CN112710292B - A Frequency Tunable Micromachined Gyroscope Based on Tunnel Magnetoresistance Detection - Google Patents

Abstract

The invention belongs to the technical field of micromachined gyroscopes, and in particular relates to a frequency-tunable micromachined gyroscope structure based on tunnel magnetoresistance detection, comprising a glass substrate, a support structure, a driving mass block, a detection mass block, a first support beam, and a second support beam, driving wire, driving feedback wire, first adjusting electrode, second adjusting electrode, third adjusting electrode, fourth adjusting electrode and conducting coil, the support structure is fixed on the glass substrate by anodic bonding, the first adjusting electrode There are four supporting beams and four second supporting beams. The supporting structure is connected with a driving mass block through the four first supporting beams, and the driving mass block is connected with a detection mass block through the four second supporting beams. The two sides of the mass block are respectively provided with driving wires and driving feedback wires. The micromachined gyroscope of the invention has reasonable structure design, simple interface circuit and high detection precision, and can solve the problem of angular rate signal detection.

Description

A frequency-tunable micromachined gyro structure based on tunnel magnetoresistance detection

technical field

The invention belongs to the technical field of micro-mechanical gyroscopes, and in particular relates to a frequency-tunable micro-mechanical gyroscope structure based on tunnel magnetoresistance detection.

Background technique

Inertial technology works in a completely autonomous manner, without contact with the outside world, and has the advantages of being autonomous, real-time, and free from interference. Gyroscope is the core device of inertial navigation technology and plays a vital role in modern aerospace, national defense and military fields.

The core of the micro-inertial system is the gyroscope. The MEMS gyroscope is an inertial device based on micro-electromechanical technology. It is used to measure the angular velocity of objects. It has the characteristics of small size, high reliability, low cost, and suitable for mass production. It is widely used in micro-inertial systems.

Micromechanical gyroscopes mainly use the Coriolis force, that is, the tangential force that a rotating object receives when it has radial motion. When the MEMS gyroscope is working, the driving mass moves back and forth in the radial direction under the action of the driving force. When there is an angular velocity input, the corresponding Coriolis force keeps changing back and forth in the lateral direction, so that the detection mass moves back and forth in the lateral direction. Do small oscillations horizontally. The MEMS gyroscope detects this small displacement through different detection methods, so as to solve the input angular velocity.

In the process of micromachined gyro processing and design, there are factors such as processing errors and damping effects, which cause differences between the resonant frequency of the actual structure test and the design simulation, and there is a frequency difference between the driving and detection resonant frequencies.

Contents of the invention

Aiming at the technical problems of machining error, damping influence, and frequency difference between the drive and detection resonant frequencies in the above-mentioned micro-mechanical gyroscope machining design process, the present invention provides a tunneling magnetoresistance-based gyroscope with high sensitivity, low cost, and high detection accuracy. The detected frequency is tunable to the micromachined gyroscopic structure.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A frequency-tunable micromechanical gyro structure based on tunnel magnetoresistance detection, including a glass substrate, a support structure, a driving mass, a detection mass, a first support beam, a second support beam, a drive wire, a drive feedback wire, a first Adjusting electrodes, second adjusting electrodes, third adjusting electrodes, fourth adjusting electrodes, and conductor coils, the supporting structure is fixed on the glass substrate by anodic bonding, and the first supporting beam and the second supporting beam have four , the supporting structure is connected to a drive mass through four first support beams, the drive mass is connected to a detection mass through four second support beams, and drive wires, Driving feedback wires, the driving mass block is respectively connected with the first adjustment electrode, the second adjustment electrode, the third adjustment electrode, and the fourth adjustment electrode, and the detection mass block is provided with a conductive coil.

It also includes a first drive electrode, a second drive electrode, a first drive feedback electrode, a second drive feedback electrode, a first detection electrode, a second detection electrode, a third detection electrode, and a fourth detection electrode. The first drive electrode , the second drive electrode, the first drive feedback electrode, the second drive feedback electrode, the first detection electrode, the second detection electrode, the third detection electrode, and the fourth detection electrode are all arranged at the edge of the support structure surface.

