Proximity sensor signal acquisition system and method

Abstract

The present invention provides a proximity sensor signal acquisition system and method. The proximity sensor signal acquisition system includes a main controller, a first signal acquisition circuit, and a second signal acquisition circuit. The first signal acquisition circuit includes a first signal generator, a first processing circuit, and a first analog-to-digital converter, while the second signal acquisition circuit includes a second signal generator, a second processing circuit, a second analog-to-digital converter, a decoder, and a relay. The number of first signal generators, first processing circuits, and relays is equal to the number of proximity sensors, while the number of second signal generators and second processing circuits is less than the number of proximity sensors. The present invention uses the first signal acquisition circuit to acquire proximity sensor signals. When a fault occurs in a circuit, fault isolation is automatically performed, and the second signal acquisition circuit is activated to take over the proximity sensor signal acquisition. The redundant acquisition circuit design uses a relatively small proportional number, resulting in low cost, simple circuit structure, small footprint, and high reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of signal acquisition, and in particular relates to a proximity sensor signal acquisition system and method. Background Art

[0002] Proximity sensors are non-contact sensors. Because they reduce mechanical damage and extend their lifespan, they are widely used for position detection and indication in landing gear retraction and extension systems on large aircraft. The inductance value of the proximity sensor in these systems must be acquired through an acquisition circuit. Because the proximity sensor signal is crucial to the retraction and extension of the landing gear system, the landing gear-level proximity sensor and its acquisition circuit are generally required to outlive the aircraft. Compared to inductive proximity sensors, which feature a simpler internal structure, no wearing parts, and a longer service life, proximity sensor acquisition circuits are more susceptible to failure. Therefore, when designing the proximity sensor and the inductance acquisition and processing circuitry, these potential failures must be considered.

[0003] Considering the aging of components in proximity sensors and data acquisition circuits over time, parameter drift within the circuit components can occur, leading to indications of distance when the sensor should be approaching and proximity when it should be far away. Furthermore, proximity sensors are typically mounted externally, making them susceptible to lightning strikes and other factors. This can easily cause signal overvoltage and overcurrent in the internal processing circuitry, leading to irreversible damage and potentially causing circuit failure. Therefore, redundant design is necessary for the proximity sensor and the inductance acquisition and processing circuitry.

[0004] The traditional method is to use dual sensors and dual redundant circuits at the same location (i.e., the number of proximity sensors and acquisition and processing circuits is 1:1) or to use a single sensor and dual redundant circuits at the same location (i.e., the number of proximity sensors and acquisition and processing circuits is 1:2). This greatly increases equipment cost, occupies a large space and has a relatively complex structure. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art and provide a proximity sensor signal acquisition system and method with a simple structure and low equipment cost.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] Proximity sensor signal acquisition system, including:

[0008] A main controller, a first signal acquisition circuit, and a second signal acquisition circuit;

[0009] The first signal acquisition circuit includes a first signal generator, a first processing circuit, and a first analog-to-digital converter. The first processing circuit includes a first amplifier and a first low-pass filter. A first end of the first signal generator is connected to the main controller, and a second end of the first signal generator is connected to a proximity sensor. A first end of the first amplifier is connected to the proximity sensor, a second end of the first amplifier is connected to a first end of the first low-pass filter, a second end of the first low-pass filter is connected to a first end of the first analog-to-digital converter, and a second end of the first analog-to-digital converter is connected to the main controller.

[0010] The second signal acquisition circuit includes a second signal generator, a second processing circuit, a second analog-to-digital converter, a decoder, and a relay. The second processing circuit includes a second amplifier and a second low-pass filter. The first end of the second signal generator is connected to the main controller, the second end of the second signal generator is connected to the first end of the relay, the second end of the relay is connected to the proximity sensor, the first end of the decoder is connected to the main controller, and the second end of the decoder is connected to the third end of the relay. The first end of the second amplifier is connected to the proximity sensor, the second end of the second amplifier is connected to the first end of the second low-pass filter, the second end of the second low-pass filter is connected to the first end of the second analog-to-digital converter, and the second end of the second analog-to-digital converter is connected to the main controller.

[0011] The number of the first signal generators, the number of the first processing circuits, and the number of the relays are equal to the number of the proximity sensors; the number of the second signal generators and the number of the second processing circuits are less than the number of the proximity sensors;

[0012] The second end of the second signal generator is connected in parallel to the plurality of relays; and the first end of the second amplifier is connected in parallel to the plurality of proximity sensors.

