Synthetic angle of attack monitoring method and system for an aircraft

Abstract

This disclosure relates to a method and system for monitoring the composite angle of attack (CAA) of an aircraft. A method for monitoring the CAA of an aircraft includes: calculating the absolute value of the difference between an estimated composite angle of attack and a vote angle of attack acquired from an angle of attack sensor; calculating an angle of attack tolerance value based on the effectiveness and skewness of different control surfaces; comparing the absolute value with the angle of attack tolerance value; and issuing an angle of attack unreliability alarm only if the absolute value is greater than the angle of attack tolerance value.

Description

Technical Field

[0001] This disclosure relates to flight control of aircraft, and in particular to a method for monitoring the composite angle of attack of an aircraft, namely, a method for monitoring the voting angle of attack of an angle of attack sensor using a composite angle of attack sensor that is not based on the angle of attack sensor. Background Technology

[0002] Angle of attack is a crucial parameter during flight, ensuring the aircraft does not operate in an irrecoverable state. Conventional methods using redundant angle of attack sensors cannot address the risks associated with encountering common modes such as icing, insects, and volcanic ash.

[0003] Currently, major aircraft manufacturers are seeking to use synthetic angle of attack (AOA) that is not based on the AOA sensor to monitor the voting AOA of the AOA sensor in order to mitigate this common-mode problem that may be encountered during flight. Summary of the Invention

[0004] To address this, this disclosure proposes a novel method for monitoring the synthetic angle of attack (SAA). The method innovatively employs different angle of attack tolerances depending on the aircraft's state (e.g., the effectiveness and skewness of individual control surfaces) to accurately monitor the voting angle of attack using the synthetic angle of attack. Furthermore, this method provides a method for monitoring the voting angle of attack under external interference, thereby improving the robustness of synthetic angle of attack monitoring in aircraft. Thus, this method allows for real-time updates of the angle of attack tolerance (also known as the threshold) based on the aircraft's state to monitor the voting angle of attack. Further, this method also utilizes delayed shutdown and latches to address the problem of monitoring the voting angle of attack when the synthetic angle of attack fluctuates.

[0005] According to a first aspect of this disclosure, a method for monitoring the composite angle of attack of an aircraft is provided, characterized by comprising: calculating the absolute value of the difference between the estimated composite angle of attack and the vote angle of attack acquired from an angle of attack sensor; calculating an angle of attack tolerance value based on the effectiveness and skewness of different control surfaces; comparing the absolute value with the angle of attack tolerance value, and issuing an angle of attack unreliable alarm only if the absolute value is greater than the angle of attack tolerance value.

[0006] According to one embodiment, the different control surfaces include at least one of spoiler, rudder, elevator, aileron, and horizontal stabilizer, and calculating the angle of attack tolerance value based on the effectiveness and skewness of the different control surfaces includes: determining the corresponding tolerance increment of each control surface based on the effectiveness and skewness of each of the different control surfaces; and superimposing the base value of the angle of attack tolerance with each corresponding tolerance increment to obtain the angle of attack tolerance value.

[0007] According to another embodiment, the method further includes increasing the angle of attack tolerance value by a first predetermined value in the event of a landing gear signal failure.

[0008] According to another embodiment, determining the tolerance increment corresponding to a control surface based on the effectiveness and skewness of each of the different control surfaces includes: in the event of control surface failure, the tolerance increment corresponding to that control surface is greater than zero.

[0009] According to yet another embodiment, determining the corresponding tolerance increment for each of the different control surfaces based on the effectiveness and skewness further includes, for each of the elevator, aileron, and horizontal stabilizer: When the control surface is effective, the tolerance increment corresponding to the control surface is equal to zero; Regarding spoilers: When the spoiler skewness is greater than the first value, the corresponding tolerance increment for the spoiler is greater than zero. When the spoiler deflection is less than or equal to the first value, the tolerance increment corresponding to the spoiler is zero; Regarding the rudder: When the rudder deflection is greater than the second value, the corresponding tolerance increment for the rudder is greater than zero. When the rudder deflection is less than or equal to the second value, the tolerance increment corresponding to the rudder is zero.

