Aircraft ground steering system and aircraft ground steering control method

Abstract

The invention provides an aircraft ground steering system and an aircraft ground steering control method, which can realize steering and runway separation of an aircraft under a low-speed condition even if a front wheel turning system cannot work normally, and can inhibit or avoid additional weight increase. The aircraft ground steering system comprises a turning hand wheel assembly used for controlling a front wheel turning system to achieve steering of an aircraft when the aircraft slides on the ground at a low speed; the brake system comprises a brake control part, and the brake control part is used for controlling the brake pressure of the left main undercarriage wheel and the brake pressure of the right main undercarriage wheel; and a standby turning control unit capable of switching to a standby mode in which the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel are controlled via a brake control unit according to the angle of the hand wheel of the turning hand wheel assembly operated by a pilot.

Description

Technical Field

[0001] The invention relates to an aircraft ground steering system and an aircraft ground steering control method. Background Art

[0002] In the past, large civil aircraft typically relied on hydraulically actuated nosewheel steering systems to achieve ground control during low-speed taxiing. For example, due to reliability issues with the hydraulic system, failure of the nosewheel steering system could render the aircraft unusable, forcing the aircraft to occupy the landing runway. This situation could significantly impact airport operational efficiency. For example, when a large civil aircraft is behind an airport, after deceleration using the aircraft's deceleration system and reducing its speed to a safe speed on the landing runway, it must then depart the takeoff / landing runway and enter a taxiway, ultimately heading to a parking stand, maintenance area, or other destination. During this process, the nosewheel steering system is typically used to steer the aircraft away from the runway. The nosewheel steering system is typically implemented through hydraulic drive and servo closed-loop control. If the hydraulic system fails or the steering system malfunctions, the aircraft loses its ability to depart the runway, forcing the aircraft to occupy the landing runway, severely impacting normal airport traffic efficiency and potentially leading to the closure of the entire airport.

[0003] To address the potential loss of an aircraft's ability to depart the runway due to, for example, low reliability of the hydraulic system and steering control system, known methods include adding a backup hydraulic accumulator for nose wheel steering and connecting another hydraulic system on the aircraft as a backup in the event of a failure of the main hydraulic system. While these methods can improve the availability of the hydraulic system, they also increase the weight and complexity of the nose wheel steering system. Furthermore, when large civil aircraft are operating at low speeds, there is a method where the pilot can depress the left and right brake pedals to create an imbalance in the braking force between the left and right main brakes, thereby causing the aircraft to deflect and depart the runway. However, this method requires extremely high pilot skill and is not typically included in airline training. Therefore, pilots generally do not risk using this manual differential braking method to depart the runway. Summary of the Invention

[0004] The present invention is completed in view of the above-mentioned problems, and its purpose is to provide an aircraft ground steering system and an aircraft ground steering control method that can easily enable the pilot to turn the aircraft even if the front wheel steering system fails to work normally, and can suppress or avoid additional weight.

[0005] In order to achieve the above-mentioned purpose, a first aspect of the present invention provides an aircraft ground steering system, comprising: a turning handwheel assembly, wherein the turning handwheel assembly is used to manipulate the nose wheel turning system to achieve the steering of the aircraft when the aircraft is taxiing at low speed on the ground; a braking system, wherein the braking system includes a brake control unit, wherein the brake control unit controls the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel; and a backup turning control unit, wherein the backup turning control unit can be switched to a backup mode of controlling the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel via the brake control unit according to the angle of the handwheel of the turning handwheel assembly operated by the pilot.

