System and method for glide-slope approach fault tolerant control upon ra failure

Abstract

The present disclosure provides a system and method for glide slope approach fault tolerant control when radio altitude is inoperative. The method can include monitoring RA validity; generating a glide slope mode vertical speed command as a function of an aircraft vertical speed and an aircraft ground speed upon monitoring that the RA is inoperative; generating a glide slope mode deviation angle command as a function of an EGS upon monitoring that the RA is inoperative, including activating an integrator for eliminating glide slope deviation based on a glide slope mode enable signal, a current integrator output, and the EGS; and summing the glide slope mode vertical speed command and the glide slope mode deviation angle command to generate a first normal acceleration command.

Description

Technical Field

[0001] This disclosure relates to the field of landing approach flight control, and more specifically to a system and method for glide slope approach fault-tolerant control in the event of radio altitude failure. Background Technology

[0002] During glide path approach, precise management of the aircraft's position and speed is required to ensure that the aircraft maintains a stable speed and attitude during the final approach phase. To ensure a smooth and accurate landing, the pilot needs to closely monitor the aircraft's position and speed, as well as the glide path angle, and adjust the aircraft's attitude as needed to maintain the correct glide path angle.

[0003] However, existing glide slope engagement logic generally relies on the integrity and consistency of multi-channel signals, lacking the ability to dynamically adapt to flight altitude status under single-point or partial failure conditions. This results in the system being unable to autonomously determine engagement timing under abnormal attitude or sensor degradation conditions, easily leading to engagement failures or false engagements, significantly reducing availability and safety during the approach phase. Current radio altitude monitoring mechanisms are mostly limited to threshold alarms or hard handover logic, lacking the ability to dynamically assess signal validity and reliability, resulting in low smooth transition and continuous controllability of the flight trajectory under fault conditions. Furthermore, the lack of human-machine collaborative command reconstruction support during the fault recovery phase leads to ambiguous pilot intervention timing and poor control handover, making it difficult to achieve a rapid and smooth recovery from an emergency state to a normal approach.

[0004] Therefore, there is an urgent need for a method and equipment to further improve the existing glide slope approach control scheme. Summary of the Invention

[0005] This summary is provided to introduce, in a simplified form, some concepts that will be further described in the following detailed description section. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to help determine the scope of the claimed subject matter.

[0006] To address the problems in the prior art, this disclosure provides a robust automatic approach glide slope fault-tolerant control system and method for radio altitude failures. The scheme in this disclosure employs altitude-adaptive glide slope engagement logic, constructs a precise control mechanism based on deviation angle tracking and conditional integral compensation to suppress steady-state errors and integral divergence caused by failures, and adopts a robust overload command generation strategy that balances dynamic response and control constraints to improve trajectory stability under failure conditions. Furthermore, it performs dynamic monitoring of radio altitude effectiveness and supports rapid and safe state recovery and command switching. This significantly improves the availability, stability, and recovery capability of the flight control system under partial failure conditions, making it suitable for precision approach missions of high-safety-level aircraft.

[0007] Specifically, in a first aspect of this disclosure, a method for glide slope approach fault-tolerant control in the event of Radio Altitude (RA) failure is disclosed, the method comprising: Monitoring the effectiveness of RA; When RA is detected to be invalid, a glide path mode vertical speed command is generated based on the aircraft's vertical speed and ground speed. When RA is detected to be invalid, a glide-slope error angle command is generated based on the glide-slope error signal (EGS), including activating the integrator based on the glide-slope mode on signal, the current integrator output, and the EGS to eliminate glide-slope error; and The first normal overload command is generated by adding the vertical speed command of the glide path mode and the deviation angle command of the glide path mode.

[0008] In an optional implementation, the method further includes: generating a second normal overload command based on the glide slope deviation distance and the glide slope deviation vertical velocity when the RA is detected to be valid; and switching from using the first normal overload command to using the second normal overload command when the RA is detected to change from invalid to valid, provided that the glide slope mode activation signal indicates that the glide slope mode has exited and reactivated and the glide slope mode pre-position signal indicates that the glide slope mode has been pre-positioned.

[0009] In the above implementation, when RA is invalid, the downslope mode activation signal indicates downslope mode activation if all of the following conditions are met: When the aircraft approaches the glide path from above, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is less than a predetermined glide angle limit value; or when the aircraft approaches the glide path from below, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is greater than or equal to the predetermined glide angle limit value. The glide path mode is already in place; The aircraft's lateral track has entered the linear zone of the heading beacon and the difference between the aircraft's heading and the runway heading is less than or equal to the predetermined deviation angle.