[0010] According to another embodiment, the basic value of the angle of attack tolerance is 0.5°; the tolerance increment corresponding to the elevator is 0.1° in the case of elevator failure; the tolerance increment corresponding to the spoiler is 0.2° in the case of spoiler failure or spoiler deflection greater than the first value; the tolerance increment corresponding to the aileron is 0.05° in the case of aileron failure; the tolerance increment corresponding to the horizontal stabilizer is 0.2° in the case of horizontal stabilizer failure; the tolerance increment corresponding to the rudder is 0.2° in the case of rudder deflection greater than the second value; the first predetermined value is 0.05°; wherein the first value is 10° and the second value is 15°.

[0011] According to another embodiment, issuing an angle-of-attack unreliable alarm only when the absolute value is greater than the angle-of-attack tolerance value includes: issuing an angle-of-attack unreliable alarm only when the duration of the absolute value being greater than the angle-of-attack tolerance value exceeds a first predetermined duration.

[0012] According to another embodiment, the method further includes, in the event that the unreliable angle of attack alarm has been issued, canceling the unreliable angle of attack alarm if the duration during which the absolute value is less than or equal to the angle of attack tolerance value exceeds a second predetermined duration.

[0013] According to a second aspect of this disclosure, an angle-of-attack monitoring system for an aircraft is provided, comprising: a difference calculation component configured to calculate the absolute value of the difference between an estimated composite angle of attack and a voted angle of attack acquired from an angle-of-attack sensor; an angle-of-attack tolerance calculation component configured to calculate an angle-of-attack tolerance value based on the effectiveness and skewness of different control surfaces; and a comparison component configured to receive the absolute value calculated by the difference calculation component and the angle-of-attack tolerance value calculated by the angle-of-attack tolerance calculation component, and to compare the two, wherein the comparison component is further configured to output trigger information for triggering an angle-of-attack unreliable alarm when the absolute value is greater than the angle-of-attack tolerance value, and to output cancellation information for canceling the angle-of-attack unreliable alarm when the absolute value is less than or equal to the angle-of-attack tolerance value.

[0014] According to a third aspect of this disclosure, an aircraft is provided, the aircraft including a processing device configured to perform the method according to a first aspect of this disclosure.

[0015] The aspects generally include, as substantially as described herein with reference to the accompanying drawings and as explained by the drawings, methods, apparatus, systems, computer program products, and processing systems.

[0016] The foregoing has broadly outlined the features and technical advantages of the examples according to this disclosure so that the following detailed description may be better understood. Additional features and advantages will be described thereafter. The disclosed concepts and specific examples can be readily used as the basis for modifying or designing other structures for implementing the same purposes as this disclosure. Such equivalent constructions do not depart from the scope of the appended claims. The characteristics of the concepts disclosed herein, in both their organization and manner of operation, and their associated advantages, will be better understood by considering the following description in conjunction with the accompanying drawings. Each drawing is provided for illustrative and descriptive purposes and does not define any limitation on the claims. Attached Figure Description

[0017] To gain a more detailed understanding of the features described above in this disclosure, reference can be made to various aspects of the above-briefly summarized content, 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. Identical reference numerals in different drawings may identify the same or similar elements.

[0018] Figure 1 A flowchart of a method for monitoring the angle of attack of an aircraft according to an embodiment of the present disclosure is shown; Figure 2A schematic block diagram of an angle-of-attack monitoring system for an aircraft according to an embodiment of the present disclosure is shown; Figure 3 A schematic logic diagram of an angle-of-attack monitoring system according to an example embodiment of the present disclosure is shown; Figures 4A-4B A simulation result diagram of angle-of-attack monitoring according to an example embodiment of the present disclosure is shown, wherein Figure 4A Simulation results are shown when the synthetic angle of attack is effective. Figure 4B Simulation results are shown with the synthetic angle of attack invalidated; and Figure 5 A schematic diagram of an aircraft according to an example embodiment of the present disclosure is shown. Detailed Implementation

[0019] The inventors recognized that aircraft manufacturers are currently seeking to use synthetic angle of attack (AOA) sensors, which are not based on AOA sensors, to monitor the sensor's voting AOA in order to mitigate common-mode problems that may be encountered during flight. The most common method for synthetic AOA is to use the aircraft's weight and overload to obtain the aircraft's lift, and then calculate the AOA through the complex relationship between lift and AOA.

[0020] The inventors innovatively discovered that, since the relationship between lift and angle of attack is related to various factors such as the aircraft's configuration, flight status, the position of each control surface, and the engine, and there is a possibility of control surface failure, the accuracy of the synthesized angle of attack varies greatly under different conditions and fluctuates under external disturbances. This makes it difficult to use the synthesized angle of attack to monitor the actual angle of attack.

