Portable airplane front wheel bearing switch in-situ detection and simulation equipment
By designing a portable in-situ detection and simulation device for aircraft nose wheel load-bearing switches, and using a host computer and laser ranging module, the device solves the problems of inaccurate and cumbersome detection in existing technologies, and realizes a high-precision and automated detection process, supporting single-person operation and multi-scenario applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-03
- Publication Date
- 2026-03-31
AI Technical Summary
The lack of comprehensive testing equipment in the current technology leads to inaccurate detection of aircraft wheel load switches, inability to simulate load switch output signals, inability to detect crosslinking faults, and the cumbersome testing process requiring the cooperation of multiple people.
Design a portable in-situ detection and simulation device for the bearing switch of an aircraft nose wheel. The device uses a host, a laser ranging module and test accessories, combined with an embedded processing module, a switch quantity detection module and a switch quantity simulation module to realize the detection and simulation of the response status and channel consistency of the bearing switch.
It achieves a high-precision, automated testing process, reduces human error, supports single-person operation, is suitable for various testing scenarios, and improves the versatility and accuracy of testing equipment.
Smart Images
Figure CN224061197U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a portable in-situ testing and simulation device for the bearing switch of an aircraft nose wheel, belonging to the field of airborne equipment testing and maintenance technology. Background Technology
[0002] The aircraft wheel bearing switch is a crucial laser ranging module used by onboard systems to determine the aircraft's ground / non-ground status. A malfunction can lead to serious problems such as abnormal control rate transitions in the fly-by-wire system and abnormal wing folding, directly threatening flight safety. Currently, there is no dedicated testing equipment with comprehensive functions to match this. Most tests rely on tools such as flight control diagnostic instruments, multimeters, and rulers to adjust and check the bearing switch's compatibility with the nose landing gear strut. The ranging methods are not rigorous enough, resulting in inaccurate measurements. Furthermore, the testing process is cumbersome, requiring multiple personnel. In addition, current testing equipment is limited in function, only detecting the bearing switch's output status and unable to simulate its output signal. Therefore, it cannot detect cross-linking faults related to the onboard cross-linking system. Moreover, the detection function and the precise ranging function are independent and cannot be used in precise coordination.
[0003] To address this issue, there is an urgent need to design a portable in-situ testing device for aircraft wheel load-bearing switches that can solve the aforementioned technical problems. Summary of the Invention
[0004] To address the shortcomings of the existing technology, a portable in-situ testing and simulation device for the aircraft nose wheel load switch is provided, which enables the verification of the load switch's response status and channel consistency, as well as the related functions of the aircraft fly-by-wire system.
[0005] This utility model is a portable in-situ detection and simulation device for the aircraft nose wheel load switch. Its special feature is that it includes a main unit 1, a laser ranging module 2, and a test accessory 3. The main unit 1 communicates with the laser ranging module 2 and the test accessory 3. The laser ranging module 2 is fixed with a clamp 4 and tightly attached to the aircraft landing gear strut 5.
[0006] The host computer 1 includes a control board 1-1, an LCD touch screen 1-2, and a lithium battery pack 1-3. The control board 1-1 comprises an embedded processing module 1-4, a switch quantity detection module 1-5, a switch quantity simulation module 1-6, a power management circuit 1-7, and a laser ranging signal detection circuit 1-8. The LCD touch screen 1-2 is used to build a host computer test display interface, facilitating operators to issue commands and read information. The embedded processing module 1-4 is used to process collected information, issue control commands, process test data, and plan the collaborative work between modules. The switch quantity detection module 1-5... The system detects the output signal of the load-bearing switch to determine the on / off state of the switch and the time difference between the changes in each switch state; the switch quantity simulation modules 1-6 simulate and output multiple load-bearing switch signals for auxiliary detection of the onboard associated system; the lithium battery pack 1-3 provides internal power; the power management circuit 1-7 meets the power supply requirements of various peripheral circuits through a voltage regulator circuit, detects the power supply status of the lithium battery pack in real time, and displays the power level and battery status data on the LCD screen; the laser ranging signal detection circuit 1-8 detects the output signal of the laser ranging module, uses an ADC for acquisition, and facilitates subsequent processing.
[0007] The laser ranging module 2 collects the compression of the landing gear strut in real time and sends it to the embedded processing modules 1-4 for further processing.
[0008] The test accessory 3 includes a wheel bearing switch, a clamp, and a connecting cable. The wheel bearing switch is connected to the host 1 via a cable. The clamp fixes the laser ranging module 2 to the aircraft landing gear strut and is connected to the host 1 via a cable.
