A proximity sensor solution system and method for landing gear retraction system

Abstract

The present invention discloses a proximity sensor calculation system for a landing gear retraction and extension system. The calculation system includes an inductance measurement module, a signal processing module, a signal generation module, a main control module, a temperature compensation module, and a bus communication module. Multiple sets of inductance values ​​are collected using an inductance measuring instrument and the calculation system to calibrate the proximity sensor's inductance measurements. This ensures that the inductance values ​​calculated by the calculation system are free from measurement errors caused by unstable parameters such as contact resistance, parasitic inductance, and parasitic capacitance of measurement circuits and connectors. This effectively addresses the complex circuit structure and calculation process, slow calculation speed, and low accuracy of existing proximity sensors. The present invention also provides a proximity sensor calculation method for a landing gear retraction and extension system.

Description

Technical Field

[0001] The present invention relates to a position indication technology for an aircraft landing gear retraction and extension system, and in particular to a proximity sensor solution system and method for the landing gear retraction and extension system. Background Art

[0002] Proximity sensors are non-contact sensors that can reduce mechanical damage and extend mechanical life. They are widely used in landing gear retraction and extension systems for large aircraft. Proximity sensors in landing gear retraction and extension systems are typically inductive. A calculation unit is required to calculate the collected inductance to accurately determine the current position of the landing gear, thereby providing a basis for the landing gear retraction and extension control system. The basic principle of a proximity sensor is to utilize the change in the position between the sensor and the target, which causes a change in the induced inductance. This inductance is then processed by back-end processing for measurement. Because the inductance of a proximity sensor is generally small, the change at the approach and distance points is even smaller, making it difficult to measure and susceptible to external interference, which can cause measurement errors. The equivalent cable impedance between the proximity sensor and the retraction and extension control box, as well as ambient temperature, significantly influences the measurement, leading to erroneous calculation results. Conventional inductance measurement methods often have complex circuit structures and calculation processes, resulting in slow calculation speed, low accuracy, and poor stability. Therefore, designing a proximity sensor calculation solution with a simple structure, high real-time performance, and high measurement accuracy has become an urgent technical challenge. Summary of the Invention

[0003] The present invention aims to provide a proximity sensor solution system for a landing gear retraction and extension system. The solution system has high real-time performance and high measurement accuracy, thereby improving the accuracy and real-time performance of inductive proximity sensor signals.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: a proximity sensor solution system, the system comprising:

[0005] The inductance measurement module includes a proximity sensor and a sampling resistor, wherein one end of the sampling resistor is connected to one end of the inductance coil of the proximity sensor;

[0006] The signal processing module includes an amplifier, a bandpass filter and an analog-to-digital conversion circuit. The amplifier includes a first amplifier and several second amplifiers. The second amplifier is used to amplify the voltage U at both ends of the proximity sensor. L And the voltage U across the sampling resistor R , the second amplifier is connected to the analog-to-digital conversion circuit, and one end of the bandpass filter is connected to the other end of the sampling resistor;

[0007] a signal generating module, configured to generate a signal source required by the proximity sensor solving system so that the proximity sensor has inductance, the signal generating module comprising a signal generator, one end of the signal generator being connected to one end of the first amplifier, and the other end of the first amplifier being connected to the other end of the bandpass filter;

[0008] A main control module, including a signal calculation module and an inductance calibration module. The signal calculation module is used to calculate the inductance measurement value L of the proximity sensor, and the inductance calibration module is used to calibrate the inductance measurement value L of the proximity sensor. The main control module is also used for signal frequency setting and modification, data acquisition, and temperature compensation algorithm calculation. The main control module is connected to the other end of the signal generator and the analog-to-digital conversion circuit respectively; the signal generation module also includes a signal frequency setting and modification unit of the main control module;

[0009] A temperature compensation module is used for temperature compensation of the proximity sensor solution system to eliminate the influence of the sampling resistor and the inductance equivalent impedance of the proximity sensor and the ambient temperature on the inductance value measurement;

[0010] The bus communication module is used to receive the control signal of the host computer and report the approach / distance status calculated by the solution system to the host computer in the form of a bus.

[0011] According to the embodiments of the present invention, the present invention can be further optimized. The following is the technical solution formed after optimization:

[0012] In one preferred embodiment, the inductance measurement module adopts an LCR bridge method, and the sampling resistor adopts a precision detection resistor.

[0013] In one preferred embodiment, the data acquisition of the main control module includes the voltage U at both ends of the proximity sensor L And the voltage U across the sampling resistor R The collection of.