[0021] To address this, this disclosure provides a novel method for monitoring the synthetic angle of attack (SAA). The method innovatively proposes using different angle of attack tolerances depending on the aircraft's various states (e.g., the effectiveness and skewness states of individual control surfaces) to accurately monitor the voting angle of attack using the synthetic angle of attack. Furthermore, this method provides a method for monitoring the voting angle of attack under external interference, thereby improving the robustness of synthetic angle of attack monitoring in aircraft. Thus, this method allows for real-time updates of the angle of attack tolerance (also known as the threshold) based on the aircraft's state to monitor the voting angle of attack. Further, this method employs delayed shutdown and latches to address the problem of monitoring the voting angle of attack when the synthetic angle of attack fluctuates.

[0022] Thus, the synthetic angle of attack monitoring method disclosed herein can: To ensure the availability of composite angle of attack monitoring in the event of partial control surface failure; To ensure the availability of composite angle of attack monitoring even when lift estimation for some control surfaces is inaccurate; To invalidate the combined angle of attack when the aircraft is outside the normal envelope, and to prevent incorrect judgment of the voting angle of attack; To ensure that the judgment of the angle of attack is not affected by short-term external disturbances; The system should be able to automatically restore the correct judgment of the voting angle of attack when the factors causing the incorrect voting angle of attack disappear.

[0023] The detailed description that follows, taken in conjunction with the accompanying drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein can be practiced. This detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details.

[0024] refer to Figure 1 The diagram shows a flowchart of an angle-of-attack monitoring method 100 for an aircraft according to an embodiment of the present disclosure.

[0025] As shown in the figure, method 100 may include, in block 110, calculating the absolute value of the difference between the estimated composite angle of attack and the vote angle of attack acquired from the angle of attack sensor.

[0026] In one embodiment of this disclosure, the composite angle of attack is obtained by using gravity and overload to generate lift, and then estimated from the complex relationship between lift, angle of attack and other parameters affecting lift, while the voting angle of attack is obtained by voting on the measurements of multiple angle of attack sensors.

[0027] The inventors innovatively discovered that the failure of certain lift-related control surfaces or excessive deflection of certain control surfaces (such as speed brakes) can affect the estimation of the composite angle of attack, resulting in an inaccurate composite angle of attack. This leads to errors when using the composite angle of attack to monitor the voting angle of attack (i.e., determining the correctness of the voting angle of attack by checking if the difference between the two exceeds the tolerance). Therefore, by adjusting the angle of attack tolerance based on the aircraft's state (instead of using a fixed angle of attack tolerance), the reliability of subsequent monitoring can be improved.

[0028] Continue to refer to Figure 1 In box 120, method 100 may include calculating angle of attack tolerance values ​​based on the effectiveness and deflection of different control surfaces.

[0029] In one embodiment of this disclosure, different control surfaces may include at least one of a spoiler, rudder, elevator, aileron, and horizontal stabilizer. In this embodiment, calculating the angle-of-attack tolerance value based on the effectiveness and skewness of the different control surfaces may include determining the corresponding tolerance increment for each control surface based on its effectiveness and skewness; and superimposing the corresponding tolerance increments onto a baseline angle-of-attack tolerance value to obtain the angle-of-attack tolerance value. According to this embodiment, the baseline angle-of-attack tolerance value may be any suitable empirical value, such as 0.47°, 0.5°, or 0.51°.

[0030] In another embodiment of this disclosure, in the event of a corresponding control surface failure, the tolerance increment corresponding to that control surface may be greater than zero; conversely, in the event of a corresponding control surface failure, the tolerance increment corresponding to that control surface may be equal to zero. In this embodiment, the tolerance increment associated with different control surfaces may vary depending on the control surface in the event of its failure. For example, these tolerance increments may be obtained empirically. To cite just a few examples, the tolerance increment corresponding to the elevator is 0.1° in the event of elevator failure; the tolerance increment corresponding to the spoiler is 0.2° in the event of spoiler failure; the tolerance increment corresponding to the aileron is 0.05° in the event of aileron failure; and the tolerance increment corresponding to the horizontal stabilizer is 0.2° in the event of horizontal stabilizer failure.

