Dynamic signal acquisition system and method

Abstract

The invention belongs to the technical field of high-precision acceleration measurement, and particularly relates to a dynamic signal acquisition system and method, and the system comprises a constant current source which is connected with an external ICP acceleration sensor in series, and is used for supplying power to the ICP acceleration sensor; the signal conditioning module comprises a biasing circuit and a fourth-order Butterworth filter, the biasing circuit is connected with the ICP acceleration sensor and used for conducting alternating current coupling on signals, and the fourth-order Butterworth filter is connected with the biasing circuit and used for filtering the signals; the A / D conversion module is used for converting an analog signal into a digital signal; and the data acquisition module is used for acquiring digital signals and storing data. A signal is biased to a preset voltage value through a biasing circuit in the signal conditioning module, so that a fourth-order Butterworth filter can be adopted to perform fourth-order Butterworth filtering, the signal acquisition precision is improved, a single power supply can be used for power supply instead of positive and negative power supply commonly used in the prior art, and the power supply requirement of the system is simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of high-precision acceleration measurement, and in particular relates to a dynamics signal acquisition system and method. Background Art

[0002] ICP (integrated circuits piezoelectric) accelerometer is a dynamic sensor based on piezoelectric effect. It can measure the acceleration of an object in three different directions. It works by converting mechanical motion into electrical signals. It has the characteristics of high sensitivity, wide-band response, low noise, built-in charge amplifier, strong durability, etc. Therefore, it can be widely used in vibration testing, structural analysis and mechanical fault diagnosis. In the dynamic signal acquisition system, the ICP accelerometer needs to be configured with a constant current source when working. Its output signal is a voltage signal with DC bias. The output signal is conditioned by amplification and filtering through the signal conditioning module, and then the analog quantity is converted into digital quantity through the A / D conversion module, and then the digital quantity output by the A / D is received and processed by the data acquisition module.

[0003] At present, sensors used for acceleration measurement are divided into charge type and voltage type. In the dynamic signal acquisition system, there are different signal conditioning module design methods for different types of sensors. Usually, the output of the acceleration sensor is relatively small, which is easily distorted by interference from external signals, and is not easy to be accurately measured by some low-resolution measuring instruments. Therefore, in the dynamic signal acquisition system, it is necessary to condition the signal through filtering, amplification and other measures. Amplifiers are usually used for signal conditioning, and amplifiers usually use positive and negative power supplies, which have high requirements for system power supply. Summary of the invention

[0004] The purpose of the present invention is to provide a dynamic signal acquisition system and method to solve the technical problem that in the prior art, signal conditioning is usually implemented using an amplifier, and the amplifier usually uses positive and negative power supplies, which has high requirements on the system power supply.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present application discloses a kinetic signal acquisition system, comprising: A constant current source is connected in series with an external ICP acceleration sensor to supply power to the ICP acceleration sensor; The signal conditioning module includes a bias circuit and a fourth-order Butterworth filter, wherein the bias circuit is connected to the ICP acceleration sensor and is used for performing AC coupling on the signal transmitted by the ICP acceleration sensor, and the bias circuit is connected to the fourth-order Butterworth filter and is used for filtering the signal after AC coupling; A / D conversion module, receiving the filtered signal and converting the analog signal into a digital signal; The data acquisition module is connected to the A / D conversion module and is used to collect digital signals.

[0006] Preferably, in the signal conditioning module, the bias circuit performs AC coupling on the signal, isolates the DC bias voltage of the ICP acceleration sensor itself, and pulls up to a preset voltage value through a resistor after AC coupling. The voltage reference source adjusts the DC bias of the signal to a preset voltage value, and the preset voltage value matches the input of the fourth-order Butterworth filter.

[0007] Preferably, in the signal conditioning module, the fourth-order Butterworth filter circuit is composed of a two-stage amplifier and a peripheral resistor-capacitor matching network, and the amplifier is powered by a single 5V.

[0008] Preferably, the data acquisition module collects 12 channels of kinetic signals simultaneously, and when storing the collected waveforms in NORFlash, the storage capacity of each channel of kinetic signals is allocated: the first 3 channels each use 256MB of storage capacity, and the last 9 channels each use 25M of storage capacity.