[0010] In one optional implementation, generating the glide slope pattern vertical speed command includes: generating a vertical speed deviation value based on a target vertical speed and the aircraft's vertical speed, and generating the glide slope pattern vertical speed command based on the vertical speed deviation value, wherein the target vertical speed is calculated based on the aircraft's ground speed and a trigonometric function with respect to the nominal glide slope angle, and the vertical speed deviation value is obtained by subtracting the target vertical speed from the aircraft's vertical speed.

[0011] In one alternative implementation, generating the glide slope mode deviation angle command includes: processing the EGS using a low-pass filter with a time constant of 3s and assigning a gain coefficient to the processed EGS to obtain the glide slope mode deviation angle command.

[0012] In one alternative implementation, activating the integrator includes: performing clipping and gain processing on the EGS; when the glide slope mode activation signal indicates that the glide slope mode is activated, comparing the current integrator output with the sign of the clipped and gained EGS to obtain steady-state error accumulation trend information; and activating the integrator when the trend information indicates that the steady-state error is accumulating in the direction of increasing aircraft-glide slope deviation angle and reaches a predetermined threshold.

[0013] In the above embodiment, when the integrator is activated, it performs time integration on the clipped and gain-processed EGS to generate pitch trim compensation commands for eliminating the steady-state error.

[0014] In a second aspect of this disclosure, a system for glide path approach fault-tolerant control in the event of RA failure is disclosed, the system comprising: The RA monitoring module is configured to monitor the effectiveness of RA; and The first normal overload instruction generation module is configured as follows: When RA is detected to be invalid, a glide path mode vertical speed command is generated based on the aircraft's vertical speed and ground speed. When RA is detected to be invalid, a glide slope mode deviation angle command is generated based on EGS, including activating the integrator to eliminate glide slope deviation based on the glide slope mode on signal, the current integrator output, and the EGS; and The first normal overload command is generated by adding the vertical speed command of the glide path mode and the deviation angle command of the glide path mode. In an optional implementation, the system further includes: a second normal overload command generation module configured to generate a second normal overload command based on the glide slope deviation distance and the glide slope deviation vertical velocity when the RA is detected to be valid; and an overload command switching module configured to switch from using the first normal overload command to using the second normal overload command when the RA is detected to change from invalid to valid, provided that the glide slope mode activation signal indicates that the glide slope mode has exited and reactivated and the glide slope mode pre-position signal indicates that the glide slope mode has been pre-positioned.

[0015] In the above embodiment, the system further includes a glide slope mode activation module, which is configured to generate a glide slope mode activation signal indicating glide slope mode activation when RA is invalid, provided that all of the following conditions are met: When the aircraft approaches the glide path from above, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is less than a predetermined glide angle limit value; or when the aircraft approaches the glide path from below, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is greater than or equal to the predetermined glide angle limit value. The glide path mode is already in place; The aircraft's lateral track has entered the linear zone of the heading beacon and the difference between the aircraft's heading and the runway heading is less than or equal to the predetermined deviation angle.

[0016] In an optional implementation, the first normal overload command generation module is further configured to generate the glide slope mode vertical speed command by: generating a vertical speed deviation value based on a target vertical speed and the aircraft vertical speed, and generating the glide slope mode vertical speed command based on the vertical speed deviation value, wherein the target vertical speed is calculated based on the aircraft ground speed and a trigonometric function for the nominal glide slope angle, and the vertical speed deviation value is obtained by subtracting the target vertical speed from the aircraft vertical speed.

[0017] In an alternative implementation, the first normal overload command generation module is further configured to generate the glide slope mode deviation angle command by processing the EGS with a low-pass filter of time constant 3s and assigning a gain coefficient to the processed EGS to obtain the glide slope mode deviation angle command.

[0018] In an alternative implementation, the first normal overload command generation module is further configured to activate the integrator by: performing amplitude limiting and gain processing on the EGS; when the glide slope mode activation signal indicates that the glide slope mode is activated, comparing the current integrator output with the sign of the amplitude-limited and gain-processed EGS to obtain steady-state error accumulation trend information; and when the trend information indicates that the steady-state error is accumulating in the direction of increasing aircraft-glide slope deviation angle and reaches a predetermined threshold, activating the integrator.

