A fully differential lissajous frequency-modulated MEMS gyroscope

Abstract

The present application relates to a kind of full differential lissajous frequency modulation MEMS gyroscopes, comprising: gyroscopic sensing unit, differential interface unit;Gyroscopic sensing unit, for generating resonance state in response to control signal, and angular rate signal is obtained in resonance state, first signal and second signal are obtained by differentially processing angular rate signal, and first signal and second signal are sent to differential interface unit;Differential interface unit, for providing control signal to gyroscopic sensing unit, and the first signal and second signal received are subjected to difference frequency harmonic filtering processing and synchronous demodulation processing, filter out the interference signal existing in first signal and second signal, obtain the angular rate signal without interference.The method can eliminate the influence of interference signal on detection accuracy, widen the usable bandwidth and the unspurious dynamic range of lissajous frequency modulation MEMS gyroscope, greatly improve the detection accuracy of lissajous frequency modulation MEMS gyroscope.

Description

Technical Field

[0001] This invention belongs to the field of microelectromechanical systems (MEMS) technology, specifically relating to a fully differential Lissajous frequency-modulated MEMS gyroscope. Background Technology

[0002] A gyroscope is an inertial sensor that detects external input angular rate or angle. MEMS gyroscopes are characterized by small size, low power consumption, and low cost, and have been widely used in image stabilization, indoor navigation, and attitude detection of wearable electronic products.

[0003] Frequency-modulated (FM) MEMS gyroscopes can directly measure the frequency-modulated signal output by the gyroscope sensor unit. Compared to the amplitude-modulated signal output by the gyroscope sensor unit, the frequency-modulated signal is less susceptible to interference. Furthermore, FM MEMS gyroscopes have a shorter and more direct signal processing link than amplitude-modulated (AM) MEMS gyroscopes, resulting in excellent scaling factor stability and zero-bias stability. Lissajous FM MEMS gyroscopes incorporate frequency modulation signal chopping, which eliminates the influence of intrinsic absolute resonant frequency drift on angular rate readout, effectively improving the accuracy of the FM MEMS gyroscope.

[0004] However, existing Lissajous frequency-modulated MEMS gyroscopes, due to their non-uniform self-sampling characteristics and intrinsic simultaneous amplitude and frequency modulation effects, inevitably introduce interference signals when reading external angular rate signals, which degrades the system's available bandwidth and spurious-free dynamic range, thus making it impossible to obtain true external angular rate information. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a fully differential Lissajous frequency-modulated MEMS gyroscope. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a fully differential Lissajous frequency-modulated MEMS gyroscope, comprising: a gyroscope sensing unit and a differential interface unit; the first, second, third, and fourth input terminals of the gyroscope sensing unit are respectively connected to the first, second, third, and fourth output terminals of the differential interface unit, and the first, second, third, and fourth output terminals of the gyroscope sensing unit are respectively connected to the first, second, third, and fourth input terminals of the differential interface unit; the gyroscope sensing unit is configured to generate a resonant state in response to a control signal, acquire an angular rate signal in the resonant state, perform differential processing on the angular rate signal to obtain a first signal and a second signal, and send the first signal and the second signal to the differential interface unit; the differential interface unit is configured to provide the control signal to the gyroscope sensing unit, and perform differential frequency harmonic filtering and synchronous demodulation processing on the received first signal and second signal to filter out interference signals present in the first signal and second signal, thereby obtaining an interference-free angular rate signal.

[0007] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention proposes a fully differential Lissajous frequency-modulated MEMS gyroscope. First, an external angular rate signal is acquired through a gyroscope sensing unit in a resonant state, resulting in a first signal and a second signal. Then, a differential interface unit is used to perform differential frequency harmonic filtering on the first and second signals, eliminating interference signals inevitably introduced during signal acquisition. Finally, the first and second signals after differential frequency harmonic filtering are synchronously demodulated to obtain an interference-free angular rate signal. Based on the gyroscope provided by this invention, the influence of interference signals on detection accuracy can be eliminated, the usable bandwidth and spurious-free dynamic range of the Lissajous frequency-modulated MEMS gyroscope can be widened, and the detection accuracy of the Lissajous frequency-modulated MEMS gyroscope can be greatly improved. Attached Figure Description

[0008] Figure 1 This is a schematic diagram illustrating the impact of the non-uniform self-sampling characteristics and intrinsic simultaneous amplitude modulation and frequency modulation effects provided in the embodiments of the present invention on the detection accuracy of traditional Lissajous frequency-modulated MEMS gyroscopes.

