass 3 to the anchor 9. Further, the anchor 9 is connected to a frame or substrate (not shown in FIG. 1) at each of the four corners in this example.

[0010] Continuing to refer to FIG. 1, the resonator mass 3 is driven in the x direction. In addition, in response to rotation about the z axis, the resonator mass 3 can experience movement in the y direction resulting from the Coriolis effect. Thus, in this embodiment, the resonator mass 3 moves in the x direction, the Coriolis effect deflects the resonator mass 3 in the y direction, and movement of the resonator mass 3 in the z direction is undesirable.

[0011] As the rotational speed increases, the displacement of the resonator mass 3 in the y-direction resulting from the Coriolis effect also increases. The motion of the resonator mass 3 in the x-direction is sensed through x-axis electrodes 5, which function as capacitive sensing elements. In certain implementations, the sensing electrodes 5 include stationary silicon beams that mesh with moving silicon beams, each attached to the resonator mass 3. In addition, the MEMS gyroscope 10 includes a y-axis electrode 6, which can be used to measure the y-axis deflection resulting from the Coriolis effect and / or to trim the motion of the resonator mass 3 in the y-direction (e.g., orthogonal trim).

[0012] Continuing to refer to Figure 1, the displacement due to angular velocity induces a change in the capacitance used, generating the output signal of the gyroscope. The micro-electromechanical gyroscope 10 can be optionally placed on a rotating object with its sensing axis positioned parallel to the axis of rotation. Thus, the micro-electromechanical gyroscope 10 can be deployed in a wide range of applications to measure one or more angular rotational speeds, including roll, pitch, and / or yaw.

[0013] MEMS gyroscopes, such as the MEMS gyroscope 10 in Figure 1, may exhibit undesirable cross-axis sensitivity. For example, a MEMS gyroscope may have a sensitivity matrix S defined by the following equation 1. equation 1

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[0014] In Equation 1, the diagonal term S ii This can correspond to the desired response (depending on the implementation as a roll, pitch, and / or yaw sensor), and the off-diagonal term S ij This indicates undesirable cross-axis sensitivity.

[0015] Cross-axis sensitivity can arise from a variety of sources, including, for example, misalignment of the sensor axis relative to the sensor packaging (e.g., a sensor soldered with a slight rotation) and / or inherent non-orthogonality in the sensor response. Reducing or minimizing cross-axis sensitivity errors is a critical requirement in certain applications, including those associated with high-performance inertial sensing and / or navigation. While cross-axis sensitivity can be reduced through careful calibration, it nevertheless varies across temperature, humidity, stress, and / or other operating parameters.

[0016] As an example, Table 1 below provides four exemplary sets of displacement, velocity, force, and sensitivity parameters for the micro-electromechanical gyroscope 10 shown in Figure 1. Table 1 [Table 1]

[0017] In Table 1, S zz This corresponds to the intended sensitivity of the MEMS gyroscope 10. For example, the resonator mass 3 is a force in the y direction.

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[0018] In addition to the intended sensitivity, Table 1 also includes various unwanted cross-axis sensitivities. For example, S zy is the cross-axis stiffness k yz (orthogonal to Coriolis) and / or sensing misalignment [Number] and in combination with the x-axis motion of resonator mass 3. Unwanted cross-axis sensitivity can also result from cross-axis stiffness k zx (orthogonal to the resonator) and / or k xy (Coriolis from the resonator).

[0019] In certain implementations, k xy (Coriolis from the resonator) can be set to zero in the orthogonal loop over the desired operating conditions to provide orthogonal trimming. However, even in such implementations, cross-axis sensitivity errors resulting from k xz (orthogonal to the resonator) and / or k yz (orthogonal to Coriolis) may remain.

[0020] A gyroscope with electrodes for tuning cross-axis sensitivity is disclosed. In certain embodiments, the MEMS gyroscope includes a resonator mass moving in a first direction (e.g., the x-direction), a sensing structure for detecting the Coriolis effect in a second direction (e.g., the y-direction), and a plurality of electrodes for controlling the cross-axis stiffness of the MEMS gyroscope by controlling the motion of the resonator mass in a third direction (e.g., the z-direction). For example, the electrodes can be used to reduce or eliminate cross-axis sensitivity resulting from cross-axis stiffness such as k xz (orthogonal to the resonator) and / or k yz (orthogonal to Coriolis).