[0019] In the above embodiment, the first normal overload command generation module is further configured to use the integrator to perform time integration on the clipped and gain-processed EGS when the integrator is activated to generate a pitch trim compensation command for eliminating the steady-state error.

[0020] In a third aspect of this disclosure, a computer-readable storage medium is disclosed, characterized in that the computer-readable storage medium stores instructions that, when executed, implement the method described in the first aspect.

[0021] Other aspects, features, and embodiments of the invention will become apparent to those skilled in the art after reading the following description of specific exemplary embodiments of the invention in conjunction with the accompanying drawings. Although features of the invention may be discussed below with reference to certain embodiments and drawings, all embodiments of the invention may include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed having certain advantageous features, one or more of such features may also be used according to the various embodiments of the invention discussed herein. Similarly, although exemplary embodiments may be discussed below as embodiments of devices, apparatuses, or methods, it should be understood that such exemplary embodiments may be implemented in various devices, apparatuses, and methods. Attached Figure Description

[0022] To gain a more detailed understanding of the features described above in this disclosure, reference can be made to a more specific description of the above-briefly summarized aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as other equivalent aspects are permissible in this description.

[0023] Figure 1 This is a schematic block diagram of a system for glide path approach fault-tolerant control in the event of RA failure, according to an embodiment of the present disclosure.

[0024] Figure 2 This is a logic diagram of glide path approach fault-tolerant control according to an embodiment of the present disclosure.

[0025] Figure 3 This is a connection logic diagram of the glide path mode according to an embodiment of the present disclosure.

[0026] Figure 4 This is a flowchart of a method for performing glide slope approach fault-tolerant control in the event of RA failure, according to an embodiment of the present disclosure.

[0027] Figure 5 This is a graph showing the changes in flight altitude trajectory change overload command, overload response change, track angle change, and glide slope deviation signal under RA failure state according to an embodiment of this disclosure. Detailed Implementation

[0028] The various embodiments will now be described in more detail with reference to the accompanying drawings, which form part of this invention and illustrate specific exemplary embodiments. However, the embodiments may be implemented in many different forms and should not be construed as limiting the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of these embodiments to those skilled in the art. The embodiments may be implemented as methods, apparatus, or devices. Therefore, these embodiments may be implemented in hardware form, entirely in software form, or in a combination of software and hardware aspects. Therefore, the following detailed description is not intended to be limiting.

[0029] The steps in each flowchart can be performed by hardware (e.g., processor, engine, memory, circuitry), software (e.g., operating system, application, driver, machine / processor executable instructions), or a combination thereof. As will be understood by those skilled in the art, the methods involved in each embodiment may include more or fewer steps than shown.

[0030] To address the problems of inaccurate timing judgment under RA failure conditions and the lack of condition constraints on the fixed deviation angle control structure and integral mechanism in existing technologies, this disclosure relates to a high-availability glide slope fault-tolerant control system and method, aiming to solve the technical problem that the glide slope capture and stable tracking capabilities of existing flight control systems are significantly reduced under RA failure conditions.

[0031] The various aspects of the present invention will now be described in detail.

[0032] Figure 1 This is a schematic block diagram of a system 100 for glide path approach fault-tolerant control in the event of RA failure, according to an embodiment of the present disclosure.

[0033] like Figure 1 As shown, in one embodiment of this disclosure, system 100 may include an RA monitoring module 102 and a first normal overload command generation module 104 (indicated by solid lines). In another optional embodiment of this disclosure, system 100 may also optionally include a second normal overload command generation module 106, an overload command selection module 108, and a glide slope mode activation module 110 (indicated by dashed lines). The following will be combined with... Figure 2 Describe these modules in detail.

[0034] In the embodiments described above, the RA monitoring module 102 can be configured to monitor RA validity. The RA monitoring module 102 can detect whether the current RA is valid, invalid, and / or has recovered from invalid to valid, and provide an RA validity signal indicating whether the RA is valid to the other modules.

[0035] In the above embodiments of this disclosure, the first normal overload command generation module 104 can be configured to generate a glide path mode vertical speed command based on the aircraft vertical speed and the aircraft ground speed when the RA is detected to be invalid (i.e., when the RA validity signal provided by the RA monitoring module 102 indicates that the current RA is invalid).

