An aircraft mechanical backup modal heading augmentation authority determination method and device

Abstract

The application belongs to the technical field of flight control system design, and relates to a method and device for determining the permission of a mechanical backup mode of an airplane. The method comprises the following steps: S1, determining state points in a plurality of preselected cruise and take-off flight envelopes; S2, simulating and calculating the permission of a Dutch roll mode stabilization in the cruise flight envelope; S3, simulating and calculating the permission of a crosswind take-off under a steering condition in the take-off flight envelope; S4, simulating and calculating the permission of a crosswind take-off under a disturbance condition in the take-off flight envelope; S5, simulating and calculating the permission of a steady sideslip roll effectiveness for all the state points; and S6, adjusting the permission of the stabilization so that the airplane mechanical backup mode meets the stability reserve requirement under the maximum rudder deflection. The application can guarantee the safe flight of the airplane.

Description

Technical Field

[0001] This application belongs to the field of flight control system design technology, and specifically relates to a method and device for determining the heading stabilization authority of an aircraft mechanical backup mode. Background Technology

[0002] In pursuit of high-performance flight, modern aircraft have relaxed the stability requirements of their aerodynamic design, even leading to directional static or dynamic instability. Therefore, it is necessary to add a directional stability augmentation control system to increase the damping ratio of the aircraft's Dutch roll mode and enhance its stability.

[0003] For directionally unstable aircraft with a mechanical backup mode, directional stabilization control in mechanical backup mode is achieved by superimposing fly-by-wire stabilization commands onto the mechanical backup rudder actuator via a stabilization servo. When the stabilization command authority is too low, it cannot improve the aircraft's directional instability; when the stabilization authority is too high, the pilot may not have sufficient control over the aircraft. For example, if the stabilization authority is 100%, meaning the stabilization module can deflect the servo to 100%, the pilot will not have enough margin to continue controlling the servo deflection, affecting flight safety. Therefore, it is necessary to determine an appropriate stabilization authority for the directional stabilization system to ensure safe flight.

[0004] Current technologies are mostly designed to provide methods for aircraft heading stability augmentation control, with little research on how to determine the authority of stability augmentation commands. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a method and apparatus for determining the heading stabilization authority of an aircraft mechanical backup mode, ensuring that the aircraft does not experience problems such as Dutch roll mode divergence or insufficient pilot control authority leading to landing failure.

[0006] The first aspect of this application provides a method for determining the authority for aircraft mechanical backup mode heading stabilization, mainly including:

[0007] Step S1: Determine the state points within the pre-selected cruise and takeoff / landing flight envelopes;

[0008] Step S2: For each state point within the cruise flight envelope, apply a full pedal displacement input to the heading channel through simulation, adjust the feedback gain, and determine the first maximum rudder deflection value generated by the heading stabilization loop that stabilizes the aircraft in Dutch roll mode and meets the preset flight quality requirements.

[0009] Step S3: For each state point within the takeoff and landing flight envelope, apply the pedal displacement input to generate a steady-state sideslip angle corresponding to a specified crosswind size through simulation. If the preset flight quality requirements are met, record the second maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority to meet the preset flight quality requirements.

[0010] Step S4: For each state point within the takeoff and landing flight envelope, apply an initial sideslip angle disturbance with the same as the steady-state sideslip angle through simulation, while keeping the rudder displacement at 0. If the preset flight quality requirements are met, record the third maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority to meet the preset flight quality requirements.

[0011] Step S5: For all state points, apply full rudder pedal in the heading channel through simulation, and at the same time apply a displacement input of no more than 75% of the full travel of the control wheel in the lateral channel. If the aircraft roll angle can be level, record the fourth maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority.

[0012] Step S6: Determine whether the aircraft mechanical backup mode meets the stability reserve requirements when the maximum value among the first maximum rudder deflection value, the second maximum rudder deflection value, the third maximum rudder deflection value, and the fourth maximum rudder deflection value is reached. If it meets the requirements, determine the corresponding stability augmentation authority; otherwise, reduce the stability augmentation authority and return to steps S2-S5 for verification. When the conditions of steps S2-S5 are met, output the current stability augmentation authority; otherwise, output the aircraft configuration abnormality.

