A time-sharing digital control system for a resonant ring micro-electromechanical gyroscope

Abstract

This invention belongs to the field of closed-loop control of resonant ring microelectromechanical gyroscopes, specifically relating to a time-division digital control system for a resonant ring microelectromechanical gyroscope. It includes: a resonant ring microelectromechanical gyroscope, two mode drive / detection electrode time-division switching modules, two mode detection modules, two analog-to-digital converters, three digital-to-analog converters, three single-ended to differential drive modules, and a digital processing unit. The digital processing unit generates drive / detection time-division control signals S1 and S2, performs digital demodulation, filtering, control calculation, direct digital frequency generation, and modulation processing on the first mode detection signal to achieve time-division stable tracking closed-loop control of the gyroscope's resonant frequency and time-division stable closed-loop control of the vibration amplitude; and performs digital demodulation, filtering, control calculation, and modulation processing on the second mode detection signal to achieve stable control of the gyroscope's orthogonal compensation and time-division stable closed-loop control of the gyroscope's angular rate.

Description

Technical Field

[0001] This invention pertains to the closed-loop control technology of resonant ring microelectromechanical gyroscopes, specifically relating to a time-division digital control system for resonant ring microelectromechanical gyroscopes. Background Technology

[0002] Resonant ring microelectromechanical gyroscopes (MEMS) are a type of MEMS gyroscope with a naturally axisymmetric structure. Based on semiconductor processing technology, they are particularly suitable for mass production and have advantages such as low cost, small size, light weight, low power consumption, and resistance to shock and vibration. They can be widely used in attitude stabilization, industrial control, consumer electronics and other fields. With the improvement of accuracy, they also have broad application prospects in the field of navigation.

[0003] Practical resonant ring microelectromechanical gyroscopes typically employ closed-loop control and detection technology. This requires the gyroscope to operate within a stable closed loop consisting of a resonant frequency tracking loop, an amplitude vibration loop, an orthogonal compensation loop, and an angular rate loop to achieve high-precision, high-bandwidth measurement of the angular rate.

[0004] Resonant ring microelectromechanical gyroscopes have many electrodes with a complex distribution. Existing closed-loop control schemes generally adopt a method of simultaneous feedback drive and detection, which also involves complex analog detection and processing circuits. This results in drawbacks such as large crosstalk in the detection signal, complex analog circuit design and implementation, and gyroscope performance being easily affected by ambient temperature. Summary of the Invention

[0005] The purpose of this invention is to provide a time-division digital control system for a resonant ring microelectromechanical gyroscope. On one hand, time-division control enables time-division feedback drive and time-division detection of the resonant frequency stabilization tracking loop, vibration amplitude stabilization loop, and angular rate stabilization loop of the resonant ring microelectromechanical gyroscope, as well as time-division detection and DC continuous feedback drive control of the orthogonal compensation stabilization loop. This reduces crosstalk of the AC feedback drive voltage to the detection and improves signal detection accuracy. On the other hand, it enables as many functional modules as possible to be implemented in the digital domain, reducing the design and implementation difficulty of analog circuits, while also reducing gyroscope resonant frequency drift caused by external environmental factors such as temperature, thus improving gyroscope measurement accuracy.

[0006] Technical solution:

[0007] A time-division digital control system for a resonant ring microelectromechanical gyroscope includes: a first mode drive / detection electrode time-division switching module, a first mode detection module, a first analog-to-digital converter, a first digital-to-analog converter, a first single-ended to differential drive module, a digital processing unit, a second mode drive / detection electrode time-division switching module, a second mode detection module, a second analog-to-digital converter, a second digital-to-analog converter, a second single-ended to differential drive module, a third digital-to-analog converter, and a third single-ended to differential drive module. The digital processing unit includes: a first synchronization detection processing module, a first interpolation filter, a first phase-sensitive demodulator, a first low-pass filter, a second low-pass filter, a first controller, a second controller, a direct digital frequency generation module, a first modulation module, a time-division control timing generation module, a second synchronization detection processing module, a second interpolation filter, a second phase-sensitive demodulator, a third low-pass filter, a fourth low-pass filter, a third controller, a fourth controller, and a second modulation module.

