Background
Different from the traditional inertia device, the MEMS (micro electro mechanical Systems) micro inertia device has the unique advantages of small volume, light weight, low cost, low energy consumption, high reliability, easy digitization, capability of meeting the application in severe environment and the like, and has wide civil prospect and important military value.
The MEMS triaxial micro gyroscope is an important member in MEMS micro inertial devices, has the advantages, and can be applied to common consumer products, industrial stable platforms, micro-nano satellites, stabilized sighting and image stabilizing systems, unmanned combat platforms and the like.
The traditional three single-axis gyroscope integration mode needs three closed-loop driving resonant circuits for control, a control circuit is complex, and signal crosstalk easily occurs among the multiple driving circuits. The three single-axis gyroscope integration mode will lead to the increase of the sensor volume, which is not beneficial to the miniaturization.
In addition, the precision, integration level and the like of the domestic monolithic integrated three-axis gyroscope still have larger gaps compared with the domestic advanced technology, and the development and application of domestic micro-inertia devices are greatly limited.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems, the invention provides a three-axis micro gyroscope based on tuning fork driving effect, which has small volume, light weight, high integration level and strong anti-interference capability.
The technical scheme is as follows: in order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows: a three-axis micro gyroscope based on tuning fork driving effect comprises an upper gyroscope structure and a lower glass substrate; the gyroscope structure comprises a left mechanical structure, a right mechanical structure, a middle mechanical structure, an upper cross beam, a lower cross beam, a short beam and an anchor point; the left mechanical structure, the middle mechanical structure and the right mechanical structure are sequentially connected and are symmetrical about a central axis of the gyroscope structure; the upper cross beam is respectively connected with the upper ends of the left mechanical structure and the right mechanical structure, and the lower cross beam is respectively connected with the lower ends of the left mechanical structure and the right mechanical structure; the short beams are respectively positioned at the left end and the right end of the upper cross beam and the lower cross beam, at the upper end of the middle part of the upper cross beam and at the lower end of the middle part of the lower cross beam and are connected with the anchor points; a metal capacitor polar plate, a signal lead and a metal electrode are arranged on the lower glass substrate; and the anchor points of the upper layer gyroscope structure are bonded on the lower layer glass substrate.
Further, the left mechanical structure is identical to the right mechanical structure.
Furthermore, the left/right mechanical structure comprises a driving frame, a first connecting beam, a first sensitive mass, a second connecting beam, movable driving comb teeth, fixed driving comb teeth, a sensitive electrode, a sensitive elastic beam and a fixed anchor point; the number of the first connecting beams is four, two of the first connecting beams are arranged on the left side and the right side of the outer upper end of the driving frame and are connected with the upper cross beam, and the other two of the first connecting beams are arranged on the left side and the right side of the outer lower end of the driving frame and are connected with the lower cross beam; the first sensitive mass is positioned inside the driving frame; the two second connecting beams are arranged on the left side and the right side of the middle end in the driving frame and connected with the first sensitive mass; the movable driving comb teeth are arranged in four rows and are respectively positioned on the left upper side, the left lower side, the right upper side and the right lower side outside the driving frame, more than two movable driving comb teeth are arranged in each row, and the movable driving comb teeth are vertically arranged on the driving frame at equal intervals; the fixed driving comb teeth are fixed on the base, are arranged in four rows, are respectively positioned on the left upper side, the left lower side, the right upper side and the right lower side outside the driving frame, and are oppositely inserted with the movable driving comb teeth; the sensitive electrodes are fixed on the base, two pairs of sensitive electrodes are arranged on the upper end and the lower end of the inside of the first sensitive mass respectively, and each pair of sensitive electrodes are parallel to each other; the sensitive elastic beams are arranged in four groups and are respectively positioned at the upper left corner, the lower left corner, the upper right corner and the lower right corner of the first sensitive mass, each group of sensitive elastic beams consists of two U-shaped beams, one end of each sensitive elastic beam is connected with the first sensitive mass, and the other end of each sensitive elastic beam is connected with the fixed anchor point.
