Constant alternating current-to-direct current micro-electro-mechanical gyroscope force balance control system and working method

Abstract

The invention discloses a force balance control system for a constant-alternating-current-to-direct-current micro-electro-mechanical gyroscope. The force balance control system comprises a gyroscope closed-loop driving module, a detection modal force balance control module and a phase shifting module, the gyroscope closed-loop driving module is used for tracking the resonant frequency of a driving mode and generating a sinusoidal signal of the resonant frequency as a self-feedback excitation signal and a vibration signal of a driving mode electrode; the phase shift module is used for performing phase shift on the vibration signal as a force balance alternating current excitation signal; and the detection modal force balance control module is used for acquiring a control signal for resisting electrode vibration in the detection modal of the micro-electro-mechanical gyroscope according to the force balance alternating current excitation signal and a force balance direct current excitation signal self-fed back in the detection modal force balance control module. The resonant frequency of the modal electrode is tracked and driven in real time, stable force balance of the modal electrode is detected, the high requirement for the dynamic performance of a circuit in a force balance feedback path is lowered, and the dynamic response speed and the anti-interference capacity of a system can be effectively improved.

Description

Technical Field

[0001] The invention relates to the field of micro-electromechanical gyroscope control, and in particular to a micro-electromechanical gyroscope force balance control system and a working method for converting constant alternating current into direct current. Background Art

[0002] The microelectromechanical gyroscope is a sensor that senses the rotation rate of a carrier based on the Coriolis effect. As an important application of MEMS technology in the field of inertial navigation, it has the advantages of small size, light weight, low cost, easy mass production and integration, and is widely used in military and civilian fields.

[0003] The traditional excitation strategy of the MEMS gyroscope based on the force balance control method usually adopts the "variable AC to constant DC" method, which adjusts the size of the external force of the gyroscope working mode by changing the amplitude of the AC signal to achieve the frequency-tracking and amplitude-stabilizing control of the driving mode and the force balance control of the detection mode. However, this method still has some shortcomings in high-dynamic detection and temperature-changing working environments. First, the variable AC signal under high-dynamic conditions requires rapid adjustment of the signal frequency and amplitude, which puts forward high requirements on the responsiveness of the force balance feedback path; secondly, the scale factor expression of the "variable AC to constant DC" method includes the amplitude of the driving mode, which is prone to drift of the scale factor in a wide temperature working environment. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a micro-electromechanical gyro force balance control system and a working method for converting constant AC to DC, so as to solve the technical problems of low control stability and efficiency in the prior art.

[0005] The present invention provides a micro-electromechanical gyro force balance control system for converting constant AC to DC, comprising: a gyro closed-loop drive module, a detection modal force balance control module and a phase shift module;

[0006] The vibration signal output end of the gyro closed-loop driving module is connected to the input end of the phase shift module; the output end of the phase shift module is connected to the excitation signal input end of the detection modal force balance control module; the output end of the detection modal force balance control module is connected to the micro-electromechanical gyroscope;

[0007] The gyro closed-loop drive module is used to track the resonant frequency of the driving mode and generate a sinusoidal signal of the resonant frequency as a self-feedback excitation signal and a vibration signal of the driving mode electrode; the phase shift module is used to phase-shift the vibration signal as a force balance AC excitation signal; the detection mode force balance control module is used to obtain a control signal for resisting the electrode vibration in the micro-electromechanical gyroscope detection mode based on the force balance AC excitation signal and the self-feedback force balance DC excitation signal inside the detection mode force balance control module.