The two ends of the driving wire are respectively connected with the first driving electrode and the second driving electrode, and the two ends of the driving feedback wire are respectively connected with the first driving feedback electrode and the second driving feedback electrode. The conductive coils are respectively connected with the first detection electrode, the second detection electrode, the third detection electrode and the fourth detection electrode.

The first adjusting electrode includes a first fixed electrode and a first moving electrode, the second adjusting electrode includes a second fixed electrode and a second moving electrode, and the third adjusting electrode includes a third fixed electrode and a third moving electrode , the fourth adjusting electrode includes a fourth fixed electrode and a fourth moving electrode, the first fixed electrode, the second fixed electrode, the third fixed electrode, and the fourth fixed electrode are all fixedly connected to the support structure, and the first fixed electrode The first moving electrode, the second moving electrode, the third moving electrode and the fourth moving electrode are all fixedly connected to the driving mass block.

The first mobile electrode, the second mobile electrode, the third mobile electrode, and the fourth mobile electrode are all composed of at least two elongated comb teeth, and the comb teeth of the first mobile electrode are arranged at positions corresponding to the second fixed electrodes. On the right side of the comb teeth, the comb teeth of the third moving electrode are arranged on the right side of the comb teeth corresponding to the third fixed electrode, and the comb teeth of the fourth moving electrode are arranged on the right side of the comb teeth corresponding to the fourth fixed electrode.

The distance between the comb teeth of the first mobile electrode, the second mobile electrode, the third mobile electrode and the fourth mobile electrode and the corresponding comb teeth of the first fixed electrode, the second fixed electrode, the third fixed electrode and the fourth fixed electrode is greater than Distance to the next comb tooth.

The first moving electrode and the second moving electrode adopt a T-shaped structure.

Compared with the prior art, the present invention has the beneficial effects of:

The invention adopts the method of adding comb teeth to the structure to introduce electrostatic force frequency modulation, which solves the problem of mismatching of drive and detection resonant frequency due to structural errors brought about in the process of processing and application environment and other unfavorable factors. At the same time, it combines electromagnetic drive, The magnetic resistance detection method solves the problem that the existing micro-mechanical gyroscope is difficult to detect the weak Coriolis force; the frequency-adjustable micro-gyroscope device designed by the present invention can realize the automatic adjustment of the resonant frequency of the driving direction through a dedicated circuit system. The induced electromotive force generated by driving the feedback wire is solved to calculate the corresponding driving resonance frequency, and the matching of the resonance frequency in the two directions of driving and detection can be realized by changing the regulating voltage applied to the regulating electrode. At the same time, the tunnel magnetoresistance effect with high sensitivity is used for detection, which improves the detection accuracy of the micro gyroscope. The invention has the advantages of reasonable structure design, simple interface circuit and high detection precision, and can solve the difficult problem of angular rate signal detection.

Description of drawings

Fig. 1 is the overall structure schematic diagram of the present invention;

Fig. 2 is a schematic diagram of the supporting structure of the present invention;

Fig. 3 is the structural representation of mobile electrode of the present invention;

Fig. 4 is the structural representation of fixed electrode of the present invention;

Fig. 5 is a schematic diagram of a simplified model of the present invention.

