Aircraft nose wheel control device

Abstract

FIELD: vehicles.SUBSTANCE: invention relates to to aircraft nose wheel control systems. The aircraft nose wheel control device comprises a first limit switch for compressing the nose landing gear strut (1), a first relay for compressing the nose landing gear strut (2), a first closing contact of the first relay (3), a switch of the nose wheel steering mechanism (NWSM) on the ground at small and large angles (4), made in the form of a button on the aircraft control handle or on the engine control handle, a second closing contact of the first relay (5), a second relay for steering the nose wheel of the landing gear strut at large angles (6), a closing contact of the second relay (7), a second limit switch for the retracted position of the flaps (8), an electrohydraulic valve for steering the nose wheel of the aircraft at large angles (12), a first crosswind speed limit setter (9), a first crosswind speed limit comparator (10), a three-digit decoder (11), a second limit indicated airspeed setter (15), a second limit indicated airspeed comparator (16), as well as a Doppler speed and drift angle meter (DISS) installed on board as standard, a third the main landing gear compression limit switch (14) and the air signal system (ASS) (17) connected in a specific manner.EFFECT: erroneous actions by flight crews in controlling the aircraft's nose wheel at an unacceptable landing speed and / or in conditions of a strong crosswind when landing the aircraft with the flaps retracted are excluded.1 cl, 3 dwg

Description

[0001] Technical field

[0002] This invention relates to vehicles, and more specifically, to aircraft nosewheel control systems. It aims to prevent flight crews from making erroneous steering decisions during unacceptable landing speeds and / or in unacceptable crosswind conditions when landing with the flaps retracted.

[0003] Technology Level

[0004] The aircraft nose wheel control device (UUPKS) [1] is known and was selected as an analogue. It consists of a circuit breaker, two limit switches, respectively, for the extended position of the nose landing gear and the compressed position of the main landing gear, two relays, respectively, with two normally open and one normally open contacts, a switch for controlling the nose landing gear wheel, an electrohydraulic valve for switching the nose wheel to large angles, and a pressure relay measuring complex (PRMC).

[0005] The UUPKS operation begins when the main landing gear is extended and continues after the nose gear contacts the runway. The nose wheel turning mechanism (NWM) operates in damping mode and turns the nose wheel at small angles to the right or left using the left or right pedal, respectively. The NWM is engaged at larger angles (taxiing mode) using a switch, which can be a lock-in button mounted either on the control stick or the throttle handle, or a switch on the left side of the cockpit instrument panel. Taxiing mode begins when the aircraft taxis from the parking position until takeoff, and ends after landing, when the aircraft taxis to the parking position and the on-board power supply is subsequently disconnected.

[0006] The advantage of the UUPKS is that it monitors the aircraft's landing speed during the landing roll using the IKRD. This prevents flight crews from erroneously engaging the nose wheel steering mechanism (NRM) in taxi mode at an unacceptable speed. The IKRD prevents the activation of the electric hydraulic valve for shifting the nose wheel to large angles until the landing speed drops below a threshold. However, this device does not take into account crosswind speed during landing, which affects aircraft control during the landing roll, and therefore does not prevent flight crews from erroneously engaging taxi mode when the crosswind speed is unacceptable.

[0007] The UUPKS [2] was selected as a prototype, which includes a limit switch for pressing the front landing gear strut, a first relay for pressing the front landing gear strut, a first closing contact of the first relay, a switch for turning the MRK at small and large angles on the ground, a second closing contact of the first relay, a second relay for turning the front wheel of the landing gear strut at large angles, a closing contact of the second relay, a limit switch for the retracted position of the flaps and an electrohydraulic valve for turning the front wheel of the aircraft at large angles.

[0008] In the UUPKS [2], erroneous actions by flight crews in switching the MRK to taxi mode during a normal or abnormal aircraft landing run are eliminated by additionally introducing a flap lock into the UUPKS [1], which is implemented using a limit switch for their extended position. However, the UUPKS [2] does not take into account a number of special flight situations that require landing the aircraft without extending the flaps. During such an abnormal landing, the lock on the extended flaps in the UUPKS is released. Taking into account the absence of an IKRD in the UUKPS [2], flight crew errors associated with engaging the MRK at an increased landing speed, as well as during an aircraft landing in a strong crosswind, may lead to serious incidents.

[0009] Essence of the invention

[0010] The objective of the invention is to create a UUPKS that ensures the elimination of erroneous actions by flight crews in controlling the MRK during an abnormal landing, both in conditions of a strong crosswind and at an increased landing speed.