Furthermore, the middle mechanical structure comprises a driving transmission beam, a driving steering mechanism, a second sensitive mass, a driving coupling mechanism, a driving elastic beam and a fixed anchor point; the two driving transfer beams are positioned at the left end and the right end of the middle mechanical structure, one end of each driving transfer beam is connected with the left mechanical structure and the right mechanical structure, and the other end of each driving transfer beam is connected with the driving steering mechanism; the four driving steering mechanisms are respectively positioned at the upper left end, the lower left end, the upper right end and the lower right end of the middle mechanical structure, one end of each driving steering mechanism is connected with the driving transfer beam, the other end of each driving steering mechanism is connected with the second sensitive mass, and the 90-degree corner of the middle end of each driving steering mechanism is connected with the fixed anchor point through the U-shaped beams which mutually form 90 degrees; the two second sensitive masses are respectively positioned at the upper end and the lower end of the middle mechanical structure; the driving coupling mechanism is positioned in the center of the middle mechanical structure, and the two second sensitive masses are connected through the driving coupling mechanism; four driving elastic beams are respectively positioned on the left side of the upper end, the right side of the upper end, the left side of the lower end and the right side of the lower end of the second sensitive mass; one end of the driving elastic beam is connected with the second sensitive mass, and the other end of the driving elastic beam is connected with the fixed anchor point; the drive transmission beam, the drive steering mechanism, the drive coupling mechanism and the drive elastic beam are all connected with the fixed anchor point.
Furthermore, the lower glass substrate comprises a metal capacitor plate, an anchor point bonding point, a signal lead and a signal electrode; the capacitor plates comprise a first capacitor plate right below the first sensitive mass and a second capacitor plate right below the second sensitive mass; the anchor point bonding point comprises a public bonding point, a ground bonding point, a comb bonding point and a sensitive electrode bonding point; one end of the signal lead is connected with the anchor point bonding point, and the other end of the signal lead is connected with the signal electrode; the signal electrodes comprise driving electrodes, driving detection electrodes, x-axis sensitive electrodes, y-axis sensitive electrodes, z-axis sensitive electrodes, common carrier electrodes and ground electrodes.
Further, an external driving circuit applies an alternating current signal with direct current bias to the driving electrode, and applies a high-frequency carrier signal to the common electrode; the driving frame drives the sensitive mass to realize X-axis simple harmonic driving, and the steering frame converts the X-axis simple harmonic driving into Y-axis simple harmonic driving of the sensitive mass, so that the driving speeds of X, Y in two directions of different sensitive masses are realized.
Furthermore, the x-axis sensitive electrode, the y-axis sensitive electrode and the z-axis sensitive electrode are connected to the metal capacitor plate through signal leads, and when the angular velocity is input from the outside, the sensitive mass is subjected to Coriolis force to generate displacement, so that variable-spacing capacitance differential detection is realized.
When the Z-axis angular velocity is input, the first sensitive mass is subjected to the action of the Coriolis force in the Y-axis direction, simple harmonic vibration is carried out along the Y axis, and sensitive displacement signals are extracted through the left and right mechanical structure sensitive electrodes; when the Y-axis angular velocity is input, the first sensitive mass is subjected to the action of the Coriolis force in the Z-axis direction, simple harmonic vibration is carried out along the Z axis, and a sensitive displacement signal is extracted through the first capacitor plate; when the angular speed of the X axis is input, the second sensitive mass is subjected to the action of the Coriolis force in the Z axis direction, simple harmonic vibration is conducted along the Z axis, and a sensitive displacement signal is extracted through the second capacitor plate.
Has the advantages that: the triaxial micro gyroscope of the invention has the advantages that: (1) the turning mechanism is designed, simple harmonic motion of an X axis and simple harmonic motion of a Y axis of a middle mechanical structure are realized by simply and harmonically driving the X axis of the left mechanical structure and the X axis of the right mechanical structure in a single direction by utilizing a tuning fork driving effect, driving speeds of different sensitive masses X, Y in two directions are realized, and consistency of driving frequency between different axes is ensured; (2) the dual-sensitive quality design and variable-spacing capacitor differential detection are adopted, the sensitive quality is driven in an opposite phase mode, the sensitive signal is output in a differential mode, and the detection in three directions is dual-quality differential detection, so that the common-mode interference of temperature, stress, acceleration and the like can be inhibited, the anti-interference capability is enhanced, the output signal is increased, and the signal-to-noise ratio of the output signal is improved; (3) the driving comb teeth and the driving detection comb teeth are designed, so that the driving displacement can be extracted by an external circuit, and the stable driving of a closed loop can be realized; (4) and a common carrier electrode is designed, so that an external circuit can extract a sensitive displacement signal by using a modulation and demodulation technology, and the stability and reliability of the gyroscope are improved.
