A design method for flare control law of fixed-horizontal-tail fly-by-wire aircraft

Abstract

The present invention provides a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft. The method comprises the following steps: when the aircraft meets a condition for entering the flare control law, recording a flight control law integral channel instruction ELE_NM_INT at a triggering moment; generating an elevator control instruction component ELE_FLARE_FWD based on a joystick displacement signal through a forward instruction shaping module; introducing the integral channel instruction ELE_NM_INT into the flare control law, and obtaining an offset instruction component ELE_FLARE_OFFSET under the flare control law after passing through an instruction limiter module; subtracting the offset instruction ELE_FLARE_OFFSET from the integral channel instruction ELE_NM_INT to obtain an instruction initial value ELE_FLARE_FADER0 that needs to be faded during instruction transition; passing the instruction initial value ELE_FLARE_FADER0 through a fader module to form a real-time rudder control instruction component ELE_FLARE_FADER; and obtaining an elevator control instruction ELE_CMD under the flare control law. The present invention can reduce switching transients by referencing the flight control law integral channel command component to enter the leveling control law, and has significant advantages in improving flight safety, optimizing flight quality, enhancing system flexibility and improving the level of automation.

Description

Technical Field

[0001] The present invention relates to the technical field of fly-by-wire flight control laws, and in particular to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft. Background Art

[0002] Conventional mechanically controlled aircraft have speed static stability, which means that to obtain and maintain a speed below the trim speed, a pull force must be applied; to obtain and maintain a speed above the trim speed, a thrust force must be applied.

[0003] During the flare phase of landing, the pilot needs to continuously decelerate with the stick to achieve touchdown attitude and ultimately complete the landing process. However, in fly-by-wire aircraft with a neutral speed stability control law configuration, the pilot no longer needs to apply force to maintain a speed below the trim speed. During the flare phase, the pilot decelerates by pulling on the stick and then promptly releases the stick to maintain attitude. This design feature, unlike traditional mechanically controlled aircraft, places an additional burden on the pilot during landing and touchdown. To ensure a consistent flare feel during the flare phase, similar aircraft (such as the A320 and A350) have designed a separate flare control law transition prior to touchdown to disrupt neutral speed stability and restore static stability. These aircraft all feature a movable horizontal tail. When entering the flare control law, the movable horizontal tail is first frozen, followed by a switch to a stick-movement-commanded elevator control law. The movable horizontal tail is typically used to unload the elevator during automatic trim. Frozen horizontal tail transfers the trim amount during level flight to the flare control law, thereby achieving a smooth transition between control law modes. For fixed-tail fly-by-wire aircraft, the automatic trim function is entirely generated by the elevator. If no processing is performed when entering the leveling control law, it will result in a large transient response. Summary of the Invention

[0004] In order to solve the problems existing in the traditional fly-by-wire flare control law, the purpose of the present invention is to provide a design method for the flare control law of a fixed-horizontal-tail fly-by-wire aircraft. This method can reduce switching transients by referencing the flight control law integral channel command component into the flare control law, and has significant advantages in improving flight safety, optimizing flight quality, enhancing system flexibility and improving the level of automation.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] A method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft, the method comprising the following steps:

[0007] When the aircraft meets the conditions for entering the leveling control law, the flight control law integral channel instruction ELE_NM_INT at the triggering moment is recorded;

[0008] Generate the elevator control command component ELE_FLARE_FWD based on the joystick displacement signal through the forward command shaping module;

[0009] The integral channel instruction ELE_NM_INT is introduced into the leveling control law, and the bias instruction component ELE_FLARE_OFFSET under the leveling control law is obtained after passing through the instruction limit module;

[0010] Subtract the offset instruction ELE_FLARE_OFFSET from the integral channel instruction ELE_NM_INT to obtain the instruction initial value ELE_FLARE_FADER0 that needs to be faded during instruction transition;

[0011] After the initial value of the command ELE_FLARE_FADER0 passes through a fader module, it forms the real-time control surface command component ELE_FLARE_FADER;

[0012] The elevator control command ELE_CMD under the leveling control law is obtained based on the elevator control command component ELE_FLARE_FWD, the offset command component ELE_FLARE_OFFSET, and the control surface control command component ELE_FLARE_FADER.

[0013] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft provided by the present invention, generating an elevator control command component ELE_FLARE_FWD includes:

[0014] The forward control logic based on the leveling control law adopts the control law configuration of the elevator with stick displacement command to make the aircraft have speed static stability;

[0015] The generated joystick displacement signal is passed through the forward command shaping module to generate the elevator control command component ELE_FLARE_FWD, which is expressed as the following formula:

[0016] ELE_FLARE_FWD=KP*DE

[0017] Among them, the forward instruction shaping module is the forward transmission ratio of the aircraft, and DE is the control stick displacement signal.

