Push-twist integrated sensor signal acquisition system

Abstract

An embodiment of the present invention discloses a push-torque integrated sensor signal acquisition system, comprising: a bridge voltage excitation circuit, a filter circuit, a reference voltage circuit, an A / D conversion circuit, and a microprocessor. The reference voltage circuit system provides a reference voltage; the push-torque integrated sensor output signal is sequentially transmitted to the microprocessor after passing through the filter circuit and the A / D conversion circuit; the push-torque integrated sensor output signal is obtained by converting the thrust and torque signals by a Wheatstone bridge circuit; the filter circuit is used to filter out common-mode interference and differential-mode interference in the output signal; the A / D conversion circuit is used to convert the analog signal into a digital signal; and the microprocessor is used to decouple, filter, and compensate the two collected digital signals, thereby achieving the purpose of signal filtering and decoupling.

Description

Technical Field

[0001] The present invention belongs to the technical field of weak signal detection, and more specifically, relates to a push-twist integrated sensor signal acquisition system. Background Art

[0002] In UAV engine testing, the thrust-torque integrated sensor can simultaneously test both thrust and torque to assess engine performance. During measurement, the basic idea is to convert the thrust and torque information output by the sensor into analog electrical signals for measurement.

[0003] Traditional torque sensor signal acquisition systems generally use a linear regulated power supply (LDO) to generate bridge voltage excitation, and an instrument amplifier to amplify the weak signal generated by the Wheatstone bridge. The amplified signal is converted into a square wave signal through voltage-frequency conversion and then output through coil coupling.

[0004] In the process of implementing the present invention, the inventors discovered that the prior art has at least the following problems:

[0005] The sensor output signal is weak and easily drowned out by noise. Instrumentation amplifiers also amplify the noise when amplifying the signal, leading to inaccurate test results. Both LDOs and instrumentation amplifiers are subject to temperature drift and Gaussian noise. The square wave signal output by the voltage-to-frequency conversion circuit is distorted after passing through the coil output, making it difficult to collect and impossible to perform software filtering and decoupling. Summary of the Invention

[0006] In view of this, an embodiment of the present invention provides a push-twist integrated sensor signal acquisition system, which at least solves the problem that filtering and decoupling cannot be performed in the prior art.

[0007] The embodiment of the present invention provides a push-twist integrated sensor signal acquisition system, comprising: a bridge voltage excitation circuit, a filter circuit, a reference voltage circuit, an A / D conversion circuit and a microprocessor;

[0008] The reference voltage circuit system provides a reference voltage;

[0009] The output signal of the push-twist integrated sensor is transmitted to the microprocessor after passing through the filter circuit and A / D conversion circuit in sequence;

[0010] The output signal of the push-torque integrated sensor is obtained by converting the thrust and torque signals by a Wheatstone bridge.

[0011] The filtering circuit is used to filter out common-mode interference and differential-mode interference of the output signal;

[0012] The A / D conversion circuit is used to convert the analog signal into a digital signal;

[0013] The microprocessor is used to decouple, filter and compensate the two channels of collected digital signals.

[0014] Optionally, it further includes a transceiver unit for transmitting the output data obtained after processing by the microprocessor to a host computer, and the transceiver unit is a wireless transceiver unit.

[0015] Optionally, the bridge voltage excitation circuit includes a reference voltage chip, a current limiting resistor R1, a resistor R2, an operational amplifier, a transistor Q1, an adjustment resistor Rs and a feedback resistor Rf;

[0016] The reference voltage chip is connected to the system power supply through the current limiting resistor R1. The current output by the reference voltage chip is transmitted to the non-inverting input terminal of the op amp through the resistor R2. The output terminal of the op amp is connected to the base of the transistor Q1. The feedback resistor Rf is connected in series between the emitter of the transistor Q1 and the inverting input terminal of the op amp. The adjustment resistor Rs is connected in series between the inverting input terminal of the op amp and the ground. The collector of the transistor Q1 is connected to the positive pole of the power supply. The adjustment resistor Rs is used to adjust the excitation voltage of the bridge circuit.