[0021] Thus, the teachings herein can be used to measure and compensate for cross-axis sensitivity using electrodes.

[0022] k xyIn contrast to orthogonal trim electrodes that control (Coriolis motion from the resonator), the electrodes of this specification are oriented orthogonally to control motion in the z-direction.

[0023] Figure 2A is a schematic diagram of another embodiment of the MEMS gyroscope 30. The MEMS gyroscope 30 includes a resonator mass 21 and a pair of electrodes 23 / 24 for cross-axis sensitivity tuning. The resonator mass 21 is driven to move in the x-direction, the Coriolis effect occurs in the y-direction, and motion of the resonator mass 21 in the z-direction is undesirable. For clarity, various structures of the MEMS gyroscope 30, such as sensing structures for detecting movement in the x and y directions, are not shown in the figure.

[0024] As shown in Figure 2A, the resonator mass voltage source 26 biases the voltage across the resonator mass 21 to voltage HV. In addition, the first electrode voltage source 27 provides voltage V CM The first electrode 23 is biased with -ΔV, while the second electrode voltage source 28 is biased with voltage V CM The second electrode 24 is biased with +ΔV. Therefore, the pair of electrodes 23 / 24 are subjected to the common-mode voltage V CM It operates with a voltage difference of 2*ΔV. This voltage difference of 2*ΔV is also referred to as differential voltage in this specification.

[0025] In the illustrated embodiment, the pair of electrodes 23 / 24 have a width w in the x direction and a thickness h in the y direction. In addition, the resonator mass 21 surrounds the pair of electrodes 23 / 24 in the air cavity and is separated from both the top and bottom of the pair of electrodes 23 / 24 by a distance d.

[0026] The pair of electrodes 23 / 24 operate to provide a force Fz in the z direction, which can be used to zero out the displacement in the z direction resulting from the cross-axis stiffness and motion of the resonator mass 21 in the x direction. Thus, the pair of electrodes 23 / 24 operate in the k xz It can be used to eliminate cross-axis sensitivity arising from cross-axis stiffness (such as orthogonal to the resonator).

[0027] In a specific implementation, a pair of electrodes 23 / 24 operate to generate a force Fz given by the following equation 2, where ε0 is the permittivity of free space and z is the amount of displacement in the z direction. equation 2

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[0028] In Equation 2, the first term

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[0029] Figure 2B is a schematic diagram of another embodiment of the MEMS gyroscope 40. The MEMS gyroscope 40 includes a resonator mass 31 and a pair of electrodes 33 / 34 for cross-axis sensitivity tuning. The resonator mass 21 is driven to move in the x-direction, the Coriolis effect occurs in the y-direction, and motion of the resonator mass 21 in the z-direction is undesirable. For clarity, various structures of the MEMS gyroscope 40, such as sensing structures for detecting movement in the x and y directions, are not shown in the figure.

[0030] The MEMS gyroscope 40 in Figure 2B is similar to the MEMS gyroscope 30 in Figure 2A, except that the MEMS gyroscope 40 in Figure 2B is mounted with electrodes 33 / 34 positioned below the resonant mass 31, rather than being surrounded by a resonant mass as in Figure 2A. In the embodiment of Figure 2B, the pair of electrodes 33 / 34 have a width w in the x direction and a length L in the y direction, and are separated from the resonant mass 31 by a distance d.

[0031] In a specific implementation, the pair of electrodes 33 / 34 operate to generate a force Fz in the z direction, given by the following equation 3. equation 3

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[0032] In Equation 3, the first term

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[0033] Figure 3A is a schematic diagram of another embodiment of the MEMS gyroscope 41. The MEMS gyroscope 41 includes a resonator mass 42, a spring 4, an anchor 9, and electrodes 43 / 44 separated from the resonator mass 42 by a distance d. The resonator mass 42 has a resonator displacement in the x-direction and a Coriolis displacement in the y-direction. Figure 3A depicts a top view of the resonator mass 42 and electrodes 43 / 44. For clarity, various structures of the MEMS gyroscope 41, such as a sensing structure for detecting the movement of the resonator mass 42, are not shown.