[0008] Further, the gyro closed-loop driving module includes: a driving mode, a first AC / DC coupling differential unit, a first D / A conversion unit, a first front-end detection unit, a first A / D conversion unit, an amplitude demodulation unit, a phase demodulation unit, an automatic gain control unit, a phase PI control unit and a direct digital frequency synthesis unit;

[0009] A constant direct current is used as an input of the first AC / DC coupled differential unit, and the output end of the first D / A conversion unit is connected to another input end of the first AC / DC coupled differential unit; the output end of the first AC / DC coupled differential unit is connected to the input end of the electrode in the driving mode; the output end of the electrode in the driving mode is connected to the input end of the first front-end detection unit; the output end of the first front-end detection unit is respectively connected to the input end of the phase shift module and the input end of the first A / D conversion unit; the output end of the first A / D conversion unit is respectively connected to the input end of the amplitude demodulation unit and the input end of the phase demodulation unit; the output end of the amplitude demodulation unit is connected to the input end of the automatic gain control unit; the output end of the phase demodulation unit is connected to the input end of the phase PI control unit; the output end of the phase PI control unit is connected to the input end of the direct digital frequency synthesis unit, and the output signal of the direct digital frequency synthesis unit is multiplied by the output signal of the automatic gain control unit as the input signal of the first D / A conversion unit;

[0010] The first AC / DC coupling differential unit is used to couple the input constant DC with the self-feedback excitation signal; and the first front-end detection unit is used to obtain the vibration signal of the driving mode electrode.

[0011] Further, the detection mode force balance control module includes: a detection mode, a second AC / DC coupling differential unit, a second D / A conversion unit, a second front-end detection unit, a second A / D conversion unit, a rate signal demodulation unit, and a force balance control unit;

[0012] The output end of the phase shift module is connected to an input end of the second AC / DC coupling differential unit; the output end of the second D / A conversion unit is connected to another input end of the second AC / DC coupling differential unit; the output end of the second AC / DC coupling differential unit is connected to the input end of the detection mode; the output end of the detection mode is connected to the input end of the second front-end detection unit; the output end of the second front-end detection unit is connected to the input end of the second A / D conversion unit; the output end of the second A / D conversion unit is connected to the input end of the rate signal demodulation unit; the output end of the rate signal demodulation unit is connected to the input end of the force balance control unit; the force balance control unit outputs an internal self-feedback force balance DC excitation signal and a control signal respectively, and the internal self-feedback force balance DC excitation signal serves as the input of the second D / A conversion unit.

[0013] Further, the phase shift module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a first operational amplifier, a second operational amplifier and a third operational amplifier;

[0014] One end of the first resistor serves as the input end of the phase shift module, and the other end is respectively connected to one end of the sixth resistor, one end of the second resistor and the reverse input end of the first operational amplifier; the positive input end of the first operational amplifier is grounded, and the output end is respectively connected to one end of the third resistor and the other end of the second resistor; the other end of the third resistor is respectively connected to one end of the first capacitor and the reverse input end of the second operational amplifier; the positive input end of the second operational amplifier is grounded, and the output end is respectively connected to the other end of the first capacitor and one end of the fourth resistor, and the output end of the second operational amplifier serves as the output end of the phase shift module; the other end of the fourth resistor is respectively connected to one end of the second capacitor, one end of the third capacitor and the reverse input end of the third operational amplifier; the other end of the third capacitor is connected to one end of the fifth resistor; the positive input end of the third operational amplifier is grounded, and the output end is respectively connected to the other end of the second capacitor, the other end of the fifth resistor and the other end of the sixth capacitor.

[0015] The present invention also provides a working method of a micro-electromechanical gyro force balance control system for converting constant AC to DC, comprising:

[0016] The working process of the gyro closed-loop drive module, the phase shifting process and the detection modal force balance control module are used to realize the force balance control process of constant AC to DC through three processes;