[0009] Preferably, the embedded processing module 1-4 uses an STM32F407VET6 as the core processor; the laser ranging module 2 uses serial communication to measure data in real time and sends it to the embedded processing module 1-4 via RS232 for further processing.
[0010] Preferably, the switch quantity detection module 1-5 includes a button debouncing circuit 1-5-1, a first optocoupler TLP521 1-5-2, and a PESD3V3L1BA device 1-5-3. The button debouncing circuit 1-5-1 utilizes the delay principle of capacitor charging and discharging to eliminate ripple; the first optocoupler TLP521 1-5-2 is used to isolate analog signals; and the PESD3V3L1BA device 1-5-3 is a low-capacitance bidirectional diode that provides electrostatic discharge protection.
[0011] Preferably, the analog switch module 1-6 includes a second optocoupler TLP521 1-6-1 and a transistor control circuit 1-6-2. The second optocoupler TLP521 1-6-1 is used for signal isolation. The transistor control circuit 1-6-2 generates high / low levels by the processor control pin to control the base of the transistor. When the processor generates a high level, the transistor is turned on, the circuit output terminal OUT is grounded, and the circuit outputs a low level. When the processor generates a low level, the transistor is not turned on, and the voltage at the circuit output terminal OUT is DC27V, thereby simulating the on / off state of the carrier switch.
[0012] Preferably, the power management circuit 1-7 includes a protection circuit 1-7-1 and a step-down circuit. The step-down circuit uses an LM2596 step-down chip 1-7-2 to generate DC 5V and an SP6205-3.3 step-down chip 1-7-3 to generate DC 3.3V. The protection circuit 1-7-1 uses a fusible fuse to prevent excessive instantaneous current from causing safety hazards and uses a TVS to prevent surges.
[0013] Preferably, the laser ranging module 2 adopts the L1 laser ranging module of Shenzhen Motian Technology. The output of this module is a 4-20mA analog signal, with a resolution of 1mm, a measurement range of 0.05-40m, and a repeatability of ±1mm.
[0014] Preferably, the laser ranging signal detection circuit 1-8 includes an input current-to-voltage conversion section 1-8-1, a voltage conditioning section 1-8-2, a filtering section 1-8-3, an AD acquisition section 1-8-4, and a voltage follower 1-8-5. The input current-to-voltage conversion section 1-8-1 is used to convert the current signal output by the laser ranging module into a voltage signal; the voltage conditioning section 1-8-2 is used to condition the voltage value and attenuate the voltage at both ends to facilitate voltage acquisition by the ADC; the filtering section 1-8-3 uses an RC filter to reduce out-of-band noise, and the cutoff frequency of the RC filter is set to match the sampling rate of the ADC; the AD acquisition section 1-8-4 is used to convert the analog signal into a digital signal to facilitate data processing by the embedded processing module; and the voltage follower 1-8-5 is used to buffer the reference voltage value of the ADC.
[0015] Preferably, the LCD touch screen 1-2 communicates with the embedded processing module 1-4 via RS232; the LCD touch screen 1-2 adopts Guangzhou Dacai's DC80480KM043 serial port screen with a resolution of 800*480.
[0016] This utility model provides a portable in-situ detection and simulation device for the bearing switch of an aircraft nose wheel, which has the following advantages:
[0017] 1. Integrated design significantly improves overall performance. This testing equipment adopts an integrated design, automating multi-channel wheel-load signal detection and high-precision measurement of landing gear strut compression under the control of a high-speed processor. This reduces human measurement errors and the difficulties of multi-person collaboration, and can be applied to various occasions such as aircraft inspection, nose landing gear replacement, load-bearing switch fault replacement, and wheel load-bearing related fault isolation. Furthermore, while performing wheel-load signal detection, it can also achieve analog output of these signals to verify the channel function of onboard systems associated with wheel-load switches. This can be used for the detection of onboard related systems and fault isolation between wheel-load switches.
[0018] 2. High detection accuracy. Through control board circuit design and detection process optimization, the multi-channel state consistency detection of the wheel bearing switch has high accuracy, with a measurement accuracy of 0.1ms; the measurement accuracy of the landing gear strut compression is also high, with a measurement accuracy of 1mm.
[0019] 3. The testing equipment is highly versatile. It can be applied to the performance testing and fault isolation of wheel bearing switches using similar technical systems, making it easy to promote and apply to other machine models and effectively improving the mutual protection capability of the same equipment.