Detailed Description
The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.
As shown in fig. 1, the three-axis micro gyroscope based on tuning fork driving effect of the present invention is used for measuring X, Y, Z angular velocity input in the axis direction, the upper layer is a silicon micro gyroscope structure made of a monocrystalline silicon wafer, the lower layer is a glass substrate 6, and the anchor point of the upper layer gyroscope structure is bonded on the lower layer glass substrate. The lower glass substrate is provided with a metal capacitor polar plate, a signal lead and a metal electrode. The upper-layer gyroscope structure comprises a left mechanical structure 1, a right mechanical structure 2, a middle mechanical structure 3, an upper crossbeam 4, a lower crossbeam 5, short beams 7-1a, 7-1b, 7-1c, 7-1d, 7-2a, 7-2b, 7-2c and 7-2d, and fixed anchor points 8-1a, 8-1b, 8-1c, 8-1d, 8-2a, 8-2b, 8-2c and 8-2 d. The left mechanical structure 1 and the right mechanical structure 2 are identical, are located on the left side and the right side of the gyroscope structure, respectively, and are symmetrical about an axis in the gyroscope structure. The middle mechanical structure 3 is located in the center of the gyroscope structure, the left end of the middle mechanical structure is connected with the left mechanical structure, and the right end of the middle mechanical structure is connected with the right mechanical structure and is symmetrical about the axis of the gyroscope structure. The upper beam 4 is respectively connected with the upper ends of the left and right mechanical structures, and the lower beam 5 is respectively connected with the lower ends of the left and right mechanical structures. The short beams 8-1a, 8-1b are positioned at the left end and the right end of the upper cross beam, the short beams 8-1d, 8-1c are positioned at the left end and the right end of the lower cross beam, the short beams 8-2a, 8-2b are positioned at the upper end of the middle part of the upper cross beam, and the short beams 8-2c, 8-2d are positioned at the lower end of the middle part of the lower cross beam and are connected with the fixed anchor points 8-1a, 8-1b, 8-1d, 8-1c, 8-2a, 8-2b, 8-2c, 8-2 d.
As shown in FIG. 2, the left mechanical structure 1 comprises a driving frame 1-1, first connecting beams 1-2a, 1-2b, 1-2c and 1-2d, first sensitive masses 1-3, second connecting beams 1-4a and 1-4b, movable driving comb teeth 1-5a, 1-5b, 1-5c and 1-5d, fixed driving comb teeth 1-6a, 1-6b, 1-6c and 1-6d, sensitive electrodes 1-7a, 1-7b, 1-8a and 1-8b, sensitive elastic beams 1-9a, 1-9b, 1-9c and 1-9d, and fixed anchor points 1-10a, 1-10b, 1-10c and 1-10 d. The first connecting beams 1-2a, 1-2b are arranged on the left and right sides of the external upper end of the driving frame 1-1 and are respectively connected with the upper cross beam 4, and the first connecting beams 1-2c, 1-2d are arranged on the left and right sides of the external lower end of the driving frame and are respectively connected with the lower cross beam 5. The first sensitive mass 1-3 is positioned in the driving frame, and the second connecting beams 1-4a and 1-4b are arranged on the left side and the right side of the middle end in the driving frame and are respectively connected with the first sensitive mass. The movable driving comb teeth 1-5a, 1-5b, 1-5c and 1-5d are respectively positioned at the upper left side, the lower left side, the upper right side and the lower right side outside the driving frame, more than two movable driving comb teeth are arranged in each row, and the movable driving comb teeth are vertically arranged on the driving frame at equal intervals. The fixed driving comb teeth 1-6a, 1-6b, 1-6c and 1-6d are fixed on the base, are respectively positioned at the upper left side, the lower left side, the upper right side and the lower right side of the outside of the driving frame, and are inserted into the movable driving comb teeth. Sensitive electrodes 1-7a, 1-7b, 1-8a and 1-8b are fixed on the base and are respectively positioned at the upper end and the lower end in the first sensitive mass. The sensitive electrode consists of a capacitor plate and a fixed anchor point, the capacitor plate and the sensitive mass are placed in parallel in a Z axis, and the fixed anchor point is connected with the lower glass substrate. The sensitive elastic beams 1-9a, 1-9b, 1-9c and 1-9d are respectively positioned at the upper left corner, the lower left corner, the upper right corner and the lower right corner of the first sensitive mass, and each group of sensitive elastic beams consists of two U-shaped beams; one end of the sensitive elastic beam is connected with the first sensitive mass, and the other end of the sensitive elastic beam is connected with the fixed anchor points 1-10a, 1-10b, 1-10c and 1-10 d.