[0017] Among them, the working process of the gyro closed-loop drive module includes: the first front-end detection unit collects the vibration signal in the form of capacitance generated by the induction electrode in the driving mode and converts it into a vibration signal in the form of voltage, which are respectively used as the input of the phase shift module and the input signal of the first A / D conversion unit; the vibration signal is A / D converted by the first A / D conversion unit and used as the input signal of the amplitude demodulation unit and the phase demodulation unit respectively; the amplitude demodulation unit outputs the amplitude signal to the automatic gain control unit after demodulation, and the automatic gain control unit generates the amplitude of the driving signal based on the amplitude signal; the phase demodulation unit outputs the phase signal to the phase after demodulation. A PI control unit is provided, and a phase PI control unit outputs a phase control amount to a direct digital frequency synthesizer unit based on a phase signal; the direct digital frequency synthesizer unit outputs a sinusoidal signal of a driving mode resonant frequency; the automatic gain control unit generates an amplitude of a driving signal and multiplies the amplitude of the driving signal by the sinusoidal signal to obtain an AC excitation signal; the AC excitation signal is converted by a first D / A conversion unit and then coupled with a constant DC input from the outside in a first AC / DC coupling differential unit to obtain a coupling signal; the coupling signal is input to an excitation electrode in a driving mode to maintain a constant vibration amplitude, and the resonant frequency of the driving mode is tracked in real time to realize a closed-loop drive of the gyro;

[0018] The phase shifting process includes: the phase shifting module performs a 90° phase shift on the input vibration signal and outputs a force-balanced AC excitation signal.

[0019] Furthermore, the working process of the detection modal force balance control module includes: the second front-end detection unit collects the vibration signal in the form of capacitance generated based on the angular velocity of the gyro sensitive axis in the detection mode and converts it into a vibration signal in the form of voltage, and uses it as an input signal of the rate demodulation unit after A / D conversion by the second A / D conversion unit; the rate demodulation unit outputs the rate signal to the force balance control unit after demodulation; the force balance control unit outputs the rate signal representing the angular velocity of the gyro sensitive axis as a control signal and a force balance DC excitation signal, the DC excitation signal and the force balance AC excitation signal are coupled in the second AC / DC coupling differential unit to form a coupling signal, and the coupling signal is input to the excitation electrode in the detection mode to balance the vibration of the detection mode electrode caused by the angular velocity of the gyro sensitive axis.

[0020] Furthermore, the scaling factor in the detection modal force balance control module is:

[0021]

[0022] In the formula, m c is the effective Coriolis mass of the gyroscope; A x is the vibration amplitude of the electrode in the gyro driving mode; ω x is the resonant frequency; K fbis the feedback gain of the modal force balance control unit; k is the gain of the 90° phase shift module.

[0023] Beneficial effects of the present invention:

[0024] The present invention adopts a constant AC to constant DC strategy to control the detection modal force balance, which can track the resonant frequency of the driving modal electrode in real time, and at the same time change the force balance DC signal to achieve long-term stable force balance of the detection modal electrode. Compared with the traditional method of changing AC to constant DC, the present invention reduces the high requirements for the dynamic performance of the circuit in the force balance feedback path, and can effectively improve the dynamic response speed and anti-interference ability of the system.

[0025] The present invention uses a phase shift module to perform 90° precise phase shifting and a scaling factor expression of the vibration amplitude that does not include a driving mode in a fixed AC to DC conversion mode, thereby further eliminating temperature sensitive items and significantly reducing the sensitivity of the system to external temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the present invention in any way. In the accompanying drawings:

[0027] Figure 1 is a system block diagram of a specific embodiment of the present invention;

[0028] Figure 2 is a circuit diagram of a phase shift module in a specific embodiment of the present invention;

[0029] Figure 3 is a Bode diagram of a phase shift module in a specific embodiment of the present invention;

[0030] Figure 4 It is a control block diagram of a detection modal force balance control module in a specific embodiment of the present invention;

[0031] Figure 5 It is a block diagram of the detection mode constant DC to AC force balance control without equivalent transformation in a specific embodiment of the present invention;

[0032] Figure 6 It is a block diagram of the detection mode constant DC to AC force balance control after equivalent transformation in a specific embodiment of the present invention;

[0033] Figure 7 It is a block diagram of the equivalent unit negative feedback detection modal force balance control after equivalent transformation in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0035] The present invention is further illustrated below in conjunction with specific embodiments. Those skilled in the art should understand that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention, and modifications to various equivalent forms of the present invention fall within the scope defined by the appended claims of this application.