[0013] Preferably, step S1 further includes:

[0014] Step S11: For the multiple initially selected state points, determine the variation law of the Dutch roll divergence based on the small perturbation equation;

[0015] Step S12: Iteratively select state points within the cruise and take-off / landing flight envelope based on the aforementioned change pattern, such that the selected state points at least include the extreme state points that cause the Dutch roll divergence to the highest degree.

[0016] Preferably, in step S3, the specified crosswind speed is 7.5 m / s or 5 m / s.

[0017] Preferably, in step S5, whether the aircraft mechanical backup mode meets the stable reserve requirements includes:

[0018] The magnitude margin calculated based on the maximum value is not less than 6 dB, and the phase margin calculated based on the maximum value is not less than 45°.

[0019] Preferably, step S2 further includes:

[0020] Given the relevant parameter fault values ​​considering the presence of an electrical fault in the aircraft, in steps S2-S5, a simulation is performed based on the fault values, and the corresponding maximum rudder deflection value is recorded.

[0021] The second aspect of this application provides an aircraft mechanical backup mode heading stabilization authority determination device, mainly comprising:

[0022] The state point determination module is used to determine state points within multiple pre-selected cruise and takeoff / landing flight envelopes;

[0023] The first maximum rudder offset recording module is used to determine the first maximum rudder offset value generated by the directional stabilization loop that stabilizes the aircraft in Dutch roll mode and meets the preset flight quality requirements for each state point within the cruise flight envelope by applying a full rudder displacement input in the directional channel through simulation and adjusting the feedback gain.

[0024] The second maximum rudder offset value recording module is used to simulate and apply the rudder displacement input to generate a steady-state sideslip angle corresponding to a specified crosswind at each state point within the take-off and landing flight envelope. If the preset flight quality requirements are met, the second maximum rudder offset value is recorded at this time; otherwise, the stability augmentation authority is adjusted to meet the preset flight quality requirements.

[0025] The third maximum rudder deflection value recording module is used to apply an initial sideslip angle disturbance with the same as the steady-state sideslip angle to each state point within the takeoff and landing flight envelope through simulation, while keeping the rudder displacement at 0. If the preset flight quality requirements are met, the third maximum rudder deflection value at this time is recorded; otherwise, the stability augmentation authority is adjusted to meet the preset flight quality requirements.

[0026] The fourth maximum rudder deflection recording module is used to simulate applying full rudder pedal in the heading channel and applying a displacement input of no more than 75% of the full travel of the control wheel in the lateral channel for all state points. If the aircraft roll angle can be level, the fourth maximum rudder deflection value is recorded at this time; otherwise, the stability augmentation authority is adjusted.

[0027] The maximum rudder deflection verification module is used to determine whether the aircraft's mechanical backup mode meets the stability reserve requirements when the maximum value among the first, second, third, and fourth maximum rudder deflection values ​​is reached. If it does, the corresponding stability augmentation authority is determined; otherwise, the stability augmentation authority is reduced. Subsequently, each maximum rudder deflection value recording module is called for verification. When the limiting conditions of each maximum rudder deflection value recording module are met, the stability augmentation authority at this time is output; otherwise, an abnormal aircraft configuration is output.

[0028] This application can ensure the safe flight of the aircraft. Attached Figure Description

[0029] Figure 1 This is a flowchart of a preferred embodiment of the method for determining the heading stabilization authority of the aircraft mechanical backup mode in this application.

[0030] Figure 2 This is a schematic diagram of the heading stabilization control law architecture.

[0031] Figure 3 This is a schematic diagram of a horizontal channel structure. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0033] The first aspect of this application provides a method for determining the authority for aircraft mechanical backup mode heading stabilization, mainly including:

[0034] Step S1: Determine the state points within the pre-selected cruise and take-off / landing flight envelopes.

