A control circuit for outputting reliable aircraft air and ground signals

Abstract

The application discloses a control circuit for outputting reliable airplane air / ground signal, which comprises a power supply, a landing switch, a landing signal input end, a power supply ground, a landing gear retracting to position switch and a power supply input end, and further comprises a magnetic latching relay; the power supply is communicated with the power supply input end of an anti-skid brake controller; the power supply is respectively communicated with the power supply input ends of the landing switch and the landing gear retracting to position switch; two positive connection terminals of the magnetic latching relay are respectively communicated with the power supply output ends of the landing switch and the landing gear retracting to position switch, and the magnetic latching relay is respectively communicated with two negative connection terminals and the power supply ground; the positive connection terminal of a working end of the magnetic latching relay is communicated with the landing signal input end; and the negative connection terminal of the working end of the magnetic latching relay is communicated with the power supply ground. The application completely solves the problems of unstable and unreliable airplane air / ground signal caused by repeated disconnection and connection of the landing gear system landing switch, loss of brake function in the airplane braking process, reduction of man-machine efficiency of the airplane and long braking distance.

Description

Technical Field

[0001] This invention relates to the field of aircraft braking system technology, and in particular to a control circuit that outputs reliable aircraft air-to-ground signals. Background Technology

[0002] The General Specification for Aircraft Wheel Anti-skid Braking Control Systems (GJB2879A-2008) describes the grounding protection function as follows: Before the aircraft touches down, or even after touchdown but before the main landing gear has fully rotated, the anti-skid braking system should prevent the application of braking pressure to the wheels. The introduction of the grounding protection function should not affect the basic function of the anti-skid braking system.

[0003] Domestically produced third-generation and fourth-generation aircraft generally adopt electromagnetic anti-skid braking systems, electronic anti-skid braking systems, and digital fly-by-wire anti-skid braking systems. These braking systems use ground switches installed on the landing gear or on the nose wheel to achieve grounding protection for the braking system.

[0004] Existing aircraft landing switches or nose wheel switches are mechanical contact switches. Force applied by the landing gear during flight or on the ground changes the state of these mechanical contact switches; for example, the air contact closes while the ground contact opens. The switching signal indicated by the landing switch is fed into the aircraft's anti-skid braking system's anti-skid controller to achieve grounding protection for the braking system.

[0005] When the aircraft is in the air, the landing switch is activated, and the anti-skid controller outputs a maximum current signal. The pilot depresses the brake pedal in mid-air, and this signal causes the electro-hydraulic pressure servo valve to output zero braking pressure, achieving grounding protection. After landing, the landing switch is activated, and the anti-skid controller outputs a minimum current signal. The pilot depresses the brake pedal on the ground, and this signal causes the electro-hydraulic pressure servo valve to output braking pressure, achieving landing braking. This avoids the problem of pressurized landing caused by the pilot depressing the brakes in mid-air, and also allows the pilot to depress the brakes in mid-air and immediately after landing. It improves aircraft efficiency, shortens braking distance, and enhances runway adaptability.

[0006] Due to changes in the aircraft's landing position and center of gravity, the landing gear experiences varying loads during ground taxiing and braking. This alters the stress state of the mechanical contact switches, causing the landing switch contacts to malfunction and close. Upon receiving this signal, the anti-skid controller releases braking pressure, resulting in loss of ground braking. Because the landing switch signal is unstable and unreliable, the ground protection function of some aircraft's anti-skid braking systems is forced to be disabled, leading to reduced ergonomics and longer braking distances. Specifically... Figure 1 This is the electrical schematic diagram of the anti-skid controller for an aircraft's electronic anti-skid braking system.

[0007] A search revealed that invention CN 104494815A discloses a method for landing protection of an aircraft anti-skid braking system, including determining the system state, determining the aircraft landing state, and determining whether to initialize the aircraft landing state. By determining and initializing the aircraft landing state, various in-flight and ground states of the aircraft can be comprehensively covered, enabling landing protection in the air and anti-skid braking on the ground, forming a closed-loop control for landing protection. This invention improves the reliability of landing protection for aircraft anti-skid braking systems and achieves landing protection for aircraft with continuous in-flight power supply. However, this invention does not solve the problem of unreliable air / ground signals in the braking system.