[0031] In another embodiment of this disclosure, for most control surfaces, when the control surface is active, the tolerance increment corresponding to the control surface is zero, that is, it has no effect on the angle of attack tolerance. For example, for each of the elevator, aileron, and horizontal stabilizer, when the control surface is active, the tolerance increment corresponding to the control surface is zero.

[0032] However, the inventors further recognized that for control surfaces whose skewness is too large to accurately calculate their impact on lift, the estimation of the combined angle of attack (or in other words, the angle of attack tolerance) can be further adjusted based on the control surface skewness. Therefore, in another embodiment of this disclosure, for the spoiler: when the spoiler skewness is greater than a first value, the tolerance increment corresponding to the spoiler is greater than zero; when the spoiler skewness is less than or equal to the first value, the tolerance increment corresponding to the spoiler is equal to zero. For the rudder: when the rudder skewness is greater than a second value, the tolerance increment corresponding to the rudder is greater than zero; when the rudder skewness is less than or equal to the second value, the tolerance increment corresponding to the rudder is equal to zero. In one embodiment of this disclosure, the tolerance increment corresponding to the spoiler is 0.2° when the spoiler skewness is greater than the first value; the tolerance increment corresponding to the rudder is 0.2° when the rudder skewness is greater than the second value. It will be understood that these control surface skewnesses can only be obtained when the control surfaces are effective. In this embodiment, the first value and the second value can be any suitable value. For example, the first value can be 10° and the second value can be 15°.

[0033] In yet another embodiment of this disclosure, the final angle of attack tolerance value may also take the landing gear signal into account. In this embodiment, in the event of landing gear signal failure, the angle of attack tolerance value is increased by a first predetermined value. For example, the first predetermined value may be 0.05° or any other suitable value.

[0034] Continue to refer to Figure 1 Method 100 may include, in block 130, comparing the absolute value with an angle-of-attack tolerance value, and issuing an angle-of-attack unreliable alarm only if the absolute value is greater than the angle-of-attack tolerance value. In other words, the absolute value being greater than the angle-of-attack tolerance value can be one of the necessary conditions for an angle-of-attack unreliable alarm.

[0035] In one embodiment of this disclosure, prior to the operation in block 130, method 100 may further include determining the validity of the estimated composite angle of attack. If the aircraft's state is not within the normal design range of the composite angle of attack, for example, if the aircraft overload exceeds the normal envelope, method 100 may include determining that the estimated composite angle of attack is invalid and omitting the operation in block 130, thereby avoiding issuing an erroneous alarm based on an invalid composite angle of attack. For example, the normal design range of the composite angle of attack may include a) normal overload greater than 0.8g and less than 1.3g; b) pitch angle greater than -20° and less than 20°; c) sideslip angle greater than -15° and less than 15°; d) flap / slat signal valid; etc. It will be understood that the normal design range of the composite angle of attack may vary from aircraft to aircraft, for example, depending on the aircraft type, payload, etc., which will not be elaborated here.

[0036] In another embodiment of this disclosure, it may also be determined whether the state of the aircraft is within the normal design range of the combined angle of attack before the combined angle of attack is estimated. Thus, in this embodiment, steps 110-130 of method 100 may not be performed if the state of the aircraft is not within the normal design range of the combined angle of attack.

[0037] Considering that external disturbances (such as wind disturbances) can cause fluctuations in the composite angle of attack, potentially leading to an absolute difference exceeding the angle of attack tolerance value within a short period, issuing an unreliable angle of attack warning under such circumstances could interfere with the pilot. Therefore, in one embodiment of this disclosure, issuing an unreliable angle of attack warning only when the absolute value exceeds the angle of attack tolerance value may include issuing the warning only if the duration of the absolute value exceeding the angle of attack tolerance value exceeds a first predetermined duration. Furthermore, if an unreliable angle of attack warning has already been issued, and the duration of the absolute value being less than or equal to the angle of attack tolerance value exceeds a second predetermined duration, the unreliable angle of attack warning is cancelled. This utilizes mechanisms such as delayed activation and latching to avoid erroneous warnings under short-term disturbance conditions; furthermore, if the aircraft is already in a voting angle of attack error situation, the unreliable angle of attack warning information can be automatically cancelled if the factors affecting the voting angle of attack error are eliminated. In this embodiment, the first and second predetermined durations can be any suitable values, such as 3 seconds or 10 seconds. Of course, the first and second predetermined durations can also be different.