[0009] Preferably, the constant current source and the ICP acceleration sensor are connected in series in a 31V power supply, the constant current source provides power to the ICP acceleration sensor, and the power supply cable also serves as a signal output line to output a low impedance signal that is positively correlated with acceleration.

[0010] Preferably, the signal conditioning module, A / D conversion module and data acquisition module are all powered by a single 5V.

[0011] In a second aspect, the present application discloses a kinetic signal acquisition method, which is implemented using any of the kinetic signal acquisition systems described above, and the method comprises: The dynamic signal is obtained through the ICP acceleration sensor, and the signal conditioning module filters the dynamic signal; The A / D conversion module converts the filtered kinetic signal into a digital signal; The data acquisition module collects the converted digital signals.

[0012] Preferably, the signal conditioning module filters the kinetic signal specifically as follows: The bias circuit performs AC coupling on the signal, isolates the DC bias voltage of the ICP acceleration sensor itself, and pulls it up to a preset voltage value through a resistor after AC coupling. The voltage reference source adjusts the DC bias of the signal to a preset voltage value, and the preset voltage value matches the input of the fourth-order Butterworth filter. The fourth-order Butterworth filter filters the signal and outputs it.

[0013] Preferably, after the data acquisition module acquires the converted digital signal, the acquired waveform is stored in NOR Flash, and the data acquisition module simultaneously acquires 12 kinetic signals. When the acquired waveform is stored in NOR Flash, the storage capacity of each kinetic signal is allocated: the first 3 channels each use 256MB of storage capacity, and the last 9 channels each use 25M of storage capacity.

[0014] Compared with the prior art, the present invention has the following beneficial effects: A dynamic signal acquisition system disclosed in the present invention is suitable for voltage-type acceleration sensors. The bias circuit in the signal conditioning module biases the signal to a preset voltage value, so that a fourth-order Butterworth filter can be used for fourth-order Butterworth filtering, thereby improving the signal acquisition accuracy. In addition, a single power supply can be used instead of the positive and negative power supplies commonly used in the prior art, thereby simplifying the power supply requirements of the system. A 16-bit high-precision A / D conversion module is used to achieve high-precision acquisition of acceleration signals. For an acceleration sensor with a sensitivity of 100mV / g, the acceleration measurement accuracy can be as accurate as 0.01g. By improving the signal conditioning module, the present application can perform excellent signal conditioning under a single-power supply state, thereby improving the measurement accuracy and simplifying the power supply requirements of the system, thereby being able to measure acceleration more accurately and conveniently. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 is a system block diagram of the present invention; Figure 2 The principle block diagram of the kinetic signal acquisition system of the present invention is designed; Figure 3 It is a fourth-order filter network principle diagram of the fourth-order Butterworth filter of the present invention; Figure 4 A fourth-order filter network filtering simulation result diagram of the fourth-order Butterworth filter of the present invention; Figure 5 It is a schematic diagram of the shape storage address allocation of the present invention. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0020] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0021] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0022] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1, the present application discloses a kinetic signal acquisition system, comprising: A constant current source is connected in series with an external ICP acceleration sensor to supply power to the ICP acceleration sensor; The signal conditioning module includes a bias circuit and a fourth-order Butterworth filter, wherein the bias circuit is connected to the ICP acceleration sensor and is used for performing AC coupling on the signal transmitted by the ICP acceleration sensor, and the bias circuit is connected to the fourth-order Butterworth filter and is used for filtering the signal after AC coupling; A / D conversion module, receiving the filtered signal and converting the analog signal into a digital signal; The data acquisition module is connected to the A / D conversion module and is used to collect digital signals.