[0014] In one preferred embodiment, the temperature compensation module includes a temperature sensor and a temperature compensation algorithm calculation unit of the main control module, and the temperature sensor is connected to the main control module.

[0015] In one preferred embodiment, the bus communication module is further configured to transmit the inductance value measured by the inductance measuring instrument to the inductance calibration module via the bus.

[0016] Based on the same concept, the present invention also provides a method for calculating inductance using the above-mentioned proximity sensor calculation system, the calculation method comprising the following steps:

[0017] Inductance calibration:

[0018] a1) Using an inductance measuring instrument and the proximity sensor calculation system, the inductance calibration module collects two inductance values ​​at the same target gap; the target gap is the distance between the target and the proximity sensor when the target moves toward the proximity sensor; the inductance measurement value of the inductance measuring instrument is recorded as the reference inductance value;

[0019] a2), changing the target gap several times and repeating step a1) accordingly to obtain multiple sets of inductance values ​​of two acquisition methods;

[0020] a3), performing quadratic polynomial fitting on the multiple sets of inductance values ​​obtained by the two acquisition methods to obtain a calibration quadratic term formula, and writing the calibration quadratic term formula into a program of the inductance value calibration module;

[0021] Inductance measurement:

[0022] b1), the main control module collects the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R ,

[0023] b2), the signal calculation module analyzes the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R , calculate and obtain the inductance measurement value L of the proximity sensor;

[0024] b3) The inductance measurement value L of the proximity sensor is transmitted to the inductance calibration module in which the calibration quadratic term formula has been written, to obtain a calibrated inductance measurement value.

[0025] In one preferred embodiment, in step a3), the multiple sets of inductance values ​​of the two acquisition methods are processed using Excel to obtain the calibration quadratic term formula L m =aL 2 +bL+c; where L m is the calibration value of the inductance measurement value L of the proximity sensor, a is a constant, b is a constant, and c is a constant.

[0026] In one preferred embodiment, the step b2) of calculating the inductance measurement value L of the proximity sensor specifically includes the following steps: comparing the voltage U across the proximity sensor L and the voltage across the sampling resistor U R The phase difference θ is calculated according to the voltage U at both ends of the proximity sensor. L , the voltage U across the sampling resistor R and the phase difference θ, the actual inductance value L is calculated.

[0027] In one preferred embodiment, the calculation formula of the inductance measurement value L of the proximity sensor is as follows:

[0028]

[0029] The calculation formula of the phase difference θ is as follows:

[0030]

[0031] Wherein, R1 is the sampling resistance value, R is the equivalent resistance value of the inductance measurement module, and f is the inductance frequency.

[0032] Compared with the existing technology, the beneficial effects of the present invention are: the proximity sensor solution system provided by the present invention has high real-time performance and high measurement accuracy, improves the accuracy and real-time performance of the inductive proximity sensor signal, and effectively solves the problems of the existing proximity sensor circuit structure and calculation process being complex, the solution speed being slow, and the accuracy being low. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of a proximity sensor solution system according to embodiment 1 of the present invention;

[0034] Figure 2 This is a signal calculation flow chart of the proximity sensor calculation system according to embodiment 1 of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention may be combined with each other.

[0036] Example 1

[0037] This embodiment provides a proximity sensor calculation system for a landing gear retraction and extension system. The calculation system includes an inductance measurement module, a signal processing module, a signal generation module, a main control module, a temperature compensation module, and a bus communication module.

[0038] The inductance measurement module includes a proximity sensor and a sampling resistor, wherein one end of the sampling resistor is connected to one end of the inductance coil of the proximity sensor;

[0039] The signal processing module includes an amplifier, a bandpass filter and an analog-to-digital conversion circuit. The amplifier includes a first amplifier and several second amplifiers. The second amplifier is used to amplify the voltage U at both ends of the proximity sensor. L And the voltage U across the sampling resistor R , the second amplifier is connected to the analog-to-digital conversion circuit, and one end of the bandpass filter is connected to the other end of the sampling resistor;

[0040] The signal generating module generates a sinusoidal signal with a pure spectrum and programmable frequency and phase, and is used to generate the signal source required by the proximity sensor solution system. The signal generating module includes a signal generator, one end of which is connected to one end of the first amplifier, and the other end of the first amplifier is connected to the other end of the bandpass filter;

[0041] The main control module includes a signal calculation module and an inductance calibration module. The signal calculation module is used to calculate the inductance measurement value L of the proximity sensor. The inductance calibration module is used to calibrate the inductance measurement value L of the proximity sensor. The main control module is also used for signal frequency setting and modification, data acquisition and temperature compensation algorithm calculation. The main control module is connected to the other end of the signal generator and the analog-to-digital conversion circuit respectively; the signal generation module also includes a signal frequency setting and modification unit of the main control module;

[0042] The temperature compensation module is used for temperature compensation of the proximity sensor solution system;

[0043] The bus communication module is configured to receive control signals from a host computer and report the approach / distance status calculated by the solving system to the host computer via a bus. In this embodiment, the bus communication module can receive control signals from the host computer via an RS422 communication interface and report the approach / distance status calculated by the solving system via a bus. The bus communication module can also enable software updates and debugging without disassembly via an RS232 communication interface, saving maintenance and debugging time.