[0018] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft provided by the present invention, a forward transmission ratio gain of a forward instruction shaping module is 0.2.

[0019] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft, an integral channel instruction ELE_NM_INT is introduced into the flare control law, which is equivalent to the effect of freezing the horizontal tail of similar aircraft and reduces the transient state during instruction transition. When the aircraft determines that the conditions for entering the flare control law are met (radio altitude is less than 15 meters), the flight control law integral channel instruction ELE_NM_INT at the triggering moment is recorded and expressed as the following formula:

[0020] ELE_NM_INT=KI*(errori+error*ts)

[0021] Wherein, KI is the integral channel control gain, KI=3; errori is the error between the expected value and the actual value at the moment before the trigger point; error is the error between the expected value and the actual value at the trigger moment; ts is the sampling step size.

[0022] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft provided by the present invention, in the event of a non-command deviation in the integrator, a command limiter module is used to ensure that the command of the integral channel does not exceed the range that the aircraft control system can handle;

[0023] When the integral channel instruction causes the offset instruction component ELE_FLARE_OFFSET to stop at the most unfavorable position due to non-instructional reasons, the amplitude of the relevant instruction will be limited by the instruction limit module, which is expressed as the following formula:

[0024]

[0025] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft provided by the present invention, the command limiter module adopts a limit range of -5 degrees to 5 degrees, that is, LIM_UP = 5 degrees, LIM_DN = -5 degrees.

[0026] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft, an initial command value ELE_FLARE_FADER0 passes through a fader module to form a real-time control surface control command component ELE_FLARE_FADER. Upon entering the flare control law, the initial command value ELE_FLARE_FADER0 is gradually faded to zero within a specified time to reduce transients caused by aircraft mode switching. The fader module uses linear fade logic with a fade time ΔT of 5 seconds, which is expressed as the following formula:

[0027] ELE_FLARE_FADER=ELE_FLARE_FADER0*f(t)

[0028] Among them, the function f(t) is the fade function, which adopts linear fade logic. The specific formula is as follows:

[0029]

[0030] Wherein, t is the real time starting from the triggering moment t=0 to enter the leveling state.

[0031] According to a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft provided by the present invention, the elevator control command of the flare control law is expressed as follows:

[0032] ELE_CMD=ELE_FLARE_FWD+ELE_FLARE_OFFSET+ELE_FLARE_FADER

[0033] Among them, ELE_FLARE_FWD is the forward control channel command; ELE_FLARE_OFFSET is the rudder offset command; ELE_FLARE_FADER is the real-time command generated by the command transition link.

[0034] It can be seen that the present invention has the following beneficial effects:

[0035] 1. The present invention ensures precise control of the aircraft attitude during the leveling phase by accurately recording the flight control law integral channel command at the triggering moment and generating control commands based on the joystick displacement signal, thereby reducing flight safety hazards caused by inaccurate control.

[0036] 2. The present invention introduces an instruction limiter module and a desalination module to limit and desalinate the control instructions, thereby preventing sudden changes in the control instructions, making the aircraft's attitude adjustment more stable and improving flight stability and safety.

[0037] 3. The present invention achieves a smooth transition of control commands by calculating the initial value of the command that needs to be faded during command transition and processing it through the fader module, avoiding jitter or instability caused by sudden changes in control commands during the leveling phase of the aircraft, thereby improving flight quality.

[0038] 4. The elevator control command ELE_CMD finally obtained by the present invention is the result of integrating the forward command, the offset command and the control surface control command components, making the control of the aircraft more comprehensive and precise, and further improving the flight quality.

[0039] 5. This method adopts a modular design concept, including a forward command shaping module, a command limiter module, and a desalinator module. This design makes the system easy to maintain and upgrade, and each module can be adjusted and optimized according to different flight requirements.

[0040] 6. By adjusting the control parameters and strategies of each module, this method can adapt to different types of fixed-horizontal-tail fly-by-wire aircraft as well as different flight environments and mission requirements, and has strong adaptability and flexibility.

[0041] 7. This invention achieves fully automated control from the moment of triggering to the generation of elevator control commands, reducing the need for human intervention and improving the level of flight automation. Automated control reduces the pilot's operational burden and psychological stress, allowing the pilot to focus more on executing the flight mission and monitoring flight status.

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a flow chart of an embodiment of a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft.