[0011] The technical result of the invention is the elimination of erroneous actions by flight crews in controlling the front wheel of an aircraft at an unacceptable landing speed and / or in conditions of a strong crosswind when landing an aircraft with the flaps retracted.

[0012] The technical result consists in expanding the functional capabilities of existing UUPKS, in which there is no blocking of the MRK turn at large angles with the flaps extended.

[0013] The most effective solution to the stated problem appears to be the inclusion in the proposed UUPKS of additional parameters received from standard onboard systems installed on all types of jet aircraft. Such systems include the Doppler ground speed and drift angle meter (hereinafter referred to as DISS) [3] and the airborne signal system (hereinafter referred to as ASS) [4].

[0014] In DISS, ground speed is determined from the frequency spectrum of the signal reflected by the earth's surface, based on the Doppler effect—the change in frequency of a signal reflected from an object depending on the object's speed. By measuring the Doppler frequency shifts along three beams with a known frequency of emitted oscillations and known projection angles, DISS determines the drift angle and ground speed. Ground speed is related to airspeed and wind speed by a navigational triangle, in which the angle between the airspeed and ground speed vectors is called the drift angle, since it is caused by a crosswind (Fig. 1). Thus, DISS can autonomously measure crosswind speed.

[0015] The use of specialized digital computers and precision primary air pressure transducers in the SVS significantly improved the accuracy of flight aerometric parameter measurements and expanded the SVS's functionality. SVS modifications differ in the range of parameters measured, the number of indicators, and electrical outputs for each parameter.

[0016] Comprehensive digital processing of existing and proposed additional parameters (maximum crosswind speed and maximum indicated airspeed) using the developed algorithm will expand the functionality of existing UUPKS by eliminating erroneous actions by flight crews in controlling the small missile system during takeoff roll in the event of emergency situations.

[0017] Implementation of the invention

[0018] Fig. 2 shows the electrical circuit diagram of the proposed UUPKS, which includes all the elements of the prototype.

[0019] The device includes:

[0020] 1 - first limit switch of the front landing gear compression (hereinafter referred to as KVOP);

[0021] 2 - the first relay for compression of the front landing gear (hereinafter referred to as the first relay);

[0022] 3 - first closing contact of the first relay;

[0023] 4 - MRK switch for small and large angles on the ground (hereinafter referred to as the MRK switch);

[0024] 5 - the second closing contact of the first relay;

[0025] 6 - the second relay for turning the front wheel of the chassis at large angles (hereinafter referred to as the second relay);

[0026] 7 - closing contact of the second relay;

[0027] 8 - second limit switch for the retracted flap position (hereinafter referred to as RLS);

[0028] 9 - the first controller of the crosswind speed limit (hereinafter referred to as the first controller);

[0029] 10 - the first crosswind speed limit comparator (hereinafter referred to as the first comparator);

[0030] 11 - three-digit decoder (hereinafter referred to as decoder);

[0031] 12 - electric hydraulic valve for turning the front wheel of the aircraft at large angles (hereinafter referred to as the electric hydraulic valve);

[0032] 13- DISS;

[0033] 14 - the third limit switch for the main landing gear compression (hereinafter referred to as MLC);

[0034] 15 - the second controller of the maximum instrument airspeed (hereinafter referred to as the second controller);

[0035] 16 - the second comparator of the maximum instrument speed (hereinafter referred to as the second comparator);

[0036] 17-SVS.

[0037] The operation of the proposed UUPKS is presented in the form of a truth table of algebra of logic, compiled according to the rule N = 2 n (Fig. 3), where

[0038] n - the number of input logical variables, which are considered, respectively, as DISS, SVS, KVZ and MRK switch.

[0039] N - the number of rows in the table, the counting of which begins from row zero, where each row of the table corresponds to a specific combination of logical (electrical) signals. The rows of the table (Fig. 3) represent combinations of input signals of the three-digit decoder 11. These combinations are generated by signals from the outputs of the on-board standard devices, respectively, DISS 13, SVS 17, KVZ 8, MRK 4. In the same rows, the "IR MRK" column shows the value of the output signal of decoder 11, which generates a control signal to turn on or off the electric hydraulic valve 12.

[0040] The following flight situations, switching and control signals correspond to the logical “0” and “1” signals of the input and output logical variables:

[0041] DISS = 1 - the crosswind speed is not less than the maximum;

[0042] DISS = 0 - permissible crosswind speed for turning on the MRK;

[0043] СВС = 1 - the instrument speed during the run is not less than the maximum;

[0044] SVS = 0 - permissible instrument speed for turning on the MRK;

[0045] KVZ = 1 - flaps extended;

[0046] KVZ = 0 - flaps retracted;

[0047] MRK = 1 - the MRK switch is on;

[0048] MRK = 0 - the MRK switch is off;

[0049] IU = 0 - the electric hydraulic valve is off;

[0050] IU = 1 - the electric hydraulic valve is on.