[0006] The aircraft ground steering system according to the present invention enables low-speed aircraft steering and runway departure even when the nosewheel steering system fails to function properly, while minimizing or avoiding the addition of additional weight, without changing pilot operating habits, or increasing airline pilot training costs. For example, if the aircraft's nosewheel steering system loses its hydraulic power, the cockpit nosewheel steering device can still be used to control the aircraft's braking system to achieve runway departure, thereby improving aircraft reliability and economic efficiency. The present invention combines the existing characteristics of the aircraft's left and right main landing gear, which can independently brake to create asymmetric braking forces, with the existing nosewheel steering handwheel assembly. In the event of a hydraulic system failure or nosewheel steering system malfunction, the cockpit steering handwheel assembly can be used to control the aircraft's braking system to achieve runway departure, thereby improving aircraft reliability and economic efficiency. The present invention utilizes existing aircraft equipment, minimizing or avoiding the addition of additional components and weight. Furthermore, the steering handwheel assembly maintains the pilot's steering method and does not increase airline training costs.

[0007] Furthermore, in the aircraft ground steering system of the present invention, the backup turn control unit may receive the aircraft speed, the aircraft wheel load signal, and the nose wheel turn availability signal, and switch to the backup mode if it determines that the aircraft speed is not higher than the available speed, the aircraft wheels are on the ground, and nose wheel turn is unavailable. This allows automatic switching to the backup mode to adjust brake pressure, thereby improving system safety.

[0008] Furthermore, in the aircraft ground steering system of the present invention, the available speed may be below 25 knots. In a preferred example, the available speed is 10 knots.

[0009] Furthermore, the aircraft ground steering system of the present invention may further include, for example, a first sensor for detecting an angle at which the hand wheel is operated, and the first sensor transmits a signal related to the detected angle at which the hand wheel is operated to the backup turn control unit.

[0010] Furthermore, in the aircraft ground steering system of the present invention, in the backup mode, when the handwheel is operated clockwise relative to the neutral position, braking pressure is generated on the right main landing gear wheel, and when the handwheel is operated counterclockwise relative to the neutral position, braking pressure is generated on the left main landing gear wheel. Thus, even if the nosewheel steering system fails to function properly, the aircraft can be steered using the steering handwheel assembly without changing the pilot's steering method. Alternatively, in the backup mode, when the handwheel is operated clockwise relative to the neutral position, the braking pressure on the left main landing gear wheel by the backup turning control unit is zero, and when the handwheel is operated counterclockwise relative to the neutral position, the braking pressure on the right main landing gear wheel by the backup turning control unit is zero.

[0011] Furthermore, in the aircraft ground steering system of the present invention, in the standby mode, the relationship between the angle at which the hand wheel is operated and the brake pressure of the left main landing gear wheel, and the relationship between the angle at which the hand wheel is operated and the brake pressure of the right main landing gear wheel may satisfy the following relationship:

[0012]

[0013] Where θ is the angle at which the handwheel is operated relative to the neutral position, and P is the braking pressure to be applied to the left or right main landing gear wheels. Thus, even if the nosewheel steering system fails to function properly, the steering handwheel assembly can still be used to steer the aircraft without changing the pilot's steering method, providing the pilot with a steering experience that is the same as, or similar to, that using the nosewheel steering system. The above control law is applicable to large civil airliners, where the braking system pressure is, for example, 3000 psi.

[0014] A second aspect of the present invention provides an aircraft ground steering control method, which is controlled by an aircraft ground steering system, wherein the aircraft ground steering system comprises: a turning handwheel assembly, wherein the turning handwheel assembly is used to manipulate the nose wheel turning system to achieve the steering of the aircraft when the aircraft is taxiing on the ground at low speed; and a braking system, wherein the braking system includes a brake control unit, wherein the brake control unit controls the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel. The method comprises: obtaining an aircraft speed, an aircraft wheel load signal, and a nose wheel turning availability signal, and when it is determined that the aircraft speed is not higher than the available speed, the aircraft wheel load is on the ground, and nose wheel turning is not available, switching to a backup mode in which the brake pressure of the left main landing gear wheel and the right main landing gear wheel are controlled via the brake control unit according to the angle of the handwheel of the turning handwheel assembly operated by the pilot.

[0015] Furthermore, in the aircraft ground steering control method of the present invention, the available speed may be less than 25 knots.