[0017] Optionally, the resistor R1 is 1.5KΩ, the resistor R2 is 1KΩ, the feedback resistor Rf is 1KΩ, the transistor Q1 is used for current expansion, and the emitter signal of the transistor Q1 is fed back to the inverting input terminal of the operational amplifier as a bridge voltage excitation.

[0018] Optionally, the filtering circuit is a first-stage filtering circuit, which includes a common-mode inductor, four Y capacitors and two X capacitors. The four Y capacitors are divided into two groups, each group includes two Y capacitors, and the two Y capacitors in each group are connected in series. The first group of Y capacitors is connected to both ends of one coil of the common-mode inductor, and the second group of Y capacitors is connected to both ends of the other coil of the common-mode inductor. One X capacitor is connected in series to the input ends of the two coils of the common-mode inductor, and the other X capacitor is connected in series to the output ends of the two coils of the common-mode inductor.

[0019] Optionally, filters with different corner frequencies can be obtained by selecting values ​​of the common-mode inductor, Y capacitor, and X capacitor.

[0020] Optionally, the X capacitors are used to eliminate differential mode interference.

[0021] Optionally, the A / D conversion circuit includes a temperature sensor to perform temperature compensation on the temperature drift characteristics of the A / D conversion circuit, and the A / D conversion circuit adopts AD7192.

[0022] Optionally, the microprocessor uses an STM32L031 series chip, and the microprocessor uses threshold filtering, sliding window filtering and Kalman filtering for combined filtering to decouple the two collected signals and eliminate the coupling of the two signals, where the two signals include a thrust signal and a torque signal.

[0023] Optionally, the wireless transceiver unit adopts E31-433T17S3, and the wireless transceiver unit is connected to the microprocessor through a serial port.

[0024] The present invention utilizes a microprocessor to decouple, filter, and compensate two collected digital signals. This achieves the purpose of signal filtering and decoupling. The filtering and decoupling are implemented in microprocessor software. The provision of a reference voltage circuit eliminates measurement errors caused by bridge voltage fluctuation noise. The reference voltage circuit utilizes a low-temperature drift, high-precision reference voltage chip with a current expansion method to provide the bridge voltage and A / D reference voltage.

[0025] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0027] Figure 1 A principle block diagram of a push-twist integrated sensor signal acquisition system according to an embodiment of the present invention is shown;

[0028] Figure 2 An electronic circuit diagram showing a reference voltage circuit according to an embodiment of the present invention;

[0029] Figure 3 An electronic circuit diagram showing a filter circuit and an A / D conversion circuit according to an embodiment of the present invention;

[0030] Figure 4 The following is a flowchart showing the working process of the push-twist integrated sensor signal acquisition system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0032] A push-twist integrated sensor signal acquisition system, comprising: a bridge voltage excitation circuit, a filter circuit, a reference voltage circuit, an A / D conversion circuit and a microprocessor;

[0033] The reference voltage circuit system provides a reference voltage;

[0034] The output signal of the push-twist integrated sensor is transmitted to the microprocessor after passing through the filter circuit and A / D conversion circuit in sequence;

[0035] The output signal of the push-torque integrated sensor is obtained by converting the thrust and torque signals by a Wheatstone bridge.

[0036] The filtering circuit is used to filter out common-mode interference and differential-mode interference of the output signal;

[0037] The A / D conversion circuit is used to convert the analog signal into a digital signal;

[0038] The microprocessor is used to decouple, filter and compensate the two channels of collected digital signals.

[0039] Optionally, it further includes a transceiver unit for transmitting the output data obtained after processing by the microprocessor to a host computer, and the transceiver unit is a wireless transceiver unit.