[0034] The pair of electrodes 43 / 44 have cross-axis stiffness k xz It operates to eliminate the resulting cross-axis sensitivity. In this embodiment, the pair of electrodes 43 / 44 are in plane with the resonator mass 42.

[0035] Figure 3B is a schematic diagram of another embodiment of the MEMS gyroscope 45. The MEMS gyroscope 45 includes a resonator mass 42 that moves in the x-direction, a spring 4, an anchor 9, and electrodes 43 / 44 separated from the resonator mass 42 by a distance d. Both a top view (shown on the left) and a cross-sectional view (shown on the right) of the MEMS gyroscope 45 are shown in Figure 3B.

[0036] Compared to the MEMS gyroscope 41 in Figure 3A, the MEMS gyroscope 45 in Figure 3B uses a pair of electrodes 43 / 44 to achieve cross-axis stiffness k yz The resulting cross-axis sensitivity is made zero. In this embodiment, the pair of electrodes 43 / 44 are out of plane with respect to the resonator mass 42.

[0037] Referring to Figures 3A and 3B, the cross-axis stiffness k depends on the direction of the resonator and the Coriolis force. yz and / or k yz This may include different combinations of electrodes to make the value zero. Furthermore, any of the embodiments herein may include orthogonal trimming (k xy It may include another pair of electrodes for )

[0038] Figure 3C is a schematic diagram of another embodiment of the MEMS gyroscope 47. The MEMS gyroscope 47 includes a resonator mass 42 that moves in the x-direction and electrodes 43 / 44 separated from the resonator mass 42 by a distance d.

[0039] In Figure 3C, the pair of electrodes 43 / 44 have a cross axis stiffness k xz It operates to zero out the cross-axis sensitivity resulting from k. Therefore, the MEMS gyroscope 47 in Figure 3C operates k xzAnother embodiment of zeroing is illustrated. Compared to the MEMS gyroscope 41 in Figure 3A, where the electrodes are aligned along the x-direction, the electrodes 43 / 44 in Figure 3C are aligned along the y-direction. Furthermore, in the embodiment of Figure 3C, a portion of the resonator mass 42 is located between the electrodes 43 / 44.

[0040] Figure 3D is a schematic diagram of another embodiment of the MEMS gyroscope 48. The MEMS gyroscope 48 includes a resonator mass 42, a spring 4, an anchor 9, and electrodes 43 / 44 separated from the resonator mass 42 by a distance d. The resonator mass 42 has a resonator displacement in the x direction and a Coriolis displacement in the y direction. For clarity in the figure, various structures of the MEMS gyroscope 48, such as a sensing structure for detecting the movement of the resonator mass 42, are not shown. Both a top view (shown at the top) and a cross-sectional view (shown at the bottom) of the MEMS gyroscope 48 are shown in Figure 3D.

[0041] The MEMS gyroscope 48 in Figure 3D is k xz Another implementation configuration of electrodes 43 / 44 for zeroing is depicted. In this example, electrodes 43 / 44 are out of plane.

[0042] Figure 3E is a schematic diagram of another embodiment of the MEMS gyroscope 49. The MEMS gyroscope 49 includes a resonator mass 42, a spring 4, an anchor 9, and electrodes 43 / 44 separated by the resonator mass 42 by a distance d.

[0043] Similar to the MEMS gyroscope 48 in Figure 3D, the MEMS gyroscope 49 in Figure 3E also has k xz Electrodes 43 / 44 are used for zeroing. In this implementation, the resonator mass 42 has an opening in the center that partially overlaps with electrodes 43 / 44.

[0044] Figure 4A is a schematic diagram of one embodiment of an x-axis sidewall 52 for a MEMS gyroscope. The x-axis sidewall 52 is attached to the substrate 51 by a support 53. Figure 4B is a schematic diagram of the x-axis sidewall 52 of Figure 4A in response to the x-axis motion of the resonator mass. Figure 4C is a schematic diagram illustrating the z-axis response motion due to the x-axis motion.

