A method and apparatus for multiplexing and controlling a three-axis micromechanical gyroscope

Abstract

The application discloses a multiplexing measurement and control method and device of a three-axis micromechanical gyroscope, which comprises the following steps: firstly, a global clock is generated; in the working clock of any gyroscope, an alternating current driving signal, a feedback force signal, a preset reference phase signal and a reference displacement signal are outputted to the gyroscope by a coordinate rotation digital computer, and the gyroscope reaches a force balance state through a driving modal control loop and a detection modal control loop, and the angular velocity of the gyroscope is obtained; the three gyroscopes multiplex the same coordinate rotation digital computer in the respective working clock. The application combines time division multiplexing with a coordinate rotation digital computer algorithm, and can accurately and synchronously detect and close-loop control the three-axis micromechanical gyroscope in real time in limited field programmable logic gate array resources. The method and device can be widely applied to concurrent processing requirements of multi-axis or multi-path high-speed, high-precision and high-integration measurement and control instruments.

Description

Technical Field

[0001] This invention relates to micromechanical gyroscopes, and more particularly to a multiplexing measurement and control method and apparatus for a three-axis micromechanical gyroscope. Background Technology

[0002] Micromechanical gyroscopes are angle or angular velocity sensors that use Coriolis force as the sensitive signal to measure the attitude of an object. They are characterized by small size, low power consumption, high integration, and mass production capability, and have broad application prospects in both the consumer market and industrial fields. In recent years, micromechanical gyroscopes have rapidly developed towards high performance and integration, such as commercial inertial navigation units, which not only possess navigation-grade performance but can also simultaneously measure three-axis angles in space with extremely small size and power consumption.

[0003] Traditional consumer-grade three-axis micromechanical gyroscopes integrate the sensing structure onto a single silicon chip, which greatly reduces system power consumption and size. However, due to the limitations of their spatial structure and control link, their performance is also greatly restricted. Industrial-grade and navigation-grade three-axis gyroscopes, on the other hand, require three single-axis gyroscopes and three matching digital signal processing chips due to the complexity of their measurement and control systems. They also require strict clock constraints to achieve independent and stable control, thus limiting their size, power consumption, cost, and debugging difficulty. Summary of the Invention

[0004] The purpose of this invention is to simplify the system complexity and significantly reduce the consumption of hardware resources while ensuring the system's measurement and control accuracy. It provides a multiplexing measurement and control method for a three-axis micromechanical gyroscope and designs and develops the circuit system for its application.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention discloses a multiplexed measurement and control method for a three-axis micromechanical gyroscope, comprising the following steps:

[0007] 1) The three-axis micromechanical gyroscope includes three gyroscopes. The field-programmable gate array (FPGA) sets a master clock that is three times the operating clock of the gyroscopes and uses the master clock as the global clock. The FPGA includes a coordinate rotation digital calculation module.

[0008] 2) Within the working clock of any gyroscope, the coordinate rotation digital calculation module outputs an AC drive signal, a feedback force signal, and a preset reference phase signal and reference displacement signal to the gyroscope, and through the drive mode control loop and the detection mode control loop, the gyroscope reaches a force balance state and the angular velocity of the gyroscope is obtained.

[0009] Each of the three gyroscopes reuses the same coordinate rotation digital calculation module within its own operating clock.

[0010] Secondly, the present invention discloses a three-axis micromechanical gyroscope multiplexing measurement and control device for implementing the measurement and control method, comprising a three-axis micromechanical gyroscope, a field-programmable gate array, three gyroscope signal conditioning circuits, three digital-to-analog converters and three digital-to-analog converters;

[0011] The field-programmable gate array is connected to three digital-to-analog converters and three digital-to-analog converters respectively. Each gyroscope has a gyroscope signal conditioning circuit, and each gyroscope signal conditioning circuit is connected to one digital-to-analog converter and one analog-to-digital converter respectively. The gyroscope signal conditioning circuit includes a driving mode control loop and a detection mode control loop.

[0012] The coordinate rotation digital calculation module in the field-programmable gate array is used to output AC drive signals, feedback force signals, and preset reference phase signals and reference displacement signals; the three-axis micromechanical gyroscope time-division multiplexed coordinate rotation digital calculation module, through the gyroscope signal conditioning circuit of each of the three gyroscopes, enables the three gyroscopes to reach a force balance state and obtains the angular velocity of the three gyroscopes.

[0013] The beneficial effects of this invention compared to the prior art are:

[0014] 1) The multiplexing measurement and control method of the present invention enables three high-performance micromechanical gyroscopes to perform driving and closed-loop force balance control simultaneously, which not only ensures the performance of the multi-axis gyroscope, but also reuses one controller resource compared with the existing three controllers for measurement and control, thus greatly reducing circuit complexity, power consumption and cost.