[0035] In this embodiment, the selected state points should cover the left boundary of the velocity and the upper boundary of the altitude of each configuration's flight envelope. In fact, during the selection process, the state points for the left boundary of velocity and the upper boundary of altitude are determined through the following embodiments.

[0036] In some alternative implementations, step S1 further includes:

[0037] Step S11: For the multiple initially selected state points, determine the variation law of the Dutch roll divergence based on the small perturbation equation;

[0038] Step S12: Iteratively select state points within the cruise and take-off / landing flight envelope based on the aforementioned change pattern, such that the selected state points at least include the extreme state points that cause the Dutch roll divergence to the highest degree.

[0039] In this embodiment, based on existing technology, starting from a steady operating state (constant altitude and constant speed), the aircraft kinematic equations are linearized to establish small perturbation equations. Then, based on the small perturbation equations, calculations are performed on multiple initially selected state points to determine that the degree of Dutch roll divergence becomes more and more obvious with higher altitude and lower speed. Therefore, this application finally selects multiple state points, including the state points at the left boundary of velocity and the upper boundary of altitude, thereby ensuring that the selected state points include the state points with the most severe Dutch roll mode divergence.

[0040] Step S2: For each state point within the cruise flight envelope, apply a full pedal displacement input to the heading channel through simulation, adjust the feedback gain, and determine the first maximum rudder deflection value generated by the heading stabilization loop that stabilizes the aircraft in Dutch roll mode and meets the preset flight quality requirements.

[0041] First, it should be noted that this application focuses on the design of the stability augmentation authority in the heading stability augmentation control law. Therefore, it is necessary to introduce yaw rate or sideslip angle (lateral overload) based on existing technology beforehand to design the initial heading stability augmentation control law. In the initial heading stability augmentation control law, yaw rate or sideslip angle (lateral overload) is the input. After processing and gaining by the control law algorithm, the rudder deflection is formed. The gain value is related to the stability augmentation authority to a certain extent; for example, the larger the stability augmentation authority, the larger the gain value. Figure 2 As shown, R is the yaw rate, BETA is the sideslip angle, RUD_LIMU and RUD_LIMD are the known rudder deflection limits of the heading control surfaces, and RUD_AUG_LIMU and RUD_AUG_LIMD are the upper and lower limits of the stability augmentation authority, where RUD_AUG_LIMU = stability augmentation authority (percentage) * RUD_LIMU, and RUD_AUG_LIMD = stability augmentation authority (percentage) * RUD_LIMD. The mechanical linear system model of the rudder deflection caused by the pedal displacement and the model of the interconnected components between the mechanical control and stability augmentation are omitted in the figure. Given initial values ​​for the feedback gain KR and KBETA, and given constants for each filter TR, WYWO, and TBETA, the stability augmentation authority in the heading stability augmentation control law is initially set to full authority.

[0042] Step S2 is used to calculate the heading stabilization authority required for Dutch roll mode stabilization, adjust the above-mentioned gain KR and KBETA values, i.e. adjust the stabilization authority, and record the maximum rudder deflection value generated by the heading stabilization loop that can stabilize the aircraft in Dutch roll mode under each state and whose corresponding damping and frequency meet the requirements of Level 3 flight quality.

[0043] Step S3: For each state point within the takeoff and landing flight envelope, apply the pedal displacement input to generate a steady-state sideslip angle corresponding to a specified crosswind size through simulation. If the preset flight quality requirements are met, record the second maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority to meet the preset flight quality requirements.

[0044] In some optional implementations, in step S3, the specified crosswind size is 7.5 m / s or 5 m / s. In this embodiment, the first maximum rudder deflection value generated by the directional stabilization loop that enables the aircraft to stabilize in the Dutch roll mode and whose corresponding damping and frequency meet the requirements of Level 3 flight quality is recorded to generate the steady-state sideslip angle corresponding to the crosswind size of 7.5 m / s (or 5 m / s) required by the national military standard.