[0024] The present invention is applicable to the field of high-precision acceleration measurement systems. Based on the commonly used sensor signal acquisition method, the present invention improves the signal conditioning module, can perform excellent signal conditioning under a single power supply state, improves the measurement accuracy, simplifies the power supply requirements of the system, and can measure acceleration more accurately and conveniently. The present application is applicable to voltage-type acceleration sensors. The signal is biased to 2.5V by the bias circuit in the signal conditioning module and a fourth-order Butterworth filter is performed, which improves the signal acquisition accuracy, and can use a single power supply, simplifying the power supply requirements of the system. A 16-bit high-precision A / D conversion module is used to achieve high-precision acquisition of acceleration signals. For an acceleration sensor with a sensitivity of 100mV / g, the acceleration measurement accuracy can be as accurate as 0.01g.

[0025] In some embodiments, in the signal conditioning module, the bias circuit performs AC coupling on the signal, isolates the DC bias voltage of the ICP acceleration sensor itself, and pulls up to a preset voltage value through a resistor after AC coupling, and the voltage reference source adjusts the DC bias of the signal to a preset voltage value, and the preset voltage value matches the input of the fourth-order Butterworth filter. The bias circuit in the signal conditioning module biases the signal to a preset voltage value and performs a fourth-order Butterworth filter, thereby improving the signal acquisition accuracy, and can use a single power supply instead of the commonly used positive and negative power supplies, simplifying the power supply requirements of the system.

[0026] Further preferably, the preset voltage value is 2.5 V. The bias circuit in the signal conditioning module biases the signal to 2.5 V and performs a fourth-order Butterworth filter, thereby improving the signal acquisition accuracy and being able to use a single power supply, thus simplifying the power supply requirements of the system.

[0027] In some embodiments, in the signal conditioning module, the fourth-order Butterworth filter circuit is composed of a two-stage amplifier and a peripheral resistor-capacitor matching network, and the amplifier is powered by a single 5V.

[0028] Based on the commonly used sensor signal acquisition method, the present invention improves the signal conditioning module, can perform excellent signal conditioning under a single power supply state, improves the measurement accuracy, simplifies the power supply requirements of the system, and can measure acceleration more accurately and conveniently. By optimizing the signal conditioning module in the dynamic signal acquisition system, a 12-channel high-precision dynamic signal acquisition system is realized, which can be applied to a variety of acceleration measurement scenarios.

[0029] In some embodiments, the input signal of the present application has a total of 12 channels of dynamic signal acquisition, the frequency of the 1st to 3rd signal channels is DC-2kHz, the designed -3dB filter frequency is 12.5kHz, and the designed sampling frequency is 50kHz; the frequency of the 4th to 12th signal channels is DC-200Hz, the designed -3dB filter frequency is 1.25kHz, and the designed sampling frequency is 5kHz.

[0030] In some embodiments, the data acquisition module collects the conditioned signal and stores the collected waveform in NOR Flash, and allocates the storage capacity of each of the 12 kinetic signals collected, as follows: the first 3 channels each use 256MB of storage capacity, and the last 9 channels each use 25M of storage capacity.

[0031] In some embodiments, the constant current source is connected in series with the ICP acceleration sensor in a 31V power supply, and the constant current source provides power to the ICP acceleration sensor. The power supply cable also serves as a signal output line to output a low impedance signal that is positively correlated with acceleration.

[0032] In some embodiments, the application circuit schematic diagram of the present application is as follows: Figure 2 The main components involved are shown in Table 1.

[0033] Table 1 Application circuit pin component list

[0034] From the principle block diagram of the application circuit, we can see that the external ICP acceleration sensor and the constant current source in the system are connected in series in the 31V power supply. The constant current source provides power to the ICP acceleration sensor. The power supply cable also serves as a signal output line, outputting a low-impedance signal that is positively correlated with acceleration.

[0035] The signal conditioning module is implemented using the architecture of a bias circuit plus a fourth-order Butterworth filter. The bias circuit performs AC coupling on the signal, isolates the DC bias voltage of about 10V of the ICP accelerometer itself, and pulls it up to 2.5V through a resistor after AC coupling. The voltage reference source adjusts the DC bias of the signal to 2.5V to match the input of the fourth-order Butterworth filter.