[0038] refer to Figure 2 The diagram shows a schematic block diagram of an angle-of-attack monitoring system 200 for an aircraft according to an embodiment of the present disclosure.

[0039] like Figure 2 As shown, the angle of attack monitoring system 200 may include a difference calculation component 201, an angle of attack tolerance calculation component 203, and a comparison component 205. It will be understood that, although... Figure 2 Only the three components mentioned above are shown, but the angle of attack monitoring system 200 may include any other suitable number of components, such as at least two of these components may be combined into a single component, or these components may be broken down into more components, as long as they can perform the corresponding functions.

[0040] In one embodiment of this disclosure, the difference calculation component 201 may be configured to calculate the absolute value of the difference between the estimated composite angle of attack and the voting angle of attack acquired from the angle of attack sensor. In this embodiment, the difference calculation component 201 may receive the voting angle of attack and the estimated composite angle of attack as inputs and output the absolute value of the difference between the two.

[0041] In one embodiment of this disclosure, the angle-of-attack tolerance calculation component 203 may be configured to calculate the angle-of-attack tolerance value based on the effectiveness and deflection of different control surfaces. In one example, the angle-of-attack tolerance calculation component 203 may be configured to calculate the angle-of-attack tolerance value using the following formula:

[0042] in: This indicates the angle of attack tolerance value; This represents the baseline value for the angle of attack tolerance. This represents the angle of attack tolerance increment in case of elevator failure, which is 0.1° when the elevator fails and 0° when the elevator is functioning normally. This represents the increment of the angle of attack tolerance for aileron failure, which is 0.05° when the aileron fails and 0 when it is normal. This represents the increment of the angle of attack tolerance for horizontal stabilizer failure, which is 0.2° when the horizontal stabilizer fails and 0° when it is normal. This represents the angle of attack tolerance increment when the landing gear signal fails. It is 0.05° when the landing gear signal fails and 0° when it is normal. This represents the angle of attack tolerance increment when the spoiler signal fails; it is 0.2° when the spoiler signal fails and 0° when it is normal. This indicates the angle of attack tolerance increment when the spoiler deflection exceeds the allowable value. It is 0.2° when the spoiler deflection is greater than 10° and 0° when it is less than or equal to 10°. This represents the increment of the angle of attack tolerance when the rudder deflection exceeds the tolerance. It is 0.2° when the rudder deflection is greater than 15° and 0° when it is less than or equal to 15°.

[0043] In one embodiment of this disclosure, the comparison component 205 may be configured to receive an absolute value calculated by the difference calculation component 201 and an angle-of-attack tolerance value calculated by the angle-of-attack tolerance calculation component 203, and compare the two. In this embodiment, the comparison component 205 may be configured to output triggering information for triggering an angle-of-attack unreliable alarm when the absolute value is greater than the angle-of-attack tolerance value, and to output cancellation information for canceling the angle-of-attack unreliable alarm when the absolute value is less than or equal to the angle-of-attack tolerance value.

[0044] Considering that external disturbances (such as wind disturbances) can cause fluctuations in the composite angle of attack, potentially leading to an absolute difference exceeding the angle of attack tolerance value within a short period, issuing an unreliable angle of attack warning under such circumstances could interfere with the pilot. Therefore, optionally, in one embodiment of this disclosure, the angle of attack monitoring system 200 may further include an unreliable angle of attack confirmation component 207, such as... Figure 2 The dashed box in the figure shows the angle of attack unreliable alarm. In this embodiment, the issuance or cancellation of the angle of attack unreliable alarm is not based immediately on the output result from the comparison component 205. Instead, the angle of attack unreliable confirmation component 207 confirms the output result from the comparison component 205 to avoid the influence of fluctuations. According to this embodiment, the angle of attack unreliable confirmation component 207 can issue an angle of attack unreliable alarm if the duration of the absolute value being greater than the angle of attack tolerance value exceeds a first predetermined duration, and cancel the angle of attack unreliable alarm if the duration of the absolute value being less than or equal to the angle of attack tolerance value exceeds a second predetermined duration after the alarm has been issued. In this way, by using mechanisms such as delayed activation and latching, erroneous alarms under short-term disturbance conditions can be avoided; furthermore, if the factors affecting the voting angle of attack error are eliminated when the aircraft is already in a voting angle of attack error situation, the angle of attack unreliable warning information can be automatically eliminated.