[0036] like Figure 1 As shown, the present invention provides a micro-electromechanical gyro force balance control system for constant AC to DC conversion, comprising: a gyro closed-loop drive module 100, a detection modal force balance control module 200 and a phase shift module 300;

[0037] The vibration signal output end of the gyro closed-loop drive module is connected to the input end of the phase shift module; the output end of the phase shift module is connected to the excitation signal input end of the detection modal force balance control module; the output end of the detection modal force balance control module is connected to the micro-electromechanical gyroscope;

[0038] The gyro closed-loop drive module is used to track the resonant frequency of the driving mode and generate a sinusoidal signal of the resonant frequency as a self-feedback excitation signal and a vibration signal of the driving mode electrode; the phase shift module is used to perform phase shift on the vibration signal as a force balance AC excitation signal; the detection mode force balance control module is used to obtain a control signal for resisting the electrode vibration in the micro-electromechanical gyroscope detection mode according to the force balance AC excitation signal and the force balance DC excitation signal of the self-feedback inside the detection mode force balance control module;

[0039] The gyro closed-loop driving module includes: a driving mode excitation electrode 101, a driving mode vibration structure 102, a driving mode sensing electrode 103, a driving mode AC / DC coupling differential unit 104, a driving mode D / A conversion unit 106, a driving mode front-end detection unit 105, a driving mode A / D conversion unit 107, an amplitude demodulation unit 108, a phase demodulation unit 109, an automatic gain control unit 110, a phase PI control unit 111 and a direct digital frequency synthesis unit 112;

[0040] A constant DC is used as an input of a driving mode AC / DC coupling differential unit 104; an output end of a driving mode D / A conversion unit 106 is connected to another input end of the driving mode AC / DC coupling differential unit 104; an output end of the driving mode AC / DC coupling differential unit 104 is connected to an input end of a driving mode excitation electrode 101; an output end of the driving mode excitation electrode 101 is connected to an input end of a driving mode vibration structure 102; an output end of the driving mode vibration structure 102 is connected to an input end of a driving mode sensing electrode 103; an output end of the driving mode sensing electrode 103 is connected to an input end of a driving mode front-end detection unit 105; and output ends of the driving mode front-end detection unit 105 are respectively connected to phase shift modules. The input end of the driving mode A / D conversion unit 107 is connected; the output end of the driving mode A / D conversion unit 107 is respectively connected to the input end of the amplitude demodulation unit 108 and the input end of the phase demodulation unit 109; the output end of the amplitude demodulation unit 108 is connected to the input end of the automatic gain control unit 110; the output end of the phase demodulation unit 109 is connected to the input end of the phase PI control unit 111; the output end of the phase PI control unit 111 is connected to the input end of the direct digital frequency synthesis unit 112, and the output signal of the direct digital frequency synthesis unit 112 is multiplied by the output signal of the automatic gain control unit 110 as the input signal of the driving mode D / A conversion unit 106;

[0041] The driving mode AC / DC coupling differential unit 104 is used to couple the input constant DC with the self-feedback excitation signal; the driving mode front-end detection unit 105 is used to obtain the vibration signal of the driving mode electrode;

[0042] The detection mode force balance control module includes: a detection mode excitation electrode 201, a detection mode vibration structure 202, a detection mode sensing electrode 203, a detection mode AC / DC coupling differential unit 204, a detection mode D / A conversion unit 206, a detection mode front-end detection unit 205, a detection mode A / D conversion unit 207, a rate signal demodulation unit 208 and a detection mode force balance control unit 209;

[0043] The output end of the phase shift module is connected to one input end of the detection mode AC / DC coupling differential unit 204; the output end of the detection mode D / A conversion unit 206 is connected to the other input end of the detection mode AC / DC coupling differential unit 204; the output end of the detection mode AC / DC coupling differential unit 204 is connected to the input end of the detection mode excitation electrode 201; the output end of the detection mode excitation electrode 201 is connected to the input end of the detection mode vibration structure 202; the output end of the detection mode vibration structure 202 is connected to the input end of the detection mode induction electrode 203; the output end of the detection mode induction electrode 203 is connected to the detection mode The input end of the front-end detection unit 205 is connected; the output end of the detection mode front-end detection unit 205 is connected to the input end of the detection mode A / D conversion unit 207; the output end of the detection mode A / D conversion unit 207 is connected to the input end of the rate signal demodulation unit 208; the output end of the rate signal demodulation unit 208 is connected to the input end of the detection mode force balance control unit 209; the detection mode force balance control unit 209 outputs the internal self-feedback force balance DC excitation signal and the control signal respectively, and the internal self-feedback force balance DC excitation signal serves as the input of the detection mode D / A conversion unit 206.