[0008] A search revealed an invention with publication number CN 10S000173A: an aircraft brake grounding protection system and method. This system includes a brake command sensor, a brake electronic control unit, left / right brake control valves, left / right main landing gear wheel speed sensors and wheel-mounted sensors, and an aircraft inertial navigation system. This invention ensures that during landing, if the pilot accidentally applies the brakes, the system does not generate brake pressure, keeping the brakes in a released state. When the aircraft wheel-mounted signal malfunctions, it prevents the aircraft from entering a brake grounding protection state at low speeds, ensuring the aircraft can still use the brakes at low speeds and improving landing safety. However, this invention does not address the problem of unreliable air / ground signals in the brake system.

[0009] A search revealed an invention with publication number CN 105523177A: an aircraft brake grounding protection system. The system includes a brake controller, a brake control valve, wheel speed sensors, and wheel-mounted sensors. This invention ensures that during landing, if the pilot accidentally applies the brakes, the system will not output braking pressure, preventing the system from braking while landing and causing tire blowouts due to dragging, thus improving landing safety. However, this invention does not address the problem of unreliable air / ground signals in the braking system.

[0010] A search revealed that the invention with announcement number CN105620455A determines the aircraft's high / low speed status signal through logical operations of the low-speed detection unit in the anti-skid control box. The anti-skid control box collects the wheel speed signals of the left and right main landing gear wheels, processes and converts them, and uses them as a reference speed voltage signal to simulate the aircraft's speed. The low-speed detection unit of the anti-skid control box then provides the aircraft's high / low speed status. This invention ensures that the aircraft is in the air when it takes off again after landing, solving the problem of the grounding protection functioning only once. When the aircraft is on the ground, it is in a ground state, and its air / ground status is "1"; when the pilot depresses the brake pedal, the braking system outputs braking pressure to stop the aircraft; this solves the problem of brake failure caused by the grounding protection functioning at low speeds after landing. However, this invention does not solve the problem of unreliable air / ground signals in the braking system. Summary of the Invention

[0011] The purpose of this invention is to propose a control circuit that outputs reliable air-to-ground signals from aircraft, in order to solve the problem of loss of braking function during aircraft braking caused by unstable and unreliable air-to-ground signals provided by the landing switch.

[0012] To achieve the above objectives, the following technical solution is adopted: a control circuit that outputs reliable aircraft air-to-ground signals, including a power supply, a landing switch, a landing signal input terminal, a power ground, a landing gear retraction position switch and a power input terminal, and also includes a magnetic latching relay;

[0013] The power supply is connected to the power input terminal of the anti-skid brake controller;

[0014] The power supply is connected to the power input terminals of the floor switch and the landing gear retraction position switch, respectively.

[0015] The two positive terminals of the magnetic latching relay are connected to the power output terminals of the floor switch and the landing gear retraction position switch, respectively.

[0016] The two negative terminals of the magnetic latching relay are connected to the power ground.

[0017] The positive terminal of the magnetic latching relay is connected to the grounded signal input terminal;

[0018] The negative terminal of the magnetic latching relay is connected to the power supply ground.

[0019] Preferably, the magnetic latching relay is model JMX-3M RG4.520.137-9.

[0020] Preferably, the magnetic latching relay is a dual-coil single-contact or dual-contact magnetic latching relay.

[0021] Preferably, the rated voltage of the magnetic latching relay is 36V DC, the normal operating or reset voltage is no greater than 24V DC, and the maximum value is no greater than 32V DC.

[0022] Preferably, the magnetic latching relay includes a J1 coil and a J2 coil, where the J1 coil is a reset coil and the J2 coil is a set coil. The power output terminal of the landing gear retraction switch 2 is connected to the positive terminal of the magnetic latching relay J1 coil; the negative terminal of the magnetic latching relay J1 coil is connected to the power ground; the power output terminal of the landing gear retraction position switch is connected to the positive terminal of the magnetic latching relay J2 coil; and the negative terminal of the magnetic latching relay J2 coil is connected to the power ground.

[0023] Preferably, the power supply is a +28V DC power supply.