[0045] Step S4: For each state point within the takeoff and landing flight envelope, apply an initial sideslip angle disturbance with the same as the steady-state sideslip angle through simulation, while keeping the rudder displacement at 0. If the preset flight quality requirements are met, record the third maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority to meet the preset flight quality requirements.

[0046] In this step, the principle is the same as in step S3, only the input values ​​of the simulation model are different. The second maximum rudder deflection value generated by the heading stabilizer that can stabilize the aircraft in Dutch roll mode and whose corresponding damping and frequency meet the requirements of Level 3 flight quality is recorded.

[0047] Step S5: For all state points, apply full rudder pedal pressure in the heading channel through simulation, and at the same time apply a displacement input of no more than 75% of the full travel of the control wheel (or control stick lateral displacement) in the lateral channel. If the aircraft roll angle can be level, record the fourth maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority.

[0048] This step is used to calculate the heading stabilization authority required for steady sideslip roll performance. For all state points, the stabilization authority is further designed based on the aircraft roll angle level, and the fourth maximum rudder deflection value generated by the heading stabilizer at each state point is recorded.

[0049] refer to Figure 3 The lateral passage structure is shown in the figure below, where φ is the aircraft's current roll angle. The roll angle command value (0) is output after passing through a PI integrator and used as the lateral control surface deflection command. In the figure, AIL_LIMU and AIL_LIMD are the lateral control surface deflection limits. In step S5, by applying displacement in the directional channel, i.e. the lateral channel, the roll angle is controlled to be 0 when the aircraft reaches steady state in steady-state sideslip (the roll angle remains horizontal), and the fourth maximum rudder deflection value generated by the directional stabilization loop at each state point is recorded.

[0050] In steps S2-S5 above, the gain limits in the initial heading stabilization control law can usually meet the conditions specified in the steps. However, the gain limits may be too large and need to be further reduced in step S6, including reducing the stabilization limits and each feedback gain KR and KBETA as needed.

[0051] Step S6: Determine whether the aircraft's mechanical backup mode meets the stability reserve requirements when the maximum value among the first, second, third, and fourth maximum rudder deflection values ​​is reached. If it does, determine the corresponding stability augmentation authority; otherwise, reduce the stability augmentation authority and return to steps S2-S5 for verification. When the conditions of steps S2-S5 are met, output the current stability augmentation authority; otherwise, output an abnormal aircraft configuration. In this step, the ratio of the maximum rudder deflection value to the heading control surface limit value is the heading stability augmentation command authority. When reducing the stability augmentation authority, it is usually sufficient to reduce it directly to the minimum value that meets the stability reserve requirements.

[0052] In some optional implementations, in step S5, whether the aircraft mechanical backup mode meets the stability reserve requirements includes: the amplitude margin calculated based on the maximum value is not less than 6dB, and the phase margin calculated based on the maximum value is not less than 45°.

[0053] In some alternative implementations, step S2 is further preceded by:

[0054] Given the relevant parameter fault values ​​considering the presence of an electrical fault in the aircraft, in steps S2-S5, a simulation is performed based on the fault values, and the corresponding maximum rudder deflection value is recorded.

[0055] In this embodiment, if the mechanical backup mode superimposed with electrical faults (such as sensor signal reversal) is considered, the corresponding sensor feedback signal (such as yaw rate) should be set to the maximum value that the fault can produce during the above simulations or calculations. Then, the relevant sideslip angle disturbance or pedal displacement input should be given, and the maximum rudder deflection value should be recorded.