[0044] like Figure 2 As shown, the phase shift module is a 90° precision phase shift circuit, including: a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a sixth resistor, a capacitor C1, a capacitor C2, a capacitor C3, an operational amplifier A, an operational amplifier B and an operational amplifier C;

[0045] One end of the resistor R1 serves as the input end of the phase shift module, and the other end is respectively connected to one end of the sixth resistor, one end of the resistor R2 and the reverse input end of the operational amplifier A; the positive input end of the operational amplifier A is grounded, and the output end is respectively connected to one end of the resistor R3 and the other end of the resistor R2; the other end of the resistor R3 is respectively connected to one end of the capacitor C1 and the reverse input end of the operational amplifier B; the positive input end of the operational amplifier B is grounded, and the output end is respectively connected to the other end of the capacitor C1 and one end of the resistor R4, and the output end of the operational amplifier B serves as the output end of the phase shift module; the other end of the resistor R4 is respectively connected to one end of the capacitor C2, one end of the capacitor C3 and the reverse input end of the operational amplifier C; the other end of the capacitor C3 is connected to one end of the resistor R5; the positive input end of the operational amplifier C is grounded, and the output end is respectively connected to the other end of the capacitor C2, the other end of the resistor R5 and the other end of the sixth resistor.

[0046] The circuit of the phase shift module can be divided into three parts. The operational amplifier A forms a reverse amplification circuit, and the amplification factor is adjusted by adjusting the ratio of resistor R2 to resistor R1; the operational amplifier B, resistor R3 and capacitor C1 form an integration circuit. If there is a DC component in the input signal, the output of the integration circuit will gradually increase to saturation; the operational amplifier C and resistors R4, R5, capacitor C2 and capacitor C3 form a feedback circuit. The feedback circuit feeds back the DC component in the integrator output to the input end, and forms an adder through the reverse amplification circuit to inject it into the input end of the integrator, forming a negative feedback of the DC signal, thereby eliminating the DC component in the integrator output.

[0047] The transfer function of the phase shift module is:

[0048]

[0049] The phase-frequency characteristic analysis of the transfer function can be rewritten as:

[0050]

[0051] The phase angle is:

[0052]

[0053] like Figure 3 As shown in the figure, the amplitude-frequency characteristic curve and phase-frequency characteristic curve of the phase shift module are shown. The simulation results show that when the phase changes by 90°, the frequency is 8.7KHz, and the phase angle change is very small and relatively stable within the gyro resonance frequency range.

[0054] The present invention also provides a working method of a micro-electromechanical gyro force balance control system for converting constant AC to DC, comprising:

[0055] The working process of the gyro closed-loop drive module, the phase shifting process and the detection modal force balance control module are used to realize the force balance control process of constant AC to DC through three processes;

[0056] Among them, the working process of the gyro closed-loop drive module includes: the driving mode front-end detection unit 105 collects the vibration signal in the form of capacitance generated by the driving mode and converts it into a vibration signal in the form of voltage, which are respectively used as the input of the phase shift module and the input signal of the driving mode A / D conversion unit 107; the vibration signal is A / D converted by the driving mode A / D conversion unit 107 and used as the input signal of the amplitude demodulation unit and the phase demodulation unit 109; the amplitude demodulation unit outputs the amplitude signal to the automatic gain control unit 110 after demodulation, and the automatic gain control unit 110 generates the amplitude of the driving signal based on the amplitude signal; the phase demodulation unit 109 outputs the phase signal to the phase after demodulation. The PI control unit 111 is a bit PI control unit, and the phase PI control unit 111 outputs a phase control amount to a direct digital frequency synthesizer unit based on a phase signal; the direct digital frequency synthesizer unit 112 outputs a sinusoidal signal of a driving mode resonant frequency; the automatic gain control unit 110 generates an amplitude of a driving signal and multiplies the amplitude of the driving signal by the sinusoidal signal to obtain an AC excitation signal; the AC excitation signal is converted by the driving mode D / A conversion unit 106 and then coupled with a constant DC input from the outside in the driving mode AC / DC coupling differential unit 104 to obtain a coupling signal; the coupling signal is input to the excitation electrode in the driving mode to maintain a constant vibration amplitude, and the resonant frequency of the driving mode is tracked in real time to realize a closed-loop drive of the gyro;