[0013] The present invention collects and processes the signal of the proximity sensor through the first signal acquisition circuit, and can also synchronously take over the signal acquisition and processing of the proximity sensor through the second signal acquisition circuit when a fault occurs in a certain circuit; compared with the dual-redundancy circuit, the present invention adopts a smaller proportional number for redundant acquisition circuit design, which can ensure that the proximity sensor signal is normally obtained when the acquisition circuit fails, and has the advantages of reduced cost, simple circuit structure, small space occupation and high reliability.

[0014] Furthermore, the quantity relationship between the second signal generator and the proximity sensor is shown in the following formula:

[0015] ;

[0016] Wherein, s is the number of second signal generators, n is the number of proximity sensors, and [ ] indicates taking the integer part of the number in the brackets.

[0017] Furthermore, the quantity relationship between the second processing circuit and the proximity sensor is shown in the following formula:

[0018] ;

[0019] Wherein, t is the number of second processing circuits, n is the number of proximity sensors, and [ ] represents taking the integer part of the number in the brackets. Based on the same inventive concept, the present invention also provides a proximity sensor signal acquisition method, comprising the following process:

[0020] Connecting the first signal generator, the first processing circuit, and the first analog-to-digital converter of the n proximity sensors, disconnecting the decoder, disconnecting the second signal generator, the second processing circuit, the second analog-to-digital converter, and the relay of the n proximity sensors, and collecting signals from the n proximity sensors;

[0021] When the main controller fails to receive a signal from the i-th proximity sensor, the first signal generator, the first processing circuit, and the first analog-to-digital converter of the i-th proximity sensor are disconnected, the decoder is turned on, and the second signal generator, the second processing circuit, the second analog-to-digital converter, and the relay of the i-th proximity sensor are connected, where i=1, 2, ..., n.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention collects and processes the proximity sensor signal through the first signal acquisition circuit, and can also automatically isolate the fault when a fault occurs in a certain circuit and enable the second signal acquisition circuit to take over the proximity sensor signal acquisition. Compared with the dual-redundancy circuit, the present invention adopts a smaller proportional number for redundant acquisition circuit design, which can ensure that the proximity sensor signal is normally obtained when the acquisition circuit fails. It has the advantages of reduced cost, simple circuit structure, small space occupation and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a first signal acquisition circuit of a proximity sensor of the present invention;

[0025] Figure 2 Schematic diagram of first and second signal acquisition circuits of a proximity sensor of the present invention;

[0026] Figure 3 Schematic diagram of a first signal acquisition circuit for eight proximity sensors of the present invention;

[0027] Figure 4 Schematic diagram of the first and second signal acquisition circuits of eight proximity sensors of the present invention;

[0028] Figure 5 Schematic diagram of the flow of the proximity sensor signal acquisition method of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the following embodiments. It should be noted that the embodiments and features of the embodiments may be combined unless they conflict. For ease of description, the words "upper," "lower," "left," and "right" appearing below merely indicate the directions of upper, lower, left, and right relative to the accompanying drawings and do not limit the structure. Example

[0030] This embodiment provides a proximity sensor signal acquisition system. This system addresses the issue of component aging and parameter drift in circuit components caused by long-term operation of proximity sensors and acquisition circuits, resulting in the display of a moving object when it should be moving closer and another moving object when it should be moving farther away. Furthermore, proximity sensors are typically mounted externally on the body of a device and are susceptible to lightning strikes and other factors, which can easily cause signal overvoltage and overcurrent in the internal processing circuitry, resulting in irreversible damage to the circuitry and leading to failure of the proximity sensor signal acquisition circuit. This system, featuring a simple circuit structure, small footprint, low cost, and high reliability, ensures proper acquisition of proximity sensor signals in a faulty path without requiring redundant circuitry.

[0031] like Figure 1-4 The proximity sensor signal acquisition system of this embodiment includes: a main controller, a first signal acquisition circuit, and a second signal acquisition circuit.

[0032] The first signal acquisition circuit includes a first signal generator, a first processing circuit, and a first analog-to-digital converter (ADC chip). The first processing circuit includes a first amplifier and a first low-pass filter. The first end of the first signal generator is connected to the main controller, and the second end of the first signal generator is connected to the proximity sensor. The first end of the first amplifier is connected to the proximity sensor, the second end of the first amplifier is connected to the first end of the first low-pass filter, the second end of the first low-pass filter is connected to the first end of the first analog-to-digital converter, and the second end of the first analog-to-digital converter is connected to the main controller.