[0051] Using the table (Fig. 3) allows for a line-by-line analysis of all flight and ground situations for transferring the aircraft to taxi mode:

[0052] - 0-line - in flight, the electric hydraulic valve 12 for turning the front wheel of the aircraft at large angles is disabled;

[0053] - 1st line - switching the MRK to large angles for taxiing (tacking) from the place (to the place) of the aircraft parking or for maneuvering when taxiing before takeoff;

[0054] - 2, 3, 6, 7, 10, 11, 14, 15-line - blocking the inclusion of the MRK at large angles with the flaps extended;

[0055] - 0, 4, 8, 12-line - when the flaps are retracted, the MRK 4 switch is not turned on, therefore the electric hydraulic valve 12 is also not turned on;

[0056] - 5th line - blocking of erroneous activation of the MRK at large angles with the flaps retracted at an instrument speed greater than or equal to the maximum permissible speed;

[0057] - 9th line - blocking of erroneous activation of the MRK at large angles with the flaps retracted at a crosswind speed greater than or equal to the maximum permissible;

[0058] - 13th line - blocking of erroneous activation of the MRK at large angles with the flaps retracted at values ​​of the indicated airspeed and crosswind speed greater than or equal to the permissible values.

[0059] The device operates from the moment the KVOO 14 is triggered during the aircraft's landing run. Through its contact, power is simultaneously supplied to the first 9 and second 15 setters, as well as the circuits of the DISS 13 and SVS 17 precision primary measuring transducers, and all devices are activated. Signals from the outputs of the first 9 and second 15 setters, and from the outputs of the DISS 13 and SVS 17 measuring circuits, are fed to the first 10 and second 16 comparators. The comparators generate inhibiting (logical "0") or enabling (logical "1") signals.

[0060] If the nose landing gear is not compressed (takeoff, landing, flight), then the KVOP 1 is open. Relay 2 is de-energized, its first contact 3 opens the circuit of the MRK switch 4, generating a logical "0" signal at its output (lines 0, 2, 4, 6, 8, 10, 12, 14). As a result, the second relay 6 is de-energized and the circuit supplying the control signal to the electric hydraulic valve 12 is open. Thus, in all flight and ground situations, the actuator (hereinafter referred to as AU) of the MRK, which is the electric hydraulic valve 12, is not supplied with power, therefore, the MRK cannot turn at large angles.

[0061] After the front landing gear is lowered, the KVOP contact 1 closes, power is supplied to the first relay 2. The relay, with its first normally open contact 3, prepares the circuit for turning on the MRK switch 4, and with its second normally open contact 5, prepares the circuit for turning on the second relay 6. Moving the MRK switch 4 to the on position ensures the operation of the second relay 6, which, with its normally open contact 7, prepares the circuit for turning on the KVZ 8. In the event of flaps retraction, the electrical circuit is broken and the logical "0" signal is supplied to the first input of the decoder 11. If the crosswind speed and the indicated airspeed of the aircraft are less than the maximum permissible values, then logical "0" signals are supplied from the outputs of the first 10 and second 16 comparators, respectively, to the second and third inputs of the decoder 11. The combination of "0-0-0" signals at the inputs of the decoder 11 generates a logical "1" signal at its only output, which corresponds to the supply power supply to the electric crane 12.From this moment on, the front wheel of the aircraft can turn at large angles (row 1 of the table in Fig. 3).

[0062] When the flaps are extended, the logical "1" signal from the output of the KVZ 8 is sent to the first input of the decoder 11 via the following circuit: "+" of the on-board network - closed contact 7 of the second relay - closed contact of the KVZ 8. Any combination of signals associated with the supply of a logical "1" signal to the first input of the decoder 11 (lines 2, 3, 6, 7, 10, 11, 14, 15) results in the appearance of a logical "0" signal at the corresponding lines of its outputs, which are not used. Power is not supplied to the electric hydraulic crane 12 and turning the missile ship at large angles is impossible.

[0063] If the crosswind speed during landing is not less than the maximum crosswind speed set by the first setter 9 (a logical "1" signal is present at its output), a logical "1" signal is sent from the DISS output 13 to the second input of the first comparator 10. A combination of "1-1" signals at the inputs of the first comparator 10 results in the formation of a logical "1" signal at its output, which is sent to the second input of the decoder 11. Any combination of signals associated with the supply of a logical "1" signal to the second input of the decoder 11 (lines 8-15) results in the appearance of a logical "0" signal at the corresponding lines of its outputs. Power is not supplied to the electric hydraulic crane 12, and large-angle turns of the MRK are impossible.