[0040] like Figure 2 As shown, the bridge voltage excitation circuit includes a reference voltage chip, a current limiting resistor R1, a resistor R2, an operational amplifier, a transistor Q1, an adjustment resistor Rs and a feedback resistor Rf;

[0041] The reference voltage chip is connected to the system power supply through the current limiting resistor R1. The current output by the reference voltage chip is transmitted to the non-inverting input terminal of the op amp through the resistor R2. The output terminal of the op amp is connected to the base of the transistor Q1. The feedback resistor Rf is connected in series between the emitter of the transistor Q1 and the inverting input terminal of the op amp. The adjustment resistor Rs is connected in series between the inverting input terminal of the op amp and the ground. The collector of the transistor Q1 is connected to the positive pole of the power supply. The adjustment resistor Rs is used to adjust the excitation voltage of the bridge circuit.

[0042] The resistor R1 is 1.5KΩ, the resistor R2 is 1KΩ, the feedback resistor Rf is 1KΩ, the transistor Q1 is used for current expansion, and the emitter signal of the transistor Q1 is fed back to the inverting input terminal of the operational amplifier as a bridge voltage excitation.

[0043] like Figure 3As shown, the filtering circuit is a first-stage filtering circuit, which includes a common-mode inductor, four Y capacitors and two X capacitors. The four Y capacitors are divided into two groups, each group includes two Y capacitors, and the two Y capacitors in each group are connected in series. The first group of Y capacitors is connected to both ends of one coil of the common-mode inductor, and the second group of Y capacitors is connected to both ends of the other coil of the common-mode inductor. One X capacitor is connected in series to the input ends of the two coils of the common-mode inductor, and the other X capacitor is connected in series to the output ends of the two coils of the common-mode inductor.

[0044] Optionally, filters with different corner frequencies can be obtained by selecting values ​​of the common-mode inductor, Y capacitor, and X capacitor.

[0045] Optionally, the X capacitors are used to eliminate differential mode interference.

[0046] Optionally, the A / D conversion circuit includes a temperature sensor to perform temperature compensation on the temperature drift characteristics of the A / D conversion circuit, and the A / D conversion circuit adopts AD7192.

[0047] Optionally, the microprocessor uses an STM32L031 series chip, and the microprocessor uses threshold filtering, sliding window filtering and Kalman filtering for combined filtering to decouple the two collected signals and eliminate the coupling of the two signals, where the two signals include a thrust signal and a torque signal.

[0048] Optionally, the wireless transceiver unit adopts E31-433T17S3, and the wireless transceiver unit is connected to the microprocessor through a serial port.

[0049] In a specific application scenario,

[0050] like Figure 1 As shown, a push-torque integrated sensor signal acquisition system includes a reference voltage circuit, a first-stage filtering circuit, an A / D conversion circuit, a bridge voltage excitation circuit, a low-power microprocessor, and a wireless transceiver unit. The reference voltage circuit generates a high-precision, low-temperature drift 2.5V reference voltage, which is supplied to the bridge voltage excitation circuit for current expansion and A / D conversion reference. The Wheatstone bridge converts the thrust and torque signals into weak electrical signals and outputs them to the first-stage filtering circuit, which removes some common-mode and differential-mode interference. The output signals are then transmitted to the A / D conversion circuit, which is connected to the low-power microprocessor via a serial port. The low-power microprocessor decouples, filters, and compensates the two acquired digital signals before transmitting the processed data to the wireless transceiver unit for transmission to a host computer.

[0051] The Wheatstone bridge excitation voltage requires high precision and low temperature drift, which are difficult to achieve with conventional LDOs, and the output capacity of the reference voltage chip is limited. Using a reference voltage current expansion method not only meets the high precision and low temperature drift requirements, but also improves the load capacity. At the same time, the bridge voltage serves as the reference voltage for the A / D conversion circuit. When the bridge voltage fluctuates, the A / D conversion circuit reference voltage also fluctuates, and the A / D conversion result remains unchanged.