[0033] The second signal acquisition circuit includes a second signal generator, a second processing circuit, a second analog-to-digital converter (ADC chip), a decoder, and a relay. The second processing circuit includes a second amplifier and a second low-pass filter. The first end of the second signal generator is connected to the main controller, the second end of the second signal generator is connected to the first end of the relay, the second end of the relay is connected to the proximity sensor, the first end of the decoder is connected to the main controller, and the second end of the decoder is connected to the third end of the relay. The first end of the second amplifier is connected to the proximity sensor, the second end of the second amplifier is connected to the first end of the second low-pass filter, the second end of the second low-pass filter is connected to the first end of the second analog-to-digital converter, and the second end of the second analog-to-digital converter is connected to the main controller.

[0034] The number of the first signal generators, the number of the first processing circuits, and the number of the relays are equal to the number of the proximity sensors; the number of the second signal generators and the number of the second processing circuits are less than the number of the proximity sensors.

[0035] The second end of the second signal generator is connected in parallel to a plurality of relays; and the first end of the second amplifier is connected in parallel to a plurality of proximity sensors.

[0036] The quantitative relationship between the second signal generator and the proximity sensor is shown in the following formula:

[0037] ;

[0038] Wherein, s is the number of second signal generators, n is the number of proximity sensors, and [ ] indicates taking the integer part of the number in the brackets.

[0039] The quantitative relationship between the second processing circuit and the proximity sensor is shown in the following formula:

[0040] ;

[0041] Wherein, t is the number of the second processing circuits, n is the number of proximity sensors, and [ ] represents taking the integer part of the number in the brackets.

[0042] The quantitative relationship between the second analog-to-digital converter and the proximity sensor is shown in the following formula:

[0043] ;

[0044] Wherein, m is the number of the second analog-to-digital converters, n is the number of proximity sensors, and [ ] indicates taking the integer part of the number in the brackets.

[0045] The number of decoders is equal to the number of second signal generators.

[0046] The main controller controls the frequency setting and modification of the first and second signal generators, controls the on / off switching of the first and second signal generators, controls the operation of the decoder, and receives digital inductance signals. Frequency setting involves setting the initial frequency of each proximity sensor channel uniformly through the main controller software; frequency modification involves modifying the initial frequency within the main controller software; when controlling the on / off switching of the first or second signal generator, the main controller sets the initial frequency of the first or second signal generator to a non-zero value to generate an excitation source; setting the initial frequency of the first or second signal generator to zero to disconnect the excitation source; when controlling the operation of the decoder, enabling the decoder enable terminal and assigning different digital values ​​to the decoder's control pins controls the operation of the decoder; and selecting the first or second analog-to-digital converter allows normal reception of the proximity sensor inductance signal.

[0047] The first signal generator and the second signal generator mainly generate sinusoidal frequency signals to provide the required excitation source for the proximity sensor.

[0048] The first processing circuit and the second processing circuit mainly amplify and filter the collected inductance value in the form of voltage to provide input signals suitable for the first analog-to-digital converter and the second analog-to-digital converter.

[0049] The first analog-to-digital converter and the second analog-to-digital converter mainly convert the analog inductance signal into a digital inductance signal.

[0050] The decoder is mainly selected by the input terminal to ensure that one of the output terminals of the second signal acquisition circuit is working. The relay mainly receives the set 1 signal from the decoder and connects the circuit where the relay is located.

[0051] The first signal acquisition circuit of a proximity sensor is as follows Figure 1 As shown in the figure, the circuit excitation terminal refers to the circuit terminal where the proximity sensor receives signals, and the signal feedback terminal refers to the circuit terminal where the proximity sensor sends feedback signals. The proximity sensor is a passive, two-wire inductive proximity sensor consisting of a stainless steel housing, a magnetic core contained within the housing, and a coil wound around the core. When the excitation signal generated by the first or second signal generator flows through the proximity sensor coil assembly, the coil generates a magnetic field. As a target moves toward the proximity sensor, the distance between the proximity sensor and the target changes, causing the magnetic resistance of the proximity sensor coil loop to change, thereby affecting the coil inductance. The resulting inductance value is transmitted as an analog voltage through amplification, filtering, and analog-to-digital conversion. The main controller then calculates the corresponding inductance value based on an algorithm.