[0044] Figure 2 The present invention is a logic principle diagram of a flight control law in an embodiment of a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft.

[0045] Figure 3 The present invention is a logic principle diagram of a flare control law in an embodiment of a method for designing a flare control law for a fixed horizontal tail fly-by-wire aircraft.

[0046] Figure 4 The present invention is a schematic diagram of a time domain curve of a test flight result of an aircraft landing flare process in an embodiment of a method for designing a flare control law for a fixed horizontal tail type fly-by-wire aircraft. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0048] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] Level-off control law: The level-off control law is the control law used by the flight control system and thrust control system during the level-off phase of automatic landing. It ensures the stability and safety of the aircraft before touchdown.

[0050] Flight control laws: These are algorithms used by the flight control system to generate control commands. They describe the functional relationship between controlled state variables and system input signals. During the flare phase, these algorithms calculate and output appropriate control commands based on the aircraft's actual state (such as speed, altitude, and attitude) and the pilot's inputs (or autopilot commands).

[0051] The present invention is a control law design that can be applied to a fixed-horizontal-tail fly-by-wire aircraft to obtain a conventional flare feeling during the landing flare phase. The invention has a simple structure and can be extended to all fixed-horizontal-tail fly-by-wire transport aircraft with neutral speed stability for application.

[0052] See also Figures 1 to 4 The present invention provides a method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft, the method comprising the following steps:

[0053] Step S1: When the aircraft meets the conditions for entering the leveling control law, the flight control law integral channel instruction ELE_NM_INT at the triggering moment is recorded;

[0054] Step S2, generating an elevator control command component ELE_FLARE_FWD through a forward command shaping module based on the joystick displacement signal;

[0055] Step S3: Introducing the integral channel instruction ELE_NM_INT into the flare control law, which is equivalent to the effect of freezing the horizontal tail of similar aircraft and reducing the transient state during instruction transition. After passing through the instruction limiter module, the integral channel instruction ELE_NM_INT obtains the offset instruction component ELE_FLARE_OFFSET under the flare control law;

[0056] Step S4, subtracting the offset instruction ELE_FLARE_OFFSET from the integral channel instruction ELE_NM_INT to obtain the instruction initial value ELE_FLARE_FADER0 that needs to be faded during instruction transition;

[0057] Step S5, the initial command value ELE_FLARE_FADER0 is passed through a fader module to form a real-time control surface control command component ELE_FLARE_FADER;

[0058] Step S6: Obtain the elevator control command ELE_CMD under the flare control law based on the elevator control command component ELE_FLARE_FWD, the offset command component ELE_FLARE_OFFSET, and the control surface control command component ELE_FLARE_FADER.

[0059] In step S1 above, when the aircraft meets the conditions for entering the leveling control law, recording the ELE_NM_INT command value at the triggering moment generally involves the following steps:

[0060] Monitoring flight status: The flight control system will continuously monitor the actual status of the aircraft, including speed, altitude, attitude, etc.

[0061] Determine entry conditions: When the aircraft's state meets the preset conditions for entering the leveling control law (such as reaching a specific altitude, speed or attitude range), the flight control system will make a judgment.

[0062] Calculating control instructions: Once the leveling control law is entered, the flight control system will calculate the control instructions based on the current flight status and the preset control law algorithm.

[0063] Record instruction values: In this process, ELE_NM_INT is one of the control instructions of the integral channel, and its value will be calculated and recorded in real time.

[0064] In the above step S2, the elevator control command component ELE_FLARE_FWD is generated, including:

[0065] The forward control logic based on the leveling control law adopts the control law configuration of the elevator with stick displacement command to make the aircraft have speed static stability, which is expressed as the following formula:

[0066] ELE_FLARE_FWD=KP*DE

[0067] Among them, DE is the control stick displacement signal;

[0068] The generated joystick displacement signal is passed through the forward command shaping module to generate the elevator control command component ELE_FLARE_FWD;

[0069] Among them, the forward instruction shaping module is the forward transmission ratio of the aircraft, which is related to the design characteristics and design intentions of the aircraft.

[0070] In this embodiment, the forward transmission ratio gain of the forward instruction shaping module is 0.2.

[0071] Specifically, in an aircraft's control system, the forward command shaping module is responsible for receiving commands from the pilot or other control sources and preprocessing, adjusting, or shaping these commands to ensure they are suitable for reception and execution by the aircraft's actuators. The forward transmission ratio can be thought of as the gain or attenuation ratio applied by the forward command shaping module to the input command, determining the degree to which the command is amplified or reduced during transmission.