[0056] The method for determining the heading stabilization authority of a mechanically backed-up heading-unstable aircraft proposed in this application can analyze and design the Dutch roll mode characteristics of a natural aircraft within the full configuration and full envelope, according to the relevant technical requirements of the National Military Standard. By providing different simulation conditions, the method ensures that the aircraft meets flight quality requirements such as Dutch roll mode characteristics, takeoff and landing in crosswinds, and roll control effectiveness during steady sideslip. It also designs and verifies the appropriateness of the determined heading stabilization authority. This ensures that the aircraft will not experience pilot loss of control due to Dutch roll mode divergence or electrical failures during flight due to inappropriate stabilization authority, thus guaranteeing safe flight.

[0057] The second aspect of this application provides an aircraft mechanical backup mode heading stabilization authority determination device corresponding to the above method, mainly comprising:

[0058] The state point determination module is used to determine state points within multiple pre-selected cruise and takeoff / landing flight envelopes;

[0059] The first maximum rudder offset recording module is used to determine the first maximum rudder offset value generated by the directional stabilization loop that stabilizes the aircraft in Dutch roll mode and meets the preset flight quality requirements for each state point within the cruise flight envelope by applying a full rudder displacement input in the directional channel through simulation and adjusting the feedback gain.

[0060] The second maximum rudder offset value recording module is used to simulate and apply the rudder displacement input to generate a steady-state sideslip angle corresponding to a specified crosswind at each state point within the take-off and landing flight envelope. If the preset flight quality requirements are met, the second maximum rudder offset value is recorded at this time; otherwise, the stability augmentation authority is adjusted to meet the preset flight quality requirements.

[0061] The third maximum rudder deflection value recording module is used to apply an initial sideslip angle disturbance with the same as the steady-state sideslip angle to each state point within the takeoff and landing flight envelope through simulation, while keeping the rudder displacement at 0. If the preset flight quality requirements are met, the third maximum rudder deflection value at this time is recorded; otherwise, the stability augmentation authority is adjusted to meet the preset flight quality requirements.

[0062] The fourth maximum rudder deflection recording module is used to simulate applying full rudder pedal in the heading channel and applying a displacement input of no more than 75% of the full travel of the control wheel in the lateral channel for all state points. If the aircraft roll angle can be level, the fourth maximum rudder deflection value is recorded at this time; otherwise, the stability augmentation authority is adjusted.

[0063] The maximum rudder deflection verification module is used to determine whether the aircraft's mechanical backup mode meets the stability reserve requirements when the maximum value among the first, second, third, and fourth maximum rudder deflection values ​​is reached. If it does, the corresponding stability augmentation authority is determined; otherwise, the stability augmentation authority is reduced. Subsequently, each maximum rudder deflection value recording module is called for verification. When the limiting conditions of each maximum rudder deflection value recording module are met, the stability augmentation authority at this time is output; otherwise, an abnormal aircraft configuration is output.

[0064] The above description is merely a specific embodiment of this application, but the scope of protection of this application 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 this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for determining the authority for aircraft mechanical backup mode heading stabilization, characterized in that, include: Step S1: Determine the state points within the pre-selected cruise and takeoff / landing flight envelopes; Step S2: For each state point within the cruise flight envelope, apply a full pedal displacement input to the heading channel through simulation, adjust the feedback gain, and determine the first maximum rudder deflection value generated by the heading stabilization loop that stabilizes the aircraft in Dutch roll mode and meets the preset flight quality requirements. Step S3: For each state point within the takeoff and landing flight envelope, apply the pedal displacement input to generate a steady-state sideslip angle corresponding to a specified crosswind size through simulation. If the preset flight quality requirements are met, record the second maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority to meet the preset flight quality requirements. Step S4: For each state point within the takeoff and landing flight envelope, apply an initial sideslip angle disturbance with the same as the steady-state sideslip angle through simulation, while keeping the rudder displacement at 0. If the preset flight quality requirements are met, record the third maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority to meet the preset flight quality requirements. Step S5: For all state points, apply full rudder pedal in the heading channel through simulation, and at the same time apply a displacement input of no more than 75% of the full travel of the control wheel in the lateral channel. If the aircraft roll angle can be level, record the fourth maximum rudder deflection value at this time; otherwise, adjust the stability augmentation authority. Step S6: Determine whether the aircraft mechanical backup mode meets the stability reserve requirements when the maximum value among the first maximum rudder deflection value, the second maximum rudder deflection value, the third maximum rudder deflection value, and the fourth maximum rudder deflection value is reached. If it meets the requirements, determine the corresponding stability augmentation authority; otherwise, reduce the stability augmentation authority and return to steps S2-S5 for verification. When the conditions of steps S2-S5 are met, output the current stability augmentation authority; otherwise, output the aircraft configuration abnormality.

