A warning method for abnormal front wheel turning deflection

Abstract

This invention relates to an alarm method for abnormal front wheel steering, comprising the following steps: (1) The front wheel steering control box completes power-on self-test and starts steering / anti-sway control; (2) The front wheel steering control box determines whether the system is in a steering state. If not, the system enters the anti-sway state and does not perform front wheel abnormal steering judgment. In the anti-sway state, the solenoid valve inside the combined hydraulic valve is de-energized; if so, front wheel abnormal steering and over-limit logic judgment and handling are performed; (3) The front wheel steering control box reads the command sensor signal ZL, the feedback sensor signal FK, and the inertial navigation ground speed DS. The front wheel steering control box calculates the angle that the front wheel should deflect at the current speed, i.e., the theoretical position signal FKL of the feedback sensor; (4) The front wheel steering control box outputs the control current according to the servo valve control current algorithm based on the difference between the theoretical position signal FKL of the feedback sensor and the feedback sensor signal FK; (5) Front wheel abnormal steering judgment and handling; (6) Front wheel over-limit judgment and handling.

Description

Technical Field

[0001] This invention belongs to the field of aircraft design technology and relates to a warning method for abnormal deflection of the front wheel during turns. Background Technology

[0002] The nose wheel steering system of a certain type of aircraft employs an electro-hydraulic servo control system, primarily composed of a command sensor, a nose wheel steering control box, a steering actuator (including a feedback sensor), and a combined hydraulic valve. The electro-hydraulic servo valve within the combined hydraulic valve is a nozzle-flange type servo valve. While this type of servo valve offers fast response and high control accuracy, it lacks valve core position feedback and suffers from poor contamination resistance. During operation, servo valve jamming may occur, causing abnormal nose wheel deflection and affecting operational safety. Therefore, it is necessary to optimize the system control strategy, promptly identify nose wheel deflection trends, and immediately switch the system to anti-sway mode and issue an alarm signal when abnormal nose wheel deflection trends are observed.

[0003] Based on the above design and usage background, without changing the system hardware architecture, the system software control strategy is optimized to comprehensively judge the theoretical turning command signal and feedback sensor signal. When the abnormal front wheel deflection trend is detected, the system is switched to anti-sway state in time, and the hydraulic source of the servo valve is shut off to prevent abnormal front wheel deflection, so as to ensure the safety of aircraft taxiing. Summary of the Invention

[0004] The purpose of this invention:

[0005] This invention provides an alarm method for abnormal front wheel steering deviation. Without changing the system architecture, it optimizes the control logic of the front wheel steering control box, designs the judgment logic for abnormal front wheel steering deviation, and designs corresponding handling strategies and methods to ensure aircraft taxiing safety.

[0006] The technical solution of the present invention:

[0007] A warning method for abnormal front wheel deflection during cornering.

[0008] The front wheel steering control box collects feedback sensor signals in real time to identify the direction of front wheel deflection. It defines that when the feedback sensor signal increases, the front wheel deflects to the right, and when the feedback sensor signal decreases, the front wheel deflects to the left.

[0009] When the front wheel steering anti-sway system is in a turning state, the front wheel steering control box control board outputs a negative current, and the front wheel deflects to the right; when the front wheel steering control box control board outputs a positive current, the front wheel deflects to the left.

[0010] The front wheel steering control box determines the front wheel deflection trend in real time. If the front wheel steering control box outputs a negative current and the feedback signal decreases, or if the front wheel steering control box outputs a positive current and the feedback signal increases, it is determined that the front wheel has an abnormal deflection without command. The system switches to anti-sway mode and issues an alarm signal.

[0011] In extreme cases, if the servo valve gets stuck at the left or right extreme positions of the front wheel, the front wheel will remain at the extreme position when the turning command returns to center. At this time, if the front wheel turning control box outputs a return current and the feedback sensor signal remains unchanged when the front wheel is at the left or right extreme positions, it is determined that the front wheel has an abnormal deflection without the command. The system switches to anti-sway mode and issues an alarm signal.

[0012] If the front wheel deflection angle exceeds the limit angle at the current aircraft speed, the front wheel steering anti-sway system switches to anti-sway mode and issues an alarm signal.

[0013] Furthermore, the method includes the following steps:

[0014] (1) The front wheel steering control box completes its power-on self-test and begins steering / anti-sway control;

[0015] (2) The front wheel steering control box determines whether the system is in a turning state. If not, the system enters the anti-sway state and does not perform front wheel abnormal deviation judgment. In the anti-sway state, the solenoid valve inside the combined hydraulic valve is de-energized; if so, front wheel abnormal deviation and over-limit logic judgment and handling are performed.