[0072] If the forward transmission ratio gain is greater than 1, the input command will be amplified. Gain equal to 1: In this case, the input command remains unchanged, that is, the forward command shaping module does not perform any amplification or reduction on the command. Gain less than 1 (such as 0.2): When the gain is 0.2, the input command will be significantly reduced, which helps limit the output range, enhance system stability, and may reduce the impact of external interference on the system.

[0073] In this embodiment, a fly-by-wire aircraft with automatic longitudinal trim typically adopts a proportional-integral control law configuration. The proportional channel is used to track the deviation from the desired command and, when a deviation exists, correct it in real time; while the integral channel is used to eliminate the steady-state error of the control system, which is equivalent to the trim component of the aircraft during level flight. The integral channel instruction ELE_NM_INT is introduced into the leveling control law, which is equivalent to the effect of freezing the horizontal tail of similar aircraft and reduces the transient state during command transition. When the aircraft determines that the conditions for entering the leveling control law are met (radio altitude is less than 15m), the flight control law integral channel instruction ELE_NM_INT at the triggering moment is recorded and expressed as the following formula:

[0074] ELE_NM_INT=KI*(errori+error*ts)

[0075] Among them, KI is the integral channel control gain, and in this patent, KI=3; errori is the error between the expected value and the actual value at the moment before the trigger point; error is the error between the expected value and the actual value at the trigger moment; and ts is the sampling step size.

[0076] In step S3, the limit value of the command limit module is limited by the aircraft's control performance. It is used to ensure that the aircraft still has acceptable landing and leveling capabilities when the integral channel command is in an abnormal position due to reasons such as non-command in the integrator, resulting in the offset command component ELE_FLARE_OFFSET being stopped at the most unfavorable position.

[0077] In this embodiment, in the event of a non-commanded deviation in the integrator, the command limiter module is used to ensure that the integral channel command does not exceed the range that the aircraft control system can handle;

[0078] When the integral channel instruction causes the bias instruction component ELE_FLARE_OFFSET to stop at the most unfavorable position due to non-instructional reasons, the amplitude of the relevant instruction will be limited by the instruction limiting module.

[0079] In this embodiment, the instruction limiting module adopts a limiting range of -5 degrees to 5 degrees.

[0080] Specifically, the integral channel command ELE_NM_INT passes through the command limiter module to obtain the bias command component ELE_FLARE_OFFSET under the flare control law. The limit value of the command limiter module is limited by the aircraft's control efficiency. It is used to ensure that the aircraft still has acceptable landing flare capability when the integral channel command is in an abnormal position due to reasons such as non-command in the integrator, causing the bias command component ELE_FLARE_OFFSET to stop at the most unfavorable position. It is expressed as the following formula:

[0081]

[0082] In this embodiment, the instruction limit module adopts a limit range of -5 degrees to 5 degrees, that is, LIM_UP = 5 degrees, LIM_DN = -5 degrees.

[0083] In the above step S4, the offset instruction ELE_FLARE_OFFSET is subtracted from the integral channel instruction ELE_NM_INT to obtain the instruction initial value ELE_FLARE_FADER0 that needs to be faded during instruction transition. The calculation formula is as follows:

[0084]

[0085] In this embodiment, the initial command value ELE_FLARE_FADER0 passes through a fader module to form the real-time control surface control command component ELE_FLARE_FADER. Starting at the moment the leveling control law is entered, the initial command value ELE_FLARE_FADER0 is gradually faded to zero over a specified time period to reduce transients caused by aircraft mode switching. In this embodiment, the fader module uses linear fade logic, with a fade time of ΔT = 5 seconds.

[0086] ELE_FLARE_FADER=ELE_FLARE_FADER0*f(t)

[0087] Among them, the function f(t) is the fade function. This patent adopts linear fade logic. The specific formula is as follows:

[0088]

[0089] Wherein, t is the real time starting from the triggering moment t=0 to enter the leveling state.

[0090] In this embodiment, the transition time design of the desalinator module is limited by the transient response size of the aircraft.

[0091] In this embodiment, the fader module employs a 5-second linear fade logic. Within this fader module, the initial command value ELE_FLARE_FADER0 gradually fades to zero over a 5-second period. Specifically, within each time step, the initial command value ELE_FLARE_FADER decreases at a fixed rate until it reaches zero. This demonstrates that the fader module employing a 5-second linear fade logic in this embodiment is a simple yet effective control strategy for reducing transient response during aircraft control mode switching.