[0052] like Figure 2 For the same proximity sensor, the hardware is equivalent to setting up two loops, where Figure 2 Processing circuit and Figure 1 The processing circuit in the circuit is identical, including an amplifier and a low-pass filter. The first signal acquisition circuit is used to receive and feedback proximity sensor signals when the normal route indicator circuit is not faulty. A second signal acquisition circuit is added to receive and feedback proximity sensor signals after a route indicator circuit fault occurs. To ensure the service life of components, in the initial state, the main controller software connects the first signal generator and first analog-to-digital converter in the first signal acquisition circuit and disconnects the second signal generator and second analog-to-digital converter in the second signal acquisition circuit. This ensures the operation of the first signal acquisition circuit and unaffects the service life of the components in the second signal acquisition circuit. When the main controller cannot receive the inductance signal of the proximity sensor of the first signal acquisition circuit, it is considered that the first signal acquisition circuit is faulty. Considering that if the fault occurs in the first analog-to-digital converter, the first signal generator can still send a normal excitation source. At this time, there will be two excitation sources in the circuit acting on the same proximity sensor at the same time. This situation is not allowed. Therefore, it is necessary to disconnect the first signal generator and the first analog-to-digital converter in the first signal acquisition circuit in the main controller software and connect the second signal generator and the second analog-to-digital converter in the second signal acquisition circuit. At the same time, it is necessary to turn on the decoder enable terminal, give the corresponding digital quantity to the control pin of the decoder, control the decoder output pin connected to the corresponding relay to 1, and power on the corresponding relay. Only then can the second signal acquisition circuit be fully connected to ensure that the excitation source generated by the second signal generator passes through the proximity sensor, so that the main controller can still receive the correct inductance signal of the proximity sensor. See the flowchart of the automatic switching from normal operation of the above circuit to failure. Figure 5 shown.

[0053] like Figure 3 The figure shows the first signal acquisition circuit diagram of 8 proximity sensors. Each proximity sensor has an inductance value generation and inductance value acquisition process. Considering that the proximity sensor and the circuit have been working for a long time, the components have aged and the parameters of the components in the circuit assembly have drifted. When it is close, it will be displayed as far away, and when it is far away, it will be displayed as close. In addition, the proximity sensor is installed outside the body and is susceptible to lightning strikes and other factors, which may cause signal overvoltage and overcurrent in the internal circuit, causing the acquisition circuit to malfunction (the inductive proximity sensor has a simple internal structure, no wearing parts, and a long service life. Therefore, the possibility of failure is very small, so the failure caused by the proximity sensor itself is not considered). In order not to affect the normal operation of the circuit, an alternative circuit design is required for the acquisition circuit. See Figure 4The first signal acquisition circuit and the second signal acquisition circuit of the eight proximity sensors shown in the figure (ADCz represents the second analog-to-digital converter, signal generator z1 represents the second signal generator, and processing circuits z1 and z2 are the second processing circuits). Compared with the full double-redundancy circuit, this embodiment uses a smaller ratio for redundant acquisition circuit design, such as Figure 4 The ratio of the number of proximity sensors to the number of second signal generators is 8:1, and the ratio of the number of proximity sensors to the number of second processing circuits is 4:1.

[0054] Figure 4 A second signal acquisition circuit has been added. Considering the service life of the electronic components of the second signal acquisition circuit, in the initial state, the main controller software sets the first signal generator and the first analog-to-digital converter of the first signal acquisition circuit of each proximity sensor to an on state (the ARM-side software of the main controller uniformly sets an initial non-zero frequency for the first signal acquisition circuit channel and sends it to the main controller via the bus. The main controller controls the first signal generator via the SPI interface to generate a sine wave at that frequency and applies it to the circuit. The corresponding control register bit in the first signal generator is set to 0 via software to ensure that the first signal generator can generate a normal frequency). This ensures the normal operation of the proximity sensor. The second signal generator and the second analog-to-digital converter of the second signal acquisition circuit are set to an off state (the ARM-side software of the main controller uniformly sets an initial zero frequency for the second signal acquisition circuit channel and sends it to the main controller via the bus. The main controller controls the second signal generator via the SPI interface to generate a zero-frequency sine wave and applies it to the circuit, or the corresponding control register bit in the second signal generator is set to 1 via software to prevent the second signal generator from emitting a normal frequency). This ensures that the second signal acquisition circuit is in an inoperative state.