[0057] The phase shifting process includes: the phase shifting module performs a 90° phase shift on the input vibration signal and outputs a force-balanced AC excitation signal.

[0058] The working process of the detection mode force balance control module includes: the detection mode front-end detection unit 205 collects the vibration signal in the form of capacitance generated based on the angular velocity of the gyro sensitive axis in the detection mode and converts it into a vibration signal in the form of voltage, and uses it as the input signal of the rate demodulation unit after A / D conversion by the detection mode A / D conversion unit 207; the rate demodulation unit outputs the rate signal to the detection mode force balance control unit 209 after demodulation; the detection mode force balance control unit 209 outputs the rate signal representing the angular velocity of the gyro sensitive axis as the control signal and the force balance DC excitation signal, the DC excitation signal and the force balance AC excitation signal are coupled in the detection mode AC / DC coupling differential unit 204 to form a coupling signal, and the coupling signal is input to the excitation electrode in the detection mode to balance the vibration of the detection mode electrode caused by the angular velocity of the gyro sensitive axis.

[0059] like Figure 4 As shown, the feedback signal F is adjusted by adjusting the amplitude of the DC signal. f The feedback signal F f Coriolis signal F of gyro detection mode c After the difference is made, the input is to the gyro detection modal transfer function G y(s), the displacement change of the detection mode detection electrode 203 is generated, thereby causing a capacitance change, and the capacitance change is converted into a voltage through the detection mode front-end detection circuit 205, and its gain is K yv The voltage is processed by the detection mode A / D conversion circuit 207 and in the rate signal demodulation module 208F lpf (s) is filtered after multiplication modulation, and the rate-related signal is output and input to the detection modal force balance controller 209F fb (s) generates a force balance DC signal, which is converted by D / A and amplified, and then input together with the detection mode AC signal into the detection mode AC / DC coupling differential circuit 204 as a feedback path, and its gain is K fb ·k·A x ·sin(ω x t), feedback output signal F f The angular velocity output of the MEMS gyro detection mode can be represented by the output of the detection mode force balance controller 209.

[0060] Figure 5 Is Figure 4 After equivalent conversion, the input signal of the detection mode feedback loop is firstly combined with the unit sinusoidal signal sin(ω x t) and then the transfer function of the feedback loop after the equivalent, the gain is K fb ·k·A x , the final output force feedback signal F f .

[0061] Figure 6 Is Figure 5 After equivalent transformation, the detected modal Coriolis signal F is obtained. c And the detection modal force feedback signal F f The sin(ω x t) is equivalently converted to a subtractor and obtained. Figure 6 The link in the dotted box can be characterized by Euler transformation as the gyro detection modal equivalent transfer function G e (s).

[0062] Figure 7 Is Figure 6 After equivalent conversion, it is obtained by converting the detection modal force balance control loop gain K in the negative feedback link fb ·k·A x Equivalently converted to the forward path, the scaling factor is:

[0063]

[0064] In the formula, m c is the effective Coriolis mass of the gyroscope; A x is the vibration amplitude of the electrode in the gyro driving mode; ω x is the resonant frequency; K fb is the feedback gain of the modal force balance control unit; k is the gain of the 90° phase shift module.

[0065] The expression of the scale factor SF does not include the driving mode amplitude A x , which can improve the temperature stability of the gyroscope.