[0015] 2) Due to resource reuse, the measurement and control method of the present invention can use more resources of the field programmable gate array for a higher precision coordinate rotation digital calculation module, which can greatly reduce the noise of gyroscope signal detection.

[0016] 3) Compared with existing measurement and control circuits, the three-axis micromechanical gyroscope measurement and control device of the present invention has the characteristics of full digitalization, which can realize the programmable control of each control signal, reduce the complexity of analog circuits, and at the same time has flexibility, which can be used for concurrent fusion measurement and control of other types of high-speed and high-precision sensors. Attached Figure Description

[0017] Figure 1 This is a block diagram illustrating the principle of a multiplexed measurement and control method for a three-axis micromechanical gyroscope.

[0018] Figure 2 This is a block diagram of the single-channel gyroscope signal control in this invention.

[0019] Figure 3 This is a schematic diagram of the device module in this invention.

[0020] Figure 4 This is a schematic diagram of the clock planning for time-division multiplexing in this invention.

[0021] Figure 5 This is a simulation diagram of the multiplexed signal of this invention.

[0022] Figure 6 This is a frequency sweep experiment diagram of the three-axis micromechanical gyroscope of the present invention. Detailed Implementation

[0023] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0024] This invention is based on a three-axis micromechanical gyroscope and a field-programmable gate array chip. It utilizes time-division multiplexing technology and high-precision modulation and demodulation algorithms of digital rotating computers to achieve independent measurement and control of the three-axis gyroscope while ensuring gyroscope performance. At the same time, it greatly reduces the size, power consumption and cost of the system, which is the development direction of multi-channel high-speed and high-performance sensor measurement and control systems.

[0025] The triaxial micromechanical gyroscope of the present invention includes three gyroscopes, namely gyroscope x, gyroscope y and gyroscope z. The three gyroscopes measure the angular velocity in the x, y and z directions respectively, realizing the accurate measurement of angular velocity in three-dimensional space.

[0026] like Figure 1 As shown, the implementation steps of the multiplexing measurement and control method for a three-axis micromechanical gyroscope are as follows:

[0027] The multi-channel real-time measurement and control method adopted is a time-division multiplexing strategy, and the core signal processing method used for each channel is the coordinate rotation digital calculation method.

[0028] The main control chip sets a main operating clock frequency three times that of the single-channel gyroscope based on the operating clock of the gyroscope, and confirms the global clock; the global clock is located at [location missing]. Figure 1 The dashed box in the middle section will change the three working clocks into three states in sequence: time-sharing 1, time-sharing 2, and time-sharing 3.

[0029] First, at time division 1, gyroscope x enters the measurement and control operation. Figure 1 The driving mode control loop and the detection mode control loop within the dashed box operate in time-sharing mode 1. Then, the measurement and control of gyroscope y and gyroscope z are performed in the same way. Gyroscope x, gyroscope y, and gyroscope z share the driving mode control loop and the detection mode control loop in time-sharing mode 1, time-sharing mode 2, and time-sharing mode 3, respectively.

[0030] In this invention, the input and output interfaces of each measurement and control loop are named and categorized to ensure that the excitation, detection, and control loops correspond one-to-one during operation. Furthermore, the basic signal processing links, such as gyroscope displacement detection, carrier demodulation, drive signal demodulation, amplitude and phase calculation, and feedback force generation, are processed by calling the coordinate rotation digital calculation module. Figure 2 As shown. Pipeline design is employed to ensure signal synchronization, data synchronization, and clock synchronization, guaranteeing that no signal loss or inter-channel interference occurs during multiplexing.

[0031] This invention implements a coordinate rotation digital calculation module based on the principle of pseudo-rotation equations. It performs pipeline design of corresponding levels according to the controlled phase accuracy, and expands the phase to -180° to 180° through the entire coordinate rotation.

[0032] Finally, the three-way gyroscope measurement and control links are divided into global clocks. By switching states, the signals of each axis gyroscope can be multiplexed using the same AC drive signal acquisition link and output to their respective interface registers, thus achieving channel separation.

[0033] Figure 1 The specific algorithms for the driving modal control loop and the detection module control loop are as follows: Figure 2 As shown in the two dashed boxes at the top and bottom.

[0034] Figure 2 The dashed box at the top shows the flowchart of the coordinate rotation digital calculation module obtaining the AC drive signal, preset reference phase signal, and reference displacement signal. The coordinate rotation digital calculation module acquires the gyroscope displacement signal, which is then converted into a digital signal through analog-to-digital conversion of the drive mode sampling. After carrier demodulation and quadrature demodulation, and then low-pass filtering and digital-to-analog conversion, the AC drive signal with changed amplitude and frequency is obtained. The coordinate rotation digital calculation module inputs the AC drive signal with changed amplitude and frequency to the gyroscope. The coordinate rotation digital calculation module outputs the preset reference phase signal and reference displacement signal to the gyroscope. Then, through a phase-locked loop and automatic gain control dual loop, closed-loop control of constant frequency and constant amplitude of the drive mode is realized.