Among them: 1 is the glass substrate, 2 is the support structure, 3 is the driving mass, 4 is the detection mass, 5 is the first support beam, 6 is the second support beam, 7 is the driving wire, 8 is the driving feedback wire, 9 10 is the second regulating electrode, 11 is the third regulating electrode, 12 is the fourth regulating electrode, 13 is the conducting coil, 14 is the first driving electrode, 15 is the second driving electrode, 16 is the first Driving feedback electrode, 17 is the second driving feedback electrode, 18 is the first detection electrode, 19 is the second detection electrode, 20 is the third detection electrode, 21 is the fourth detection electrode, 9a is the first fixed electrode, 9b is the first detection electrode One moving electrode, 10a is the second fixed electrode, 10b is the second moving electrode, 11a is the third fixed electrode, 11b is the third moving electrode, 12a is the fourth fixed electrode, 12b is the fourth moving electrode.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right" etc. are based on the attached The orientation or positional relationship shown in the figure is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the referred combination or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be interpreted as a reference to this invention. Invention Limitations.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral Ground connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

A frequency-tunable micromechanical gyroscope structure based on tunnel magnetoresistance detection, as shown in Figure 1 and Figure 2, includes a glass substrate 1, a support structure 2, a drive mass 3, a detection mass 4, a first support beam 5, The second support beam 6, the driving wire 7, the driving feedback wire 8, the first adjustment electrode 9, the second adjustment electrode 10, the third adjustment electrode 11, the fourth adjustment electrode 12, the wire coil 13, and the support structure 2 through anodic bonding Fixed on the glass substrate 1, there are four first support beams 5 and four second support beams 6, the support structure 2 is connected with the drive mass 3 through the four first support beams 5, and the drive mass 3 is connected through the four second support beams 5. The supporting beam 6 is connected with a detection mass 4, and the two sides of the driving mass 3 are respectively provided with a driving wire 7 and a driving feedback wire 8, and the driving mass 3 is respectively connected with a first adjusting electrode 9, a second adjusting electrode 10, a third adjusting electrode The adjusting electrode 11 , the fourth adjusting electrode 12 , and the detection mass 4 are provided with a conducting coil 13 .

Further, it also includes the first drive electrode 14, the second drive electrode 15, the first drive feedback electrode 16, the second drive feedback electrode 17, the first detection electrode 18, the second detection electrode 19, the third detection electrode 20, the fourth Detection electrode 21, first drive electrode 14, second drive electrode 15, first drive feedback electrode 16, second drive feedback electrode 17, first detection electrode 18, second detection electrode 19, third detection electrode 20, fourth The detection electrodes 21 are all arranged at the edge of the surface of the support structure 2 .

Further, the two ends of the driving wire 7 are respectively connected with the first driving electrode 14 and the second driving electrode 15, and the two ends of the driving feedback wire 8 are respectively connected with the first driving feedback electrode 16 and the second driving feedback electrode 17. The conductive coils 13 on 4 are respectively connected with the first detection electrode 18 , the second detection electrode 19 , the third detection electrode 20 and the fourth detection electrode 21 .

Further, as shown in Fig. 3 and Fig. 4, the first adjusting electrode 9 includes a first fixed electrode 9a and a first moving electrode 9b, the second adjusting electrode 10 includes a second fixed electrode 10a, a second moving electrode 10b, and the third adjusting electrode 9a The electrode 11 includes a third fixed electrode 11a, a third moving electrode 11b, a fourth adjusting electrode 12 includes a fourth fixed electrode 12a, a fourth moving electrode 12b, a first fixed electrode 9a, a second fixed electrode 10a, and a third fixed electrode 11a. , the fourth fixed electrode 12a are all fixedly connected to the supporting structure 2 , and the first moving electrode 9b , the second moving electrode 10b , the third moving electrode 11b , and the fourth moving electrode 12b are all fixedly connected to the driving mass 3 .

Further, the first mobile electrode 9b, the second mobile electrode 10b, the third mobile electrode 11b, and the fourth mobile electrode 12b are all composed of at least two elongated comb teeth, and the comb teeth of the first mobile electrode 9b are arranged on the same side as the second mobile electrode. The fixed electrode 10a corresponds to the right side of the comb teeth, the comb teeth of the third mobile electrode 11b are arranged on the right side of the comb teeth corresponding to the third fixed electrode 11a, and the comb teeth of the fourth mobile electrode 12b are arranged on the corresponding comb teeth of the fourth fixed electrode 12a. to the right.