[0045] Referring to Figures 4A to 4C, when there is no motion of the resonator mass in the x-direction, there is no z-axis motion of the resonator mass (dz=0). However, when an input force X along the x-axis is applied, the x-axis motion is converted into z-axis motion (dz≠0).

[0046] For example, Figure 4C illustrates the z-axis reaction motion across four quadrants due to x-axis motion.

[0047] Therefore, the x-axis motion of the resonator mass is converted into z-axis motion.

[0048] Figure 5A is a schematic diagram of one embodiment of a y-axis sidewall 54 for a MEMS gyroscope. The y-axis sidewall 54 is attached to the substrate 51 by a support 55. Figure 5B is a schematic diagram of the y-axis sidewall 54 of Figure 5A in response to the z-axis motion of the resonator mass. Figure 5C is a schematic diagram illustrating the y-axis response motion due to the z-axis motion.

[0049] In the illustrated embodiment, when there is no motion of the resonator mass in the z-direction, there is no y-axis motion of the resonator mass (dy=0). However, when motion occurs along the z-axis, the z-axis motion is converted into y-axis motion (dy≠0).

[0050] Referring to Figures 4A to 5C, the x-axis motion of the resonator mass is converted into z-axis motion, which is then converted into y-axis motion. Therefore, the resonator mode

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[0051] By including one or more pairs of electrodes according to the teachings of this specification, z-axis motion can be canceled. Thus, dz can be controlled to 0 even when the resonator mass moves in the x-direction during the operation of the MEMS gyroscope.

[0052] Figure 6 is a schematic diagram of another embodiment of the MEMS gyroscope 80. The MEMS gyroscope 80 includes a substrate 61, a cap 62, a resonator mass 63, a first pair of electrodes 73 / 74 for cross-axis sensitivity tuning, and a second pair of electrodes 75 / 76 for cross-axis sensitivity tuning. During operation of the MEMS gyroscope 80, the resonator mass 63 moves in the x-direction, the Coriolis effect occurs in the y-direction, and motion of the resonator mass 63 in the z-direction is undesirable. For clarity, various structures of the MEMS gyroscope 80, such as sensing structures for detecting movement in the x and y directions, are not shown in the figure.

[0053] In the illustrated embodiment, multiple pairs of electrodes are included for z-axis motion compensation. For example, the MEMS gyroscope 80 includes a first pair of electrodes 73 / 74 formed on a polysilicon layer on a substrate 61, and a second pair of electrodes 75 / 76 formed on a cap 62 on a resonator mass 63. The depicted electrodes may be patterned such that the z-axis force is equal from the top and bottom.

[0054] In this example, each pair of first electrodes (73 and 75) has a first voltage V1 = V CM -ΔV is received, while each pair of second electrodes (74 and 76) receives a second voltage V2 = V CM We receive +ΔV.

[0055] In this embodiment, the differential voltage 2*ΔV can be controlled to cancel out motion in the z direction.

[0056] In implementations involving only one pair of electrodes (e.g., only the first pair of electrodes 73 / 74), a unidirectional common-mode force is applied, and therefore the effectiveness is only half that of both the upper and lower electrodes, as illustrated.

[0057] In the illustrated embodiment, the common mode voltage V CM It operates to provide adjustment to the resonator frequency, which can be used to avoid higher-order harmonic overlap across temperature.

[0058] Figure 7 is a schematic diagram of one embodiment of a cross-axis sensitivity tuning circuit 120 for a MEMS gyroscope. The cross-axis sensitivity tuning circuit 120 includes a self-test circuit 101, a differential voltage control circuit 102, a common-mode voltage control circuit 103, an orthogonal trim control circuit 104, and a sensitivity matrix detection circuit 105.

[0059] The cross-axis sensitivity tuning circuit 120 generates a first voltage V1 and a second voltage V2 to control the first pair of electrodes 111 / 112 used for z-axis motion compensation. In a particular implementation, the cross-axis sensitivity tuning circuit 120 is k xy Further generating are a third voltage V3 and a fourth voltage V4 to control a second pair of electrodes 113 / 114 used for compensation. For example, the first pair of electrodes 111 / 112 can block the path from the x-direction to the z-direction and then to the y-direction, thereby indirectly canceling the y-direction motion resulting from the x-direction motion. In addition, the second pair of electrodes 113 / 114 are located in the xy-plane and can be used to directly cancel the y-direction motion resulting from the x-direction motion.