[0009] Figure 2 This is a structural block diagram of the fully differential Lissajous frequency-modulated MEMS gyroscope provided in an embodiment of the present invention;

[0010] Figure 3 This is a schematic diagram of the circuit composition of the fully differential Lissajous frequency-modulated MEMS gyroscope provided in an embodiment of the present invention;

[0011] Figure 4 This is a schematic diagram illustrating the working principle of each unit in the differential interface unit provided in this embodiment of the invention.

[0012] Figure label:

[0013] 1: Gyroscope sensing unit; 2: Resonance maintenance module; 3: Frequency readout module; 4: Differential frequency demodulation module; 11: In-phase sensing unit; 12: Out-of-phase sensing unit; 21: Resonance channel X1; 22: Resonance channel Y1; 23: Resonance channel X2; 24: Resonance channel Y2; 41: Differential frequency harmonic elimination module; 42: Scale factor stabilization module; 43: Demodulation reference extraction module; 44: Demodulation output module; 5: Differential interface unit. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0015] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0016] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0017] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0018] To address the problem that existing Lissajous frequency-modulated MEMS gyroscopes inevitably introduce interference signals when reading external angular rate signals due to their non-uniform self-sampling characteristics and intrinsic simultaneous amplitude and frequency modulation effects, thus degrading the system's available bandwidth and spurious-free dynamic range and preventing the acquisition of true external angular rate information, this invention proposes a fully differential Lissajous frequency-modulated MEMS gyroscope, which can effectively expand the available bandwidth and spurious-free dynamic range, reduce the influence of interference signals, and improve detection accuracy.

[0019] To clearly understand the characteristics of non-uniform self-sampling and the intrinsic simultaneous amplitude modulation and frequency modulation effects, Figure 1 This is a schematic diagram illustrating the impact of the non-uniform self-sampling characteristics and intrinsic simultaneous amplitude modulation / frequency modulation effects provided in this embodiment of the invention on the detection accuracy of a traditional Lissajous frequency-modulated MEMS gyroscope. Figure 1 As shown, in traditional Lissajous frequency-modulated MEMS gyroscopes, the frequency-to-digital converter (FDC) of the gyroscope sensing unit exhibits fluctuations in the resonant frequency of the external angular rate signal. At higher resonant frequencies, the FDC collects more sampling points, resulting in dense acquisition of the angular rate signal within a single acquisition cycle; conversely, at lower resonant frequencies, the FDC collects fewer sampling points, resulting in sparse acquisition of the angular rate signal within a single acquisition cycle. This non-uniform self-sampling characteristic introduces difference frequency harmonics into the output signal. Furthermore, the specific location of these difference frequency harmonics is within 2Δf-f. A and 2Δf+f A Within the bandwidth range. The conventional operating method is to use a low-pass filter with a bandwidth of 1.5Δf to eliminate the difference frequency harmonics. However, this limits the bandwidth of the external input angular rate to within the range of Δf / 2, degrading the system's available bandwidth and spurious-free dynamic range. Furthermore, this elimination method cannot completely eliminate the difference frequency harmonics, and the residual difference frequency harmonics will simultaneously affect the detection accuracy in both amplitude and frequency ranges.