[0020] 4. This testing equipment uses an embedded processing module to automate the testing process. It employs a single testing terminal, offering ease of operation. The test process is programmed, ensuring high accuracy and consistent results across multiple tests. The embedded processing module reads signal changes, and a high-precision laser rangefinder measures the landing gear strut compression, significantly improving testing performance.
[0021] This utility model adopts a portable design with a simple and user-friendly human-machine interface. It adopts a universal and integrated design, is small in size and light in weight, requires no other supporting equipment, and is easy to operate and use in the field, meeting the in-situ testing requirements of aircraft wheel load-bearing switches. Attached Figure Description
[0022] Figure 1 This utility model relates to a portable in-situ testing and simulation device for the bearing switch of an aircraft nose wheel.
[0023] Structural block diagram;
[0024] Figure 2 This is a block diagram of the control board circuit.
[0025] Figure 3 Design diagram for embedded processor module interface;
[0026] Figure 4 This is a power management circuit diagram;
[0027] Figure 5 This is the circuit diagram for the switch quantity detection module;
[0028] Figure 6 This is a circuit diagram for analog switching signals;
[0029] Figure 7 This is a layout diagram of the front panel of this utility model;
[0030] Figure 8 This is a circuit diagram of the laser ranging signal detection circuit of this utility model;
[0031] Figure 9 This is a schematic diagram of the laser ranging module of this utility model being fixed to the nose wheel strut of an aircraft using a clamp. Detailed Implementation
[0032] This embodiment details a portable in-situ detection and simulation device for an aircraft nose wheel load-bearing switch, as described in the attached document. Figure 1-9 It includes a main unit 1, a laser ranging module 2, and a test accessory 3. The main unit 1 communicates with the laser ranging module 2 and the test accessory 3. The laser ranging module 2 is fixed in place by a clamp 4 and tightly attached to the aircraft landing gear strut 5.
[0033] Main Unit 1 Reference Appendix Figure 2 The system includes a control board 1-1, an LCD touchscreen 1-2, and a lithium battery pack 1-3. The control board 1-1 comprises an embedded processing module 1-4, a switch quantity detection module 1-5, a switch quantity simulation module 1-6, a power management circuit 1-7, and a laser ranging signal detection circuit 1-8. The LCD touchscreen 1-2 is used to build a host computer test display interface, facilitating operators to issue commands and read information. The embedded processing module 1-4 is used to process collected information, issue control commands, process test data, and plan the collaborative work between various modules. The switch quantity detection module 1-5 completes the detection of the load switch output signal, determines the switch on / off state, and the time difference between the changes in each switch state. The switch quantity simulation module 1-6 simulates the output of multiple load switch signals for auxiliary testing of the on-board associated system. The lithium battery pack 1-3 provides internal power. The power management circuit 1-7 meets the power supply requirements of various peripheral circuits through a voltage regulator circuit, detects the power supply status of the lithium battery pack in real time, and displays the power and battery status data on the LCD screen. The laser ranging signal detection circuit 1-8 is used to detect the output signal of the laser ranging module, uses an ADC for acquisition, and facilitates subsequent processing. Use clamp 4 to fix the laser rangefinder module 2 to the aircraft's nose landing gear strut 5, as shown in the diagram. Figure 9 As shown, the laser ranging module 2 can be fixed in the groove inside the clamp 4, move with the aircraft's nose landing gear strut 5, and measure the compression of the landing gear strut.
[0034] The core of embedded processing modules 1-4 is an embedded microprocessor, which has high-speed computing and data processing capabilities, rich peripheral interfaces, supports various communication interfaces, timers, ADCs, etc., and adopts advanced low-power technology, making it widely used in industrial control, the Internet of Things, and other fields. Embedded systems have advantages such as small size, low power consumption, fast computing speed, short interrupt response time, and support for real-time multitasking.