[0024] The beneficial effects achieved by this invention are as follows:

[0025] This invention provides a control circuit for outputting reliable aircraft air-to-ground signals. After takeoff and landing gear retraction, the landing gear retraction switch is activated, energizing the coil of the magnetic latching relay J2 and resetting its contacts, indicating the aircraft is in the air. After landing, the landing switch is normally closed, energizing the coil of the magnetic latching relay J1 and resetting its contacts, indicating the aircraft is on the ground. This completely solves the problem of unstable and unreliable air-to-ground signals during landing due to the repeated opening and closing of the landing gear system's landing switch, which causes loss of braking function, reduced ergonomics, and longer braking distances. This significantly improves the safety of the anti-skid controller. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of existing technology.

[0027] Figure 2 This is a schematic diagram of the control circuit of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] See appendix Figure 2 A control circuit that outputs reliable aircraft air-to-ground signals includes a power supply 1, a landing switch 2, a landing signal input terminal 3, a power ground 4, a landing gear retraction position switch 7, and a power input terminal 8, and also includes a magnetic latching relay 5.

[0030] Power supply 1 is connected to the power input terminal 8 of the anti-skid brake controller;

[0031] Power supply 1 is connected to the power input terminals of floor switch 2 and landing gear retraction position switch 7, respectively;

[0032] The two positive terminals of the magnetic latching relay 5 are connected to the power output terminals of the floor switch 2 and the landing gear retraction position switch 7, respectively.

[0033] The two negative terminals of the magnetic latching relay 5 are connected to the power supply ground.

[0034] The positive terminal of the magnetic latching relay is connected to the ground signal input terminal 3;

[0035] The negative terminal of the magnetic latching relay is connected to the power supply ground.

[0036] Power supply 1 is a +28V DC power supply.

[0037] Specifically, the magnetic latching relay 5 includes a J1 coil 51 and a J2 coil 52. The J1 coil 51 is a reset coil, and the J2 coil 52 is a set coil. The power output terminal of the landing gear retraction switch 2 is connected to the positive terminal of the magnetic latching relay J1 coil. The negative terminal of the magnetic latching relay J1 coil is connected to the power ground. The power output terminal of the landing gear retraction position switch 7 is connected to the positive terminal of the magnetic latching relay J2 coil. The negative terminal of the magnetic latching relay J2 coil is connected to the power ground.

[0038] After the landing gear retracts into position during takeoff, the landing gear retraction switch is activated, the coil of the magnetic latching relay J2 is energized, and the contacts of the magnetic latching relay are reset and closed, putting the aircraft in the air. After the aircraft lands, the landing switch is in the normally closed state, the coil of the magnetic latching relay J1 is energized, and the contacts of the magnetic latching relay are set and opened, putting the aircraft on the ground.

[0039] This invention adds magnetic latching relays to the input terminals of the landing gear retraction switch and the landing gear retraction position switch of the original anti-skid controller. By utilizing the landing gear system landing gear switch, the landing gear retraction position switch, and the magnetic latching relay, a control circuit that outputs reliable aircraft air-to-ground signals is proposed. This completely solves the problems of unstable and unreliable aircraft air-to-ground signals caused by the repeated opening and closing of the landing gear system landing gear switch during the landing phase, which leads to loss of braking function, reduced aircraft ergonomics, and longer braking distance. This improves the safety of the anti-skid controller.

[0040] The present invention also provides an aircraft air-to-ground signal control method, which, utilizing the above-mentioned control circuit, specifically includes the following steps:

[0041] a. Determine the magnetic latching relay

[0042] A magnetic latching relay is an automatic switch. Normally, the open and closed states of its contacts are held in place by the magnetic force generated by a permanent magnet. This embodiment selects a dual-coil, dual-contact normally closed electromagnetic latching relay as the automatic control element for the air / ground signal of the aircraft brake system's anti-skid controller. The dual coils are J1 and J2, with J1 being the reset coil and J2 the set coil. The magnetic latching relay is powered by a DC pulse or capacitor pulse to achieve contact switching. After contact switching, the armature inside the relay is held by the permanent magnet, and the contacts are in a holding state.

[0043] This embodiment determines the pulse width of the DC pulse or capacitor pulse supply to the dual-coil single-contact or dual-contact magnetic latching relay; determines the rated voltage; determines the contact actuation or reset voltage; and determines the contact actuation or reset time.

[0044] A magnetic latching relay with a DC voltage of 36V was selected, which meets the aircraft's +28V DC power supply requirement.

[0045] The DC pulse signal required for the state transition of the magnetic latching relay is in the millisecond range. The landing switch signal output by the landing gear system's landing switch and the landing gear retraction switch signal output by the landing gear retraction position switch are continuous DC voltage signals. Therefore, the landing switch signal and the landing gear retraction position switch signal of the aircraft landing gear system can drive the magnetic latching relay to complete the state transition.