[0036] The amplifier in the fourth-order Butterworth filter circuit uses a single 5V power supply, and is composed of a two-stage amplifier ADA4077-2-EP (bandwidth 3.9MHz, meeting application requirements) and its peripheral resistor-capacitor matching network. The high-frequency interference in the circuit is filtered out by filtering, which improves the signal quality and thus improves the acquisition accuracy. For application scenarios with a maximum vibration frequency of 2kHz, the fourth-order filter network used is as follows Figure 3 The simulation results are shown in Figure 4 For application scenarios where the vibration frequency is up to 200Hz, the filtering effect can be adjusted by adjusting different resistor and capacitor configurations to adapt to the collection of vibration signals of different frequencies.

[0037] The A / D conversion module is an A / D converter, and the model of the A / D converter is AD7606BSTZ. After signal filtering, under the control of FPGA (Field-Programmable Gate Array), an A / D converter of the AD7606BSTZ model is used to convert the conditioned signal and collect it. The AD7606BSTZ is powered by a single 5V, has a resolution of 16 bits, a maximum sampling rate of 200kHz, and a signal-to-noise ratio of 95.5dB. The collected waveform is stored in NOR Flash. In order to increase the total sampling time as much as possible, the storage capacity of each channel is allocated: the first 3 channels each use 256MB of storage capacity, and the last 9 channels each use 25M of storage capacity. The first two of the four 8-bit Flash chips are used in parallel, and the last two chips are used in parallel. The storage address allocation is as follows: Figure 5 shown.

[0038] In some embodiments, the signal conditioning module, A / D conversion module, and data acquisition module in the kinetic signal acquisition system all use a single 5V power supply instead of the commonly used positive and negative power supplies, thereby simplifying the power supply requirements of the system.

[0039] The present application also discloses a kinetic signal acquisition method, which is implemented by using any one of the kinetic signal acquisition systems described above, and the method comprises: The dynamic signal is obtained through the ICP acceleration sensor, and the signal conditioning module filters the dynamic signal; The A / D conversion module converts the filtered kinetic signal into a digital signal; The data acquisition module collects digital signals and stores them.

[0040] In some embodiments, the signal conditioning module filters the kinetic signal specifically as follows: The bias circuit performs AC coupling on the signal, isolates the DC bias voltage of the ICP acceleration sensor itself, and pulls it up to a preset voltage value through a resistor after AC coupling. The voltage reference source adjusts the DC bias of the signal to a preset voltage value, and the preset voltage value matches the input of the fourth-order Butterworth filter. The fourth-order Butterworth filter filters the signal and outputs it.

[0041] The dynamic signal acquisition system disclosed in this application has been applied to a satellite that is about to be launched and operated in my country, and has successfully achieved high-precision sampling of acceleration values ​​at 12 parts of the satellite.

[0042] After a large number of tests and verifications, the dynamic signal acquisition system is stable, reliable and safe, and has the value of promotion and application.

[0043] In summary, the present invention discloses a dynamic signal acquisition system and method, which is suitable for voltage-type acceleration sensors. The system incorporates innovative bias circuit technology in the signal conditioning module, which achieves accurate biasing of the original signal output by the sensor to 2.5V, and adopts a fourth-order Butterworth filter on this basis. This improvement not only significantly improves the signal acquisition accuracy, but also effectively filters out high-frequency noise and interference, ensuring the purity and stability of the signal. More importantly, the system cleverly adopts a single-power supply solution, subverting the complexity of traditional multi-power supply, greatly simplifying the power supply requirements of the system, reducing energy consumption and costs, and making the entire system more concise and efficient.

[0044] Furthermore, the present invention adopts a 16-bit high-precision A / D conversion module. This high-precision data acquisition technology enables the system to accurately capture subtle changes in acceleration signals for acceleration sensors with a sensitivity of up to 100mV / g, and the measurement accuracy of acceleration has reached an unprecedented level of 0.01g, which is undoubtedly of great significance in many high-precision measurement occasions. Through this series of careful design and optimization, the signal conditioning module proposed in this application can not only excellently complete the signal conditioning task under the condition of single power supply, but also substantially improve the accuracy of acceleration measurement, providing scientific researchers and technicians with a more accurate, convenient and efficient acceleration measurement method. This innovation not only broadens the application scope of acceleration sensors in the field of precision measurement, but also provides strong support for scientific research and technological progress in related fields.