[0066] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A micro-electromechanical gyroscopic force balance control system with constant AC to DC conversion, characterized in that: include: Gyro closed-loop drive module, detection modal force balance control module and phase shift module; The vibration signal output end of the gyro closed-loop driving module is connected to the input end of the phase shift module; The output end of the phase shift module is connected to the excitation signal input end of the detection modal force balance control module; the output end of the detection modal force balance control module is connected to the micro-electromechanical gyroscope; The gyro closed-loop drive module is used to track the resonant frequency of the driving mode and generate a sinusoidal signal of the resonant frequency as a self-feedback excitation signal and a vibration signal of the driving mode electrode; the phase shift module is used to phase-shift the vibration signal as a force balance AC excitation signal; the detection mode force balance control module is used to obtain a control signal for resisting the electrode vibration in the micro-electromechanical gyroscope detection mode based on the force balance AC excitation signal and the self-feedback force balance DC excitation signal inside the detection mode force balance control module.

2. The constant AC to DC micro-electromechanical gyro force balance control system according to claim 1, characterized in that: The gyro closed-loop driving module includes: a driving mode, a first AC / DC coupling differential unit, a first D / A conversion unit, a first front-end detection unit, a first A / D conversion unit, an amplitude demodulation unit, a phase demodulation unit, an automatic gain control unit, a phase PI control unit and a direct digital frequency synthesis unit; A constant direct current is used as an input of the first AC / DC coupled differential unit, and the output end of the first D / A conversion unit is connected to another input end of the first AC / DC coupled differential unit; the output end of the first AC / DC coupled differential unit is connected to the input end of the electrode in the driving mode; the output end of the electrode in the driving mode is connected to the input end of the first front-end detection unit; the output end of the first front-end detection unit is respectively connected to the input end of the phase shift module and the input end of the first A / D conversion unit; the output end of the first A / D conversion unit is respectively connected to the input end of the amplitude demodulation unit and the input end of the phase demodulation unit; the output end of the amplitude demodulation unit is connected to the input end of the automatic gain control unit; the output end of the phase demodulation unit is connected to the input end of the phase PI control unit; the output end of the phase PI control unit is connected to the input end of the direct digital frequency synthesis unit, and the output signal of the direct digital frequency synthesis unit is multiplied by the output signal of the automatic gain control unit as the input signal of the first D / A conversion unit; The first AC / DC coupling differential unit is used to couple the input constant DC with the self-feedback excitation signal; and the first front-end detection unit is used to obtain the vibration signal of the driving mode electrode.

3. The constant AC to DC micro-electromechanical gyro force balance control system according to claim 1, characterized in that: The detection mode force balance control module includes: a detection mode, a second AC / DC coupling differential unit, a second D / A conversion unit, a second front-end detection unit, a second A / D conversion unit, a rate signal demodulation unit and a force balance control unit; The output end of the phase shift module is connected to an input end of the second AC / DC coupling differential unit; the output end of the second D / A conversion unit is connected to another input end of the second AC / DC coupling differential unit; the output end of the second AC / DC coupling differential unit is connected to the input end of the detection mode; the output end of the detection mode is connected to the input end of the second front-end detection unit; the output end of the second front-end detection unit is connected to the input end of the second A / D conversion unit; the output end of the second A / D conversion unit is connected to the input end of the rate signal demodulation unit; the output end of the rate signal demodulation unit is connected to the input end of the force balance control unit; the force balance control unit outputs an internal self-feedback force balance DC excitation signal and a control signal respectively, and the internal self-feedback force balance DC excitation signal serves as the input of the second D / A conversion unit.