[0036] Figure 2 This is a logic diagram of glide path approach fault-tolerant control according to an embodiment of the present disclosure.

[0037] In one alternative implementation, such as Figure 2 As shown in operation block 2 (Calculation of Glide Slope Mode Vertical Speed ​​Command when RA is Invalid), the first normal overload command generation module 104 can also be configured to generate the glide slope mode vertical speed command by: generating a vertical speed deviation value based on the target vertical speed and the aircraft vertical speed (in mps), and generating the glide slope mode vertical speed command based on the vertical speed deviation value. The target vertical speed can be calculated based on the aircraft ground speed (in mps) and a trigonometric function with respect to the nominal glide slope angle (γ, in rad), and the vertical speed deviation value is obtained by subtracting the target vertical speed from the aircraft vertical speed. In an optional embodiment, the nominal glide slope angle can be ±3° or any other suitable glide slope angle.

[0038] In a non-limiting example, the target vertical velocity (Vzgiv) can be obtained from the aircraft ground speed (Vground) using the following formula: Vzgiv = Vground × sin(γ). As those skilled in the art will understand, in other embodiments of this disclosure, the target vertical velocity can also be determined by any other suitable trigonometric function calculation method, not limited to the above-described method, and can also be determined by any other suitable method, not limited to trigonometric function calculation.

[0039] In another alternative implementation, the vertical velocity deviation of the aircraft relative to the nominal glide slope of -3° can be limited and then processed by gain (RA_InValid_KHdot_deltaVz_d) to maintain the aircraft approaching at the vertical velocity required for the glide slope angle.

[0040] In the above embodiments of this disclosure, such as Figure 2 As shown in operation box 3 (Calculation of glide slope mode deviation angle command when RA is invalid), the first normal overload command generation module 104 can be further configured to generate a glide slope mode deviation angle command based on EGS (in deg) when RA is detected to be invalid, including activating the integrator based on the glide slope mode on signal, the current integrator output and the EGS to eliminate glide slope deviation.

[0041] In an alternative implementation, the first normal overload command generation module 104 can also be configured to generate the glide slope mode deviation angle command by processing the EGS with a low-pass filter of time constant 3s and assigning a gain coefficient to the processed EGS to obtain the glide slope mode deviation angle command, thereby controlling the aircraft to remain on the glide slope. The first normal overload command generation module 104 can generate a corresponding control quantity by multiplying the low-pass filtered EGS by a gain coefficient (which can be determined by a one-dimensional lookup table based on the aircraft's radio altitude RA; any suitable gain coefficient can be used, not limited to any specific gain coefficient) to control the aircraft to eliminate glide slope deviation, thereby maintaining the aircraft's approach at the required glide slope angle at different altitudes.

[0042] In one alternative implementation, such as Figure 2 As shown in operation block 4 (Integrator Activation Judgment), the first normal overload command generation module 104 can also be configured to activate the integrator through the following operations: performing amplitude limiting and gain processing on the EGS; when the glide slope mode activation signal indicates that the glide slope mode is activated, comparing the current integrator output with the sign of the amplitude-limited and gain-processed EGS to obtain steady-state error accumulation trend information; and activating the integrator when the trend information indicates that the steady-state error is accumulating in the direction of increasing aircraft-glide slope deviation angle and reaches a predetermined threshold. Otherwise, the integrator is not activated. As those skilled in the art will understand, the predetermined threshold can be any suitable threshold obtained by parameter tuning based on engineering experience, and is not limited to any specific threshold.

[0043] In the above optional implementations, such as Figure 2 As shown in operation block 5 (Integral Compensation), the first normal overload command generation module 104 can also be configured to use the integrator to perform time integration on the clipped and gain-processed EGS when the integrator is activated to generate a pitch trim compensation command for eliminating the aforementioned steady-state error. As those skilled in the art will understand, the specific integration method can be any suitable integration method, and is not limited to any particular integration method.

[0044] In the above embodiments of this disclosure, the first normal overload command generation module 104 may also be configured to add the glide slope mode vertical speed command and the glide slope mode deviation angle command to generate the first normal overload command.

[0045] In another optional embodiment of this disclosure, system 100 may also optionally include a second normal overload command generation module 106, an overload command selection module 108, and a glide slope mode activation module 110 (indicated by dashed lines). The following will be combined with... Figure 2 and Figure 3 Describe these modules in detail.