[0045] In another embodiment of this disclosure, the angle of attack monitoring system 200 may further include a synthetic angle of attack effectiveness determination component ( Figure 2 (Not shown in the image). In this embodiment, the angle of attack validity determination component can be configured to determine that if the aircraft's state is not within the normal design range of the composite angle of attack (e.g., the aircraft is overloaded beyond its normal envelope), the estimated composite angle of attack is invalid, thereby causing the difference calculation component 201, angle of attack tolerance calculation component 203, comparison component 205, and angle of attack unreliable confirmation component 207 to suspend the current execution to prevent issuing erroneous alarms.

[0046] In this embodiment, the normal design range for the combined angle of attack may include a) normal overload greater than 0.8g and less than 1.3g; b) pitch angle greater than -20° and less than 20°; c) sideslip angle greater than -15° and less than 15°; d) flap / slat signal valid; etc. It will be understood that the normal design range for the combined angle of attack can vary depending on the aircraft, for example, depending on the aircraft model, payload, etc., which will not be elaborated further here.

[0047] The following is a specific implementation example of the technical solution disclosed herein.

[0048] refer to Figure 3 The diagram shows a schematic logic diagram of an angle-of-attack monitoring system 300 according to an example embodiment of the present disclosure.

[0049] like Figure 3As shown, the estimated combined angle of attack 12 and the voted angle of attack 13 from the angle of attack sensor are input into the difference calculation module 1 to obtain the absolute value a of the difference between the two.

[0050] The control surface deflection 14 and control surface effectiveness 15 are input into the angle of attack tolerance calculation module 2 to determine the angle of attack tolerance value b.

[0051] The absolute value 'a' and the angle of attack tolerance value 'b' are input into the difference comparison module 4 to obtain the angle of attack exceedance signal 'c'. The calculation logic for the angle of attack exceedance signal 'c' is as follows: When the absolute value a is less than or equal to the angle of attack tolerance value b, the angle of attack exceedance signal c is a logic value of "0"; When the absolute value a is greater than the angle of attack tolerance value b, the angle of attack exceedance signal c is a logic value "1"; Aircraft state 16 (which may include multiple parameters such as normal overload, sideslip angle, flap / slat state, and pitch angle) is input to the composite angle of attack validity determination module 3 to obtain a signal d indicating whether the composite angle of attack is valid. When aircraft state 16 meets the normal design range of the composite angle of attack, signal d is a logic value "1", otherwise it is a logic value "0".

[0052] The angle-of-attack unreliable confirmation module 5 is used to confirm the angle-of-attack exceeding signal c, and includes AND logic 6, NOT logic 7, AND logic 8, delay enable module 9, delay enable module 10, and latch module 11. The working logic of the angle-of-attack unreliable confirmation module 5 is as follows: When the angle of attack exceeds the signal c and the synthesized angle of attack validity signal is a logic value of "1", the output signal e of logic 6 is a logic value of "1", otherwise it is a logic value of "0". When the angle of attack exceeds the signal c, the output signal f of non-logic 7 is the logic value "0"; when the angle of attack exceeds the signal c, the output signal f of non-logic 7 is the logic value "1". When signal f is logic value "1" and the synthesized angle of attack validity signal is logic value "1", the output signal g of logic 8 is logic value "1", otherwise it is logic value "0". When signal e is logic value "1" and can last for 10 seconds (the duration can be adjusted according to the actual disturbance and the accuracy of the synthesized angle of attack), the output signal h of the delay activation module 9 is logic value "1", otherwise it is logic value "0". When signal g is logic value "1" and can last for 10 seconds (the duration can be adjusted according to the actual disturbance and the accuracy of the synthesized angle of attack), the output signal i of the delay start module 10 is logic value "1", otherwise it is logic value "0". When signal i is logic value "1", the angle-of-attack unreliable signal 17 output by latch module 11 is logic value "0". When signal i is logic value "0", if input signal h is always logic value "0", then the output angle-of-attack unreliable signal 17 is "0". When input signal h changes to logic value "1", the angle-of-attack unreliable signal 17 will continue to be logic value "1" regardless of the value of input signal h thereafter. It will be clear that an angle-of-attack unreliable signal 17 being logic value "1" indicates that an angle-of-attack unreliable alarm is issued, and an angle-of-attack unreliable signal 17 being logic value "0" indicates that the angle-of-attack unreliable alarm is canceled.