[0008] The positive and negative terminals of the first mode drive / detection electrode of the resonant ring MEMS gyroscope are connected to the two input / output terminals of the first mode drive / detection electrode time-division switching module, respectively. The first mode drive / detection electrode time-division switching module, the first mode detection module, the first analog-to-digital converter, the first synchronization detection processing module, the first interpolation filter, and the first phase-sensitive demodulator are connected in sequence. The first output terminal of the first phase-sensitive demodulator is connected to the first low-pass filter, the first controller, and the first modulation module in sequence. The second output terminal of the first phase-sensitive demodulator is connected to the second low-pass filter, the second controller, and the direct digital frequency generation module in sequence. The direct digital frequency generation module generates two signals, cos and sin. One sin signal is connected to the second modulation module, and the other cos signal is connected to the first modulation module. The output terminal of the first modulation module is connected to the input terminal of the first digital-to-analog converter, the first single-ended to differential drive module, and the first mode drive / detection electrode time-division switching module. The signal returns to the first mode drive / detection electrode on the resonant ring MEMS gyroscope after passing through the first mode drive / detection electrode time-division switching module.

[0009] Meanwhile, the positive and negative terminals of the second mode drive / detection electrode on the resonant ring MEMS gyroscope are connected to the two input / output terminals of the second mode drive / detection electrode time-division switching module, respectively. The second mode drive / detection electrode time-division switching module is sequentially connected to the second mode detection module, the second analog-to-digital converter, the second synchronous detection processing module, the second interpolation filter, and the second phase-sensitive demodulator. The first output terminal of the second phase-sensitive demodulator is sequentially connected to the third low-pass filter, the third controller, the second modulation module, the second digital-to-analog converter, the second single-ended to differential drive module, and the second mode drive / detection electrode time-division switching module. After passing through the second mode drive / detection electrode time-division switching module, the signal returns to the second mode drive / detection electrode on the resonant ring MEMS gyroscope. The second output terminal of the second phase-sensitive demodulator is sequentially connected to the fourth low-pass filter, the fourth controller, the third digital-to-analog converter, and the third single-ended to differential drive module. The two output terminals of the third single-ended to differential drive module are connected to the two orthogonal electrodes of the resonant ring MEMS gyroscope.

[0010] One output of the time-division control timing generation module is connected to the control terminals of the first mode driving / detection electrode time-division switching module, the second mode driving / detection electrode time-division switching module, the first mode detection module, and the second mode detection module; the other output of the time-division control timing generation module is connected to the control terminals of the first synchronization detection processing module and the second synchronization detection processing module.

[0011] The time-division control timing generation module in the digital processing unit is used to generate the first mode and the second mode drive and detection time-division control signals S1 and S2. The two signals have the same frequency, so that the gyroscope is in an alternating working mode of drive period and detection period.

[0012] Further, the control signal S1 generated by the time-sharing control timing generation module in the digital processing unit has two states, high and low. When S1 is in the high state, the first-mode drive / detection electrode time-sharing switching module connects the first single-ended to differential drive module to the first-mode drive / detection electrodes X+ and X-, disconnects the first-mode detection module from the first-mode drive / detection electrodes X+ and X-, and resets the first-mode detection module. At the same time, the second-mode drive / detection electrode time-sharing switching module connects the second single-ended to differential drive module to the second-mode drive / detection electrodes X+ and X-, disconnects the second-mode detection module from the second-mode drive / detection electrodes X+ and X-, and resets the second-mode detection module. The gyroscope is in the drive working period. When S1 is in the low state, the first-mode drive / detection electrode time-sharing switching module disconnects the first single-ended to differential drive module from the first-mode drive / detection electrodes X+ and X, connects the first-mode detection module to the first-mode drive / detection electrodes X+ and X. At the same time, the second-mode drive / detection electrode time-sharing switching module disconnects the second single-ended to differential drive module from the second-mode drive / detection electrodes X+ and X, connects the second-mode detection module to the second-mode drive / detection electrodes X+ and X. The gyroscope is in the detection working period.

[0013] Further, the control signal S2 generated by the time-sharing control timing generation module in the digital processing unit has two states, high and low. Only when S2 is in the high state, the first synchronous detection processing module and the second synchronous detection processing module respectively perform integral accumulation processing on the output signals of the first analog-to-digital converter and the second analog-to-digital converter, and respectively obtain the instant position detection information of the first mode and the second mode of the gyroscope.

[0014] Further, the control signals S1 and S2 generated by the time-sharing control timing generation module in the digital processing unit are in the form of square waves with the same frequency, and the frequency is f s , f s is at least 10 times greater than f d , where f d is the resonance frequency of the gyroscope drive mode.

[0015] Further, the periods of the two control signals S1 and S2 are T, the high-state time of S1 is T1, the low-state time of S1 is T2, the high-state time of S2 is T3, and they satisfy the relationships: 0 < T1 < T, 0 < T2 < T, T1 + T2 = T, 0 < T3 < T2, and the rising edge of S1 coincides with the falling edge of S2.