[0020] Figure 2 This is a structural block diagram of the fully differential Lissajous frequency-modulated MEMS gyroscope provided in an embodiment of the present invention. Figure 2As shown, the gyroscope includes: a gyroscope sensing unit 1 and a differential interface unit 5; the first, second, third, and fourth input terminals of the gyroscope sensing unit 1 are respectively connected to the first, second, third, and fourth output terminals of the differential interface unit 5, and the first, second, third, and fourth output terminals of the gyroscope sensing unit 1 are respectively connected to the first, second, third, and fourth input terminals of the differential interface unit 5; the gyroscope sensing unit 1 is used to generate a resonant state in response to a control signal, acquire an angular rate signal in the resonant state, perform differential processing on the angular rate signal to obtain a first signal and a second signal, and send the first and second signals to the differential interface unit 5; the differential interface unit 5 is used to provide a control signal to the gyroscope sensing unit 1, and perform difference frequency harmonic filtering and synchronous demodulation processing on the received first and second signals to filter out interference signals present in the first and second signals, obtaining interference-free angular rate signals. Here, the interference signal is a difference frequency harmonic signal.

[0021] It should be understood that the term "gyroscope sensing unit" here can also be used in other ways, such as "fully differential Lissajous frequency modulation gyroscope sensing unit".

[0022] Please continue to refer to Figure 2 The differential interface unit 5 includes a resonance sustaining module 2 and a demodulation processing module (not shown in the figure). The first, second, third, and fourth input terminals of the resonance sustaining module 2 are connected to the first, second, third, and fourth output terminals of the gyroscope sensing unit 1, respectively. The resonance sustaining module 2 generates control signals and sends them to the gyroscope sensing unit 1. The first, second, third, and fourth output terminals of the resonance sustaining module 2 are connected to the first, second, third, and fourth input terminals of the gyroscope sensing unit 1, respectively. The fifth, sixth, seventh, eighth, ninth, and tenth output terminals of the resonance sustaining module 2 are connected to the first, second, third, fourth, fifth, and sixth input terminals of the demodulation processing module, respectively. The demodulation processing module receives and reads the first and second signals, performs difference frequency harmonic filtering and synchronous demodulation processing on the first and second signals, filters out interference signals present in the first and second signals, and obtains interference-free angular rate signals.

[0023] Please continue to refer to Figure 2The demodulation processing module includes a frequency readout module 3 and a differential frequency demodulation module 4. The first, second, third, and fourth input terminals of the frequency readout module 3 are connected to the fifth, sixth, seventh, and eighth output terminals of the resonance sustaining module 2, respectively. The first, second, third, and fourth output terminals of the frequency readout module 3 are also connected to the first, second, third, and fourth input terminals of the differential frequency demodulation module 4, respectively. The frequency readout module 3 receives and reads the first and second signals. The fifth and sixth input terminals of the differential frequency demodulation module 4 are connected to the ninth and tenth output terminals of the resonance sustaining module 2, respectively. The differential frequency demodulation module 4 performs differential frequency harmonic filtering and synchronous demodulation processing on the first and second signals, filtering out interference signals present in the first and second signals to obtain interference-free angular rate signals.

[0024] Please continue to refer to Figure 2 The gyroscope sensing unit 1 includes a non-in-phase sensing unit 11 and an inverting sensing unit 12; the resonance maintenance module 2 includes a resonant channel X1, a resonant channel X2, a resonant channel Y1, a resonant channel Y2, and an inverting motion controller 25. The inverting motion controller 25 can send control signals to the resonant channels X1, X2, Y1, and Y2 respectively. The resonant channels X1 and Y1 control the non-in-phase sensing unit 11 to be in a resonant state by changing the driving voltage of the non-in-phase sensing unit 11, and the resonant channels X2 and Y2 control the inverting sensing unit 12 to be in a resonant state by changing the driving voltage of the inverting sensing unit 12. Furthermore, the inverting motion controller 25 can acquire changes in the natural resonant frequency of the gyroscope sensing unit in real time and make timely adjustments.

[0025] Here, the driving voltage values ​​of the in-phase sensing unit 11 and the out-of-phase sensing unit 12 are the same, and their motion trajectories are opposite. For example, the in-phase sensing unit 11 performs clockwise motion, while the out-of-phase sensing unit 12 synchronously performs counterclockwise motion. The in-phase sensing unit 11 and the out-of-phase sensing unit 12 acquire the vibration frequency of the external angular rate signal and describe it using the gyroscope displacement information inside the in-phase sensing unit 11 or the out-of-phase sensing unit 12.