4. The constant AC to DC micro-electromechanical gyro force balance control system according to any one of claims 1 to 3, characterized in that: The phase shift module includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first capacitor, a second capacitor, a third capacitor, a first operational amplifier, a second operational amplifier and a third operational amplifier; One end of the first resistor serves as the input end of the phase shift module, and the other end is respectively connected to one end of the sixth resistor, one end of the second resistor and the reverse input end of the first operational amplifier; the positive input end of the first operational amplifier is grounded, and the output end is respectively connected to one end of the third resistor and the other end of the second resistor; the other end of the third resistor is respectively connected to one end of the first capacitor and the reverse input end of the second operational amplifier; the positive input end of the second operational amplifier is grounded, and the output end is respectively connected to the other end of the first capacitor and one end of the fourth resistor, and the output end of the second operational amplifier serves as the output end of the phase shift module; the other end of the fourth resistor is respectively connected to one end of the second capacitor, one end of the third capacitor and the reverse input end of the third operational amplifier; the other end of the third capacitor is connected to one end of the fifth resistor; the positive input end of the third operational amplifier is grounded, and the output end is respectively connected to the other end of the second capacitor, the other end of the fifth resistor and the other end of the sixth capacitor.

5. A working method of a constant AC to DC micro-electromechanical gyroscopic force balance control system, applicable to the constant AC to DC micro-electromechanical gyroscopic force balance control system as claimed in any one of claims 1 to 4, characterized in that: The working method comprises: The working process of the gyro closed-loop drive module, the phase shifting process and the detection modal force balance control module are used to realize the force balance control process of constant AC to DC through three processes; Among them, the working process of the gyro closed-loop drive module includes: the first front-end detection unit collects the vibration signal in the form of capacitance generated by the induction electrode in the driving mode and converts it into a vibration signal in the form of voltage, which are respectively used as the input of the phase shift module and the input signal of the first A / D conversion unit; the vibration signal is A / D converted by the first A / D conversion unit and used as the input signal of the amplitude demodulation unit and the phase demodulation unit respectively; the amplitude demodulation unit outputs the amplitude signal to the automatic gain control unit after demodulation, and the automatic gain control unit generates the amplitude of the driving signal based on the amplitude signal; the phase demodulation unit outputs the phase signal to the phase after demodulation. A PI control unit is provided, and a phase PI control unit outputs a phase control amount to a direct digital frequency synthesizer unit based on a phase signal; the direct digital frequency synthesizer unit outputs a sinusoidal signal of a driving mode resonant frequency; the automatic gain control unit generates an amplitude of a driving signal and multiplies the amplitude of the driving signal by the sinusoidal signal to obtain an AC excitation signal; the AC excitation signal is converted by a first D / A conversion unit and then coupled with a constant DC input from the outside in a first AC / DC coupling differential unit to obtain a coupling signal; the coupling signal is input to an excitation electrode in a driving mode to maintain a constant vibration amplitude, and the resonant frequency of the driving mode is tracked in real time to realize a closed-loop drive of the gyro; The phase shifting process includes: the phase shifting module performs a 90° phase shift on the input vibration signal and outputs a force-balanced AC excitation signal.

6. The working method of the constant AC to DC micro-electromechanical gyro force balance control system according to claim 5, characterized in that: The working process of the detection mode force balance control module includes: the second front-end detection unit collects the vibration signal in the form of capacitance generated based on the angular velocity of the gyro sensitive axis in the detection mode and converts it into a vibration signal in the form of voltage, and uses it as the input signal of the rate demodulation unit after A / D conversion by the second A / D conversion unit; the rate demodulation unit outputs the rate signal to the force balance control unit after demodulation; the force balance control unit outputs the rate signal representing the angular velocity of the gyro sensitive axis as the control signal and the force balance DC excitation signal, the DC excitation signal and the force balance AC excitation signal are coupled in the second AC / DC coupling differential unit to form a coupling signal, and the coupling signal is input to the excitation electrode in the detection mode to balance the vibration of the detection mode electrode caused by the angular velocity of the gyro sensitive axis.

7. The working method of the constant AC to DC micro-electromechanical gyro force balance control system according to claim 6, characterized in that: The scaling factor in the detection modal force balance control module is: In the formula, m c is the effective Coriolis mass of the gyroscope; A x is the vibration amplitude of the electrode in the gyro driving mode; ω x is the resonant frequency; K fb is the feedback gain of the modal force balance control unit; k is the gain of the 90° phase shift module.

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