[0035] In this invention, at the initial moment, the coordinate rotation digital calculation module outputs a preset AC drive signal, a reference phase signal, and a reference displacement signal to the gyroscope; at other moments, the coordinate rotation digital calculation module acquires the displacement signal of the gyroscope and converts it into a digital signal. The digital signal is then subjected to carrier demodulation, quadrature demodulation, low-pass filtering, and digital-to-analog conversion in sequence to obtain an AC drive signal with altered amplitude and frequency.

[0036] In a specific embodiment of the present invention, the gyroscope receives the AC drive signal and vibrates to generate a vibration signal. The gyroscope picks up the vibration signal as a pickup signal and performs closed-loop control on the pickup signal according to the received preset reference phase signal and reference displacement signal. Through phase-locked loop and automatic gain control, the gyroscope is made to vibrate with a constant amplitude and frequency.

[0037] Specifically, the gyroscope demodulates the picked-up signal to obtain the gyroscope's displacement signal and displacement phase signal; it performs closed-loop control on the gyroscope's displacement phase signal based on a received preset reference phase signal, fixing the gyroscope in a resonant state through a phase-locked loop; and it performs closed-loop control on the gyroscope's displacement signal based on a received preset reference displacement signal, maintaining a constant amplitude of the gyroscope through automatic gain control.

[0038] Figure 2 The dashed box below illustrates the flowchart of the coordinate rotation digital calculation module obtaining the feedback force signal. This module acquires the displacement signal of the gyroscope when it vibrates at a constant amplitude and frequency and converts it into a digital signal. This digital signal undergoes carrier demodulation, angular velocity demodulation, low-pass filtering, and digital-to-analog conversion sequentially to obtain the feedback force signal. The coordinate rotation digital calculation module then inputs this feedback force signal to the gyroscope, which obtains its angular velocity through a detection mode control loop. Specifically, the gyroscope's angular velocity is obtained by using a signal of the same frequency as the drive unit to perform force balance control, keeping the displacement of the detection mode zero. The magnitude of the applied force from the in-phase signal characterizes the gyroscope's angular velocity.

[0039] When the gyroscope reaches a force balance state, the detection mode of the gyroscope is in a zero displacement state.

[0040] The aforementioned coordinate rotation digital calculation modules all employ a pipelined structure to ensure signal real-time performance. To prevent interference with the three gyroscope signals during modulation and demodulation, this invention imposes strict clock constraints on the number of stages in the pipeline, see [link to relevant documentation]. Figure 4 To ensure the output order of the three gyroscope signals from the pipeline is x, y, z, the pipeline stage number needs to be a multiple of 3. The subsequent demodulation process for the three states also follows a pipelined structure. To ensure synchronization of each demodulated signal and prevent crosstalk between channels, 3*3N is the primary condition for the pipeline stage number of the coordinate rotation digital calculation module in this system, where N is a positive integer. The simulation results for the field-programmable gate array are shown below. Figure 5 The simulation diagram of the multiplexed signal shows that the driving force and demodulated amplitude of the x, y, and z axes are input and output sequentially, realizing the reliability and accuracy of time-division multiplexing.

[0041] Figure 3The circuit structure of the invention is illustrated in the figure. The three parts within the dashed box—the digital-to-analog converter, the analog-to-digital converter, and the field-programmable gate array (FPGA) chip—are assembled on a digital circuit board, serving as the algorithm and signal processing device for multi-channel measurement and control. The gyroscope signal conditioning circuit is located in the analog circuit section, serving as the electrical interface device for the micro-mechanical gyroscope. Each axis of the micro-mechanical gyroscope uses the circuit device within the dashed box as its measurement and control unit, sharing a common FPGA.

[0042] The measurement and control device of this invention includes a three-axis micromechanical gyroscope, gyroscope signal conditioning circuits for each gyroscope, and a digital measurement and control circuit based on a field-programmable gate array (FPGA) (e.g., Figure 3 (as shown in the dashed box).

[0043] The gyroscope signal processing circuit is responsible for processing the drive signals, detecting the capacitance signals, and conditioning the signals of the three gyroscopes. A digital measurement and control circuit based on a field-programmable gate array (FPGA) is connected to the three gyroscope signal processing circuits. It uses an analog-to-digital converter (ADC) to detect the displacement signals of the three gyroscopes (six modes in total) and generates carrier signals, drive force signals, and detection force balance control signals through multiple high-speed digital-to-analog converters, achieving fully digital measurement and control.