[0046] The normal operating voltage for the magnetic latching relay is no more than 24V DC, and the maximum voltage is no more than 32V DC.

[0047] In this embodiment, a dual-coil single-contact or dual-contact magnetic latching relay with model number JMX-3M RG4.520.137-9 is selected. Its rated voltage is 36V.DC, and the normal operating or reset voltage is no more than 24V.DC, with a maximum value of no more than 32V.DC.

[0048] Determine the aircraft ground status control logic

[0049] After the main landing gear wheel of the aircraft touches the ground, the landing gear system's landing switch is disconnected, the aircraft is in a ground state, the coil of the magnetic latching relay J1 is energized, and the magnetic latching relay contacts are set to open.

[0050] After the aircraft's main landing gear lands, the coil of the magnetic latching relay J1 is energized, causing the magnetic latching relay contacts to open.

[0051] 1. Determine aircraft air signals

[0052] After takeoff, the landing gear retracts, the landing gear retraction position switch is activated, and the aircraft is in the air. The coil of the magnetic latching relay J2 is energized, the magnetic latching relay contacts are reset and closed, and the magnetic latching relay contacts return to the holding state.

[0053] Determine the aircraft air / ground control logic

[0054] The air / ground signal of the aircraft braking system anti-skid controller consists of the landing gear system landing switch, the landing gear retraction position switch, and the magnetic latching relay.

[0055] After the landing gear retracts into position, the landing gear retraction switch is activated, and the aircraft is in the air. The landing gear retraction switch controls the magnetic latching relay's secondary coil to be energized, the magnetic latching relay contacts are closed, and the magnetic latching relay is in the reset state. The magnetic latching relay sends the air status to the landing signal input terminal, and the anti-skid brake controller switches the control logic to the air status.

[0056] After the aircraft's main wheels touch down, the landing switch is turned off, and the aircraft is in a ground state. The landing switch controls the main coil of the magnetic latching relay to be energized, the contacts of the magnetic latching relay are opened, and the magnetic latching relay is in the set state. The magnetic latching relay sends the ground state to the landing signal input terminal, and the anti-skid brake controller switches the control logic to the ground state.

[0057] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A control circuit for outputting reliable aircraft air-to-ground signals, comprising a power supply, a landing switch, a landing signal input terminal, a power ground, a landing gear retraction position switch, and a power input terminal, characterized in that: It also includes magnetic latching relays; The power supply is connected to the power input terminal of the anti-skid brake controller; The power supply is connected to the power input terminals of the floor switch and the landing gear retraction position switch, respectively. The two positive terminals of the magnetic latching relay are connected to the power output terminals of the floor switch and the landing gear retraction position switch, respectively. The two negative terminals of the magnetic latching relay are connected to the power supply ground. The positive terminal of the magnetic latching relay is connected to the grounded signal input terminal; The negative terminal of the magnetic latching relay is connected to the power supply ground; The magnetic latching relay includes a J1 coil and a J2 coil. The J1 coil is a reset coil, and the J2 coil is a set coil. The power output terminal of the landing gear retraction switch is connected to the positive terminal of the magnetic latching relay J1 coil; the negative terminal of the magnetic latching relay J1 coil is connected to the power ground; the power output terminal of the landing gear retraction position switch is connected to the positive terminal of the magnetic latching relay J2 coil; the negative terminal of the magnetic latching relay J2 coil is connected to the power ground.

2. The control circuit for outputting reliable aircraft air-to-ground signals according to claim 1, characterized in that: The magnetic latching relay is a dual-coil single-contact or dual-contact magnetic latching relay.

3. The control circuit for outputting reliable aircraft air-to-ground signals according to claim 1 or 2, characterized in that: The magnetic latching relay is model JMX-3M RG4.520.137-9.

4. The control circuit for outputting reliable aircraft air-to-ground signals according to claim 2, characterized in that: The rated voltage of the magnetic latching relay is 36V DC, and the normal operating or reset voltage is no greater than 24V DC, with a maximum value of no greater than 32V DC.

5. The control circuit for outputting reliable aircraft air-to-ground signals according to claim 1, characterized in that: The power supply is a +28V DC power supply.

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