[0026] For clarity, Figure 3 This is a schematic diagram of the circuit composition of the fully differential Lissajous frequency-modulated MEMS gyroscope provided in an embodiment of the present invention. Figure 3As shown, each resonant channel includes: a C / V conversion circuit and an amplitude / frequency control module; wherein, the C / V conversion circuit and the amplitude / frequency control module are connected in series, the input terminal of the C / V conversion circuit serves as the first input terminal of the resonant channel, the input terminal of the amplitude / frequency control module serves as the second input terminal of the resonant channel, the output terminal of the amplitude / frequency control module serves as the first output terminal of the resonant channel, and the output terminal of the C / V conversion circuit serves as the second output terminal of the resonant channel.

[0027] Here, the amplitude / frequency control module can be a self-excited oscillation module that includes automatic gain control, or a phase-locked loop control module that combines amplitude automatic gain control with frequency control. It acquires vibration information through a C / V conversion circuit and outputs a corresponding control voltage to keep the in-phase sensing unit 11 and the out-of-phase sensing unit 12 in a stable resonant state.

[0028] Please continue to refer to Figure 3 The frequency readout module includes: multiple frequency-to-digital converters; multiple frequency-to-digital converters connected in parallel, and one output terminal of the C / V conversion circuit in each resonant channel is connected to one input terminal of a frequency-to-digital converter, and one output terminal of a frequency-to-digital converter is connected to one input terminal of the differential frequency demodulation module.

[0029] Please continue to refer to Figure 3 The differential frequency demodulation module 4 includes: a differential frequency harmonic filtering module 41, a scaling factor stabilization module 42, a reference signal generation module 43, and a demodulation output module 44; wherein, the first, second, third, and fourth input terminals of the differential frequency harmonic filtering module 41 are respectively connected to the first, second, third, and fourth output terminals of the frequency readout module 3; the first and second output terminals of the differential frequency harmonic filtering module 41 are respectively connected to the first and second input terminals of the scaling factor stabilization module 42; the output terminal of the scaling factor stabilization module 42 is connected to the first input terminal of the demodulation output module 44; the first and second input terminals of the reference signal generation module 43 are respectively connected to the resonant frequency reading module 44. The ninth and tenth output terminals of the support module 2 are connected; the output terminal of the reference signal generation module 43 is connected to the second input terminal of the demodulation output module 44; the output terminal of the demodulation output module is used to output an interference-free angular rate signal; the difference frequency harmonic filtering module 41 is used to cancel the interference signals contained in the first and second signals to obtain the third and fourth signals; the scaling factor stabilization module 42 is used to sequentially add and filter the third and fourth signals to obtain the total frequency modulation signal; the reference signal generation module 43 is used to generate a reference signal synchronized with the total frequency modulation signal; the demodulation output module 44 is used to demodulate the total frequency modulation signal using the reference signal to obtain an interference-free angular rate signal.

[0030] Please continue to refer to Figure 3 The difference frequency harmonic filtering module 41 includes a first adder and a second adder; the scaling factor stabilization module 42 includes a third adder and a first low-pass filter; the demodulation output module 44 includes a first multiplier and a second low-pass filter; and the reference signal generation module 43 includes a second multiplier and a third low-pass filter; wherein, the first input terminal of the first adder is connected to the first output terminal of the frequency readout module 3, the second input terminal of the first adder is connected to the third output terminal of the frequency readout module 3, and the output terminal of the first adder is connected to the first input terminal of the third adder; the first input terminal of the second adder is connected to the second output terminal of the frequency readout module 3, and the second input terminal of the second adder is connected to the first input terminal of the frequency readout module 3. The fourth output terminal of the first multiplier is connected to the third multiplier; the output terminal of the second multiplier is connected to the second input terminal of the third multiplier; the output terminal of the third multiplier is connected to the input terminal of the first low-pass filter; the output terminal of the first low-pass filter is connected to the first input terminal of the first multiplier; the ninth output terminal of the resonance sustaining module 2 is connected to the first input terminal of the second multiplier; the tenth output terminal of the resonance sustaining module 2 is connected to the second input terminal of the second multiplier; the output terminal of the second multiplier is connected to the input terminal of the third low-pass filter; the output terminal of the third low-pass filter is connected to the second input terminal of the first multiplier; the output terminal of the first multiplier is connected to the input terminal of the second low-pass filter; the output terminal of the second low-pass filter is used to output an interference-free angular rate signal.