[0046] In the above optional embodiments, the second normal overload command generation module 106 can be configured to generate a second normal overload command based on the glide slope deviation distance and the glide slope deviation vertical velocity when the RA is detected to be valid (i.e., when the RA validity signal provided by the RA monitoring module 102 indicates that the current RA is valid). gl The system generates an overload command based on the aircraft's vertical velocity deviation relative to the glide slope, controlling the aircraft to capture the glide slope and complete the approach. Specifically, the aircraft's vertical velocity deviation relative to the glide slope is generated by using complementary filtering (as an example, and not a limitation, a high-pass filter with a time constant of 5s and a differential filter with a time constant of 5s) to generate the glide slope deviation distance and the aircraft's vertical velocity deviation relative to the nominal glide slope of -3°. This is then adjusted by gain (such as RA_Valid_KHdot_deltaVz_d) to maintain the aircraft's vertical velocity at the required glide slope angle for the approach. Simultaneously, the glide slope deviation distance is processed by a low-pass filter and an altitude-adjusted gain (such as RA_Valid_Kegl_deltaZ_d) to control the aircraft to eliminate the glide slope deviation distance. The two (i.e., the glide slope deviation vertical velocity and the glide slope deviation distance) are added together and converted into a corresponding normal overload command (i.e., a second normal overload command) through gain (such as Knz) to control the aircraft to complete the approach along the actual glide slope.

[0047] In the above optional embodiments, such as Figure 2As shown in operation box 6 (RA validity monitoring and glide slope overload command selection), the overload command selection module 108 can be configured to switch from using the first normal overload command to using the second normal overload command when the RA is detected to change from invalid to valid (i.e., when the RA validity signal provided by the RA monitoring module 102 indicates that the RA validity has recovered), and when the glide slope mode activation signal indicates that the glide slope mode has exited and re-activated, and the glide slope mode pre-position signal indicates that the glide slope mode is pre-positioned (involving the coordinated judgment of the glide slope mode activation signal and the glide slope mode pre-position signal). In a non-limiting example, above 800ft (radio altitude), if the RA signal fails and then recovers, exiting the glide slope mode and re-activating it can be switched back to APPRI from APPRII. Specifically, two stages need to be met before the glide slope mode can be activated: first, the glide slope mode is pre-positioned (e.g., by the pilot pressing the APPR button on the flight mode control panel), and then the glide slope mode is activated only after all conditions are met. If the RA signal fails and then recovers, the glide slope mode must be completely exited and re-engaged (for example, requiring the addition of a pilot manual operation rather than human-machine interaction is more in line with the pilot's expectations). Only then can the APPRII (the control law corresponding to the RA failure state, i.e., the first normal overload command) be switched back to APPRII (the control law corresponding to the RA effective state, i.e., the second normal overload command).

[0048] Figure 3 This is a connection logic diagram of the glide path mode according to an embodiment of the present disclosure.

[0049] In the above optional embodiments, such as Figure 3 As shown, the glide slope mode activation module 110 can be configured to generate a glide slope mode activation signal indicating glide slope mode activation when RA is invalid, provided that all of the following conditions are met (i.e., conditions 1-3): Condition 1: When the aircraft approaches the glide path from above, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is less than a predetermined glide angle limit value; or when the aircraft approaches the glide path from below, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is greater than or equal to the predetermined glide angle limit value.

[0050] Once the glide path pattern is pre-positioned, the aircraft should begin acquiring the glide path before intersecting with it. An altitude-adaptive glide path engagement strategy was designed. This strategy no longer relies on a fixed deviation angle threshold but instead integrates flight status and system health to achieve dynamic engagement decisions, ensuring optimal engagement timing.

[0051] Specifically, in one optional implementation, the radio altitude signal is intercepted when it fails, meaning the aircraft can complete approaches above and below the glide path even with the RA in a failed state. The specific activation logic is as follows: When the RA signal is invalid and the aircraft approaches the glide path from above, the following conditions should be met:

[0052] When the RA signal is invalid and the aircraft approaches the glide path from below, the following conditions must be met:

[0053] Where, ε gl The glide slope beamband signal is acquired by inertial and navigation system data sensors, ε gl process is the glide slope beamband signal after integration processing, above_threshold_DDM and below_threshold_DDM are given glide slope limit values, obtained based on engineering experience (not limited to specific values), and the unit is DDM.