[0035] Switch quantity detection modules 1-5, see Figure 5 The module includes a button debouncing circuit 1-5-1, a first optocoupler TLP521 1-5-2, and a PESD3V3L1BA device 1-5-3. The button debouncing circuit 1-5-1 utilizes the delay principle of capacitor charging and discharging to eliminate ripple; the first optocoupler TLP521 1-5-2 is used to isolate analog signals; and the PESD3V3L1BA device 1-5-3 is a low-capacitance bidirectional diode that provides electrostatic protection. This module needs to acquire multiple status signals and uses a multi-channel I / O interface circuit for status reading. Switch signals undergo hardware debouncing, optocoupler isolation, and finally edge capture using microcontroller interrupt processing. The rising and falling edges of the signals are captured, and the time difference of each signal is recorded starting from the first capture point. This module sends the acquired data to an embedded processing module for processing and display. The switch detection module 1-6 needs to read two sets of four status signals each, using eight I / O channels. After hardware debouncing, the switch signals are optocoupled and then edge-captured using microcontroller interrupt handling. The rising and falling edges of the signals are recorded, with the first capture point as the starting point. The collected data is displayed and analyzed. If the time interval exceeds a set threshold, an alarm is triggered; if not all switch signals are detected, an error is displayed.
[0036] The switch quantity simulation modules 1-6 utilize multi-channel transistor control circuits. Through the control level output from the embedded processing module, they output multiple switch signals to simulate the output signals of the aircraft wheel load-bearing switch. This is used to verify whether the aircraft fly-by-wire system can accurately detect the wheel load signal status. The switch quantity simulation modules 1-6 also use transistor control circuits, with a microcontroller controlling I / O level changes, to simulate four status signals and output four I / O switch signals to simulate the switching signals of the aircraft wheel load-bearing switch. This is used to verify whether the fly-by-wire computer can accurately detect the wheel load status. The four simulated signals can be manually controlled via a human-machine interface, including one-button connection and one-button disconnection.
[0037] Digital input / output analog modules 1-6, as shown Figure 6As shown, the analog switch module 1-6 includes a second optocoupler TLP521 1-6-1 and a transistor control circuit 1-6-2. The second optocoupler TLP521 1-6-1 is used for signal isolation. The transistor control circuit 1-6-2 generates high / low levels by the processor control pin to control the base of the transistor. When the processor generates a high level, the transistor is turned on, the circuit output terminal OUT is grounded, and the circuit outputs a low level. When the processor generates a low level, the transistor is not turned on, and the voltage at the circuit output terminal OUT is DC27V, thereby simulating the on / off state of the carrier switch.
[0038] The LCD touchscreen 1-2 communicates with the embedded processing module 1-4 via RS232. The human-machine interface is implemented using the LCD touchscreen, allowing direct user operation and function switching via touch. Functions include precise distance measurement, acquisition channel status consistency, and analog switch status output, with test data displayed on the interface. The display has high resolution, a large display area, and high color fidelity. It has its own driver circuit. In this embodiment, the LCD touchscreen 1-2 can communicate with the embedded processing module via RS232, exhibiting high touch sensitivity and stable information transmission. The LCD touchscreen 1-2 uses a Guangzhou Dacai DC80480KM043 serial port screen with a resolution of 800*480, a large display area, and high color fidelity. This screen is a resistive touchscreen, using serial communication, and features high touch sensitivity and stable information transmission.
[0039] The laser ranging module 2 uses the L1 laser ranging module from Shenzhen Motian Technology, which has a resolution of 1mm, a measurement range of 0.05-40m, a repeatability of ±1mm, and a serial communication interface. It features high measurement accuracy, simple control method, and easy installation.
[0040] The power supply function of the equipment is mainly achieved through power management circuits 1-7 and lithium battery packs 1-3. For example... Figure 4As shown, the power management circuit 1-7 includes a protection circuit 1-7-1 and a step-down circuit. The step-down circuit uses an LM2596 step-down chip 1-7-2 to generate DC 5V and an SP6205-3.3 step-down chip 1-7-3 to generate DC 3.3V. The protection circuit 1-7-1 uses a fusible fuse to prevent excessive instantaneous current from causing safety hazards and a TVS to prevent surges. According to the specifications, the external power supply is DC 27V, and the detection and simulation equipment is powered by a lithium battery. The power requirements of the core control board include DC 27V for the switch quantity simulation module, DC 5V for the display processing module, and DC 3.3V for the processor module. Fusible fuses are used to prevent excessive instantaneous current from causing safety hazards, and TVS is used to prevent surges. In terms of battery selection, lithium batteries have a longer lifespan than lead-acid batteries and a smaller size than nickel-metal hydride batteries. Therefore, in order to meet the requirements of portability, miniaturization, support for independent use in the field, and continuous operation for no less than 5 hours, this testing equipment mainly uses lithium batteries as its power source.