[0044] The proximity sensor calculation system uses the signal generator to generate a sinusoidal excitation source, causing current to flow through the proximity sensor's inductor coil. This inductor generates a magnetic field, and the magnitude of the inductance is affected by the magnetic resistance of the magnetic circuit within which the proximity sensor's inductor coil resides. Specifically, as a target moves toward the proximity sensor, the change in the gap between the target and the proximity sensor causes a change in the magnetic resistance of the proximity sensor's inductor circuit. When the target approaches the proximity sensor, the inductance increases, and vice versa. Therefore, the proximity sensor's proximity / removal state can be determined by measuring this change in inductance.

[0045] The greater the voltage across the proximity sensor inductor, the higher the sampling accuracy of the solution system. To maximize the voltage across the proximity sensor inductor while ensuring that the sampling resistor is not damaged by excessive power consumption, the solution system uses a precision detection resistor connected in series with the detection circuit, and the inductance measurement module employs an LCR bridge.

[0046] Furthermore, the data acquisition of the main control module includes the voltage U at both ends of the proximity sensor L And the voltage U across the sampling resistor R The collection of.

[0047] As a circuit operates over time, the temperature of components such as resistors in the circuit changes, causing changes in their resistance. Because the calculation of the inductance value is related to the resistance value, this ultimately affects the calculated inductance value. The temperature compensation module uses a temperature compensation algorithm to offset the temperature increase, ensuring that the resistance value remains unchanged despite the temperature increase, and the final calculated inductance value is not affected.

[0048] Furthermore, the temperature compensation module includes a temperature sensor connected to the main control module and a temperature compensation algorithm calculation unit of the main control module. The temperature compensation module uses the temperature sensor to collect real-time inter-PCB temperature and performs temperature compensation to effectively eliminate the effects of sampling resistance, inductor equivalent cable impedance, and ambient temperature on inductance measurement.

[0049] The inductance calibration module collects multiple sets of inductance values ​​using an inductance measuring instrument and the calculation system to calibrate the inductance measurements of the proximity sensor, ensuring that the inductance values ​​calculated by the calculation system are free from measurement errors caused by unstable parameters such as contact resistance, parasitic inductance, and parasitic capacitance of measurement lines and connectors. Furthermore, the bus communication module is configured to transmit the inductance values ​​measured by the inductance measuring instrument to the inductance calibration module via a bus.

[0050] When the gap between the target and the proximity sensor changes, the approach and distance state of the target is determined by the change of the calibrated inductance value.

[0051] Figure 1 In, R L is the equivalent resistance of the proximity sensor.

[0052] Example 2

[0053] This embodiment provides a proximity sensor solution method for a landing gear retraction system, and the implementation steps are as follows:

[0054] Inductance calibration:

[0055] a1) Using an inductance measuring instrument and the proximity sensor calculation system, the inductance calibration module collects two inductance values ​​at the same target gap; the target gap is the distance between the target and the proximity sensor when the target moves toward the proximity sensor; the inductance measurement value of the inductance measuring instrument is recorded as the reference inductance value;

[0056] a2), changing the target gap several times and repeating step a1) accordingly to obtain multiple sets of inductance values ​​of two acquisition methods;

[0057] a3), performing quadratic polynomial fitting on the multiple sets of inductance values ​​obtained by the two acquisition methods to obtain a calibration quadratic term formula, and writing the calibration quadratic term formula into a program of the inductance value calibration module;

[0058] Inductance measurement:

[0059] b1), the main control module collects the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R ,

[0060] b2), the signal calculation module analyzes the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R , calculate and obtain the inductance measurement value L of the proximity sensor;

[0061] b3) The inductance measurement value L of the proximity sensor is transmitted to the inductance calibration module in which the calibration quadratic term formula has been written, to obtain a calibrated inductance measurement value.