2. The method for determining the authority for aircraft mechanical backup mode heading stabilization as described in claim 1, characterized in that, Step S1 further includes: Step S11: For the multiple initially selected state points, determine the variation law of the Dutch roll divergence based on the small perturbation equation; Step S12: Iteratively select state points within the cruise and take-off / landing flight envelope based on the aforementioned change pattern, such that the selected state points at least include the extreme state points that cause the Dutch roll divergence to the highest degree.

3. The method for determining the authority for aircraft mechanical backup mode heading stabilization as described in claim 1, characterized in that, In step S3, the specified crosswind speed is 7.5 m / s or 5 m / s.

4. The method for determining the authority for aircraft mechanical backup mode heading stabilization as described in claim 1, characterized in that, In step S6, whether the aircraft's mechanical backup mode meets the stable reserve requirements includes: The magnitude margin calculated based on the maximum value is not less than 6 dB, and the phase margin calculated based on the maximum value is not less than 45°.

5. The method for determining the authority for aircraft mechanical backup mode heading stabilization as described in claim 1, characterized in that, Step S2 further includes: Given the relevant parameter fault values ​​considering the presence of an electrical fault in the aircraft, in steps S2-S5, a simulation is performed based on the fault values, and the corresponding maximum rudder deflection value is recorded.

6. A device for determining the authority to perform mechanical backup mode heading stabilization on an aircraft, characterized in that, include: The state point determination module is used to determine state points within multiple pre-selected cruise and takeoff / landing flight envelopes; The first maximum rudder offset recording module is used to determine the first maximum rudder offset value generated by the directional stabilization loop that stabilizes the aircraft in Dutch roll mode and meets the preset flight quality requirements for each state point within the cruise flight envelope by applying a full rudder displacement input in the directional channel through simulation and adjusting the feedback gain. The second maximum rudder offset value recording module is used to simulate and apply the rudder displacement input to generate a steady-state sideslip angle corresponding to a specified crosswind at each state point within the take-off and landing flight envelope. If the preset flight quality requirements are met, the second maximum rudder offset value is recorded at this time; otherwise, the stability augmentation authority is adjusted to meet the preset flight quality requirements. The third maximum rudder deflection value recording module is used to apply an initial sideslip angle disturbance with the same as the steady-state sideslip angle to each state point within the takeoff and landing flight envelope through simulation, while keeping the rudder displacement at 0. If the preset flight quality requirements are met, the third maximum rudder deflection value at this time is recorded; otherwise, the stability augmentation authority is adjusted to meet the preset flight quality requirements. The fourth maximum rudder deflection recording module is used to simulate applying full rudder pedal in the heading channel and applying a displacement input of no more than 75% of the full travel of the control wheel in the lateral channel for all state points. If the aircraft roll angle can be level, the fourth maximum rudder deflection value is recorded at this time; otherwise, the stability augmentation authority is adjusted. The maximum rudder deflection verification module is used to determine whether the aircraft's mechanical backup mode meets the stability reserve requirements when the maximum value among the first, second, third, and fourth maximum rudder deflection values ​​is reached. If it does, the corresponding stability augmentation authority is determined; otherwise, the stability augmentation authority is reduced. Subsequently, each maximum rudder deflection value recording module is called for verification. When the limiting conditions of each maximum rudder deflection value recording module are met, the stability augmentation authority at this time is output; otherwise, an abnormal aircraft configuration is output.

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