[0016] Further, the first interpolation filter and the second interpolation filter in the digital processing unit upsample the digital processing sampling frequencies of the first-mode and second-mode detection signals from f s to f clkThis effectively reduces phase noise in subsequent phase-sensitive demodulation processing and also functions as a low-pass filter. Wherein, f clk This refers to the operating frequency of the digital processing unit.

[0017] Furthermore, the first analog-to-digital converter, the first digital-to-analog converter, the second analog-to-digital converter, and the second digital-to-analog converter all employ high-speed converters, with a conversion sampling rate that is the same as the operating frequency of the digital processing unit, which is f. clk .

[0018] Furthermore, the direct digital frequency generation module in the digital processing unit simultaneously generates cosine cosine and sine sinine AC digital signals based on the signals processed by the first phase-sensitive demodulator (quadrature demodulation), the second low-pass filter, and the second controller. The cosine signal is used as the carrier signal for the first and second modulation modules, while the sinine and cosine signals are used as in-phase and quadrature demodulation reference signals for the first and second phase-sensitive demodulators, respectively.

[0019] Furthermore, the first modulation module and the second modulation module in the digital processing unit only output the modulation signal normally when the gyroscope is in the driving working period, and output a constant zero signal during the detection working period.

[0020] Furthermore, both the first and second mode driving of the gyroscope adopt differential driving methods, and both the first and second mode detection adopt differential detection methods. Moreover, the differential driving common-mode voltage and the differential detection common-mode voltage both have a DC voltage difference V with the voltage applied to the gyroscope mass. DC ,|V DC |>0.

[0021] Beneficial effects:

[0022] (1) The resonant ring microelectromechanical gyroscope time-division digital control system proposed in this invention enables the driving and detection work of the first mode and the second mode of the gyroscope to be carried out alternately in time, with complementary overlap in time, avoiding crosstalk between the strong AC driving signal and the weak detection signal. At the same time, the digital processing of the detection signal adopts integral accumulation and interpolation filtering, which effectively improves the signal-to-noise ratio of the detection processing signal.

[0023] (2) The resonant ring microelectromechanical gyroscope time-division digital control system proposed in this invention uses a time-division control timing generation module in the digital processing unit to generate the time-division control timing sequence. The time-division operating frequency and the time ratio of the driving and detection periods can be flexibly adjusted to adapt to different gyroscope head characteristics. In addition, most of the functions are completed by the digital processing unit, which greatly reduces the design and implementation difficulty of analog circuits, and at the same time reduces the drift of the gyroscope resonant frequency caused by factors such as external ambient temperature, thereby improving the gyroscope measurement accuracy. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention, and a functional block diagram of the time-division digital control system for a resonant ring microelectromechanical gyroscope.

[0025] Figure 2 This is a time-sharing control timing diagram of the present invention. Detailed Implementation

[0026] The following will provide a more detailed description of the invention in conjunction with the accompanying drawings and embodiments.

[0027] Combination Figure 1 This invention proposes a time-division digital control system for a resonant ring microelectromechanical gyroscope, comprising a resonant ring microelectromechanical gyroscope 01, a first mode drive / detection electrode time-division switching module 02, a first mode detection module 03, a first analog-to-digital converter 04, a first digital-to-analog converter 06, a first single-ended to differential drive module 07, a digital processing unit 05, a second mode drive / detection electrode time-division switching module 08, a second mode detection module 09, a second analog-to-digital converter 10, a second digital-to-analog converter 11, a second single-ended to differential drive module 12, a third digital-to-analog converter 32, and a third single-ended to differential drive module 13.

[0028] The digital processing unit 05 further includes a first synchronization detection processing module 14, a first interpolation filter 15, a first phase-sensitive demodulator 16, a first low-pass filter 17, a second low-pass filter 20, a first controller 18, a second controller 21, a direct digital frequency generation module 22, a first modulation module 19, a time-division control timing generation module 23, a second synchronization detection processing module 24, a second interpolation filter 25, a second phase-sensitive demodulator 26, a third low-pass filter 27, a fourth low-pass filter 30, a third controller 28, a fourth controller 31, and a second modulation module 29.

[0029] The system's connections are as follows: the positive and negative terminals of the first mode drive / detection electrode of the resonant ring microelectromechanical gyroscope 01 are connected to the two input / output terminals of the first mode drive / detection electrode time-division switching module 02, respectively. The first mode drive / detection electrode time-division switching module 02, the first mode detection module 03, the first analog-to-digital converter 04, the first synchronization detection processing module 14, the first interpolation filter 15, and the first phase-sensitive demodulator 16 are connected in sequence. The first output terminal of the first phase-sensitive demodulator 16 is connected in sequence to the first low-pass filter 17, the first controller 18, and the first modulation module 19. The second output terminal of the first phase-sensitive demodulator 16 is connected to... After the second low-pass filter 20, the second controller 21, and the direct digital frequency generation module 22 are connected in sequence, the direct digital frequency generation module 22 generates two signals, cos and sin. One sin signal is connected to the second modulation module 29, and the other cos signal is connected to the first modulation module 19. The output of the first modulation module 19 is connected to the input of the first digital-to-analog converter 06, the first single-ended to differential drive module 07, and the first mode drive / detection electrode time-division switching module 02. The signal returns to the first mode drive / detection electrode on the resonant ring microelectromechanical gyroscope 01 through the first mode drive / detection electrode time-division switching module 02.

