Feasibility Analysis Method of TAWS Envelope Simulation Based on Flight Simulator

Abstract

The present invention discloses a TAWS envelope simulation feasibility analysis method based on a flight simulator, which relates to the technical field of flight simulation and aims to solve the problem of triggering an alarm when testing and simulating touching an envelope with an excessively large inclination angle on a flight simulator. The key points of the technical solution are to construct an envelope formula, select a number of extreme points or inflection points, and use the envelope formula to evaluate whether a warning will be issued. According to TAWS, a warning will be issued when the radio altitude is lower than the envelope or the flight inclination angle is greater than the envelope; the conditions for issuing a warning are obtained. The present invention achieves the analysis of whether the aircraft can achieve a flight attitude that meets the ATM envelope under a specific state on a flight simulator, and finally analyzes whether it is feasible in combination with actual conditions, which plays a guiding role in flight training.

Description

Technical Field

[0001] The invention relates to the technical field of flight simulation, and in particular to a TAWS envelope simulation feasibility analysis method based on a flight simulator. Background Art

[0002] TAWS (Terrain Awareness and Warning System) is a general term for terrain warning systems. Many companies also call it EGPWS (Enhanced Ground Proximity Warning System). The two have very similar functions. GPWS was proposed by the U.S. Air Force in the 1960s and 1970s to avoid controlled flight into terrain (CFIT). It consists of a ground proximity warning computer, warning lights and a control panel. Its core is the ground proximity warning computer. Once an unsafe state is detected, the driver is notified by lights and sounds until the driver takes measures to escape the unsafe state. The signal terminates. After the emergence of GPWS, the occurrence of accidents has been reduced to a certain extent, but there are still many shortcomings and such problems have not been fundamentally solved. Therefore, TAWS came into being. This system is an enhanced version of GPWS. It adds forward-looking functions to the six modes of the GPWS system at night, including terrain warning and terrain display functions.

[0003] The main program in TAWS is seven types of warnings, namely: (1) excessive descent rate; (2) excessive terrain closure rate; (3) insufficient altitude climb after takeoff or go-around; (4) unsafe obstacle clearance altitude in non-landing state; (5) excessive glide path deviation; (6) excessive bank angle; (7) reactive wind shear, in addition to ground test, terrain display and obstacle warning.

[0004] As a pilot, on the one hand, you need to be familiar with the sound and image representation of various ground proximity warning signals in order to respond quickly; on the other hand, you should also know how to operate to avoid these dangers faster and more effectively. Therefore, the pilot will operate the aircraft to avoid after a certain period of delay. The pilot's series of actions after receiving the warning are abstracted into the pilot response model, which is also subdivided into the pilot's response delay model representing the pilot's delay and the pilot operation model representing the aircraft's avoidance.

[0005] In the flight of civil aviation twin-engine narrow-body aircraft (such as Boeing 737 and Airbus A320, C919, etc.), each aircraft has special requirements for the warning of excessive rotation angle in mode 6 of TAWS terrain awareness and warning system. For example, according to the A-320 aircraft manual provided by Airbus and the pilot crew manual issued by the Civil Aviation Administration of China, it can be learned that the maximum tilt angle of all civil aircraft is 45° when all engines are effective, but the authority or airlines generally only allow pilots to achieve a maximum of 30°, and the autopilot can only make a maximum tilt angle of 30°. Since the A-320 is an electronically controlled aircraft, the flight control system will forcibly intervene to prevent excessive tilt angle even when it is manually driven. This is a protection mechanism. It can be seen that it is basically impossible to make a 35° tilt angle at an altitude of 200Ft on an A-320 aircraft as required by ATM (air traffic management). Therefore, it is necessary to analyze whether the aircraft can achieve a flight attitude that meets the ATM envelope under specific conditions on the flight simulator, and analyze whether it is feasible based on actual conditions. Summary of the invention

[0006] The purpose of the present invention is to provide a TAWS envelope simulation feasibility analysis method based on a flight simulator, to analyze whether an aircraft can achieve a flight attitude that meets the ATM envelope under a specific state on the flight simulator, and finally to analyze whether it is feasible in combination with actual conditions, thereby playing a guiding role in flight training.

[0007] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0008] A TAWS envelope simulation feasibility analysis method based on a flight simulator comprises the following steps:

[0009] According to the envelope description of TAWS mode six, construct the envelope formula:

[0010] ;

[0011] Among them, x d is the tilt angle, f(x d ) is the radio altitude;

[0012] Select several extreme points or inflection points and use the envelope formula to evaluate whether a warning will be issued. According to TAWS, a warning will be issued when the radio altitude is lower than the envelope or the flight inclination angle is greater than the envelope.

[0013] Get the radio altitude and bank angle at which the warning was issued.