[0041] Laser ranging signal detection circuits 1-8, see attached diagram. Figure 8 The system includes an input current-to-voltage conversion section 1-8-1, a voltage conditioning section 1-8-2, a filtering section 1-8-3, an AD acquisition section 1-8-4, and a voltage follower 1-8-5. The input current-to-voltage conversion section 1-8-1 converts the current signal output from the laser ranging module into a voltage signal. The voltage conditioning section 1-8-2 conditions the voltage value and attenuates the voltage across the terminals for easier voltage acquisition by the ADC. The filtering section 1-8-3 uses an RC filter to reduce out-of-band noise, and the cutoff frequency of the RC filter is set to match the sampling rate of the ADC. The AD acquisition section 1-8-4 converts the analog signal into a digital signal for data processing by the embedded processing module. The voltage follower 1-8-5 buffers the reference voltage value of the ADC. The power supply requirements of each module within the device are met by a step-down circuit. The step-down chip must meet the requirements of a wide input voltage range and high conversion efficiency. Furthermore, considering the stability of the power system, necessary power isolation and protection are implemented before connecting the load.
[0042] This device uses an external DC27V power supply for power and charging. It features a built-in lithium battery that is small in size and has a long lifespan, meeting the requirements for portability and miniaturization, and supporting independent use in the field. The lithium battery pack has a status monitoring function; the embedded processing module reads the internal operating status of the battery via IIC communication, and reads and displays parameters such as battery temperature, battery operating voltage, and battery charge.
[0043] Power consumption calculation: The main electrical components in the equipment are LCD screen, laser rangefinder, and microcontroller module. Based on theoretical calculations and actual measurements, the maximum power consumption of the equipment does not exceed 4W, the peak current does not exceed 600mA, and the power consumption for continuous operation for 5 hours does not exceed 20W. Therefore, the selected battery is a DC27V 31Wh lithium battery with a maximum discharge current of 2A or more. Thus, it meets the requirements in terms of both power consumption and maximum discharge current.
[0044] The lithium battery pack has a status monitoring function. The microcontroller reads the internal operating status of the battery through IIC communication. In this embodiment, it mainly reads and displays the battery temperature, battery operating voltage, and battery charge.
[0045] The buck circuit design primarily aims to meet the power supply requirements of the microprocessor, switch quantity detection module, and communication module. Considering the direct use of DC27 for power supply, the buck chip selection must also meet the requirements of a wide input voltage range and high conversion efficiency. Furthermore, considering the stability of the power system, power isolation and protection must be implemented before connecting to the core control board. The LM2596-5V and SP6205-3.3V modules are selected to generate DC5V and DC3.3V respectively.
[0046] The portable in-situ detection and simulation device for the bearing switch of an aircraft front wheel according to this embodiment has the following advantages:
[0047] 1. Integrated design significantly improves overall performance. Compared to traditional testing methods that rely on diverse and complex tools and equipment such as flight control diagnostic tools, multimeters, and stopwatches, and are performed manually, the convenience, accuracy, and consistency of testing are difficult to guarantee. This testing equipment adopts an integrated design, automating the testing process, including multi-channel wheel-mounted signal detection and high-precision measurement of landing gear strut compression, under the control of a high-speed processor. This reduces human measurement errors and the difficulties of multi-person collaboration, and can be applied to various occasions such as aircraft inspections, nose landing gear replacement, load-bearing switch fault replacement, and wheel load-bearing related fault isolation. In addition, while completing wheel-mounted signal detection, it can also realize the analog output of such signals to verify the channel function of the onboard systems associated with the wheel-mounted switches. This can be used for the detection of onboard related systems and fault isolation between the wheel-mounted switches and the system.
[0048] 2. High precision of the testing equipment. Through control board circuit design and testing process optimization, the multi-channel state consistency detection of the wheel bearing switch has high precision, with a measurement accuracy of 0.1ms; the measurement accuracy of the landing gear strut compression is also high, with a measurement accuracy of 1mm.
[0049] 3. The testing equipment is highly versatile. It can be applied to the performance testing and fault isolation of wheel bearing switches using similar technical systems, making it easy to promote and apply to other machine models and effectively improving the mutual protection capability of the same equipment.
[0050] The above embodiments have provided a detailed description of the present invention. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the protection scope of the present invention.