[0030] Meanwhile, the positive and negative terminals of the second mode drive / detection electrode on the resonant ring microelectromechanical gyroscope 01 are connected to the two input / output terminals of the second mode drive / detection electrode time-division switching module 08, respectively. The second mode drive / detection electrode time-division switching module 08 is sequentially connected to the second mode detection module 09, the second analog-to-digital converter 10, the second synchronous detection processing module 24, the second interpolation filter 25, and the second phase-sensitive demodulator 26. The first output terminal of the second phase-sensitive demodulator 26 is connected to the third low-pass filter 27, the third controller 28, the second modulation module 29, and the second digital-to-analog converter. Device 11, second single-ended to differential drive module 12, and second mode drive / detection electrode time-division switching module 08 are connected in sequence. After passing through the second mode drive / detection electrode time-division switching module 08, the signal returns to the second mode drive / detection electrode on the resonant ring microelectromechanical gyroscope 01. The second output terminal of the second phase-sensitive demodulator 26 is connected in sequence to the fourth low-pass filter 30, the fourth controller 31, the third digital-to-analog converter 32, and the third single-ended to differential drive module 13. The two output terminals of the third single-ended to differential drive module 13 are connected to the two orthogonal electrodes of the resonant ring microelectromechanical gyroscope 01.

[0031] One output terminal of the time-division control timing generation module 23 is connected to the control terminal of the first mode driving / detection electrode time-division switching module 02, the control terminal of the second mode driving / detection electrode time-division switching module 08, the control terminal of the first mode detection module 03, and the control terminal of the second mode detection module 09; the other output terminal of the time-division control timing generation module 23 is connected to the control terminal of the first synchronous detection processing module 14 and the control terminal of the second synchronous detection processing module 24.

[0032] The control signals S1 and S2 generated by the time-division control timing generation module 23 in the digital processing unit 05 are as follows: Figure 2 As shown. Both S1 and S2 have two states: high and low. When S1 is in the high state, the first mode drive / detection electrode time-division switching module 02 connects the first single-ended to differential drive module 07 to the first mode drive / detection electrodes X+ and X-, and disconnects the first mode detection module 03 from the first mode drive / detection electrodes X+ and X-, and resets the first mode detection module 03. At the same time, the second mode drive / detection electrode time-division switching module 08 connects the second single-ended to differential drive module 12 to the second mode drive / detection electrodes X+ and X-, and disconnects the second mode detection module 09 from the second mode drive / detection electrodes X+ and X-, and resets the second mode detection module 09. Upon reset, the gyroscope enters the driving operation period. When S1 is low, the first mode driving / detection electrode time-division switching module 02 disconnects the first single-ended to differential driving module 07 from the first mode driving / detection electrodes X+ and X-, and connects the first mode detection module 03 to the first mode driving / detection electrodes X+ and X-. Simultaneously, the second mode driving / detection electrode time-division switching module 08 disconnects the second single-ended to differential driving module 12 from the second mode driving / detection electrodes X+ and X-, and connects the second mode detection module 09 to the second mode driving / detection electrodes X+ and X-, placing the gyroscope in the detection operation period. Furthermore, only when S2 is high, the first synchronous detection processing module 14 and the second synchronous detection processing module 24 perform integration and accumulation processing on the output signals of the first analog-to-digital converter 04 and the second analog-to-digital converter 11, respectively, to obtain the real-time position detection information of the gyroscope in the first and second modes.