[0062] Both the inductance meter and the proximity sensor calculation system are used to measure inductance. The inductance meter offers high precision and is the preferred inductance measurement device for ground-based testing. However, due to factors such as its large size, lack of an interface with a host computer, and inability to guarantee electromagnetic compatibility, it is not a preferred measurement device for use on a machine. Therefore, it is necessary to develop a proximity sensor calculation system with comparable accuracy to that of the inductance meter. Therefore, in this embodiment, the inductance value measured by the inductance meter is used as the baseline inductance value.

[0063] In this embodiment, the calibration quadratic term formula between the multiple groups of inductance values ​​of the two acquisition methods is obtained through Excel. The step a3) specifically includes the following steps:

[0064] S1, open Excel, enter multiple sets of inductance values ​​of the two acquisition methods, and the multiple sets of inductance values ​​of each acquisition method are a column of values;

[0065] In s2, select two columns of data, choose "Insert Chart", "All Chart Types";

[0066] s3. In the "Insert Chart" dialog box, select "Scatter Chart", select the first one in "Scatter Chart", and click "OK";

[0067] s4, generating a graph, wherein the graph displays scattered points, wherein the abscissa is the inductance measurement value L of the proximity sensor, and the ordinate is the inductance measurement value of the inductance measuring instrument;

[0068] s5. Select one of the scattered points, right-click, and select "Add Trend Line";

[0069] Step 6. In the "Trend Line Options" dialog box, select "Trend Forecast / Regression Analysis Type", "Polynomial", select 2 for "Sequence", select "Show Formula", and click "Close".

[0070] S7, Excel displays the trend line and quadratic term formula of the scattered points, where the quadratic term formula is the calibration quadratic term formula.

[0071] In step s7), the calibration quadratic term formula can be expressed as L m =aL 2 +bL+c, where L m is the calibration value of the inductance measurement value L of the proximity sensor, a is a constant, b is a constant, and c is a constant.

[0072] In the step b2), the inductance measurement value L of the proximity sensor is calculated, which specifically includes the following steps: comparing the voltage U at both ends of the proximity sensor and the inductance measurement value L of the proximity sensor; L and the voltage across the sampling resistor U R The phase difference θ is calculated according to the voltage U at both ends of the proximity sensor. L , the voltage U across the sampling resistor R and the phase difference θ, and calculate the inductance measurement value L of the proximity sensor. The calculation formula of the inductance measurement value L of the proximity sensor is as follows:

[0073]

[0074] The calculation formula of the phase difference θ is as follows:

[0075]

[0076] Wherein, R1 is the sampling resistance value, R is the equivalent resistance value of the inductance measurement module, and f is the inductance frequency.

[0077] Example 3

[0078] In this embodiment, the main control module is ZYNQ7020, which combines the processing power of the ARM processor and the flexibility of the FPGA; the signal generator is AD9833; the first amplifier is OP07; the bandpass filter is a third-order passive low-pass filter; the second amplifier is GS8054;

[0079] The host computer sends control instructions through the RS422 bus, controls the excitation source signal generator AD9833 through the main control module ZYNQ7020 to emit a fixed sine wave frequency signal, and obtains the signal of the amplitude and frequency required by the inductance of the proximity sensor through the first amplifier OP07 and the bandpass filter.

[0080] The main control module collects the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R , amplified by the second amplifier into a voltage signal that can be collected by the ADC chip ADS131M02, and then converted into an analog-to-digital signal by the ADC chip ADS131M02. L 、U R The signal is then transferred to the FPGA acquisition channel and then transferred to the signal analysis unit (ARM processor) through the FPGA acquisition channel for analysis, and the U L and the U R The phase difference θ, then according to the U L 、The U R and the phase difference θ, and calculate the inductance measurement value L of the proximity sensor.

[0081] The temperature sensor collects the temperature between PCB boards in real time and uploads it to the FPGA, and temperature compensation calculation is performed in the FPGA to ensure that the inductance value output by the solution system is not affected by the sampling resistor, the inductor equivalent cable impedance and the ambient temperature change.

[0082] Through the inductance measuring instrument and the solution system, the inductance calibration module collects multiple sets of inductance values ​​L si , L i Among them, L si is the i-th group of inductance values ​​collected by the inductance tester, 1≤i≤n, n is the number of groups of collected inductance values. si and L i Perform quadratic fitting to obtain the calibration quadratic term formula L m =aL 2 +bL+c, where L mis the calibration value of the proximity sensor's inductance measurement value L. The calibration quadratic term formula is written into the inductance calibration module to ensure that the inductance value output through the bus during subsequent inductance measurement is the calibrated inductance value.

[0083] In this embodiment, the real-time performance of the calculation system is no more than 10 ms (milliseconds), the real-time performance of multi-channel simultaneous measurement is also guaranteed to be no more than 10 ms (milliseconds), and the inductance measurement accuracy reaches ±0.01 mH (millihenry).