[0044] Figure 6 The results are experimental findings of the multiplexing measurement and control method and device for the three-axis micromechanical gyroscope in this invention. The three-axis micromechanical gyroscope simultaneously performs frequency sweeping within its respective frequency range, proving the accuracy of the measurement and control method and device.

[0045] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. Those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A multiplexing method for measuring and controlling a three-axis micromechanical gyroscope, characterized in that, Comprising the following steps: 1) The tri-axis micromechanical gyroscope comprises three gyroscopes, and the field programmable gate array sets a main working clock which is 3 times of the working clock of the gyroscopes according to the working clock of the gyroscopes, and takes the main working clock as a global clock; the field programmable gate array comprises a coordinate rotation digital computer module; 2) In the working clock of any gyroscope, the coordinate rotation digital computer module outputs an alternating current driving signal, a feedback force signal, and a preset reference phase signal and a reference displacement signal to the gyroscope, and makes the gyroscope reach a force balance state through a driving modal control loop and a detection modal control loop, and obtains an angular velocity of the gyroscope; wherein the three gyroscopes multiplex the same coordinate rotation digital computer module in the working clock of each gyroscope; At an initial moment, the coordinate rotation digital computer module outputs a preset alternating current driving signal, a reference phase signal and a reference displacement signal to the gyroscope; at other moments, the coordinate rotation digital computer module obtains a displacement signal of the gyroscope and converts it into a digital signal, the digital signal is sequentially subjected to carrier demodulation, quadrature demodulation, low-pass filtering and digital-to-analog conversion to obtain an alternating current driving signal with changed amplitude and frequency, and the coordinate rotation digital computer module inputs the alternating current driving signal with changed amplitude and frequency to the gyroscope, at the same time, the coordinate rotation digital computer module outputs a preset reference phase signal and a reference displacement signal to the gyroscope; the gyroscope is vibrated at a constant amplitude and frequency through a phase-locked loop and an automatic gain control; the coordinate rotation digital computer module obtains a displacement signal of the gyroscope when the gyroscope is vibrated at a constant amplitude and frequency and converts it into a digital signal, the digital signal is sequentially subjected to carrier demodulation, angular velocity demodulation, low-pass filtering and digital-to-analog conversion to obtain a feedback force signal, and the coordinate rotation digital computer module inputs the feedback force signal to the gyroscope, and the gyroscope obtains an angular velocity of the gyroscope through a detection modal control loop.

2. The multiplexing method of a tri-axis micromachined gyroscope according to claim 1, wherein, The gyroscope receives the alternating current driving signal and vibrates to generate a vibration signal, picks up the vibration signal as a pickup signal, and performs closed-loop control on the pickup signal according to the received preset reference phase signal and reference displacement signal, so that the gyroscope is vibrated at a constant amplitude and frequency through a phase-locked loop and an automatic gain control.

3. The multiplexing method of claim 2, wherein, The gyroscope demodulates the pickup signal to obtain a displacement signal and a phase signal of the gyroscope; the phase signal of the gyroscope is controlled in a closed loop according to the received preset reference phase signal, so that the gyroscope is fixed in a resonant state through a phase-locked loop; the displacement signal of the gyroscope is controlled in a closed loop according to the received preset reference displacement signal, so that the gyroscope maintains a constant amplitude through an automatic gain control.

4. The multiplexing method of claim 1, wherein, When the gyroscope reaches a force balance state, the detection modal of the gyroscope is in a 0 displacement state.

5. A multiplexed measurement and control device for a three-axis micromechanical gyroscope implementing the method of claim 1, characterized in that it comprises: Comprise a tri-axis micromechanical gyroscope, a field programmable gate array, three gyroscope signal conditioning circuits, three digital-to-analog converters and three digital-to-analog converters; The field programmable gate array is connected with three digital-to-analog converters and three analog-to-digital converters respectively, one gyroscope has a gyro signal conditioning circuit, and each gyro signal conditioning circuit is connected with one digital-to-analog converter and one analog-to-digital converter respectively; the gyro signal conditioning circuit comprises a driving modal control loop and a detection modal control loop. The coordinate rotation digital computer module in the field programmable gate array is used to output an alternating current driving signal, a feedback force signal, and a preset reference phase signal and a reference displacement signal; the three-axis micro-mechanical gyroscope time-division multiplexes the coordinate rotation digital computer module and makes the three gyroscopes reach a force balance state through the gyro signal conditioning circuits of the three gyroscopes, and the angular velocities of the three gyroscopes are obtained.

6. The tri-axial micromechanical gyroscope multiplexed measurement and control device according to claim 5, characterized in that, The number of pipeline stages of the coordinate rotation digital computer module is 3×3N; wherein N is a positive integer.

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