[0031] Now combined Figure 3 This describes the process of obtaining an interference-free angular rate signal from a mathematical perspective. It should be noted that, for the sake of brevity, the meanings of the same terms or symbols appearing repeatedly in the following text will not be explained again.

[0032] Here, the first signal is obtained by adding the resonant frequency signal and the angular rate signal corresponding to the in-phase sensing unit, and the second signal is obtained by subtracting the resonant frequency signal and the angular rate signal corresponding to the out-of-phase sensing unit.

[0033] Specifically, the in-phase sensing unit 11 and the out-of-phase sensing unit 12 in the gyroscope sensing unit 1 have the same X-mode intrinsic resonant frequency and Y-mode intrinsic resonant frequency, denoted as f, respectively. ox and f oy The splitting frequency of gyroscope sensing unit 1 is denoted as Δf = f ox -f oyUnder the control of the resonance maintenance module 2, the equivalent mass block motion trajectories of the in-phase sensing unit 11 and the out-of-phase sensing unit 12 are out of phase. According to the Coriolis effect, the resonant frequency and vibration amplitude of the in-phase sensing unit 11 and the out-of-phase sensing unit 12 are modulated in reverse by the external input angular rate (i.e., the external angular rate signal). Furthermore, because the resonance maintenance module 2 can track the resonant frequency change of the gyroscope sensing unit 1 in real time, it keeps the gyroscope sensing unit 1 in a resonant state and keeps the vibration out of phase and the vibration amplitude as stable as possible.

[0034] Therefore, the first signal (i.e., the vibration displacement of the in-phase sensing unit 11) can be expressed as:

[0035]

[0036]

[0037] Where x1 refers to the X-mode vibration displacement of the in-phase sensing unit 11, X refers to the X-mode vibration amplitude, and φ x1 (t) refers to the phase of the X-mode vibration displacement of the in-phase sensing unit 11, t refers to the acquisition time, y1 refers to the Y-mode vibration displacement of the in-phase sensing unit 11, Y refers to the Y-mode vibration amplitude, and φ y1 (t) refers to the phase of the Y-mode vibration displacement of the in-phase sensing unit 11. This refers to the frequency of the X-mode vibration displacement of the in-phase sensing unit 11. α0 refers to the frequency of the Y-mode vibration displacement of the in-phase sensing unit 11, α0 refers to the angular gain of the gyroscope sensing unit 1, and V x This refers to the X-mode vibration velocity, V y This refers to the Y-mode vibration velocity, Ω refers to the externally input angular rate signal, and A... A This refers to the magnitude of the external angular velocity, f. A It refers to the frequency of the external angular rate.

[0038] Furthermore, the second signal (i.e., the vibration displacement of the antiphase sensing unit 12) can be expressed as:

[0039]

[0040] Where x2 refers to the X-mode vibration displacement of the anti-phase sensing unit 12, y2 refers to the Y-mode vibration displacement of the anti-phase sensing unit 12, and φ x2 (t) refers to the phase of the X-mode vibration displacement of the anti-phase sensing unit 12, φ y2 (t) refers to the phase of the Y-mode vibration displacement of the anti-phase sensing unit 12. This refers to the frequency of the X-mode vibration displacement of the anti-phase sensing unit 12. It refers to the frequency of the Y-mode vibration displacement of the antiphase sensing unit 12.

[0041] When α0Ω << 2πΔf, we can solve for: As can be seen from the above equation, the vibrations of the in-phase sensing unit 11 and the out-of-phase sensing unit 12 are out of phase, and the vibration amplitude remains stable. When there is an external input angular velocity, the external input angular velocity is modulated out of phase onto the resonant frequency of the two sensing units. This phenomenon is also called chopper modulation of the frequency modulation signal.