[0084] The contents described in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications to the embodiments made by those skilled in the art fall within the scope defined by the claims attached to the present invention.

Claims

1. A proximity sensor solution system, characterized in that: The solution system includes: The inductance measurement module includes a proximity sensor and a sampling resistor, wherein one end of the sampling resistor is connected to one end of the inductance coil of the proximity sensor; The signal processing module includes an amplifier, a bandpass filter and an analog-to-digital conversion circuit. The amplifier includes a first amplifier and several second amplifiers. The second amplifier is used to amplify the voltage U at both ends of the proximity sensor. L And the voltage U across the sampling resistor R , the second amplifier is connected to the analog-to-digital conversion circuit, and one end of the bandpass filter is connected to the other end of the sampling resistor; A signal generating module, configured to generate a signal source required by the proximity sensor solution system, the signal generating module comprising a signal generator, one end of the signal generator being connected to one end of the first amplifier, and the other end of the first amplifier being connected to the other end of the bandpass filter; A main control module, including a signal calculation module and an inductance calibration module. The signal calculation module is used to calculate the inductance measurement value L of the proximity sensor, and the inductance calibration module is used to calibrate the inductance measurement value L of the proximity sensor. The main control module is also used for signal frequency setting and modification, data acquisition, and temperature compensation algorithm calculation. The main control module is connected to the other end of the signal generator and the analog-to-digital conversion circuit respectively; the signal generation module also includes a signal frequency setting and modification unit of the main control module; A temperature compensation module, used for temperature compensation of the proximity sensor solution system; The bus communication module is used to receive the control signal of the host computer and report the approach / distance status calculated by the solution system to the host computer in the form of a bus.

2. The proximity sensor solution system according to claim 1, characterized in that: The inductance measurement module adopts an LCR bridge method, and the sampling resistor adopts a precision detection resistor.

3. The proximity sensor solution system according to claim 1, characterized in that: The data acquisition of the main control module includes the voltage U at both ends of the proximity sensor L And the voltage U across the sampling resistor R The collection of.

4. The proximity sensor solution system according to claim 1, characterized in that: The temperature compensation module includes a temperature sensor and a temperature compensation algorithm calculation unit of the main control module, and the temperature sensor is connected to the main control module.

5. The proximity sensor solution system according to claim 1, characterized in that: The bus communication module is further used to transmit the inductance value measured by the inductance measuring instrument to the inductance calibration module via the bus.

6. A method for calculating inductance using the proximity sensor calculation system according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Inductance calibration: a1), using an inductance measuring instrument and the proximity sensor solution system, the inductance calibration module collects two inductance values ​​under the same target gap; the inductance measurement value of the inductance measuring instrument is recorded as the reference inductance value; a2), changing the target gap several times and repeating step a1) accordingly to obtain multiple sets of inductance values ​​of two acquisition modes; a3), performing quadratic polynomial fitting on the multiple sets of inductance values ​​obtained by the two acquisition methods to obtain a calibration quadratic term formula, and writing the calibration quadratic term formula into a program of the inductance calibration module; Inductance measurement: b1), the main control module collects the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R , b2), the signal calculation module analyzes the voltage U at both ends of the proximity sensor L and the voltage across the sampling resistor U R , calculate and obtain the inductance measurement value L of the proximity sensor; b3) The inductance measurement value L of the proximity sensor is transmitted to the inductance calibration module in which the calibration quadratic term formula has been written, to obtain a calibrated inductance measurement value.

7. The method according to claim 6, characterized in that In step a3), the multiple sets of inductance values ​​of the two acquisition methods are processed using Excel to obtain the calibration quadratic term formula L m =aL 2 +bL+c; where L m is the calibration value of the inductance measurement value L of the proximity sensor, a is a constant, b is a constant, and c is a constant.

8. The method according to claim 6, characterized in that The step b2) of calculating the inductance measurement value L of the proximity sensor specifically includes the following steps: comparing the voltage U across the proximity sensor L and the voltage across the sampling resistor U R The phase difference θ is calculated according to the voltage U at both ends of the proximity sensor. L , the voltage U across the sampling resistor R and the phase difference θ, and calculate the inductance measurement value L of the proximity sensor.

9. The method according to claim 8, characterized in that The calculation formula of the inductance measurement value L of the proximity sensor is as follows: The calculation formula of the phase difference θ is as follows: Wherein, R1 is the sampling resistance value, R is the equivalent resistance value of the inductance measurement module, and f is the inductance frequency.

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