The right mechanical structure is identical to the left mechanical structure.
As shown in FIG. 3, the intermediate mechanical structure comprises drive transmission beams 3-1a, 3-1b, drive steering mechanisms 3-2a, 3-2b, 3-2c, 3-2d, second sensitive masses 3-3a, 3-3b, drive coupling mechanisms 3-4, drive elastic beams 3-5a, 3-5b, 3-5c, 3-5d and fixed anchor points 3-6a, 3-6b, 3-6c, 3-6d, 3-7a, 3-7b, 3-7c, 3-7d, 3-8a, 3-8b, 3-9a, 3-9b, 3-9c and 3-9 d. One end of the drive transmission beam 3-1a is connected with the left mechanical structure 1, the other end is connected with the drive steering mechanisms 3-2a and 3-2b, and the middle end is connected with the fixed anchor points 3-6a and 3-6b through the U-shaped beam. One end of the drive transmission beam 3-1b is connected with the right mechanical structure 2, the other end is connected with the drive steering mechanisms 3-2c and 3-2d, and the middle end is connected with the fixed anchor points 3-6c and 3-6d through the U-shaped beam. The driving steering mechanisms 3-2a, 3-2b, 3-2c and 3-2d are respectively positioned at the upper left end, the lower left end, the upper right end and the lower right end of the middle mechanical structure, one end of the driving steering mechanism 3-2a is connected with the driving transfer beam 3-1a, the other end of the driving steering mechanism is connected with the second sensitive mass 3-3a, and the 90-degree corner is connected with the fixed anchor point 3-7a through a U-shaped beam which forms 90 degrees with each other; one end of the driving steering mechanism 3-2b is connected with the driving transmission beam 3-1b, and the other end is connected with the second sensitive mass 3-3 a; the 90-degree corner is connected with the fixed anchor points 3-7b through U-shaped beams which form 90 degrees with each other; one end of the driving steering mechanism 3-2c is connected with the driving transmission beam 3-1b, and the other end is connected with the second sensitive mass 3-3 b; the 90-degree corner is connected with the fixed anchor points 3-7c through U-shaped beams which form 90 degrees with each other; one end of the driving steering mechanism 3-2d is connected with the driving transmission beam 3-1a, and the other end is connected with the second sensitive mass 3-3 b; the 90-degree corner is connected with the fixed anchor points 3-7d through U-shaped beams which form 90 degrees with each other. Second sensitive masses 3-3a, 3-3b are located at the upper and lower ends, respectively, of the intermediate mechanical structure, symmetrically with respect to the horizontal X-axis. The driving coupling mechanism 3-4 is positioned in the center of the middle mechanical structure and consists of four multi-fold U-shaped beams, two straight beams and a central connecting block, and the central connecting block is connected with the fixed anchor points 3-8a and 3-8b through the straight beams. The second sensitive masses 3-3a, 3-3b are connected to one another by drive coupling means. The driving spring beams 3-5a, 3-5b are located on the left and right sides of the upper end of the second proof mass, and the driving spring beams 3-5d, 3-5c are located on the left and right sides of the lower end of the second proof mass. One end of the driving elastic beam 3-5a is connected with the sensitive mass 3-3a, and the other end is connected with the fixed anchor point 3-9 a. One end of the driving elastic beam 3-5b is connected with the sensitive mass 3-3a, and the other end is connected with the fixed anchor point 3-9 b. One end of the driving elastic beam 3-5c is connected with the sensitive mass 3-3b, and the other end is connected with the fixed anchor point 3-9 c. One end of the driving elastic beam 3-5d is connected with the sensitive mass 3-3b, and the other end is connected with the fixed anchor point 3-9 d.