[0016] (3) The front wheel steering control box reads the command sensor signal ZL, the feedback sensor signal FK and the inertial navigation ground speed DS. The front wheel steering control box calculates the angle that the front wheel should turn at the current speed, i.e. the theoretical position signal FKL of the feedback sensor.

[0017] (4) The front wheel steering control box outputs control current according to the difference between the theoretical position signal FKL and the feedback sensor signal FK.

[0018] (5) Judgment and handling of abnormal front wheel deflection;

[0019] (6) Judgment and handling of front wheel over-limit.

[0020] Furthermore, in step (4), the servo valve control current algorithm is as follows:

[0021] When the absolute value of the difference is greater than 3.5mm, the output control current is the maximum current, i.e., 5mA;

[0022] When the absolute value of the difference is less than 0.4mm, the output control current is 0;

[0023] When the absolute value of the difference is 0.4mm-3.5mm, the output control current varies within the range of 0-5mA.

[0024] Furthermore, step (5) includes the following three cases:

[0025] (5.1) When the inertial navigation ground speed DS received by the front wheel turning control box is less than or equal to 30 km / h, the abnormal turning deviation of the front wheel is judged and handled.

[0026] (5.2) When the inertial navigation ground speed DS received by the front wheel turning control box is (30, 120] km / h, the abnormal turning deviation of the front wheel is judged and handled.

[0027] (5.3) When the front wheel is in the extreme position, judge and deal with the abnormal deflection of the front wheel when turning.

[0028] Furthermore, in (5.1), when the inertial navigation ground speed DS received by the current wheel turning control box is less than or equal to 30 km / h, the following logic applies to judgment and handling:

[0029] a) Check if the feedback sensor signal FK is within (-11mm, 11mm). If yes, do not judge the front wheel deflection trend and continue with the normal turning procedure. If no, proceed to step b).

[0030] b) If the feedback sensor signal FK is not within (-11mm, 11mm), then the front wheel deflection trend is determined. That is, if the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA and the feedback sensor signal FK changes in the opposite direction, then the front wheel deflection is determined to be abnormal. When the displacement of the feedback sensor signal FK in the opposite direction exceeds 5mm and lasts for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve and steering indicator signal, the system enters the anti-sway state and issues an alarm signal.

[0031] Furthermore, in (5.2), when the inertial navigation ground speed DS received by the current wheel turning control box is in the range of (30, 120] km / h, the following logic is applied for judgment and handling:

[0032] If the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA and the feedback sensor signal FK changes in the opposite direction, then the front wheel is determined to be abnormally deflected. When the displacement of the feedback sensor signal FK in the opposite direction exceeds 3mm and lasts for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve and steering indicator signal, the system enters the anti-sway state and issues an alarm signal.

[0033] Furthermore, the opposite direction of the change in the feedback sensor signal FK means that the front wheel steering control box outputs a negative current and the feedback signal decreases, or the front wheel steering control box outputs a positive current and the feedback signal increases.

[0034] Furthermore, in (5.3), when the front wheel is in the extreme position, the following logic is used for judgment and handling: In the turning state, the front wheel turning control box judges in real time whether the front wheel is in the extreme position, that is, whether the feedback sensor signal FK is within ±3mm of the maximum stroke allowed by the control law at the current aircraft speed; if not, the front wheel deflection trend is judged according to the methods of (5.1) and (5.2) to determine whether it is normal; if so, the following method is used for judgment: when the absolute value of the theoretical control current output by the front wheel turning control box is greater than 4mA, the feedback sensor signal FK remains unchanged and lasts for 0.3s, the front wheel turning control box cuts off the output of the solenoid valve, servo valve and turning indicator signal, the system enters the anti-sway state and issues an alarm signal.

[0035] Furthermore, the front wheel over-limit judgment and handling are as follows: During a turn, the front wheel steering control box determines in real time whether the front wheel deflection angle exceeds the limit, that is, whether the feedback sensor signal FK is greater than the maximum allowable travel tolerance of 3mm at the current aircraft speed by the control law and lasts for 0.1s. If so, the front wheel steering control box cuts off the output of the solenoid valve, servo valve, and turn indication signal, the system enters the anti-sway state, and issues an alarm signal.