[0014] The present invention is further configured as follows: the step of selecting a plurality of limit points or inflection points and using an envelope formula to evaluate whether a warning will be issued comprises:

[0015] According to the description of ATM, the turning angle is limited to 35° at 200ft. Substituting 200ft into formula ②, the envelope inclination angle is x d =40.3°, the flight inclination angle of 35° at an altitude of 200ft is less than the envelope of 40.3°, that is, a turning angle of 35° at 200ft will not cause a corresponding alarm.

[0016] The present invention is further configured as follows: the step of selecting a plurality of limit points or inflection points and using an envelope formula to evaluate whether a warning will be issued comprises:

[0017] The wingspan of the A-320 aircraft is determined to be 34.1m and the radius is 17.05m, which is converted to 56ft, which is the maximum safe altitude of the flight simulator when the inclination angle reaches the maximum 90°. Substituting 56ft as the radio altitude into formula ①, we get x d =16.5°, according to the trigonometric formula:

[0018] ;

[0019] Substituting α=16.5° and hypotenuse length=56ft into formula ③, we get the opposite side length=15.9ft. When the flight inclination angle is 16.5°, the radio altitude of 15.9ft is lower than the envelope altitude of 56ft, which meets the alarm condition.

[0020] The present invention is further configured as follows: the step of selecting a plurality of limit points or inflection points and using an envelope formula to evaluate whether a warning will be issued comprises:

[0021] According to airline regulations, when the maximum limit inclination angle of the flight simulator is 30°, the envelope altitude is 110ft and the radio altitude is 28ft respectively when substituted into formulas ① and ③. The radio altitude is lower than the envelope, meeting the alarm conditions.

[0022] The present invention is further configured as follows: the step of selecting a plurality of limit points or inflection points and using an envelope formula to evaluate whether a warning will be issued comprises:

[0023] The first inflection point of the envelope appears at x d =10°, substituting into formula ③, the radio altitude is 9.72ft, which is 30ft lower than the envelope altitude and meets the alarm condition.

[0024] The present invention is further configured as follows: based on the analysis of the limit points and the inflection points, it is concluded that, excluding other factors, when the radio altitude is 30-110ft, a corresponding warning may be obtained when the inclination angle is greater than 10°-30°, following the linear growth trend of formula ①.

[0025] The present invention is further configured to evaluate the success rate of resetting and rescuing by combining warning envelopes of different joystick landing speeds and warning envelopes of different pilot delay times.

[0026] In summary, the beneficial technical effects of the present invention are:

[0027] The present invention analyzes whether an aircraft can achieve a flight attitude that meets the ATM envelope under a specific state on a flight simulator, and finally analyzes whether it is feasible in combination with actual conditions, thereby playing a guiding role in flight training. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a method flow chart of an embodiment of the present invention;

[0029] Figure 2 is a schematic diagram of the envelope of TAWS mode 6 in an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram for illustrating the rotation of a flight simulator in an embodiment of the present invention;

[0031] Figure 4 Schematic diagram of alarm envelopes for different joystick landing speeds in an embodiment of the present invention;

[0032] Figure 5 Schematic diagram of the ground warning envelope for different pilot delay times in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] Reference Figure 1 The present invention discloses a TAWS envelope simulation feasibility analysis method based on a flight simulator. The present invention is based on an A-320 aircraft model and includes the following steps:

[0034] S1. According to the TAWS mode 6 envelope description, according to Figure 2 It can be seen that the horizontal axis is the tilt angle of the aircraft, the vertical axis is the current radio altitude of the aircraft, and the area on the right side of the envelope is the area where an alarm will be triggered when the tilt angle is too large. The tilt angle and radio altitude are linearly related and can be divided into three sections. Let the tilt angle be x d , let the radio altitude be f(x d ), the envelope formula can be constructed based on the three coordinate points (10,30), (40,150), and (55,2450):

[0035] ;

[0036] Among them, x d is the tilt angle, f(x d ) is the radio altitude. So when the radio altitude is lower than the envelope or the flight inclination angle is greater than the envelope, lights and warnings will be triggered.

[0037] S2. Select several limit points or inflection points and use the envelope formula to evaluate whether a warning will be issued.

[0038] S3. Obtain the radio altitude and bank angle at which the warning was issued.

[0039] In step S2, points are selected and evaluated, specifically including the following steps:

[0040] S21. According to the description of ATM, the turning angle is limited to 35° at 200ft. Substituting 200ft into formula ②, the envelope inclination angle is x d =40.3°, the flight inclination angle of 35° at an altitude of 200ft is less than the envelope of 40.3°, that is, a turning angle of 35° at 200ft will not cause a corresponding alarm.

[0041] S22, query A-320AMM (Aircraft Maintenance Manual), refer to Figure 3 , the wingspan of the A-320 aircraft is determined to be 34.1m, and the radius is 17.05m, which is converted to 56ft, which is the maximum safe altitude of the flight simulator when the inclination angle reaches the maximum 90°. Substituting 56ft as the radio altitude into formula ①, we get x d =16.5°, according to the trigonometric formula:

[0042] ;

[0043] Substituting α=16.5° and hypotenuse length=56ft into formula ③, we get the opposite side length=15.9ft. When the flight inclination angle is 16.5°, the radio altitude of 15.9ft is lower than the envelope altitude of 56ft, which meets the alarm condition.