[0053] Thus, the angle-of-attack unreliable confirmation module 5 can be implemented through the above logic: a) The aircraft invalidates the combined angle of attack when it is outside the normal envelope, to prevent incorrect judgment of the voting angle of attack; b) Short-term external disturbances will not affect the judgment of the angle of attack. c) When the factors causing the incorrect angle of attack in the voting test disappear, the correct judgment of the angle of attack in the voting test can be automatically restored.

[0054] refer to Figures 4A-4B It shows a simulation result diagram of angle-of-attack monitoring according to an example embodiment of the present disclosure, wherein Figure 4A Simulation results are shown when the synthetic angle of attack is effective. Figure 4B The simulation results are shown with the synthetic angle of attack disabled.

[0055] from Figure 4A As can be seen, when the composite angle of attack is effective, if a control surface malfunction occurs within 10-30 seconds or the lift estimation of some control surfaces is inaccurate, the angle of attack tolerance can change accordingly, thus avoiding erroneous unreliable angle of attack alarms. If a voting angle of attack error occurs within 40-60 seconds, the composite angle of attack can correctly monitor and indicate unreliable angle of attack. When the situation causing the voting angle of attack error disappears at 60 seconds, the composite angle of attack monitoring can automatically return to the correct result after a period of time, avoiding erroneous unreliable angle of attack alarms. If external disturbances occur within 75-80 seconds, although the angle of attack difference exceeds the tolerance for some time, the composite angle of attack monitoring remains stable despite short-term disturbances. This demonstrates that the technical solution disclosed in this paper improves the accuracy and robustness of the composite angle of attack monitoring.

[0056] from Figure 4B As can be seen, when the composite angle of attack is invalid, regardless of the relationship between the absolute value of the angle of attack difference and the angle of attack tolerance, no indication will be given that the angle of attack is unreliable, meaning that the composite angle of attack monitoring will be suspended.

[0057] Figure 5A schematic diagram of an aircraft 500 according to an example embodiment of the present disclosure is shown. In one embodiment of the present disclosure, the aircraft 500 may include a processing device configured to perform methods according to various embodiments of the present disclosure, such as method 100.

[0058] The above detailed description includes references to the accompanying drawings, which form part of the detailed description. The drawings illustrate specific embodiments that can be practiced by way of illustration. These embodiments are also referred to herein as “examples.” Such examples may include elements other than those shown or described. However, examples including the shown or described elements are also contemplated. Furthermore, examples of any combination or arrangement of those elements shown or described are contemplated, or with reference to specific examples (or one or more aspects thereof) shown or described herein, or with reference to other examples (or one or more aspects thereof) shown or described herein.

[0059] In the appended claims, the terms “comprising” and “including” are open-ended, meaning that a system, apparatus, article of manufacture, or process containing elements other than those listed after such terms in a claim is still considered to fall within the scope of that claim. Furthermore, in the appended claims, the terms “first,” “second,” and “third,” etc., are used merely as designations and are not intended to indicate a numerical order of their contents.

[0060] Furthermore, the order of operations described in this specification is exemplary. In alternative embodiments, the operations may be performed in a different order than that shown in the accompanying drawings, and the operations may be combined into a single operation or broken down into more operations.

[0061] The above description is intended to be illustrative and not restrictive. For example, the examples described above (or one or more aspects thereof) may be used in conjunction with other embodiments. Other embodiments may be used by those skilled in the art after reviewing the above description. The abstract allows the reader to quickly determine the nature of this technical disclosure. This abstract is submitted and it is understood that it is not intended to interpret or limit the scope or meaning of the claims. Furthermore, in the above detailed description, various features may be grouped together to make this disclosure flow smoothly. However, the claims may not state every feature disclosed herein, as embodiments may characterize a subset of said features. Furthermore, embodiments may include fewer features than those disclosed in a particular example. Therefore, the appended claims are thus incorporated into the detailed description, with each claim existing independently as a separate embodiment. The scope of the embodiments disclosed herein should be determined by reference to the full scope of the appended claims and equivalents of such claims.

Claims

1. A method for monitoring the synthetic angle of attack of an aircraft, characterized in that, include: The absolute value of the difference between the estimated composite angle of attack and the voted angle of attack acquired from multiple angle of attack sensors is calculated, wherein the composite angle of attack is estimated from the relationship between lift, angle of attack and parameters affecting lift, and the voted angle of attack is obtained by voting on the measurements of the multiple angle of attack sensors, and wherein the lift is obtained using gravity and overload. The angle of attack tolerance is calculated based on the effectiveness and deflection of different control surfaces; The absolute value is compared with the angle of attack tolerance value, and an angle of attack unreliable alarm is issued only if the absolute value is greater than the angle of attack tolerance value.