[0036] The beneficial effects of this invention are:

[0037] This invention provides an alarm method for abnormal front wheel steering. Based on the original hardware of the system, this invention optimizes and modifies the software of the front wheel steering control box to add alarms for abnormal front wheel steering and excessive front wheel steering, thereby improving system safety. It has been applied to specific models and provides a reference for the design of front wheel steering alarm logic in subsequent models. Attached Figure Description

[0038] Figure 1 This is a functional schematic diagram of the front wheel steering system.

[0039] Figure 2 Procedure for Front Wheel Abnormal Turning Warning Figure 1 ;

[0040] Figure 3 Procedure for Front Wheel Abnormal Turning Warning Figure 2 . Detailed Implementation

[0041] This invention relates to a novel alarm method for abnormal nose wheel steering deflection, involving the design of control software for an aircraft nose wheel steering system, and its application in specific models. Addressing the problem of unauthorized abnormal nose wheel deflection caused by internal jamming of the nose wheel steering combination hydraulic valve, this invention uses software to collect real-time nose wheel position feedback information to determine if the nose wheel deflection trend is correct. If abnormal nose wheel deflection occurs, the system is promptly switched to anti-sway mode and an alarm signal is issued to ensure aircraft taxiing safety.

[0042] One embodiment of the present invention is: the method includes the following steps:

[0043] 1) The front wheel steering control box collects feedback sensor signals in real time to identify the direction of front wheel deflection. It defines that when the feedback sensor signal increases, the front wheel deflects to the right, and when the feedback sensor signal decreases, the front wheel deflects to the left.

[0044] 2) When the front wheel turning anti-sway system is in a turning state, the front wheel turning control box control board is defined to output a negative current, and the front wheel turns to the right; when the front wheel turning control box control board outputs a positive current, the front wheel turns to the left.

[0045] 3) The front wheel steering control box judges the front wheel deflection trend in real time. If the front wheel steering control box outputs a negative current and the feedback signal decreases, or if the front wheel steering control box outputs a positive current and the feedback signal increases, it is determined that the front wheel has an abnormal deflection without command. The system switches to anti-sway state and issues an alarm signal.

[0046] 4) In extreme cases, if the servo valve gets stuck at the left or right extreme positions (where there are mechanical limits), the front wheels will remain at the extreme positions when the turning command returns to center. In this case, the front wheel deflection trend described in 3) cannot be used for judgment. Therefore, if the front wheel turning control box outputs a centering current when the front wheels are at the left or right extreme positions, and the feedback sensor signal remains unchanged, it is determined that the front wheels have experienced abnormal deflection without a command. The system switches to anti-sway mode and issues an alarm signal.

[0047] 5) To ensure aircraft taxiing safety, if the front wheel deflection angle exceeds the limit angle at the current aircraft speed (inertial navigation ground speed), the front wheel steering anti-sway system switches to anti-sway mode and issues an alarm signal to prevent the front wheel deflection angle from exceeding the boundary and causing safety hazards during the process of the front wheel steering control box judging the front wheel deflection trend.

[0048] The second embodiment of the present invention is:

[0049] 1) such as Figure 1 As shown, the system is composed of a command sensor, a front wheel steering control box, a combined hydraulic valve, and a steering actuator (including a feedback sensor). The front wheel steering control box receives the inertial navigation ground speed and navigation status from the receiver for steering / anti-sway control and control law calculation.

[0050] 2) such as Figure 2 As shown, the front wheel steering control box completes its power-on self-test and begins steering / anti-sway control.

[0051] 3) The front wheel steering control box determines whether the system is in a turning state. If not, the system enters the anti-sway state and does not perform front wheel abnormal deviation judgment (in the anti-sway state, the solenoid valve inside the combined hydraulic valve is de-energized, and the servo valve will not cause abnormal front wheel deviation even if it is stuck); if so, it performs front wheel abnormal deviation and over-limit logic judgment and handling.

[0052] 4) The front wheel steering control box reads the command sensor signal (ZL), the feedback sensor signal (FK), and the inertial navigation ground speed (DS). The front wheel steering control box calculates the angle that the front wheel should turn at the current speed, which is the theoretical position signal of the feedback sensor (FKL).

[0053] 5) The front wheel steering control box outputs control current according to the servo valve control current algorithm based on the difference between the theoretical position signal (FKL) and the feedback sensor signal (FK).

[0054] The servo valve control current algorithm is as follows:

[0055] When the absolute value of the difference is greater than 3.5mm, the output control current is the maximum current, i.e., 5mA;

[0056] When the absolute value of the difference is less than 0.4mm, the output control current is 0;

[0057] When the absolute value of the difference is 0.4mm-3.5mm, the output control current varies within the range of 0-5mA.