[0042] Figure 4 This is a schematic diagram illustrating the working principle of each unit in the differential interface unit provided in this embodiment of the invention. For example... Figure 4 As shown, the first signal x1, y1 is first converted into a first voltage signal V through resonant channels X1 and Y1. FAX1 V FAY1 And through resonant channels X2 and Y2, the second signal x2,y2 is converted into the second voltage signal V. FAX2 V FAY2 The voltage signals are read by the frequency readout module 3 and the differential frequency demodulation module 4. Since the first voltage signal and the second voltage signal read by the frequency readout module 3 are out of phase, the difference frequency harmonics contained in the first voltage signal and the second voltage signal are also out of phase. Therefore, by subtracting the two adders in the difference frequency harmonic filtering module 41, the difference frequency harmonics contained in the first voltage signal and the second voltage signal can be canceled, and the image frequency components generated by non-uniform sampling can also be eliminated.

[0043] Please continue to refer to Figure 4 After being processed by the difference frequency harmonic filtering module 41, the third signal V is obtained. AX and the fourth signal V AY It can be represented as:

[0044]

[0045] Continue using the third adder in the scaling factor stabilization module 42 to process the third signal V. AX and the fourth signal V AY Perform addition to obtain the added signal V. AΩ Added signal V AΩ It can be represented as:

[0046]

[0047] Here, V AΩ It contains the sum of two terms that are reciprocals of each other, that is and Under ideal conditions, the vibration velocity in gyroscope sensing unit 1 remains stable, i.e., V x =V yHowever, under non-ideal conditions, when the vibration velocity in the screw sensor unit 1 fluctuates, and Adding them together can greatly reduce the impact of vibration velocity fluctuations on the stability of the scaling factor. Then, using the first low-pass filter on V... AΩ Perform time-delay synchronization to obtain the total frequency modulation signal V. A ' Ω Total frequency modulation signal V A ' Ω It can be represented as:

[0048]

[0049] Please continue to refer to Figure 4 The reference signal V generated by the reference signal generation module 43 ref It can be represented as:

[0050] V ref =A·sin(2πΔf·t+φ);

[0051] Where A refers to the amplitude of the reference signal, and φ refers to the phase delay of the third low-pass filter.

[0052] Please continue to refer to Figure 4 In the demodulation output module 44, V A ' Ω and V ref Multiplication enables synchronous demodulation and resists the generation of orthogonal errors. In traditional Lissajous frequency-modulated gyroscopes, because the total frequency modulation signal contains a DC intrinsic resonant frequency signal, the bandwidth of its low-pass filter must be lower than Δf to ensure the elimination of the DC intrinsic resonant frequency of the total frequency modulation signal. However, in this embodiment of the invention, the difference frequency harmonic filtering module 41 can eliminate the intrinsic resonant frequency signal. Therefore, in the demodulation output module 44, simply setting the bandwidth of the second low-pass filter at Δf is sufficient to eliminate the second harmonic component generated during multiplication, obtaining an interference-free angular rate signal Ω.

[0053] To address the problem that existing Lissajous frequency-modulated MEMS gyroscopes, due to their non-uniform self-sampling characteristics and intrinsic simultaneous amplitude and frequency modulation effects, inevitably introduce interference signals when reading external angular rate signals, degrading the system's usable bandwidth and spurious-free dynamic range, thus failing to acquire true external angular rate information, this invention proposes a fully differential Lissajous frequency-modulated MEMS gyroscope. First, the external angular rate signal is acquired through a gyroscope sensing unit, resulting in a first signal and a second signal. Then, a differential interface unit is used to perform difference frequency harmonic filtering on the first and second signals to eliminate the interference signals inevitably introduced during signal acquisition. Finally, the first and second signals after difference frequency harmonic filtering are synchronously demodulated to obtain the interference-free angular rate signal. Based on the gyroscope provided by this invention, the impact of interference signals on detection accuracy can be eliminated, the usable bandwidth and spurious-free dynamic range of the Lissajous frequency-modulated MEMS gyroscope can be widened, and the detection accuracy of the Lissajous frequency-modulated MEMS gyroscope can be greatly improved.