[0054] In another alternative implementation, the glide slope beamband signal after integration processing can be, but is not limited to, the following: The specific connection logic can also be: When the RA signal is invalid and the aircraft approaches the glide path from above, the following conditions should be met:

[0055] When the RA signal is invalid and the aircraft approaches the glide path from below, the following conditions must be met:

[0056] Here, s is a Laplace complex variable, and the purpose of integrating the glide slope beam segment signal is to introduce the aircraft's distance from the glide slope deviation ε. gl The rate of change is used to assist in the trigger logic judgment when there is no radio altitude, so as to achieve a consistent intercept response when the aircraft approaches the glide path at different altitudes. The purpose of introducing the glide path overload command (the overload command calculated in glide path mode) is to judge the overload command received by the aircraft before the glide path mode is activated, so as to avoid unexpected attitude interception such as nose-up interception when the aircraft is below the glide path.

[0057] Condition 2: The glide slope mode is pre-positioned.

[0058] Condition 3: The aircraft's lateral track has entered the localizer linearity zone and the difference between the aircraft's heading and the runway heading is less than or equal to a predetermined deviation angle. In an optional implementation, whether the aircraft's lateral track has entered the localizer linearity zone can be determined by |ε loclim The deviation angle between the aircraft's heading and the runway's heading can be determined by whether it is ≤0.155DDM. It can be calculated by the aircraft's inertial data and navigation data through the localizer approach control system. The unit is deg. The predetermined deviation angle can be, for example, 30°.

[0059] like Figure 3 As shown, 4 is the logical "AND" judgment, that is, 1, 2 and 3 must be satisfied at the same time for the output to be "true"; 5 is the signal latch, when the input is true, the signal at this moment is latched. The purpose of latching is to prevent interruption once the connection condition is met, until the glide path approach process is completed; 6 is the output glide path mode connection signal, the signal is "1" to indicate connection, and "0" to indicate non-connection.

[0060] Figure 4 This is a flowchart of a method 400 for glide path approach fault-tolerant control in the event of RA failure, according to an embodiment of the present disclosure.

[0061] like Figure 4 As shown, method 400 may begin at step 402, monitoring the effectiveness of RA.

[0062] Next, method 400 continues to step 404, whereby a glide slope pattern vertical speed command is generated based on the aircraft's vertical speed and ground speed when RA is detected to be invalid. In an optional implementation, this step may include: generating a vertical speed deviation value based on a target vertical speed and the aircraft's vertical speed, and generating the glide slope pattern vertical speed command based on the vertical speed deviation value, wherein the target vertical speed is calculated based on the aircraft's ground speed and a trigonometric function with respect to the nominal glide slope angle, and the vertical speed deviation value is obtained by subtracting the target vertical speed from the aircraft's vertical speed.

[0063] Then, method 400 continues to step 406, whereby, upon detecting an invalid RA, a glide slope mode deviation angle command is generated based on the EGS, including activating the integrator based on the glide slope mode activation signal, the current integrator output, and the EGS to eliminate glide slope deviation. In an optional embodiment, this step may include: processing the EGS using a low-pass filter with a time constant of 3s and assigning a gain coefficient to the processed EGS to obtain the glide slope mode deviation angle command. In an optional embodiment, activating the integrator includes: performing amplitude limiting and gain processing on the EGS; when the glide slope mode activation signal indicates that the glide slope mode is activated, comparing the sign of the current integrator output with that of the amplitude-limited and gain-processed EGS to obtain steady-state error accumulation trend information; and activating the integrator when the trend information indicates that the steady-state error is accumulating in the direction of increasing aircraft glide slope deviation angle and reaching a predetermined threshold. In the above optional embodiment, the integrator, when activated, performs time integration on the amplitude-limited and gain-processed EGS to generate a pitch trim compensation command for eliminating glide slope deviation.

[0064] Finally, method 400 continues to step 408, adding the glide slope mode vertical speed command and the glide slope mode deviation angle command to generate a first normal overload command.