[0033] During the detection period, the first-mode detection module 03 picks up the signals of the first-mode detection electrodes X+ and X-. After passing through the first analog-to-digital converter 04, the first synchronous detection processing module 14, the first interpolation filter 15, and the first phase-sensitive demodulator 16 in the digital processing unit 05, on the one hand, through in-phase demodulation, filtering by the first low-pass filter 17, the first controller 18, and the first modulation module 19 for arithmetic processing, and then through the first digital-to-analog converter 06 and the first single-ended to differential drive module 07, it is fed back to the first-mode drive electrodes X+ and X- during the drive period to achieve stable closed-loop control of the gyro vibration amplitude. On the other hand, through quadrature demodulation, filtering by the second low-pass filter 20, the second controller 21, the direct digital frequency generation module 22, and the first modulation module 19 for arithmetic processing, it also passes through the first digital-to-analog converter 06 and the first single-ended to differential drive module 07 and is fed back to the first-mode drive electrodes X+ and X- during the drive period to achieve stable closed-loop tracking control of the gyro resonance frequency;

[0034] Meanwhile, during the detection period, the second-mode detection module 09 picks up the signals of the second-mode detection electrodes Y+ and Y-. After passing through the second analog-to-digital converter 10, the second synchronous detection processing module 24, the second interpolation filter 25, and the second phase-sensitive demodulator 26 in the digital processing unit 05, on the one hand, through in-phase demodulation, filtering by the third low-pass filter 27, the third controller 28, and the second modulation module 29 for arithmetic processing, and then through the second digital-to-analog converter 11 and the second single-ended to differential drive module 12, it is fed back to the second-mode drive electrodes Y+ and Y- during the drive period to achieve stable closed-loop control of the gyro angular rate. On the other hand, through quadrature demodulation, filtering by the fourth low-pass filter 30, and the fourth controller 31 for arithmetic processing, it passes through the third digital-to-analog converter 32 and the third single-ended to differential drive module 13 and is fed back to the quadrature electrodes Q+ and Q- to achieve stable closed-loop control of the gyro quadrature compensation.

[0035] Combined Figure 2 , the time-sharing control timing generation module 23 in the digital processing unit 05 generates control signals S1 and S2 in the form of square waves with the same frequency, and its frequency is f s , the period is T, and f s is at least 10 times greater than f d , where f d is the resonance frequency of the gyro drive mode. The high-state time of S1 is T1, the low-state time is T2, the high-state time of S2 is T3, and they satisfy the relationship: 0 < T1 < T, 0 < T2 < T, T1 + T2 = T, 0 < T3 < T2, and the rising edge of S1 coincides with the falling edge of S2.

[0036] The first interpolation filter 15 and the second interpolation filter 25 in the digital processing unit 05 up-sample the digital processing sampling frequency of the first-mode and second-mode detection signals from f s to f clkIt can effectively reduce the phase noise of subsequent phase-sensitive demodulation processing, and also has the function of low-pass filtering, where f clk The operating frequency of the digital processing unit;

[0037] The direct digital frequency generation module 22 in the digital processing unit 05 generates cosine cosine and sine sinine AC digital signals simultaneously based on the signals processed by the first phase-sensitive demodulator 16 (quadrature demodulation), the second low-pass filter 20 (filtering), and the second controller 21 (operation processing). The cosine signal is used as the carrier signal of the first modulation module 19 and the second modulation module 29, while the sinine and cosine signals are used as the in-phase and quadrature demodulation reference signals of the first phase-sensitive demodulator 16 and the second phase-sensitive demodulator 26, respectively.

[0038] The first modulation module 19 and the second modulation module 29 in the digital processing unit 05 only output the modulation signal normally when the gyroscope is in the driving working period, and output a constant zero signal during the detection working period.

[0039] The first controller 18, the second controller 21, the third controller 28, and the fourth controller 31 in the digital processing unit 05 typically employ proportional-integral control; the first modulation module 19 and the second modulation module 29 typically employ multiplier modulation; and the first phase-sensitive demodulator 16 and the second phase-sensitive demodulator 26 typically employ multiplier demodulation.

[0040] The gyroscope's first and second mode driving both employ differential driving, and its first and second mode detections also employ differential detection. Furthermore, both the differential driving common-mode voltage and the differential detection common-mode voltage have a DC voltage difference V with the voltage applied to the gyroscope's mass. DC And |V DC |>0.

[0041] In summary, this invention discloses a time-division digital control system for a resonant ring microelectromechanical gyroscope. The time-division control timing generation module 23 in the digital processing unit 05 controls the first mode drive / detection electrode time-division switching module 02, the second mode drive / detection electrode time-division switching module 08, the first mode detection module 03, the second mode detection module 09, the first synchronization detection processing module 14, and the second synchronization detection processing module 24 via control signals S1 and S2, enabling the gyroscope to operate in an alternating driving and detection phase. This achieves stable tracking of the gyroscope's driving amplitude, driving resonant frequency, orthogonal compensation, and stable closed-loop control of the angular rate. Most of the functions of this invention are performed by the digital processing unit 05, which greatly reduces the difficulty of implementing the system's analog circuitry. The time-division digital control effectively reduces crosstalk, improves the signal-to-noise ratio of the detection circuit, enhances gyroscope accuracy, and reduces the impact of ambient temperature on gyroscope accuracy.