[0064] If the indicated airspeed of the aircraft on landing is not less than the maximum indicated airspeed set by the second setter 15 (there is a logical "1" signal at the setter output), then a logical "1" signal is sent from the output of the SVS 17 to the second input of the second comparator 16. The combination of signals "1-1" at the inputs of the second comparator 16 leads to the formation of a logical "1" signal at its output, which is sent to the third input of the decoder 11. Any combination of signals associated with the supply of a logical "1" signal to the third input of the decoder 11 (lines 4, 5, 6, 7, 12, 13, 14, 15) leads to the appearance of a logical "0" signal at the corresponding lines of its outputs. Power is not supplied to the electric hydraulic crane 12 and turning the MRK at large angles is impossible.

[0065] The proposed UUPKS in terms of carrying out all ground checks of the MRK is no different from the prototypes, and can be implemented on all types of aircraft that have the same method of controlling the MRK.

[0066] Literature

[0067] 1. Mamulin A.V. IPC B64C 25 / 50. Invention application 92007515 / 1 1 dated 23.11.1992. Aircraft nose wheel control device. Application published on 20.10.1996.

[0068] 2. MiG-23UB Pilot's Manual. Part One. Flight Operation. Military Publishing House of the Ministry of Defense. 1980 (open access).

[0069] 3. Aircraft Instrumentation. Study Guide. Ulyanovsk Higher Aviation School of Civil Aviation. 2014.

[0070] 4. Aircraft Electronic Equipment and Its Flight Operation. Study Guide. Saint Petersburg State University of Civil Aviation. 2006.

Claims

A device for controlling the nose wheel of an aircraft, comprising a first limit switch for compressing the nose landing gear strut (1), a first relay for compressing the nose landing gear strut (2), a first closing contact of the first relay (3), a switch for turning the nose wheel of the aircraft (NWT) on the ground at small and large angles (4), made in the form of a button on the control handle of the aircraft or on the engine control handle, a second closing contact of the first relay (5), a second relay for turning the nose wheel of the landing gear strut at large angles (6), a closing contact of the second relay (7), a second limit switch for the retracted position of the flaps (8), an electrohydraulic valve for turning the nose wheel of the aircraft at large angles (12), characterized in that, in order to eliminate errors by the flight crew in controlling the nose wheel of the aircraft at an unacceptable landing speed and / or in conditions of an unacceptable crosswind during an abnormal landing with the flaps retracted,it additionally includes a first crosswind limit speed controller (9), a first crosswind limit speed comparator (10), a three-digit decoder (11), a second limit instrument speed controller (15), a second limit instrument speed comparator (16), as well as a Doppler speed and drift angle meter (DSA) (13), a third limit switch for compressing the main chassis strut (14) and an air signals system (ASS) (17) installed as standard on board, wherein the inputs of the first limit switch for compressing the front chassis strut (1), the third limit switch for compressing the main chassis strut (14), the first closing contact of the first relay (3) for compressing the front chassis strut, the first closing contact of the second relay (7) for turning the front wheel of the chassis strut at large angles are connected to the positive bus of the on-board network, and the outputs of the first (2),the second relay (6) and the output of the electrohydraulic valve for turning the front wheel of the aircraft at large angles (12) are connected to the negative bus of the on-board network, the output of the first limit switch for compressing the front landing gear strut (1) is connected to the input of the first relay (2), the output of the first closing contact of the first relay (3) is connected to the input of the MRK switch (4), the output of the first closing contact of the second relay (7) is connected to the input of the second limit switch for the retracted position of the flaps (8), the output of the MRK switch (4) is connected to the input of the second closing contact of the first relay (5), the output of which is connected to the input of the second relay (6), then the output of the third limit switch for compressing the main landing gear strut (14) is simultaneously connected to the inputs of the first (9) and second setters (15), DISS (13) and SVS (17), the outputs of which are connected, respectively, of the first (9) and second setters (15) to the first inputs of the first (10) and second comparators (16),and the outputs of the DISS (13) and SVS (17) with the second inputs of the first (10) and second comparators (16), the outputs of the second limit switch of the retracted position of the flaps (8), the first (10) and second comparators (16) are connected, respectively, to the first, second and third inputs of the three-digit decoder (11), the output of which is connected to the input of the electrohydraulic valve for turning the front wheel of the aircraft at large angles (12).,

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