[0016] Furthermore, in the aircraft ground steering control method of the present invention, in the standby mode, the relationship between the angle at which the hand wheel is operated and the brake pressure of the left main landing gear wheel, and the relationship between the angle at which the hand wheel is operated and the brake pressure of the right main landing gear wheel may satisfy the following relationship:

[0017]

[0018] Wherein, θ is the angle at which the hand wheel is operated relative to the neutral position, and P is the braking pressure to be applied to the left main landing gear wheel or the braking pressure to be applied to the right main landing gear wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The structure of the main parts of the aircraft ground steering system according to one embodiment of the present invention is schematically shown.

[0020] Figure 2 The structure of the main part of the braking system of an aircraft to which the aircraft ground steering system according to one embodiment of the present invention is applied is schematically shown.

[0021] Figure 3 This is a diagram for explaining an aircraft ground steering system and an aircraft ground steering control method according to one embodiment of the present invention.

[0022] Explanation of symbols

[0023] 1 Turning handwheel assembly

[0024] 2 spare turn control unit

[0025] 3Brake control unit

[0026] 4Right main landing gear brake device

[0027] 5 Left main landing gear brake device

[0028] 11 base

[0029] 12 hand wheels

[0030] 100 aircraft ground steering system

[0031] 200 brake system

[0032] 201 wheel speed sensor

[0033] 202 pressure sensor

[0034] 203 control unit

[0035] 204 control valve

[0036] 205 brake actuator

[0037] 206 wheel DETAILED DESCRIPTION

[0038] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0039] <First embodiment>

[0040] Figure 1 The structure of the main parts of the aircraft ground steering system 100 according to the first embodiment of the present invention is schematically shown. Figure 2 The structure of the main parts of the brake system 200 is schematically shown.

[0041] The aircraft ground steering system 100 includes a steering wheel assembly 1 , a brake control unit 3 , and a backup steering control unit 2 .

[0042] The turning handwheel assembly 1 is used to operate the front wheel turning system (not shown) to achieve the turning of the aircraft when the aircraft is taxiing on the ground at a low speed (for example, the aircraft speed is below 20 knots). The turning handwheel assembly 1 includes a base 11 and a handwheel 12 rotatably arranged on the base 11. The turning handwheel assembly 1 serves as the front wheel turning control handwheel in the cockpit, and the pilot controls the steering angle of the aircraft by turning the handwheel 12. The other components of the turning handwheel assembly 1 can adopt a known structure. In addition, the above-mentioned front wheel turning system can adopt a known structure, such as using a front wheel turning system based on hydraulic actuation.

[0043] The aircraft ground steering system 100 further includes a first sensor (angle sensor) (not shown) for detecting the angle at which the steering wheel 12 of the steering wheel assembly 1 is operated. The first sensor transmits a signal related to the detected angle at which the steering wheel assembly 1 is operated to the backup turning control unit 2 .

[0044] The brake control unit 3 controls the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel. The brake control unit 3 adjusts the brake pressure through the brake system 200, for example.

[0045] For example, an aircraft utilizing the aircraft ground steering system 100 includes a braking system 200. Braking system 200 is used for deceleration during landing. Its primary function is to automatically adjust brake pressure under various runway conditions to maintain an ideal frictional state between wheels 206 (including the left and right main landing gear wheels) and the ground, thereby achieving safe deceleration and stopping of the aircraft. This prevents wheel lock-induced tire drag, improves braking efficiency, and shortens landing roll distance.