Claims
1. A portable aircraft nose wheel load switch in situ detection and simulation apparatus, characterized by The main machine, the laser ranging module and the test accessory are in communication, and the laser ranging module is fixed on the aircraft landing gear strut by using the clamp and closely adheres to the aircraft landing gear strut; The main machine comprises a control board, a liquid crystal touch screen and a lithium battery pack; the control board comprises an embedded processing module, a switching value detection module, a switching value simulation module, a power management circuit and a laser ranging signal detection circuit; The liquid crystal touch screen is used to build a display interface of the upper computer for facilitating the operator to issue instructions and read information; The embedded processing module is used to process collected information, issue control instructions, process test data and plan cooperative work among modules; The switching value detection module detects the output signal of the bearing switch, judges the on-off state of the switch and the time difference when the state of each switch changes; The switching value simulation module simulates the output of multiple bearing switch signals and is used for auxiliary detection of the on-off system on the aircraft; The lithium battery pack is used for internal power supply; The power management circuit meets the power supply requirements of each peripheral circuit through a voltage stabilizing circuit, detects the power supply state of the lithium battery pack in real time and displays the power and battery state data on the liquid crystal display screen; The laser ranging signal detection circuit is used to detect the output signal of the laser ranging module and is collected by using an ADC for subsequent processing; The laser ranging module collects the compression amount of the landing gear strut in real time and sends it to the embedded processing module for further processing.
2. A portable aircraft nose landing gear load switch in situ detection and simulation apparatus according to claim 1, characterised in that The test accessory comprises a wheel bearing switch, a clamp and a connecting cable; the wheel bearing switch is connected to the main machine through the cable; and the clamp is used to fix the laser ranging module on the aircraft landing gear strut and is connected to the main machine through the cable.
3. A portable aircraft nose landing gear load switch in situ detection and simulation apparatus according to claim 1, wherein The embedded processing module adopts STM32F407VET as the core processor; the laser ranging module adopts serial communication, measures data in real time and sends the data to the embedded processing module through RS232 for further processing.
4. A portable aircraft nose landing gear load switch in situ detection and simulation apparatus according to claim 1, wherein The switching value detection module comprises a key dithering elimination circuit, a first optocoupler TLP521 and a PESD3V3L1BA device; the key dithering elimination circuit eliminates ripple by using the delay principle of capacitor charging and discharging; the first optocoupler TLP521 is used for isolating an analog signal; and the PESD3V3L1BA device is a low-capacitance bidirectional diode and is used for electrostatic protection.
5. A portable aircraft nose wheel steering switch in-place detection and simulation device in accordance with claim 1, wherein The switching value simulation module comprises a second optocoupler TLP521 and a triode control circuit; the second optocoupler TLP521 is used for signal isolation; the triode control circuit generates a high / low level by a control pin of the processor, controls the base of the triode, and when the processor generates a high level, the triode is turned on, the output end OUT of the circuit is grounded, and the circuit outputs a low level; when the processor generates a low level, the triode is not turned on, the voltage of the output end OUT of the circuit is DC 27V, thereby simulating the on / off state of the bearing switch.
6. A portable aircraft nose wheel steering switch in-place detection and simulation device in accordance with claim 1, wherein The power management circuit comprises a protection circuit and a step-down circuit; the step-down circuit selects an LM2596 step-down chip to convert and generate DC 5V and selects an sp6205-3.3 step-down chip to generate DC 3.3V; the protection circuit adopts a fusible fuse to prevent safety hazards caused by excessive instantaneous current and adopts a TVS to prevent surges.
7. A portable aircraft nose wheel steering switch in-place detection and simulation device in accordance with claim 1, wherein The output of the laser ranging module is a 4-20mA analog signal, the resolution reaches 1mm, the measurement range is 0.05-40m, and the repeat accuracy is ±1mm.
8. A portable aircraft nose landing gear load switch in situ detection and simulation apparatus according to claim 1, wherein The laser ranging signal detection circuit comprises an input current-voltage conversion part, a voltage conditioning part, a filtering part, an AD acquisition part and a voltage follower, the input current-voltage conversion part is used for converting the current signal output by the laser ranging module into a voltage signal, the voltage conditioning part is used for conditioning the voltage value and attenuating the voltage at both ends, so as to facilitate the voltage acquisition of the ADC, the filtering part uses an RC filter to reduce the out-of-band noise, the cut-off frequency of the RC filter is set to match the sampling rate of the ADC, the AD acquisition part is used for converting the analog signal into a digital signal, so as to facilitate the data processing of the embedded processing module, and the voltage follower is used for buffering the reference voltage value of the ADC.
9. A portable aircraft nose wheel steering switch in-place detection and simulation device in accordance with claim 1, wherein The liquid crystal touch screen communicates with the embedded processing module through RS232.