[0054] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A fully differential Lissajous frequency-modulated MEMS gyroscope, characterized in that, include: Gyroscope sensing unit, differential interface unit; The first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the gyroscope sensing unit are respectively connected to the first output terminal, the second output terminal, the third output terminal, and the fourth output terminal of the differential interface unit, and the first output terminal, the second output terminal, the third output terminal, and the fourth output terminal of the gyroscope sensing unit are respectively connected to the first input terminal, the second input terminal, the third input terminal, and the fourth input terminal of the differential interface unit. The gyroscope sensing unit is configured to generate a resonant state in response to a control signal, acquire an angular rate signal in the resonant state, perform differential processing on the angular rate signal to obtain a first signal and a second signal, and send the first signal and the second signal to the differential interface unit. The differential interface unit is used to provide the control signal to the gyroscope sensing unit, and to perform differential frequency harmonic filtering and synchronous demodulation processing on the received first signal and second signal to filter out interference signals present in the first signal and second signal and obtain interference-free angular rate signals.

2. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 1, characterized in that, The differential interface unit includes: a resonance sustaining module and a demodulation processing module; wherein... The first, second, third, and fourth input terminals of the resonance sustaining module are respectively connected to the first, second, third, and fourth output terminals of the gyroscope sensing unit; the resonance sustaining module is used to generate the control signal and send the control signal to the gyroscope sensing unit. The first, second, third, and fourth output terminals of the resonance sustaining module are connected to the first, second, third, and fourth input terminals of the gyroscope sensing unit, respectively. The fifth, sixth, seventh, eighth, ninth, and tenth output terminals of the resonance sustaining module are connected to the first, second, third, fourth, fifth, and sixth input terminals of the demodulation processing module, respectively. The demodulation processing module is used to receive and read the first signal and the second signal, perform difference frequency harmonic filtering and synchronous demodulation processing on the first signal and the second signal, filter out interference signals present in the first signal and the second signal, and obtain the interference-free angular rate signal.

3. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 2, characterized in that, The demodulation processing module includes: a frequency readout module and a differential frequency demodulation module; wherein... The first, second, third, and fourth input terminals of the frequency readout module are respectively connected to the fifth, sixth, seventh, and eighth output terminals of the resonance sustaining module; the first, second, third, and fourth output terminals of the frequency readout module are respectively connected to the first, second, third, and fourth input terminals of the differential frequency demodulation module; the frequency readout module is used to receive and read the first signal and the second signal; The fifth and sixth input terminals of the differential frequency demodulation module are connected to the ninth and tenth output terminals of the resonance maintenance module, respectively. The differential frequency demodulation module is used to perform differential frequency harmonic filtering and synchronous demodulation processing on the first signal and the second signal to filter out interference signals present in the first signal and the second signal and obtain the interference-free angular rate signal.

4. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 3, characterized in that, The differential frequency demodulation module includes: a differential frequency harmonic filtering module, a scaling factor stabilization module, a reference signal generation module, and a demodulation output module; wherein... The first, second, third, and fourth input terminals of the difference frequency harmonic filtering module are respectively connected to the first, second, third, and fourth output terminals of the frequency readout module, and the first and second output terminals of the difference frequency harmonic filtering module are respectively connected to the first and second input terminals of the scaling factor stabilization module. The output of the scaling factor stabilization module is connected to the first input of the demodulation output module. The first and second input terminals of the reference signal generation module are connected to the ninth and tenth output terminals of the resonance sustaining module, respectively; the output terminal of the reference signal generation module is connected to the second input terminal of the demodulation output module; the output terminal of the demodulation output module is used to output the interference-free angular rate signal. The difference frequency harmonic filtering module is used to cancel the interference signals contained in the first signal and the second signal to obtain the third signal and the fourth signal; The scaling factor stabilization module is used to sequentially add and filter the third signal and the fourth signal to obtain the total frequency modulation signal. The reference signal generation module is used to generate a reference signal that is synchronized with the total frequency modulation signal; The demodulation output module is used to demodulate the total frequency modulation signal using the reference signal to obtain the interference-free angular rate signal.

5. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 3, characterized in that, The gyroscope sensing unit includes: a in-phase sensing unit and an out-of-phase sensing unit; the resonance maintenance module includes: a resonant channel X1, a resonant channel X2, a resonant channel Y1, a resonant channel Y2, and an out-of-phase motion controller; wherein... The first input terminal of X1 is connected to the first output terminal of the in-phase sensing unit, the second input terminal is connected to the first output terminal of the in-phase motion controller, the first output terminal is connected to the first input terminal of the in-phase sensing unit, and the second output terminal is connected to the first input terminal of the frequency readout module and the fifth input terminal of the differential frequency demodulation module. The first input terminal of Y1 is connected to the second output terminal of the in-phase sensing unit, the second input terminal is connected to the second output terminal of the out-of-phase motion controller, the first output terminal is connected to the second input terminal of the in-phase sensing unit, and the second output terminal is connected to the second input terminal of the frequency readout module. The first input terminal of X2 is connected to the first output terminal of the inverting sensor unit, the second input terminal is connected to the third output terminal of the inverting motion controller, the first output terminal is connected to the first input terminal of the inverting sensor unit, and the second output terminal is connected to the third input terminal of the frequency readout module. The first input terminal of Y2 is connected to the second output terminal of the inverting sensor unit, the second input terminal is connected to the fourth output terminal of the inverting motion controller, the first output terminal is connected to the second input terminal of the inverting sensor unit, and the second output terminal is connected to the fourth input terminal of the frequency readout module and the sixth input terminal of the differential frequency demodulation module.

6. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 5, characterized in that, Each resonant channel includes: a C / V conversion circuit and an amplitude / frequency control module; wherein, the C / V conversion circuit and the amplitude / frequency control module are connected in series, the input terminal of the C / V conversion circuit serves as the first input terminal of the resonant channel, the input terminal of the amplitude / frequency control module serves as the second input terminal of the resonant channel, the output terminal of the amplitude / frequency control module serves as the first output terminal of the resonant channel, and the output terminal of the C / V conversion circuit serves as the second output terminal of the resonant channel.

7. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 6, characterized in that, The frequency readout module includes: multiple frequency-to-digital converters; the multiple frequency-to-digital converters are connected in parallel, and one output terminal of the C / V conversion circuit in each resonant channel is connected to one input terminal of one frequency-to-digital converter, and one output terminal of one frequency-to-digital converter is connected to one input terminal of the differential frequency demodulation module.

8. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 4, characterized in that, The difference frequency harmonic filtering module includes: a first adder and a second adder; the scaling factor stabilization module includes: a third adder and a first low-pass filter; the demodulation output module includes: a first multiplier and a second low-pass filter; and the reference signal generation module includes: a second multiplier and a third low-pass filter; wherein, The first input terminal of the first adder is connected to the first output terminal of the frequency readout module, the second input terminal of the first adder is connected to the third output terminal of the frequency readout module, and the output terminal of the first adder is connected to the first input terminal of the third adder. The first input terminal of the second adder is connected to the second output terminal of the frequency readout module, the second input terminal of the second adder is connected to the fourth output terminal of the frequency readout module, and the output terminal of the second adder is connected to the second input terminal of the third adder. The output of the third adder is connected to the input of the first low-pass filter, and the output of the first low-pass filter is connected to the first input of the first multiplier. The ninth output terminal of the resonance sustaining module is connected to the first input terminal of the second multiplier, and the tenth output terminal of the resonance sustaining module is connected to the second input terminal of the second multiplier; the output terminal of the second multiplier is connected to the input terminal of the third low-pass filter, and the output terminal of the third low-pass filter is connected to the second input terminal of the first multiplier. The output of the first multiplier is connected to the input of the second low-pass filter, and the output of the second low-pass filter is used to output the interference-free angular rate signal.

9. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 5, characterized in that, The first signal is obtained by adding the resonant frequency signal corresponding to the in-phase sensing unit and the angular rate signal, and the second signal is obtained by subtracting the resonant frequency signal corresponding to the out-of-phase sensing unit and the angular rate signal.

10. The fully differential Lissajous frequency-modulated MEMS gyroscope according to claim 1, characterized in that, The interference signal is a difference frequency harmonic signal.

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