[0046] The brake system 200 is a closed-loop control system based on brake pressure, and the brake hydraulic pressure can be controlled to the expected pressure value through closed-loop control. For example, the brake system 200 includes: sensors, including wheel speed sensors 201, pressure sensors 202, etc., for real-time monitoring of parameters such as the rotation speed and brake pressure of the wheels, and transmitting data (signals related to the detected wheel rotation speed and brake pressure) to the control unit 203; the control unit 203 can use a microprocessor or a digital computer to calculate the slip rate of the wheel according to the signal from the sensor, and compare it with the preset slip rate to generate a corresponding control signal; the actuator is mainly composed of a control valve 204, a brake actuator 205, etc., which can adjust the brake pressure according to the instructions of the control unit to achieve brake control of the wheel. The brake system 200 can control the brake devices on the left and right landing gears, namely the left main landing gear brake device 5 and the right main landing gear brake device 4 ( Figure 2 Only the main parts of the brake system 200 related to the brake device of one of the left main landing gear wheel and the right main landing gear wheel are shown. For example, the above-mentioned actuators and sensors are part of the left main landing gear brake device 5 (or the right main landing gear brake device 4). As an example of using the brake system 200, after the aircraft lands, the pilot steps on the brake pedal (not shown), and the brake system starts to work; the wheel speed sensor 201 monitors the rotation speed of the wheel in real time and transmits the data to the control unit 203; the control unit 203 calculates the slip ratio based on the wheel rotation speed and automatically optimizes the ideal slip ratio point. When the ideal slip ratio point is exceeded, the control unit 203 will issue a command to reduce the brake pressure through the control valve 204 to resume the rotation of the wheel; conversely, when the slip ratio is too low, the control unit will increase the brake pressure in order to maintain it near the ideal slip ratio. In this embodiment, the control unit 203 also serves as the brake control unit 3 in the aircraft ground steering system 100. In the standby mode for turning, by controlling the required brake pressure on the corresponding landing gear brake (for example, when turning right, controlling the right brake to apply pressure), a differential braking turning effect can be achieved on both landing gears. This turning effect becomes increasingly pronounced as the brake pressure increases. Alternatively, the brake system may employ other known structures that control the brake pressure on the left and right main landing gear wheels via a brake control unit.

[0047] The standby turn control unit 2 can utilize the existing components of the aircraft, such as the landing gear controller, the flight control computer and other controllers, and store the relevant software. The standby turn control unit 2 can switch to a standby mode that controls the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel through the brake control unit 3 according to the angle of the handwheel 12 of the turning handwheel assembly 1 operated by the pilot. The standby mode can be triggered manually by the pilot (for example, by inputting a switching instruction to the standby turn control unit 2), or it can be triggered automatically when the specified conditions are met. The standby turn control unit 2 receives the instruction of the turning angle and simultaneously calculates and outputs the brake pressure signal (differential braking instruction) for the left main landing gear wheel and the right main landing gear wheel. The brake control unit 3 receives the differential braking instruction and issues instructions to the brake devices of the left main landing gear wheel and the right main landing gear wheel (sometimes referred to as "left and right wheels") respectively to achieve an imbalance in the brake pressure of the left and right wheels, thereby achieving an unbalanced ground friction of the left and right wheels, and realizing the turning action of the aircraft, such as Figure 3 As shown (the arrow in the figure indicates the brake pressure).

[0048] Preferably, the backup turn control unit 2 obtains aircraft speed, aircraft wheel load signal, and nose wheel turn availability signal. If it determines that the aircraft speed is not higher than the usable speed, the aircraft wheels are on the ground, and nose wheel turn is not available, it switches to the backup mode. To improve the safety of the system and prevent the aircraft from overrunning the runway due to malfunction of the system, the backup turn control unit 2 introduces aircraft speed, aircraft wheel load signal, and nose wheel turn availability signal as conditions for the use of the backup turn function (corresponding to the backup mode). The backup turn function is activated only when the three conditions of aircraft speed not higher than the usable speed, aircraft wheels on the ground, and nose wheel turn not available are simultaneously met. Aircraft speed-related signals, aircraft wheel load signal, and nose wheel turn availability signal are all commonly used aircraft status data and can be obtained via the avionics bus. Aircraft speed can be obtained from the inertial navigation system. The aircraft wheel load signal can be obtained from the landing gear system. The nose wheel turn availability status signal can be obtained from the nose wheel turning system. Regarding the front wheel turning availability status signal, the control unit of the front wheel turning system can determine whether turning is available based on relevant information (such as sensor detection results). If the front wheel turning is not available, a signal indicating that the front wheel turning is not available is sent to the backup turning control unit 2.