[0045] It should be understood by those skilled in the art that the embodiments of the present invention may be provided as methods or systems, and therefore, the present invention may be in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention is described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific implementation of the present invention may still be modified or replaced by equivalents, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention shall be covered within the scope of protection of the claims of the present invention.

Claims

1. A kinetic signal acquisition system, characterized in that: include: A constant current source is connected in series with an external ICP acceleration sensor to supply power to the ICP acceleration sensor; The signal conditioning module includes a bias circuit and a fourth-order Butterworth filter, wherein the bias circuit is connected to the ICP acceleration sensor and is used for performing AC coupling on the signal transmitted by the ICP acceleration sensor, and the bias circuit is connected to the fourth-order Butterworth filter and is used for filtering the signal after AC coupling; A / D conversion module, receiving the filtered signal and converting the analog signal into a digital signal; The data acquisition module is connected to the A / D conversion module and is used to collect digital signals.

2. A kinetic signal acquisition system according to claim 1, characterized in that: In the signal conditioning module, the bias circuit performs AC coupling on the signal, isolates the DC bias voltage of the ICP acceleration sensor itself, and pulls up to a preset voltage value through a resistor after AC coupling. The voltage reference source adjusts the DC bias of the signal to a preset voltage value, and the preset voltage value matches the input of the fourth-order Butterworth filter.

3. A kinetic signal acquisition system according to claim 1, characterized in that: In the signal conditioning module, the fourth-order Butterworth filter circuit is composed of a two-stage amplifier and a peripheral resistor-capacitor matching network, and the amplifier is powered by a single 5V.

4. A kinetic signal acquisition system according to claim 1, characterized in that: The data acquisition module acquires the conditioned signal and stores the acquired waveform in the NOR Flash.

5. A kinetic signal acquisition system according to claim 4, characterized in that: The data acquisition module simultaneously acquires 12 channels of kinetic signals, and when storing the acquired waveforms in NOR Flash, the storage capacity of each channel of kinetic signals is allocated: the first 3 channels each use 256MB of storage capacity, and the last 9 channels each use 25M of storage capacity.

6. A kinetic signal acquisition system according to claim 1, characterized in that: The constant current source and the ICP acceleration sensor are connected in series in a 31V power supply through a power supply cable. The constant current source provides power to the ICP acceleration sensor. The power supply cable also serves as a signal output line to output a low-impedance signal that is positively correlated with acceleration.

7. A kinetic signal acquisition system according to claim 1, characterized in that: The signal conditioning module, A / D conversion module and data acquisition module are all powered by a single 5V.

8. A method for collecting dynamic signals, characterized in that: The method is implemented by using the kinetic signal acquisition system according to any one of claims 1 to 7, and comprises: The dynamic signal is obtained through the ICP acceleration sensor, and the signal conditioning module filters the dynamic signal; The A / D conversion module converts the filtered kinetic signal into a digital signal; The data acquisition module collects the converted digital signals.

9. A method for collecting dynamic signals according to claim 8, characterized in that: The signal conditioning module filters the kinetic signal, specifically: The bias circuit performs AC coupling on the signal, isolates the DC bias voltage of the ICP acceleration sensor itself, and pulls it up to a preset voltage value through a resistor after AC coupling. The voltage reference source adjusts the DC bias of the signal to a preset voltage value, and the preset voltage value matches the input of the fourth-order Butterworth filter. The fourth-order Butterworth filter filters the signal and outputs it.

10. A method for collecting kinetic signals according to claim 8, characterized in that: After the data acquisition module acquires the converted digital signal, the acquired waveform is stored in the NOR Flash. The data acquisition module simultaneously acquires 12 channels of kinetic signals. When the acquired waveform is stored in the NOR Flash, the storage capacity of each channel of kinetic signals is allocated: the first 3 channels each use 256MB of storage capacity, and the last 9 channels each use 25M of storage capacity.

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