[0042] The following is based on the above implementation details, and in conjunction with... Figure 1 and Figure 2 To illustrate further, we will provide examples.

[0043] Example 1

[0044] As an embodiment of the present invention, the gyroscope resonant frequency f d =12KHz, the operating clock frequency f of digital processing unit 05 clk =20MHz, the time-division control timing generation module 23 generates control signals S1 and S2, frequency f s =500KHz, T1:T2=3:1, meaning that the high-state ratio used for feedback driving accounts for 75%, and the low-state ratio used for detection accounts for 25%. During time period T3, the transition process of the first modal detection module 03 ends, and it enters a relatively stable working state. Its output signal is sampled at high speed by the first analog-to-digital converter 04, with a sampling rate of f. clk The first synchronous detection and processing module 14 performs integral accumulation processing, and the sampling rate becomes f. s The first interpolation filter 15 processes the data, using a 40x upsampling, resulting in a sampling rate of f. clk Then, on the one hand, after in-phase sin phase demodulation by the first phase-sensitive demodulator 16, filtering by the first low-pass filter 17, and processing by the first controller 18 and the first modulation module 19, the signal is fed back to the first mode drive / detection electrodes X+ and X- during the T1 drive period of the next time-division cycle, realizing stable closed-loop control of the gyroscope vibration amplitude. On the other hand, after quadrature cos phase demodulation by the first phase-sensitive demodulator 16, filtering by the second low-pass filter 20, generating a cos digital AC signal by the second controller 21 and the direct digital frequency generation module 22, and modulation processing by the first modulation module 19, the signal is fed back to the first mode drive / detection electrodes X+ and X- during the T1 drive period of the next time-division cycle, realizing stable tracking closed-loop control of the gyroscope resonant frequency. Similarly, during the T3 period, the transition process of the second mode detection module 09 ends, and it is in a relatively stable working state. Its output signal is sampled at high speed by the second analog-to-digital converter 10, with a sampling rate of f. clk The second synchronous detection and processing module 24 performs integral accumulation processing, and the sampling rate becomes f. s The second interpolation filter 25 processes the data, using a 40x upsampling, resulting in a sampling rate of f. clkThen, on the one hand, after in-phase sin-phase demodulation by the second phase-sensitive demodulator 26, filtering by the third low-pass filter 27, and processing by the third controller 28 and the second modulation module 29, the data is fed back to the second mode drive / detection electrodes Y+ and Y- during the drive period T1 of the next time-sharing cycle, realizing stable closed-loop control of the gyroscope angular rate; on the other hand, after quadrature cos-phase demodulation by the second phase-sensitive demodulator 26, filtering by the fourth low-pass filter 30, and processing by the fourth controller 31, the data is fed back to the gyroscope quadrature electrodes Q+ and Q- through the third digital-to-analog converter 32 and the third single-end to differential drive module 13, realizing stable closed-loop control of gyroscope quadrature compensation. Since the drive period in this embodiment accounts for 75% of the entire time-sharing cycle T, the drive capability is 0.75 times that of the non-time-sharing under the same conditions, indicating strong drive capability, which is suitable for the control of resonant ring microelectromechanical gyroscopes with small Q values.