[0055] When the main controller fails to receive the inductance value (in the form of a voltage signal) signal from the jth proximity sensor, it is considered that the first signal acquisition circuit of the jth proximity sensor is faulty. At this time, the main controller controls the first signal generator and the first analog-to-digital converter of the jth proximity sensor to be disconnected (in the main controller, the initial frequency of the first signal generator of the jth proximity sensor is modified to 0, or the corresponding position of the control register in the first signal generator of the jth proximity sensor is set to 1 through software to block the first signal generator of the jth proximity sensor from emitting a normal frequency). This ensures that the first signal generator of the jth proximity sensor no longer sends a sine wave signal and no longer collects the inductance value signal fed back by the first analog-to-digital converter of the jth proximity sensor. At the same time, the second signal generator and the second analog-to-digital converter of the jth proximity sensor are connected. Pass (set the corresponding frequency of the second signal generator of the jth proximity sensor to non-zero through software, and set the corresponding position of the control register in the second signal generator of the jth proximity sensor to 0 in the software to turn on the second signal generator of the jth proximity sensor to ensure that the normal frequency is emitted), provide a signal source for the jth proximity sensor, and at the same time turn on the decoder enable terminal, give the corresponding digital quantities to the three control pins of the decoder, control the decoder output pin connected to the corresponding relay to 1, and power up the relay, ensuring that the excitation source generated by the second signal generator of the jth proximity sensor passes through the proximity sensor, and the inductance value of the jth proximity sensor can be collected through the second analog-to-digital converter of the jth proximity sensor, so that the main controller can still receive the inductance value of the jth proximity sensor, so that the system works normally; j = 1, 2, ..., 8.

[0056] The contents illustrated 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 of the present invention by those skilled in the art shall fall within the scope defined by the claims attached to this application.

Claims

1. A proximity sensor signal acquisition system, characterized in that: include: A main controller, a first signal acquisition circuit, and a second signal acquisition circuit; The first signal acquisition circuit includes a first signal generator, a first processing circuit, and a first analog-to-digital converter. The first processing circuit includes a first amplifier and a first low-pass filter. A first end of the first signal generator is connected to the main controller, and a second end of the first signal generator is connected to a proximity sensor. A first end of the first amplifier is connected to the proximity sensor, a second end of the first amplifier is connected to a first end of the first low-pass filter, a second end of the first low-pass filter is connected to a first end of the first analog-to-digital converter, and a second end of the first analog-to-digital converter is connected to the main controller. The second signal acquisition circuit includes a second signal generator, a second processing circuit, a second analog-to-digital converter, a decoder, and a relay. The second processing circuit includes a second amplifier and a second low-pass filter. The first end of the second signal generator is connected to the main controller, the second end of the second signal generator is connected to the first end of the relay, the second end of the relay is connected to the proximity sensor, the first end of the decoder is connected to the main controller, and the second end of the decoder is connected to the third end of the relay. The first end of the second amplifier is connected to the proximity sensor, the second end of the second amplifier is connected to the first end of the second low-pass filter, the second end of the second low-pass filter is connected to the first end of the second analog-to-digital converter, and the second end of the second analog-to-digital converter is connected to the main controller. The number of the first signal generators, the number of the first processing circuits, and the number of the relays are equal to the number of the proximity sensors; the number of the second signal generators and the number of the second processing circuits are less than the number of the proximity sensors; The second end of the second signal generator is connected in parallel to the plurality of relays; and the first end of the second amplifier is connected in parallel to the plurality of proximity sensors.

2. The proximity sensor signal acquisition system according to claim 1, characterized in that: The quantitative relationship between the second signal generator and the proximity sensor is shown in the following formula: ； Wherein, s is the number of second signal generators, n is the number of proximity sensors, and [ ] indicates taking the integer part of the number in the brackets.

3. The proximity sensor signal acquisition system according to claim 1, characterized in that: The quantitative relationship between the second processing circuit and the proximity sensor is shown in the following formula: ； Wherein, t is the number of second processing circuits, n is the number of proximity sensors, and [ ] indicates taking the integer part of the number in the brackets.

4. A proximity sensor signal acquisition method, characterized in that: Using the proximity sensor signal acquisition system according to any one of claims 1 to 3, The following processes are included: Connecting the first signal generator, the first processing circuit, and the first analog-to-digital converter of the n proximity sensors, disconnecting the decoder, disconnecting the second signal generator, the second processing circuit, the second analog-to-digital converter, and the relay of the n proximity sensors, and collecting signals from the n proximity sensors; When the main controller fails to receive a signal from the i-th proximity sensor, the first signal generator, the first processing circuit, and the first analog-to-digital converter of the i-th proximity sensor are disconnected, the decoder is turned on, and the second signal generator, the second processing circuit, the second analog-to-digital converter, and the relay of the i-th proximity sensor are connected, where i=1, 2, ..., n.

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