[0060] In the illustrated embodiment, the cross-axis sensitivity tuning circuit 120 controls the common mode voltage V CMBy controlling the common-mode voltage V, adjustment to the resonator frequency is provided, which can be used to avoid higher-order harmonic overlap across temperature. For example, providing such frequency adjustment can be very useful in avoiding third-harmonic (3f0) modal interaction. CM Controlling this can also be used for orthogonal mode frequency tuning for applications where such tuning is desirable.

[0061] Continuing to refer to Figure 7, the self-test circuit 101 is used to generate a self-test signal on the electrode, which is monitored by the sensitivity matrix detection circuit 105 via the sensing structure 117 to determine how the sensitivity matrix S is changing.

[0062] In some implementations, the detected sensitivity matrix S can be used to compensate for the reported velocity measurement (e.g., open loop). In other implementations, the common-mode voltage V on the electrode is used. CM Using a self-test signal and frequency tuning via [a specific method], the cross-axis stiffness can be kept constant across temperature, humidity, stress, and / or other operating parameters (e.g., closed loop).

[0063] In certain implementation configurations, one or more pairs of electrodes are k xz (Orthogonal to the resonator) and / or k yz These are used to counteract cross-axis stiffness (such as Coriolis orthogonal) and the cross-axis sensitivity they produce. The voltage used to control such electrodes can be determined by the cross-axis sensitivity tuning circuit 120 by sensing orthogonal motion in the sensing structure 117 and tuning the cross-axis displacement to approximately zero (e.g., closed loop).

[0064] The cross-axis sensitivity tuning circuit 120 can dynamically control the voltage supplied to the electrodes over time to compensate for fluctuations in operating parameters. In one example, the cross-axis sensitivity tuning circuit 120 controls the electrode voltage to compensate for cross-axis stiffness over at least one of temperature, humidity, or stress.

[0065] knot The preceding description may refer to elements or features being “connected” or “joined.” Where used herein, unless otherwise specified, “connected” means that one element / feature is directly or indirectly connected to another element / feature, not necessarily mechanically. Similarly, unless otherwise specified, “joined” means that one element / feature is directly or indirectly joined to another element / feature, not necessarily mechanically. Thus, while the various schematic diagrams shown in the figures illustrate exemplary arrangements of elements and components, additional intervening elements, devices, features, or components may be present in actual embodiments (assuming the functionality of the depicted circuits is not adversely affected).

[0066] While specific embodiments have been described, these embodiments are presented merely as examples and are not intended to limit the scope of this disclosure. In fact, the novel devices, methods, and systems described herein can be embodied in a variety of other forms, and furthermore, various omissions, substitutions, and modifications can be made in the forms of the methods and systems described herein without departing from the spirit of this disclosure. For example, while the disclosed embodiments are presented in a given arrangement, alternative embodiments may perform similar functionality with different components and / or circuit topologies, and some elements may be removed, moved, added, subdivided, combined, and / or modified. Each of these elements can be implemented in a variety of different ways. Any preferred combination of elements and actions of the various embodiments described above can be combined to provide further embodiments. Accordingly, the scope of the invention is defined only by reference to the appended claims.

[0067] The claims presented herein are in a sole dependent form for filing with the USPTO, but it should be understood that any claim may be dependent on any prior claim of the same type, unless it is clearly not technically feasible. [Explanation of Symbols]

[0068] 10 MEMS Gyroscope 21 Resonator mass 23 First electrode 24 Second electrode 26. Resonator Mass Voltage Source 27 First electrode voltage source 28 Second electrode voltage source 30 MEMS Gyroscope 31 Resonator mass 40 MEMS Gyroscope 41 MEMS Gyroscope 42 Resonator mass 45 MEMS Gyroscope 47 MEMS Gyroscope 48 MEMS Gyroscope 49 MEMS Gyroscope 51 circuit boards 52 x-axis side wall 53 Support 54 y-axis side wall 55 Support 61 circuit boards 62 caps 63 Resonator mass 80 MEMS Gyroscope 101 Self-test circuit 102 Differential Voltage Control Circuit 103 Common-mode voltage control circuit 104 Orthogonal trim control circuit 105 Sensitivity Matrix Detection Circuit 117 Sensing structure 120 Cross-axis sensitivity tuning circuit