Further, the comb teeth of the first moving electrode 9b, the second moving electrode 10b, the third moving electrode 11b, and the fourth moving electrode 12b are connected with the first fixed electrode 9a, the second fixed electrode 10a, the third fixed electrode 11a, and the fourth fixed electrode. The distance between the electrodes 12a corresponding to the comb teeth is greater than the distance from the next comb teeth.

Further, preferably, in order to ensure that the direction of the electrostatic force is consistent with the driving direction, more comb teeth are added to increase the electrostatic force, the first moving electrode 9b and the second moving electrode 10b adopt a T-shaped structure, in order to ensure that the direction of the electrostatic force is consistent with the driving direction At the same time, more comb teeth are added to increase the electrostatic force.

As shown in FIG. 5 , the abscissa is the applied regulation voltage, and the ordinate is the resonant frequency value. Use COMSOL to establish a simplified model, and apply fixed constraints to the support structure 2, the first fixed electrode 9a, the second fixed electrode 10a, the third fixed electrode 11a, and the fourth fixed electrode 12a. The first mobile electrode 9b, the second mobile electrode 10b, the third mobile electrode 11b, and the fourth mobile electrode 12b apply a positive potential, and the first fixed electrode 9a, the second fixed electrode 10a, the third fixed electrode 11a, and the fourth fixed electrode 12a Apply zero potential, sweep the applied voltage parametrically, and observe the change in the desired characteristic frequency. "o" is the resonant frequency value in the driving direction, and "*" is the resonant frequency value in the detection direction. When the adjustment voltage is applied properly, the two frequencies can be matched.

The working principle of the present invention is: the micro-gyroscope device of the present invention is driven by electromagnetism, and by applying an AC drive current on the drive wire 10, the drive mass 3 and the detection mass 4 are driven to reciprocate under the action of the magnetic field provided by the magnet. On the other side, the drive feedback wire 8 cuts the magnetic induction line to generate a motional electromotive force. By detecting this motional electromotive force, the resonance frequency of the driving direction is tracked, and the adjustment signal is finally output to the adjustment electrode through a special circuit system, which is manifested as adjustment. When the voltage of the electrode changes, the generated electrostatic force also changes, and finally the resonant frequency in the driving direction is adjusted to match the resonant frequency in the detecting direction.

From the perspective of theoretical derivation, it is understood that after adding the electrostatic tuning force, the kinematic equation becomes:

m is the resonant mass, c is the damping coefficient, k is the stiffness coefficient of the suspension beam, F _d (t) is the driving force, and F _e (t) is the electrostatic force generated by the electrostatic coupling comb.

The top and bottom electrostatic coupling capacitors are:

Using the principle of electric potential energy and virtual displacement theory, and bringing the capacitance formula into it:

Bringing the F _e (t) calculation formula into the kinematic equation, the natural frequency can be obtained as:

The above results can be understood as the electrostatic frequency modulation method can generate electrostatic stiffness, thereby affecting the structural resonance frequency. k _e is the resulting electrostatic stiffness coefficient.

In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Only the preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-mentioned embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various modifications can also be made without departing from the gist of the present invention. Various changes should be included within the protection scope of the present invention.

Claims (7)

1. A frequency tunable micromechanical gyroscope structure based on tunnel magnetic resistance detection is characterized in that: including glass substrate (1), bearing structure (2), drive quality piece (3), proof mass piece (4), first supporting beam (5), second supporting beam (6), drive wire (7), drive feedback wire (8), first regulation electrode (9), second regulation electrode (10), third regulation electrode (11), fourth regulation electrode (12), wire circle (13), bearing structure (2) are fixed on glass substrate (1) through the anodic bonding, first supporting beam (5), second supporting beam (6) all have four, bearing structure (2) are connected with drive quality piece (3) through four first supporting beam (5), drive quality piece (3) are connected with proof mass piece (4) through four second supporting beam (6), the both sides of drive quality piece (3) are provided with drive wire (7), drive feedback wire (8) respectively, drive quality piece (3) are connected with first regulation electrode (9), second regulation electrode (10), third regulation electrode (11), fourth regulation electrode (12) respectively, be provided with proof mass piece (13) on proof mass piece (4).