[0052] like Figure 2 As shown, the voltage reference chip features low temperature drift and high precision. It is connected to the system power supply via current-limiting resistor R1. The 2.5V output is connected to the non-inverting input of op amp A1 via resistor R2. The output of op amp A1 is connected to the base of current-expanding transistor Q1, whose collector is connected to the system power supply. The emitter of transistor Q1 serves as the bridge circuit excitation source, simultaneously delivering power to the reference level input pins of the bridge circuit and the A / D converter circuit. It is also connected to the inverting input of op amp A1 via feedback resistor Rf. The inverting input of op amp A1 is connected to ground via adjustment resistor Rs, allowing for adjustment of the bridge circuit excitation voltage.

[0053] The Wheatstone bridge output signal is weak, and during engine and other motor testing, significant interference can often drown out this weak signal. Therefore, it's essential to filter this weak signal through a first-stage filter to remove high-frequency common-mode and differential-mode interference. This weak signal is first filtered through an improved π-type filter circuit and then fed into an A / D acquisition circuit for analog-to-digital conversion.

[0054] The A / D conversion circuit uses the AD7192, a 24-bit A / D converter chip with integrated PGA. It is connected to a micro-power processor via the SPI bus and supplemented by external circuitry. An internal differential amplifier mitigates the effects of external amplifier temperature drift, offset voltage, and electromagnetic interference. An integrated temperature sensor compensates for temperature drift in the A / D conversion circuit. The chip supports both system calibration and on-chip calibration, effectively eliminating system errors.

[0055] The microprocessor uses the STM32L031 series chip to read the conversion results of the A / D conversion circuit, and adopts a combined filtering algorithm of threshold filtering, sliding window smoothing filtering and Kalman filtering for filtering. The least squares method is used to decouple and calibrate the push-torque integrated sensor.

[0056] The bridge voltage excitation circuit uses a low-temperature drift reference voltage chip to expand the current to provide the bridge voltage, reducing the temperature drift of the bridge voltage. At the same time, the excitation voltage is used as the reference voltage for A / D conversion. Based on this, the fluctuation of the sensor output signal caused by the bridge voltage fluctuation caused by interference can be eliminated during the A / D conversion process.

[0057] The primary filter circuit adopts an improved π-type filter circuit and is supplemented by X capacitors to eliminate differential mode interference.

[0058] like Figure 3 As shown in Figure 1, the improved π-type filter circuit includes common-mode inductor L1, Y-capacitors CY1-CY4, and X-capacitors CX1 and CX2, forming the first signal filter circuit. Common-mode inductor L2, Y-capacitors CY5-CY8, and X-capacitors CX3 and CX4 form the second signal filter circuit. By selecting the values ​​of the inductor and capacitors, filters with different corner frequencies can be obtained. The reference level of the A / D converter circuit is the same as the bridge circuit excitation voltage, eliminating the effects of bridge voltage fluctuations. The AD7192 has an internal temperature sensor that compensates for temperature-induced drift, thereby improving test accuracy.

[0059] The microprocessor is implemented using the STM32L031 series chip. It employs a combination of threshold filtering, sliding window filtering, and Kalman filtering, achieving a sampling accuracy of 0.02%. The microprocessor decouples the collected thrust and torque signals, eliminating any coupling between them. It is a low-power processor.

[0060] Push-torque sensors are often used in applications such as engine testing and motor power testing. They are subject to frequent pulse interference, coupled with Gaussian noise from their own circuits, which can drown out weak signals. While the first-stage filter can remove some high-frequency noise, it has little effect on periodic pulse interference, Gaussian noise, and quantization noise. Software filtering algorithms can effectively filter out these interferences, Gaussian noise, and quantization noise.

[0061] like Figure 4 As shown in FIG, the combination of threshold filtering, sliding window filtering and Kalman filtering algorithms can filter out both pulse interference and Gaussian noise while maintaining good frequency characteristics.

[0062] The wireless transceiver unit uses 433M wireless transmission to transparently transmit data from the push-twist integrated sensor to the receiver. The receiver is connected to the host computer through the serial port, making data storage and processing very convenient.