[0044] S23. According to the regulations of the airline, when the maximum limit inclination angle of the flight simulator is 30°, the envelope height is 110ft and the radio height is 28ft respectively when substituted into formulas ① and ③. The radio height is lower than the envelope, which meets the alarm conditions.

[0045] S24, according to Figure 1 As can be seen from the envelope diagram, the warning of excessive tilt angle in mode 6 appears first, that is, the first turning point appears at x d =10°, substituting into formula ③, the radio altitude is 9.72ft, which is 30ft lower than the envelope altitude and meets the alarm condition.

[0046] Step S3 summarizes the analysis of the above steps S21-S24 and draws the following conclusion: excluding other factors, when the radio altitude is 30-110ft, following the linear growth trend of formula ①, a corresponding warning can be obtained when the inclination angle is greater than 10°-30°.

[0047] Combine the warning envelopes of different joystick speeds and different pilot delay times to evaluate the success rate of reset and rescue. Even if the conditions for warning are created, whether it can be remedied is still a problem that needs to be studied in depth. Otherwise, if the aircraft cannot be pulled up or adjusted in time at a low radio altitude, all warnings are meaningless. According to the warning envelopes of different joystick speeds (refer to Figure 4 ), and the ground warning envelopes for different pilot delay times (refer to Figure 5 ) It can be seen that under the conditions of low radio altitude and low descent rate, the warning envelopes of the three pilot delay times are almost the same, while the envelope of the pilot with a higher operating rate is shifted to the left as a whole with a certain height difference Δh=h0_0.01-h0_0.015, which means that the pilot has more time and altitude for avoidance, and the success rate of reset and rescue will be higher.

[0048] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A TAWS envelope simulation feasibility analysis method based on a flight simulator, characterized in that: The following steps are involved: According to the envelope description of TAWS mode six, construct the envelope formula: ； Among them, x d is the tilt angle, f(x d ) is the radio altitude; Select several extreme points or inflection points and use the envelope formula to evaluate whether a warning will be issued. According to TAWS, a warning will be issued when the radio altitude is lower than the envelope or the flight inclination angle is greater than the envelope. Get the radio altitude and bank angle at which the warning was issued.

2. The TAWS envelope simulation feasibility analysis method based on a flight simulator according to claim 1, characterized in that: The method of selecting several limit points or inflection points and using the envelope formula to evaluate whether a warning will be issued includes: According to the description of ATM, the turning angle is limited to 35° at 200ft. Substituting 200ft into formula ②, the envelope inclination angle is x d =40.3°, the flight inclination angle of 35° at an altitude of 200ft is less than the envelope of 40.3°, that is, a turning angle of 35° at 200ft will not cause a corresponding alarm.

3. The TAWS envelope simulation feasibility analysis method based on a flight simulator according to claim 2, characterized in that: The method of selecting several limit points or inflection points and using the envelope formula to evaluate whether a warning will be issued includes: The wingspan of the A-320 aircraft is determined to be 34.1m and the radius is 17.05m, which is converted to 56ft, which is the maximum safe altitude of the flight simulator when the inclination angle reaches the maximum 90°. Substituting 56ft as the radio altitude into formula ①, we get x d =16.5°, according to the trigonometric formula: ； Substituting α=16.5° and hypotenuse length=56ft into formula ③, we get the opposite side length=15.9ft. When the flight inclination angle is 16.5°, the radio altitude of 15.9ft is lower than the envelope altitude of 56ft, which meets the alarm condition.

4. The TAWS envelope simulation feasibility analysis method based on a flight simulator according to claim 3 is characterized in that: The method of selecting several limit points or inflection points and using the envelope formula to evaluate whether a warning will be issued includes: According to airline regulations, when the maximum limit inclination angle of the flight simulator is 30°, the envelope altitude is 110ft and the radio altitude is 28ft respectively when substituted into formulas ① and ③. The radio altitude is lower than the envelope, meeting the alarm conditions.

5. The TAWS envelope simulation feasibility analysis method based on a flight simulator according to claim 4, characterized in that: The method of selecting several limit points or inflection points and using the envelope formula to evaluate whether a warning will be issued includes: The first inflection point of the envelope appears at x d =10°, substituting into formula ③, the radio altitude is 9.72ft, which is 30ft lower than the envelope altitude and meets the alarm condition.

6. The TAWS envelope simulation feasibility analysis method based on a flight simulator according to claim 5, characterized in that: The success rate of reset and rescue is evaluated by combining the warning envelopes of different joystick landing speeds and the warning envelopes of different pilot delay times.

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