[0058] 6) Logic for judging and handling abnormal front wheel deflection

[0059] 6.1) When the inertial navigation ground speed (DS) received by the current wheel turning control box is less than or equal to 30 km / h, the following logic shall be followed for judgment and handling:

[0060] a) Check if the feedback sensor signal (FK) is within (-11mm, 11mm). If yes, do not judge the front wheel deflection trend and continue with the normal turning procedure. If not, proceed to step b).

[0061] b) If the feedback sensor signal (FK) is not within (-11mm, 11mm), then the front wheel deflection trend is determined. That is, if the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA, and the direction of change of the feedback sensor signal (FK) is opposite (negative current and (FK) value is smaller than the previous cycle, positive current and (FK) value is larger than the previous cycle), then the front wheel deflection is determined to be abnormal. When the displacement of the feedback sensor signal (FK) in the opposite direction exceeds 5mm and lasts for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve and steering indicator signal, the system enters the anti-sway state and issues an alarm signal.

[0062] 6.2) When the inertial navigation ground speed (DS) received by the current wheel turning control box is in the range of (30, 120] km / h, the following logic shall be followed for judgment and handling:

[0063] If the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA, and the direction of change of the feedback sensor signal (FK) is opposite (negative current and (FK) value is smaller than the previous cycle, positive current and (FK) value is larger than the previous cycle), then abnormal front wheel deflection is determined. When the displacement of the feedback sensor signal (FK) in the opposite direction exceeds 3mm and lasts for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve and steering indicator signal, the system enters the anti-sway state and issues an alarm signal.

[0064] 6.3) When the current wheel is in its extreme position, the following logic shall be followed for judgment and handling:

[0065] During a turn, the front wheel steering control box continuously checks whether the front wheel is at its limit position, i.e., whether the feedback sensor signal (FK) is within ±3mm of the maximum travel allowed by the control law at the current aircraft speed. If not, it checks whether the front wheel deflection trend is normal according to steps 6.1 and 6.2. If it is normal, it checks as follows: when the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA, the feedback sensor signal (FK) remains unchanged for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve, and turning indicator signal, the system enters the anti-sway state, and an alarm signal is issued.

[0066] 7) Logic for judging and handling front wheel over-limit conditions

[0067] During a turn, the front wheel steering control box continuously checks whether the front wheel deflection angle exceeds the limit, i.e., whether the feedback sensor signal (FK) is greater than the maximum allowable travel tolerance of 3mm at the current aircraft speed and lasts for 0.1s. If so, the front wheel steering control box cuts off the output of the solenoid valve, servo valve, and turn indication signal, the system enters the anti-sway state, and issues an alarm signal.

Claims

1. A warning method for abnormal front wheel deflection during cornering, characterized in that: The front wheel steering control box collects feedback sensor signals in real time to identify the front wheel yaw direction. It defines that when the feedback sensor signal increases, the front wheel yaws to the right, and when the feedback sensor signal decreases, the front wheel yaws to the left. When the front wheel steering anti-sway system is in a turning state, the front wheel steering control box outputs a negative current, indicating right yaw, and outputs a positive current, indicating left yaw. The front wheel steering control box continuously judges the front wheel yaw trend; if the control box outputs a negative current and the feedback signal decreases, or if the control box outputs a positive current and the feedback signal increases, it determines the direction of yaw. If the front wheel exhibits an abnormal, uninstructed deflection, the system switches to anti-sway mode and issues an alarm signal. In extreme cases, if the servo valve of the front wheel becomes stuck at its left or right extreme positions, the front wheel will remain at its extreme position when the turn command returns to center. If the front wheel turning control box outputs a centering current and the feedback sensor signal remains unchanged when the front wheel is at its left or right extreme positions, it is determined that the front wheel has exhibited an abnormal, uninstructed deflection, and the system switches to anti-sway mode and issues an alarm signal. If the front wheel deflection angle exceeds the limit angle at the current aircraft speed, the front wheel turning anti-sway system switches to anti-sway mode and issues an alarm signal. The method includes the following steps: (1) The front wheel steering control box completes its power-on self-test and begins steering / anti-sway control; (2) The front wheel steering control box determines whether the system is in a turning state. If not, the system enters the anti-sway state and does not perform the front wheel abnormal deflection judgment. In the anti-sway state, the solenoid valve inside the combined hydraulic valve is de-energized; if so, the front wheel abnormal deflection and over-limit logic judgment and handling are performed. (3) The front wheel steering control box reads the command sensor signal ZL, the feedback sensor signal FK and the inertial navigation ground speed DS. The front wheel steering control box calculates the angle that the front wheel should turn at the current speed, i.e. the theoretical position signal FKL of the feedback sensor. (4) The front wheel steering control box outputs control current according to the difference between the theoretical position signal FKL and the feedback sensor signal FK, based on the servo valve control current algorithm. The servo valve control current algorithm is as follows: When the absolute value of the difference is greater than 3.5mm, the output control current is the maximum current, i.e., 5mA; When the absolute value of the difference is less than 0.4mm, the output control current is 0; When the absolute value of the difference is 0.4mm-3.5mm, the output control current varies within the range of 0-5mA; (5) Judgment and handling of abnormal front wheel deflection, including the following three situations: (5.1) When the inertial navigation ground speed DS received by the front wheel turning control box is less than or equal to 30km / h, the abnormal turning deviation of the front wheel is judged and handled. (5.2) When the inertial navigation ground speed DS received by the front wheel turning control box is (30, 120] km / h, the abnormal turning deviation of the front wheel is judged and handled. (5.3) When the front wheel is in the extreme position, judge and deal with the abnormal deflection of the front wheel when turning; (6) Judgment and handling of front wheel over-limit.