2. The method according to claim 1, characterized in that, The different control surfaces include at least one of spoilers, rudders, elevators, ailerons, and horizontal stabilizers, and the angle-of-attack tolerance value is calculated based on the effectiveness and deflection of the different control surfaces, including: The corresponding tolerance increment for each of the different control surfaces is determined based on the effectiveness and skewness of that control surface. The angle of attack tolerance value is obtained by superimposing the base value of the angle of attack tolerance with the corresponding tolerance increments.

3. The method according to claim 2, characterized in that, It also includes increasing the angle of attack tolerance value by a first predetermined value in the event of landing gear signal failure.

4. The method according to claim 3, characterized in that, Determining the corresponding tolerance increment for each of the different control surfaces based on the effectiveness and skewness of each control surface includes: In the event of failure of the control surface, the tolerance increment corresponding to that control surface is greater than zero.

5. The method according to claim 4, characterized in that, Determining the corresponding tolerance increment for each of the different control surfaces, based on the effectiveness and skewness of each, also includes: For each of the elevator, ailerons, and horizontal stabilizer: When the control surface is effective, the tolerance increment corresponding to the control surface is equal to zero; Regarding spoilers: When the spoiler skewness is greater than the first value, the corresponding tolerance increment for the spoiler is greater than zero. When the spoiler deflection is less than or equal to the first value, the tolerance increment corresponding to the spoiler is zero; Regarding the rudder: When the rudder deflection is greater than the second value, the corresponding tolerance increment for the rudder is greater than zero. When the rudder deflection is less than or equal to the second value, the tolerance increment corresponding to the rudder is zero.

6. The method according to claim 5, characterized in that, The basic value for the angle of attack tolerance is 0.5°; The tolerance increment corresponding to the elevator is 0.1° in the event of elevator failure; The tolerance increment corresponding to the spoiler is 0.2° in the case of spoiler failure or spoiler deflection greater than the first value; The tolerance increment corresponding to the aileron is 0.05° in the event of aileron failure; The tolerance increment corresponding to the flat tail is 0.2° in the case of flat tail failure; The tolerance increment corresponding to the rudder is 0.2° when the rudder deflection is greater than the second value; The first predetermined value is 0.05°; The first value is 10°, and the second value is 15°.

7. The method according to claim 1, characterized in that, An angle-of-attack unreliable alarm will only be issued if the absolute value is greater than the angle-of-attack tolerance value, including: An angle-of-attack unreliable alarm will only be issued if the duration for which the absolute value is greater than the angle-of-attack tolerance value exceeds a first predetermined duration.

8. The method according to claim 1, characterized in that, The method also includes the following in the event that the unreliable angle of attack alarm has been issued: If the duration for which the absolute value is less than or equal to the angle of attack tolerance value exceeds a second predetermined duration, the angle of attack unreliable alarm is cancelled.

9. An angle-of-attack monitoring system for an aircraft, comprising: A difference calculation component, wherein the difference calculation component is configured to calculate the absolute value of the difference between the estimated composite angle of attack and the voted angle of attack acquired from a plurality of angle of attack sensors, wherein the composite angle of attack is estimated from the relationship between lift, angle of attack and parameters affecting lift, and the voted angle of attack is obtained by voting on the measurements of the plurality of angle of attack sensors, and wherein the lift is obtained using gravity and overload. An angle-of-attack tolerance calculation component, wherein the angle-of-attack tolerance calculation component is configured to calculate the angle-of-attack tolerance value based on the effectiveness and deflection of different control surfaces; A comparison component is configured to receive, and compare, the absolute value calculated by the difference calculation component and the angle-of-attack tolerance value calculated by the angle-of-attack tolerance calculation component. The comparison component is further configured to output trigger information for triggering an unreliable angle of attack alarm when the absolute value is greater than the angle of attack tolerance value, and to output cancellation information for canceling the unreliable angle of attack alarm when the absolute value is less than or equal to the angle of attack tolerance value.

10. An aircraft comprising a processing unit configured to perform the method according to any one of claims 1-8.

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