[0065] In an optional embodiment, method 400 may further include generating a second normal overload command based on the glide slope deviation distance and the glide slope deviation vertical velocity when the RA is detected to be valid; and switching from using the first normal overload command to using the second normal overload command when the RA is detected to change from invalid to valid, provided that the glide slope mode activation signal indicates that the glide slope mode has been deactivated and reactivated and the glide slope mode prepositioning signal indicates that the glide slope mode has been prepositioned. In the above optional embodiment, the glide slope mode activation signal indicates that the glide slope mode is activated when all of the following conditions are met: when the aircraft approaches the glide slope from above, the sum of the glide slope beamband signal and the integrated glide slope beamband signal is less than a predetermined glide slope angle limit value; or when the aircraft approaches the glide slope from below, the sum of the glide slope beamband signal and the integrated glide slope beamband signal is greater than or equal to the predetermined glide slope angle limit value; the glide slope mode has been prepositioned; the aircraft's lateral track has entered the localizer linearity zone and the difference between the aircraft's heading and the runway heading is less than or equal to a predetermined deviation angle.

[0066] Method 400 ends after step 408.

[0067] Figure 5 This is a graph showing the changes in flight altitude trajectory change overload command, overload response change, track angle change, and glide slope deviation signal under RA failure state according to an embodiment of this disclosure.

[0068] like Figure 5 As shown, the four figures from top to bottom represent the changes in the aircraft's flight altitude trajectory, overload command, overload response, track angle, and glide slope deviation signal under the radio altitude signal failure state. The dashed line represents the aircraft's response under the conventional control method, and the solid line represents the aircraft's response under the control method of this invention. It can be seen that: a. Regarding changes in flight trajectory, whether it is changes in altitude or changes in track angle, the control method of this patent invention exhibits higher trajectory stability than traditional control methods during the glide slope interception and tracking process under failure conditions. b. Regarding overload commands, the control method of this patented invention ensures smooth, continuous and disturbance-resistant commands under failure conditions, and has a faster response, stronger stability and higher accuracy compared to traditional control methods. c. Regarding beam deviation on the glide path, the control method of this patent invention ensures that the beam deviation signal of the aircraft relative to the glide path during glide path interception and tracking is free from overshoot and oscillation. The interception process is fast and smooth, and ultimately remains within the required accuracy range, resulting in high passenger comfort.

[0069] In summary, the proposed solution is particularly suitable for optimizing the control logic of the automatic landing system for civil aircraft under RA failure conditions, which is crucial for ensuring the safe landing of the aircraft.

[0070] The embodiments of the present invention have been described above with reference to block diagrams and / or operational descriptions of methods and apparatus according to embodiments of the present invention. The functions / actions indicated in the blocks may appear in a different order than shown in any flowchart. For example, depending on the functions / actions involved, two blocks shown consecutively may actually be executed substantially simultaneously, or these blocks may sometimes be executed in reverse order.

[0071] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for glide slope approach fault-tolerant control in the event of radio altitude (RA) failure, the method comprising: Monitoring the effectiveness of RA; When RA is detected to be invalid, a glide path mode vertical speed command is generated based on the aircraft's vertical speed and ground speed. When RA is detected to be invalid, a glide path mode deviation angle command is generated based on the glide path deviation angle signal EGS, including activating the integrator based on the glide path mode on signal, the current integrator output, and the EGS to eliminate the glide path deviation; and The first normal overload command is generated by adding the vertical speed command of the glide path mode and the deviation angle command of the glide path mode.

2. The method according to claim 1, characterized in that, The method further includes: When RA is detected as valid, a second normal overload command is generated based on the glide slope deviation distance and the vertical velocity of the glide slope deviation; and When the RA is detected to change from invalid to valid, the system switches from using the first normal overload command to using the second normal overload command, provided that the downhill mode activation signal indicates that the downhill mode has exited and reactivated and the downhill mode pre-position signal indicates that the downhill mode has been pre-positioned.

3. The method according to claim 2, characterized in that, When RA is invalid, the glide slope mode activation signal indicates glide slope mode activation if all of the following conditions are met: When the aircraft approaches the glide path from above, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is less than a predetermined glide angle limit value; or when the aircraft approaches the glide path from below, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is greater than or equal to the predetermined glide angle limit value. The glide path mode is already in place; The aircraft's lateral track has entered the linear zone of the heading beacon and the difference between the aircraft's heading and the runway heading is less than or equal to the predetermined deviation angle.

4. The method according to claim 1, characterized in that, Generating the glide slope pattern vertical speed command includes: generating a vertical speed deviation value based on the target vertical speed and the aircraft's vertical speed, and generating the glide slope pattern vertical speed command based on the vertical speed deviation value. The target vertical speed is calculated based on the aircraft ground speed and a trigonometric function with respect to the nominal glide slope angle, and the vertical speed deviation is obtained by subtracting the target vertical speed from the aircraft vertical speed.