2. The alarm method for abnormal front wheel steering deviation according to claim 1, characterized in that: In (5.1), when the ground speed DS received by the current wheel turning control box is less than or equal to 30 km / h, the following logic shall be followed for judgment and handling: a) Check if the feedback sensor signal FK is within (-11mm, 11mm). If yes, do not judge the front wheel deflection trend and continue with the normal turning procedure. If no, proceed to step b). b) If the feedback sensor signal FK is not within (-11mm, 11mm), then the front wheel deflection trend is determined. That is, if the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA and the feedback sensor signal FK changes in the opposite direction, then the front wheel deflection is determined to be abnormal. When the displacement of the feedback sensor signal FK in the opposite direction exceeds 5mm and lasts for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve and steering indicator signal, the system enters the anti-sway state and issues an alarm signal.

3. The alarm method for abnormal front wheel steering deviation according to claim 2, characterized in that: In (5.2), when the inertial navigation ground speed DS received by the current wheel turning control box is in the range of (30, 120] km / h, the following logic is used for judgment and handling: If the absolute value of the theoretical control current output by the front wheel steering control box is greater than 4mA and the feedback sensor signal FK changes in the opposite direction, then the front wheel is determined to be abnormally deflected. When the displacement of the feedback sensor signal FK in the opposite direction exceeds 3mm and lasts for 0.3s, the front wheel steering control box cuts off the output of the solenoid valve, servo valve and steering indicator signal, the system enters the anti-sway state and issues an alarm signal.

4. The alarm method for abnormal front wheel steering deviation according to claim 3, characterized in that: The opposite direction of the change in the feedback sensor signal FK means that the front wheel steering control box outputs a negative current and the feedback signal decreases, or the front wheel steering control box outputs a positive current and the feedback signal increases.

5. The alarm method for abnormal front wheel steering deviation according to claim 4, characterized in that: In (5.3), when the front wheel is in the extreme position, the following logic is used for judgment and handling: In the turning state, the front wheel turning control box judges in real time whether the front wheel is in the extreme position, that is, whether the feedback sensor signal FK is within ±3mm of the maximum stroke allowed by the control law at the current aircraft speed; if not, the front wheel deflection trend is judged according to the methods of (5.1) and (5.2) to determine whether it is normal; if so, the following method is used for judgment: when the absolute value of the theoretical control current output by the front wheel turning control box is greater than 4mA, the feedback sensor signal FK remains unchanged and lasts for 0.3s, the front wheel turning control box cuts off the output of the solenoid valve, servo valve and turning indicator signal, the system enters the anti-sway state and issues an alarm signal.

6. The alarm method for abnormal front wheel steering deviation according to claim 5, characterized in that: The front wheel over-limit judgment and handling is as follows: In the turning state, the front wheel turning control box judges in real time whether the front wheel deflection angle exceeds the limit, that is, whether the feedback sensor signal FK is greater than the maximum travel tolerance of 3mm allowed by the control law at the current aircraft speed and lasts for 0.1s. If so, the front wheel turning control box cuts off the output of the solenoid valve, servo valve and turning indication signal, the system enters the anti-sway state and issues an alarm signal.

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