2. The frequency-tunable micromechanical gyroscope structure based on tunneling magnetoresistance detection according to claim 1, characterized in that: the detection device is characterized by further comprising a first driving electrode (14), a second driving electrode (15), a first driving feedback electrode (16), a second driving feedback electrode (17), a first detection electrode (18), a second detection electrode (19), a third detection electrode (20) and a fourth detection electrode (21), wherein the first driving electrode (14), the second driving electrode (15), the first driving feedback electrode (16), the second driving feedback electrode (17), the first detection electrode (18), the second detection electrode (19), the third detection electrode (20) and the fourth detection electrode (21) are all arranged at the edge position of the surface of the supporting structure (2).

3. The frequency-tunable micromechanical gyroscope structure based on tunneling magnetoresistance detection according to claim 1, characterized in that: the two ends of the driving lead (7) are respectively connected with a first driving electrode (14) and a second driving electrode (15), the two ends of the driving feedback lead (8) are respectively connected with a first driving feedback electrode (16) and a second driving feedback electrode (17), and a conductive coil (13) on the detection mass block (4) is respectively connected with a first detection electrode (18), a second detection electrode (19), a third detection electrode (20) and a fourth detection electrode (21).

4. The frequency-tunable micromechanical gyroscope structure based on tunneling magnetoresistance detection according to claim 1, characterized in that: the first adjusting electrode (9) comprises a first fixed electrode (9 a) and a first movable electrode (9 b), the second adjusting electrode (10) comprises a second fixed electrode (10 a) and a second movable electrode (10 b), the third adjusting electrode (11) comprises a third fixed electrode (11 a) and a third movable electrode (11 b), the fourth adjusting electrode (12) comprises a fourth fixed electrode (12 a) and a fourth movable electrode (12 b), the first fixed electrode (9 a), the second fixed electrode (10 a), the third fixed electrode (11 a) and the fourth fixed electrode (12 a) are fixedly connected to the supporting structure (2), and the first movable electrode (9 b), the second movable electrode (10 b), the third movable electrode (11 b) and the fourth movable electrode (12 b) are fixedly connected to the mass block driving device (3).

5. The frequency-tunable micromechanical gyroscope structure based on tunneling magnetoresistance detection according to claim 4, wherein: the comb teeth of the first movable electrode (9 b), the second movable electrode (10 b), the third movable electrode (11 b) and the fourth movable electrode (12 b) are all composed of at least two long strip-shaped comb teeth, the comb teeth of the first movable electrode (9 b) are arranged on the right of the comb teeth corresponding to the second fixed electrode (10 a), the comb teeth of the third movable electrode (11 b) are arranged on the right of the comb teeth corresponding to the third fixed electrode (11 a), and the comb teeth of the fourth movable electrode (12 b) are arranged on the right of the comb teeth corresponding to the fourth fixed electrode (12 a).

6. The frequency-tunable micromechanical gyroscope structure based on tunneling magnetoresistance detection according to claim 5, wherein: the distance between the comb teeth of the first moving electrode (9 b), the second moving electrode (10 b), the third moving electrode (11 b) and the fourth moving electrode (12 b) and the corresponding comb teeth of the first fixed electrode (9 a), the second fixed electrode (10 a), the third fixed electrode (11 a) and the fourth fixed electrode (12 a) is larger than the distance between the comb teeth and the next comb tooth.

7. The frequency-tunable micromechanical gyroscope structure based on tunneling magnetoresistance detection according to claim 4, wherein: the first moving electrode (9 b) and the second moving electrode (10 b) adopt a T-shaped structure.

Images