Claims

1. A micro-electromechanical system (MEMS) gyroscope, A resonator mass body configured to move in a first direction, A sensing structure configured to detect the Coriolis effect on the resonant mass in a second direction when the resonant mass rotates about a third direction, A plurality of electrodes configured to control the cross-axis stiffness of the MEMS gyroscope by controlling the motion of the resonator mass in the third direction, Equipped with, The first direction, the second direction, and the third direction are orthogonal to each other. A MEMS gyroscope in which the plurality of electrodes include a first electrode and a second electrode configured to receive a differential voltage, and the differential voltage controls the force applied to the resonator mass in the third direction.

2. The MEMS gyroscope according to claim 1, wherein the cross axis stiffness is the stiffness in the third direction with respect to a force applied in the first direction (x) when the resonator mass body moves in the first direction (x).

3. The MEMS gyroscope according to claim 1, wherein the cross axis stiffness is the stiffness in the third direction with respect to a force applied in the second direction due to the Coriolis effect.

4. The MEMS gyroscope according to claim 1, wherein the common-mode voltages of the first electrode and the second electrode are adjustable to control the resonant frequency of the resonant mass body.

5. The MEMS gyroscope according to claim 1, wherein the common-mode voltages of the first electrode and the second electrode are adjustable to control harmonic modal interactions over temperature.

6. The MEMS gyroscope according to claim 1, wherein the first electrode and the second electrode are formed in the polysilicon layer between the substrate and the resonator mass.

7. The MEMS gyroscope according to claim 1, wherein the first electrode and the second electrode are formed on the cap layer on the resonator mass body.

8. The MEMS gyroscope according to claim 1, wherein the first electrode and the second electrode are formed in a polysilicon layer between the substrate and the resonator mass, and the plurality of electrodes further include a third electrode and a fourth electrode formed in a cap layer on the resonator mass.

9. The MEMS gyroscope according to claim 1, wherein the first electrode and the second electrode are configured to receive a self-test signal, and the MEMS gyroscope further comprises a cross-axis sensitivity tuning circuit configured to detect the sensitivity matrix of the resonator mass in response to the self-test signal.

10. The MEMS gyroscope according to claim 9, wherein the cross-axis sensitivity tuning circuit is configured to compensate for cross-axis stiffness over at least one of temperature, humidity, or stress.

11. The MEMS gyroscope according to claim 1, further comprising a plurality of additional electrodes configured to control orthogonal trim in the first and second directions.

12. The MEMS gyroscope according to claim 1, which is mounted on at least one of a roll sensor, a pitch sensor, or a yaw sensor.

13. A method for tuning the cross axis sensitivity in a micro-electromechanical system (MEMS) gyroscope, wherein the method is Moving the resonator mass in the first direction, Using a sensing structure, the Coriolis effect on the resonator mass in the second direction as the resonator mass rotates around the third direction is detected, The cross-axis stiffness of the MEMS gyroscope is controlled by controlling the motion of the resonator mass in the third direction using multiple electrodes, Includes, The first direction, the second direction, and the third direction are orthogonal to each other. A method for controlling the cross-axis stiffness, comprising controlling the differential voltage between a first electrode and a second electrode to control the force applied to the resonator mass in the third direction.

14. The method according to claim 13, wherein the cross axis stiffness is the stiffness in the third direction with respect to a force applied in the first direction (x) when the resonator mass body moves in the first direction (x).

15. The method according to claim 13, wherein the cross axis stiffness is the stiffness in the third direction with respect to a force applied in the second direction due to the Coriolis effect.

16. The method according to claim 13, further comprising controlling the common-mode voltages of the first electrode and the second electrode to control the resonator frequency of the resonator mass.

17. The method according to claim 13, further comprising controlling the common-mode voltages of the first electrode and the second electrode to control the harmonic modal interaction over temperature.

18. The method according to claim 13, further comprising detecting the sensitivity matrix of the resonator mass in response to a self-test signal, and controlling the differential voltage based on the sensitivity matrix.

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