As shown in fig. 4, the underlying glass substrate 6 includes capacitor plates, anchor bonds, signal leads, and signal electrodes. The capacitor plates comprise first capacitor plates 6-1a, 6-1b and second capacitor plates 6-2a, 6-2 b. The first capacitance plate is positioned at the projection position right below the first sensitive mass; the second capacitive plate is located directly below the second sensitive mass. The anchor point bonding points are regions for bonding the upper silicon structure anchor points and the lower glass substrate and comprise positive driving movable comb bonding points 6-3a and 6-3b, negative driving movable comb bonding points 6-3c and 6-3d, positive driving detection movable comb bonding points 6-4a and 6-4b, negative driving detection movable comb bonding points 6-4c and 6-4d, z-axis sensitive positive electrode bonding points 6-5a, 6-5b, 6-5c and 6-5d, z-axis sensitive negative electrode bonding points 6-6a, 6-6b, 6-6c and 6-6d, common bonding points 6-7 and ground bonding points 6-8. One end of the signal lead is connected with the anchor point bonding point, and the other end of the signal lead is connected with the signal electrode. The signal electrodes comprise driving positive electrodes 6-9, driving negative electrodes 6-10, driving detection positive electrodes 6-11, driving detection negative electrodes 6-12, x-axis sensitive positive electrodes 6-13, x-axis sensitive negative electrodes 6-14, y-axis sensitive positive electrodes 6-15, y-axis sensitive negative electrodes 6-16, z-axis sensitive positive electrodes 6-17, z-axis sensitive negative electrodes 6-18, common carrier electrodes 6-19 and ground electrodes 6-20.
The working principle of the three-axis micro gyroscope based on the tuning fork driving effect is as follows:
and a positive phase alternating current driving voltage with direct current bias is applied to the driving positive electrode 6-9, and a reverse phase alternating current driving voltage with direct current bias is applied to the driving negative electrode 6-10 to generate an alternating single-side electrostatic driving force. The left mechanical structure driving frame and the right mechanical structure driving frame realize reverse phase simple harmonic vibration on the X axis. A high frequency carrier signal is applied to the common carrier electrodes 6-19 and grounded to the ground electrodes 6-20. The external driving circuit extracts driving displacement signals of the driving detection positive electrodes 6-11 and the driving detection negative electrodes 6-12, and closed-loop driving can be achieved through the external circuit and an algorithm.
When the gyroscope realizes closed-loop driving, the first sensitive mass of the left mechanical structure and the first sensitive mass of the right mechanical structure realize X-axis reverse phase simple harmonic motion. The driving displacement acts on the steering frames 3-2a, 3-2b, 3-2c and 3-2d through the driving transmission beams 3-1a and 3-1b to enable the steering frames to twist, and Y-axis opposite-phase simple harmonic motion of the second sensitive masses 3-3a and 3-3b of the intermediate mechanical structure is achieved. Simple harmonic motion of the first sensitive mass in the X-axis direction and simple harmonic motion of the second sensitive mass in the Y-axis direction are realized through single-direction driving.
When the angular speed of the Z axis is input, the first sensitive mass is subjected to the action of the Coriolis force in the Y axis direction, and the first sensitive mass can do simple harmonic vibration along the Y axis. Sensitive displacement signals are extracted through the left and right mechanical structure sensitive electrodes 1-7a, 1-7b, 1-8a and 1-8 b. When the angular speed of the Y axis is input, the first sensitive mass is subjected to the action of the Coriolis force in the Z axis direction, and the first sensitive mass can do simple harmonic vibration along the Z axis. The sensitive displacement signal is extracted through the first capacitor plates 6-2a, 6-2 b. When the angular speed of the X axis is input, the second sensitive mass is subjected to the action of the Coriolis force in the Z axis direction, and the second sensitive mass can do simple harmonic vibration along the Z axis. The sensitive displacement signal is extracted through the second capacitor plates 6-1a, 6-1 b.
As noted above, while the present invention has been described using specific examples, it is not to be construed as limiting the invention itself. Various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims, which should be construed to be within the scope of the invention.