5. The method according to claim 1, characterized in that, Generating the glide slope mode deviation angle command includes: processing the EGS using a low-pass filter with a time constant of 3s and assigning a gain coefficient to the processed EGS to obtain the glide slope mode deviation angle command.

6. The method according to claim 1, characterized in that, Activating the integrator includes: The EGS is subjected to amplitude limiting and gain processing; When the downslope mode activation signal indicates that the downslope mode is activated, the current integrator output is compared with the sign of the EGS after clipping and gain processing to obtain the trend information of steady-state error accumulation; and The integrator is activated when the trend information indicates that the steady-state error is accumulating in the direction of increasing aircraft-glide slope deviation angle and reaches a predetermined threshold.

7. The method according to claim 6, characterized in that, When activated, the integrator performs time integration on the clipped and gain-processed EGS to generate pitch trim compensation commands to eliminate the steady-state error.

8. A system for glide slope approach fault-tolerant control in the event of radio altitude (RA) failure, the system comprising: The RA monitoring module is configured to monitor the effectiveness of RA. as well as The first normal overload instruction generation module is configured as follows: When RA is detected to be invalid, a glide path mode vertical speed command is generated based on the aircraft's vertical speed and ground speed. When RA is detected to be invalid, a glide path mode deviation angle command is generated based on the glide path deviation angle signal EGS, including activating the integrator based on the glide path mode on signal, the current integrator output, and the EGS to eliminate the glide path deviation; and The first normal overload command is generated by adding the vertical speed command of the glide path mode and the deviation angle command of the glide path mode.

9. The system according to claim 8, characterized in that, The system also includes: The second normal overload command generation module is configured to generate a second normal overload command based on the glide slope deviation distance and the glide slope deviation vertical velocity when RA is detected to be valid; and The overload command selection module is configured to switch from using the first normal overload command to using the second normal overload command when the RA is detected to change from invalid to valid, provided that the glide slope mode is exited and re-enabled by the glide slope mode activation signal and the glide slope mode is pre-positioned by the glide slope mode pre-position signal.

10. The system according to claim 9, characterized in that, The system also includes a glide slope mode activation module, which is configured to generate a glide slope mode activation signal indicating glide slope mode activation when RA is invalid, provided that all of the following conditions are met: When the aircraft approaches the glide path from above, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is less than a predetermined glide angle limit value; or when the aircraft approaches the glide path from below, the sum of the glide path beam segment signal and the integrated glide path beam segment signal is greater than or equal to the predetermined glide angle limit value. The glide path mode is already in place; The aircraft's lateral track has entered the linear zone of the heading beacon and the difference between the aircraft's heading and the runway heading is less than or equal to the predetermined deviation angle.

11. The system according to claim 8, characterized in that, The first normal overload command generation module is also configured to generate the glide slope pattern vertical speed command by: generating a vertical speed deviation value based on the target vertical speed and the aircraft vertical speed, and generating the glide slope pattern vertical speed command based on the vertical speed deviation value. The target vertical speed is calculated based on the aircraft ground speed and a trigonometric function with respect to the nominal glide slope angle, and the vertical speed deviation is obtained by subtracting the target vertical speed from the aircraft vertical speed.

12. The system according to claim 8, characterized in that, The first normal overload command generation module is also configured to generate the glide slope mode deviation angle command by processing the EGS with a low-pass filter with a time constant of 3s and assigning a gain coefficient to the processed EGS to obtain the glide slope mode deviation angle command.

13. The system according to claim 8, characterized in that, The first normal overload command generation module is also configured to activate the integrator by the following operation: The EGS is subjected to amplitude limiting and gain processing; When the glide slope mode activation signal indicates that the glide slope mode is activated, the current integrator output is compared with the sign of the EGS after limiting and gain processing to obtain the trend information of steady-state error accumulation. as well as The integrator is activated when the trend information indicates that the steady-state error is accumulating in the direction of increasing aircraft-glide slope deviation angle and reaches a predetermined threshold.

14. The system according to claim 13, characterized in that, The first normal overload command generation module is also configured to use the integrator to perform time integration on the clipped and gain-processed EGS when the integrator is activated to generate a pitch trim compensation command for eliminating the steady-state error.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores instructions that, when executed, implement the method of any one of claims 1 to 7.

Images