[0063] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A push-twist integrated sensor signal acquisition system, characterized in that: include: Bridge voltage excitation circuit, filter circuit, reference voltage circuit, A / D conversion circuit and microprocessor; The reference voltage circuit provides a reference voltage to the system; The output signal of the push-twist integrated sensor is transmitted to the microprocessor after passing through the filter circuit and A / D conversion circuit in sequence; The output signal of the push-torque integrated sensor is obtained by converting the thrust and torque signals by a Wheatstone bridge. The filtering circuit is used to filter out common-mode interference and differential-mode interference of the output signal; The A / D conversion circuit is used to convert the analog signal into a digital signal; The microprocessor is used to decouple, filter and compensate the two channels of collected digital signals; The bridge voltage excitation circuit includes a reference voltage chip, a current limiting resistor R1, a resistor R2, an operational amplifier, a transistor Q1, an adjustment resistor Rs and a feedback resistor Rf; The reference voltage chip is connected to the system power supply through the current limiting resistor R1. The current output by the reference voltage chip is transmitted to the non-inverting input terminal of the op amp through the resistor R2. The output terminal of the op amp is connected to the base of the transistor Q1. The feedback resistor Rf is connected in series between the emitter of the transistor Q1 and the inverting input terminal of the op amp. The adjustment resistor Rs is connected in series between the inverting input terminal of the op amp and the ground. The collector of the transistor Q1 is connected to the positive electrode of the power supply. The adjustment resistor Rs is used to adjust the excitation voltage of the bridge circuit. The transistor Q1 is used to expand the current. The emitter signal of the transistor Q1 is simultaneously transmitted to the Wheatstone bridge and the reference level input pin of the A / D conversion circuit as bridge voltage excitation, and is connected to the inverting input terminal of the op amp through the feedback resistor Rf.

2. The push-twist integrated sensor signal acquisition system according to claim 1, characterized in that: It also includes a transceiver unit for transmitting output data obtained after processing by the microprocessor to a host computer, and the transceiver unit is a wireless transceiver unit.

3. The push-twist integrated sensor signal acquisition system according to claim 1, characterized in that: The resistor R1 is 1.5KΩ, the resistor R2 is 1KΩ, and the feedback resistor Rf is 1KΩ.

4. The push-twist integrated sensor signal acquisition system according to claim 1, characterized in that: The filtering circuit is a first-stage filtering circuit, comprising a common-mode inductor, four Y capacitors, and two X capacitors. The four Y capacitors are divided into two groups, each group comprising two Y capacitors. The two Y capacitors in each group are connected in series, a first group of Y capacitors is connected to both ends of one coil of the common-mode inductor, a second group of Y capacitors is connected to both ends of the other coil of the common-mode inductor, one X capacitor is connected in series to the input ends of the two coils of the common-mode inductor, and the other X capacitor is connected in series to the output ends of the two coils of the common-mode inductor.

5. The push-twist integrated sensor signal acquisition system according to claim 4, characterized in that: By selecting the values ​​of the common-mode inductor, Y capacitor, and X capacitor, filters with different corner frequencies can be obtained.

6. The push-twist integrated sensor signal acquisition system according to claim 4, characterized in that: The Y capacitor and the X capacitor are used to eliminate differential mode interference.

7. The push-twist integrated sensor signal acquisition system according to claim 1, characterized in that: The A / D conversion circuit includes a temperature sensor to perform temperature compensation on the temperature drift characteristics of the A / D conversion circuit. The A / D conversion circuit adopts AD7192.

8. The push-twist integrated sensor signal acquisition system according to claim 1, characterized in that: The microprocessor adopts the STM32L031 series chip, and the microprocessor adopts threshold filtering, sliding window filtering and Kalman filtering for combined filtering to decouple the two collected signals and eliminate the coupling of the two signals, the two signals including the thrust signal and the torque signal.

9. The push-twist integrated sensor signal acquisition system according to claim 2, characterized in that: The wireless transceiver unit adopts E31-433T17S3, and the wireless transceiver unit is connected to the microprocessor through a serial port.

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