[0049] The available speed is below 25 knots. In one example, the available speed is 10 knots. In this case, the backup turning function can only be automatically activated (switched to backup mode) when the aircraft speed is less than 10 knots, the aircraft wheel-borne signal is "on ground", and the nose wheel steering is in the "disabled" state ("A / C speed < 10 knots" and "A / C on Ground = 1" and "Nose wheel steering disable = 1").

[0050] In the standby mode, when the hand wheel 12 of the steering hand wheel assembly 1 is operated clockwise relative to the neutral position, braking pressure is generated on the right main landing gear wheel, and when the hand wheel 12 of the steering hand wheel assembly 1 is operated counterclockwise relative to the neutral position, braking pressure is generated on the left main landing gear wheel.

[0051] In this embodiment, in the backup mode, when the handwheel 12 of the turning handwheel assembly 1 is turned clockwise relative to the neutral position, the brake pressure applied to the left main landing gear wheel by the backup turning control unit 2 is zero. When the handwheel 12 of the turning handwheel assembly 1 is turned counterclockwise relative to the neutral position, the brake pressure applied to the right main landing gear wheel by the backup turning control unit 2 is zero. In other words, the backup turning control unit 2 outputs the differential braking command as follows: if the handwheel 12 is turned left, brake pressure is applied to the left main landing gear wheel, and the brake pressure of the right main landing gear wheel is set to zero; if the handwheel 12 is turned right, brake pressure is applied to the right main landing gear wheel, and the brake pressure of the left main landing gear wheel is set to zero.

[0052] In the standby mode, the standby turning control unit 2 receives the angle signal of the turning hand wheel assembly and calculates the brake pressure value. The relationship between the angle at which the hand wheel 12 of the turning hand wheel assembly 1 is operated and the brake pressure of the left main landing gear wheel, and the relationship between the angle at which the hand wheel 12 is operated and the brake pressure of the right main landing gear wheel satisfy the following relationship (1):

[0053]

[0054] Wherein, θ is the angle at which the hand wheel 12 is operated counterclockwise or clockwise relative to the neutral position, and P is the brake pressure to be applied to the left main landing gear wheel or the brake pressure to be applied to the right main landing gear wheel. The above control law can be applied to large civil airliners, and the brake system pressure system is, for example, 3000 psi. When the hand wheel 12 is operated clockwise relative to the neutral position, P is the brake pressure to be applied to the right main landing gear wheel, and when the hand wheel 12 is operated counterclockwise relative to the neutral position, P is the brake pressure to be applied to the left main landing gear wheel. That is, based on the angle at which the hand wheel 12 is operated relative to the neutral position, the brake pressure to be applied to the left main landing gear wheel or the brake pressure to be applied to the right main landing gear wheel is calculated according to the relationship (1). In one example, the angle range of θ is 0 to 75 degrees. According to the turning angle of the handwheel 12 of the turning handwheel assembly 1 operated by the pilot, the greater the turning angle of the handwheel 12 of the turning handwheel assembly 1 is, the more obvious the turning effect is required, and therefore the corresponding brake pressure applied is greater.

[0055] The present invention also provides an aircraft ground steering control method, which is controlled using the above-mentioned aircraft ground steering system 100. The method includes the following steps: obtaining an aircraft speed, an aircraft wheel load signal, and a nose wheel turning availability signal; and if it is determined that the aircraft speed is not higher than the available speed, the aircraft wheels are on the ground, and nose wheel turning is not available, switching to a backup mode in which the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel are controlled via the brake control unit 3 according to the angle of the handwheel 12 of the steering handwheel assembly 1 operated by the pilot.

[0056] The aircraft ground steering system and aircraft ground steering control method of the present invention can serve as a backup system for an aircraft ground low-speed turning system to improve the aircraft's runway departure and ground control capabilities. The system is suitable for aircraft equipped with a nose wheel turning system and left and right main landing gear braking systems, and is particularly suitable for large or medium-sized civil aircraft.