[0045] Example 2

[0046] As another embodiment of the present invention, as one embodiment of the present invention, the gyroscope resonant frequency f d =15KHz, the operating clock frequency f of digital processing unit 05 clk =20MHz, the time-division control timing generation module 23 generates control signals S1 and S2, frequency f s =500KHz, T1:T2=1:3, meaning that the high-state ratio used for feedback driving accounts for 25%, and the low-state ratio used for detection accounts for 75%. During time period T3, the transition process of the first modal detection module 03 ends, and it enters a relatively stable working state. Its output signal is sampled at high speed by the first analog-to-digital converter 04, with a sampling rate of f. clk The first synchronous detection and processing module 14 performs integral accumulation processing, and the sampling rate becomes f. s The first interpolation filter 15 processes the data, using a 40x upsampling, resulting in a sampling rate of f. clkThen, on the one hand, after in-phase sin phase demodulation by the first phase-sensitive demodulator 16, filtering by the first low-pass filter 17, and processing by the first controller 18 and the first modulation module 19, the signal is fed back to the first mode drive / detection electrodes X+ and X- during the T1 drive period of the next time-division cycle, realizing stable closed-loop control of the gyroscope vibration amplitude. On the other hand, after quadrature cos phase demodulation by the first phase-sensitive demodulator 16, filtering by the second low-pass filter 20, generating a cos digital AC signal by the second controller 21 and the direct digital frequency generation module 22, and modulation processing by the first modulation module 19, the signal is fed back to the first mode drive / detection electrodes X+ and X- during the T1 drive period of the next time-division cycle, realizing stable tracking closed-loop control of the gyroscope resonant frequency. Similarly, during the T3 period, the transition process of the second mode detection module 09 ends, and it is in a relatively stable working state. Its output signal is sampled at high speed by the second analog-to-digital converter 10, with a sampling rate of f. clk The second synchronous detection and processing module 24 performs integral accumulation processing, and the sampling rate becomes f. s The second interpolation filter 25 processes the data, using a 40x upsampling, resulting in a sampling rate of f. clk Then, on the one hand, after in-phase sin phase demodulation by the second phase-sensitive demodulator 26, filtering by the third low-pass filter 27, and processing by the third controller 28 and the second modulation module 29, the data is fed back to the second mode drive / detection electrodes Y+ and Y- during the drive period T1 of the next time-sharing cycle, realizing stable closed-loop control of the gyroscope angular rate; on the other hand, after quadrature cos phase demodulation by the second phase-sensitive demodulator 26, filtering by the fourth low-pass filter 30, and processing by the fourth controller 31, the data is fed back to the gyroscope quadrature electrodes Q+ and Q- through the third digital-to-analog converter 32 and the third single-end to differential drive module 13, realizing stable closed-loop control of gyroscope quadrature compensation. Since the drive period in this embodiment accounts for 25% of the entire time-sharing cycle T, the drive capability is 0.25 times that under the same conditions without time-sharing, and the drive capability is relatively weak, it is suitable for the control of resonant ring microelectromechanical gyroscopes with large Q values.

Claims

1. A time-division digital control system for a resonant ring microelectromechanical gyroscope, characterized in that, include: The system comprises a first mode driving / detection electrode time-division switching module, a first mode detection module, a first analog-to-digital converter, a first digital-to-analog converter, a first single-ended to differential driving module, a digital processing unit, a second mode driving / detection electrode time-division switching module, a second mode detection module, a second analog-to-digital converter, a second digital-to-analog converter, a second single-ended to differential driving module, a third digital-to-analog converter, and a third single-ended to differential driving module. The digital processing unit includes: a first synchronization detection processing module, a first interpolation filter, a first phase-sensitive demodulator, a first low-pass filter, a second low-pass filter, a first controller, a second controller, a direct digital frequency generation module, a first modulation module, a time-division control timing generation module, a second synchronization detection processing module, a second interpolation filter, a second phase-sensitive demodulator, a third low-pass filter, a fourth low-pass filter, a third controller, a fourth controller, and a second modulation module. The positive and negative terminals of the first mode drive / detection electrode of the resonant ring MEMS gyroscope are connected to the two input / output terminals of the first mode drive / detection electrode time-division switching module, respectively. The first mode drive / detection electrode time-division switching module, the first mode detection module, the first analog-to-digital converter, the first synchronization detection processing module, the first interpolation filter, and the first phase-sensitive demodulator are connected in sequence. The first output terminal of the first phase-sensitive demodulator is connected to the first low-pass filter, the first controller, and the first modulation module in sequence. The second output terminal of the first phase-sensitive demodulator is connected to the second low-pass filter, the second controller, and the direct digital frequency generation module in sequence. The direct digital frequency generation module generates two signals, cos and sin. One sin signal is connected to the second modulation module, and the other cos signal is connected to the first modulation module. The output terminal of the first modulation module is connected to the input terminal of the first digital-to-analog converter, the first single-ended to differential drive module, and the first mode drive / detection electrode time-division switching module. The signal returns to the first mode drive / detection electrode on the resonant ring MEMS gyroscope after passing through the first mode drive / detection electrode time-division switching module. Meanwhile, the positive and negative terminals of the second mode drive / detection electrode on the resonant ring MEMS gyroscope are connected to the two input / output terminals of the second mode drive / detection electrode time-division switching module, respectively. The second mode drive / detection electrode time-division switching module is sequentially connected to the second mode detection module, the second analog-to-digital converter, the second synchronous detection processing module, the second interpolation filter, and the second phase-sensitive demodulator. The first output terminal of the second phase-sensitive demodulator is sequentially connected to the third low-pass filter, the third controller, the second modulation module, the second digital-to-analog converter, the second single-ended to differential drive module, and the second mode drive / detection electrode time-division switching module. After passing through the second mode drive / detection electrode time-division switching module, the signal returns to the second mode drive / detection electrode on the resonant ring MEMS gyroscope. The second output terminal of the second phase-sensitive demodulator is sequentially connected to the fourth low-pass filter, the fourth controller, the third digital-to-analog converter, and the third single-ended to differential drive module. The two output terminals of the third single-ended to differential drive module are connected to the two orthogonal electrodes of the resonant ring MEMS gyroscope. One output terminal of the time-sharing control timing generation module is connected to the control terminal of the first-mode drive / detection electrode time-sharing switching module, the control terminal of the second-mode drive / detection electrode time-sharing switching module, the control terminal of the first-mode detection module, and the control terminal of the second-mode detection module; another output terminal of the time-sharing control timing generation module is connected to the control terminal of the first synchronous detection processing module and the control terminal of the second synchronous detection processing module. The time-sharing control timing generation module in the digital processing unit is used to generate the first-mode and second-mode drive and detection time-sharing working control signals S1 and S2, which have the same frequency, so that the gyroscope is in an alternating working mode of the drive period and the detection period.

2. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The control signal S1 generated by the time-sharing control timing generation module in the digital processing unit has two states: high and low. When S1 is in the high state, the first-mode drive / detection electrode time-sharing switching module connects the first single-ended to differential drive module to the first-mode drive / detection electrodes X+ and X-, disconnects the first-mode detection module from the first-mode drive / detection electrodes X+ and X-, and resets the first-mode detection module. At the same time, the second-mode drive / detection electrode time-sharing switching module connects the second single-ended to differential drive module to the second-mode drive / detection electrodes X+ and X-, disconnects the second-mode detection module from the second-mode drive / detection electrodes X+ and X-, and resets the second-mode detection module. The gyroscope is in the drive working period. When S1 is in the low state, the first-mode drive / detection electrode time-sharing switching module disconnects the first single-ended to differential drive module from the first-mode drive / detection electrodes X+ and X-, connects the first-mode detection module to the first-mode drive / detection electrodes X+ and X-. At the same time, the second-mode drive / detection electrode time-sharing switching module disconnects the second single-ended to differential drive module from the second-mode drive / detection electrodes X+ and X-, connects the second-mode detection module to the second-mode drive / detection electrodes X+ and X-. The gyroscope is in the detection working period.

3. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The control signal S2 generated by the time-sharing control timing generation module in the digital processing unit has two states: high and low. Only when S2 is in the high state, the first synchronous detection processing module and the second synchronous detection processing module respectively perform integral accumulation processing on the output signals of the first analog-to-digital converter and the second analog-to-digital converter, and respectively obtain the instant position detection information of the first mode and the second mode of the gyroscope.

4. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The time-division control timing generation module in the digital processing unit generates control signals S1 and S2 in the form of square waves with the same frequency f. s f s At least greater than 10 times f d , where f d This is the resonant frequency of the gyroscope drive mode.

5. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 4, characterized in that, The periods of the two control signals S1 and S2 are T, the high-state time of S1 is T1, the low-state time of S1 is T2, the high-state time of S2 is T3, and they satisfy the relationships: 0 < T1 < T, 0 < T2 < T, T1 + T2 = T, 0 < T3 < T2, and the rising edge of S1 coincides with the falling edge of S2.

6. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The first interpolation filter and the second interpolation filter in the digital processing unit adjust the digital processing sampling frequency of the first mode and the second mode detection signals from f. s Upsampling to f clk This effectively reduces phase noise in subsequent phase-sensitive demodulation processing and also functions as a low-pass filter. Wherein, f clk This refers to the operating frequency of the digital processing unit.

7. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The first analog-to-digital converter, the first digital-to-analog converter, the second analog-to-digital converter, and the second digital-to-analog converter all employ high-speed converters, with a conversion sampling rate that is the same as the operating frequency of the digital processing unit, which is f. clk .

8. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The direct digital frequency generation module in the digital processing unit simultaneously generates cosine cosine and sine sinine AC digital signals based on the signals processed by the first phase-sensitive demodulator (quadrature demodulation), the second low-pass filter, and the second controller. The cosine signal is used as the carrier signal of the first modulation module and the second modulation module, while the sinine and cosine signals are used as the in-phase and quadrature demodulation reference signals of the first and second phase-sensitive demodulators, respectively.

9. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claims 1 and 2, characterized in that, The first modulation module and the second modulation module in the digital processing unit only output modulation signals normally when the gyroscope is in the driving working period, and output constant zero signals during the detection working period.

10. The time-division digital control system for a resonant ring microelectromechanical gyroscope according to claim 1, characterized in that, The gyroscope's first and second mode driving both employ differential driving, and its first and second mode detections also employ differential detection. Furthermore, both the differential driving common-mode voltage and the differential detection common-mode voltage have a DC voltage difference V with the voltage applied to the gyroscope's mass. DC ,|V DC |>0.

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