[0057] The above description specifically describes the specific embodiments of the present invention in conjunction with the accompanying drawings. However, it should be understood that the above description does not limit the present invention in any way, and the technical features of the various embodiments can be combined in any manner to form new embodiments. In addition, after understanding the above specific embodiments, those skilled in the art may make various other modifications and changes to the present invention as needed, without departing from the essence of the present invention.

Claims

1. An aircraft ground steering system, characterized in that: have: A turning handwheel assembly, which is used to manipulate the front wheel turning system to achieve the steering of the aircraft when the aircraft is taxiing at low speed on the ground; a brake system, the brake system including a brake control unit that controls the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel; and A backup turning control unit is configured to switch to a backup mode for controlling the brake pressure of the left main landing gear wheel and the right main landing gear wheel via the brake control unit according to the angle of the hand wheel of the turning hand wheel assembly operated by the pilot.

2. The aircraft ground steering system according to claim 1, characterized in that: The backup turn control unit obtains the aircraft speed, the aircraft wheel load signal, and the nose wheel turn availability signal, and switches to the backup mode when it is determined that the aircraft speed is not higher than the available speed, the aircraft wheels are on the ground, and the nose wheel turn is not available.

3. The aircraft ground steering system according to claim 2, wherein: The usable speed is below 25 knots.

4. The aircraft ground steering system according to claim 1, wherein: A first sensor for detecting an angle at which the hand wheel is operated is further provided, and the first sensor transmits a signal related to the detected angle at which the hand wheel is operated to the backup turn control unit.

5. The aircraft ground steering system according to claim 1, wherein: In the standby mode, braking pressure is generated on the right main landing gear wheel when the hand wheel is operated clockwise relative to the neutral position, and braking pressure is generated on the left main landing gear wheel when the hand wheel is operated counterclockwise relative to the neutral position.

6. The aircraft ground steering system according to claim 1, wherein: In the backup mode, when the hand wheel is operated clockwise relative to the neutral position, the brake pressure of the left main landing gear wheel based on the backup turn control unit is zero, and when the hand wheel is operated counterclockwise relative to the neutral position, the brake pressure of the right main landing gear wheel based on the backup turn control unit is zero.

7. The aircraft ground steering system according to claim 6, characterized in that: In the standby mode, the relationship between the angle at which the hand wheel is operated and the brake pressure of the left main landing gear wheel and the relationship between the angle at which the hand wheel is operated and the brake pressure of the right main landing gear wheel satisfy the following relationship: Wherein, θ is the angle at which the hand wheel is operated relative to the neutral position, and P is the braking pressure to be applied to the left main landing gear wheel or the braking pressure to be applied to the right main landing gear wheel.

8. A method for controlling aircraft ground steering, using an aircraft ground steering system for control, the aircraft ground steering system comprising: a steering handwheel assembly, the steering handwheel assembly being used to manipulate the front wheel steering system to achieve steering of the aircraft when the aircraft is taxiing at low speed on the ground; and a brake system, the brake system including a brake control unit, the brake control unit controlling the brake pressure of the left main landing gear wheel and the brake pressure of the right main landing gear wheel, It is characterized in that The system includes: obtaining an aircraft speed, an aircraft wheel load signal, and a nose wheel turning availability signal; and, if it is determined that the aircraft speed is not higher than the available speed, the aircraft wheels are on the ground, and nose wheel turning is not available, switching to a backup mode of controlling the brake pressure of the left main landing gear wheel and the right main landing gear wheel via a brake control unit according to the angle of the hand wheel of the turning hand wheel assembly operated by the pilot.

9. The aircraft ground steering control method according to claim 8, characterized in that: The usable speed is below 25 knots.

10. The aircraft ground steering control method according to claim 8, characterized in that: In the standby mode, the relationship between the angle at which the hand wheel is operated and the brake pressure of the left main landing gear wheel and the relationship between the angle at which the hand wheel is operated and the brake pressure of the right main landing gear wheel satisfy the following relationship: Wherein, θ is the angle at which the hand wheel is operated relative to the neutral position, and P is the braking pressure to be applied to the left main landing gear wheel or the braking pressure to be applied to the right main landing gear wheel.

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