[0092] In this embodiment, the fly-by-wire aircraft flight control law generally adopts the design feature of neutral speed stability, which is different from the control habits of traditional aircraft. To ensure that the aircraft can simulate the control habits of traditional aircraft before landing, civil aircraft usually design a leveling control law for transition. The significant design feature of the leveling control law is to restore static speed stability, and different aircraft implement different methods. Because the aircraft is a fixed horizontal tail fly-by-wire aircraft, different from the general civil movable horizontal tail aircraft, the design of the leveling control law will be different. Therefore, the elevator control command ELE_CMD of the leveling control law of this embodiment is the following formula:

[0093] ELE_CMD=ELE_FLARE_FWD+ELE_FLARE_OFFSET+ELE_FLARE_FADER

[0094] Among them, ELE_FLARE_FWD is the forward control channel command; ELE_FLARE_OFFSET is the rudder offset command; ELE_FLARE_FADER is the real-time command generated by the command transition link.

[0095] like Figure 4 As shown, Figure 4 The figure shows the time domain curve of the aircraft landing process using the method of this embodiment, which shows that the method is simple, reliable and effective.

[0096] In summary, the present invention ensures precise control of the aircraft attitude during the leveling phase by accurately recording the flight control law integral channel instructions at the triggering moment and generating control instructions based on the joystick displacement signal, thereby reducing flight safety hazards caused by inaccurate control.

[0097] Furthermore, the present invention introduces an instruction limiter module and a desalter module to limit and desalinate the control instructions, thereby preventing sudden changes in the control instructions, making the aircraft's attitude adjustment more stable and improving flight stability and safety.

[0098] Furthermore, the present invention achieves a smooth transition of control instructions by calculating the initial value of the instructions that need to be faded during instruction transition and processing it through a fader module, thereby avoiding jitter or instability of the aircraft caused by sudden changes in control instructions during the leveling phase, thereby improving flight quality.

[0099] Furthermore, the elevator control command ELE_CMD finally obtained by the present invention is the result of integrating the forward command, the offset command and the control surface control command components, making the control of the aircraft more comprehensive and precise, and further improving the flight quality.

[0100] Furthermore, the method adopts a modular design concept, including a forward command shaping module, a command limiter module and a desalinator module. This design makes the system easy to maintain and upgrade, and each module can be adjusted and optimized according to different flight requirements.

[0101] Furthermore, by adjusting the control parameters and strategies of each module, the present invention can adapt to different types of fixed-horizontal-tail fly-by-wire aircraft and different flight environments and mission requirements, and has strong adaptability and flexibility.

[0102] Furthermore, the present invention realizes full-process automated control from the triggering moment to the generation of elevator control instructions, reduces the need for manual intervention, and improves the level of flight automation.

[0103] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for designing a flare control law for a fixed-horizontal-tail fly-by-wire aircraft, characterized in that: The method comprises the following steps: Generate the elevator control command component ELE_FLARE_FWD based on the joystick displacement signal through the forward command shaping module; When the aircraft meets the conditions for entering the leveling control law, the flight control law integral channel instruction ELE_NM_INT at the triggering moment is recorded; The integral channel instruction ELE_NM_INT is introduced into the leveling control law, and the bias instruction component ELE_FLARE_OFFSET under the leveling control law is obtained after passing through the instruction limit module; Subtract the offset instruction ELE_FLARE_OFFSET from the integral channel instruction ELE_NM_INT to obtain the instruction initial value ELE_FLARE_FADER0 that needs to be faded during instruction transition; After the initial value of the command ELE_FLARE_FADER0 passes through a fader module, it forms the real-time control surface command component ELE_FLARE_FADER; The elevator control command ELE_CMD under the leveling control law is obtained based on the elevator control command component ELE_FLARE_FWD, the offset command component ELE_FLARE_OFFSET, and the control surface control command component ELE_FLARE_FADER.

2. The method according to claim 1, characterized in that The generating of the elevator control command component ELE_FLARE_FWD comprises: The forward control logic based on the leveling control law adopts the control law configuration of the elevator with stick displacement command to make the aircraft have speed static stability; The generated joystick displacement signal is passed through the forward command shaping module to generate the elevator control command component ELE_FLARE_FWD, which is expressed as the following formula: ELE_FLARE_FWD=KP*DE Among them, the forward instruction shaping module is the forward transmission ratio of the aircraft, and DE is the control stick displacement signal.

3. The method according to claim 2, wherein: The forward transmission ratio gain of the forward command shaping module is 0.

2.

4. The method according to claim 1, wherein: The integral channel instruction ELE_NM_INT is introduced into the flare control law, which is equivalent to the effect of freezing the horizontal tail of similar aircraft and reduces the transient state during instruction transition. When the aircraft determines that the conditions for entering the flare control law are met, the flight control law integral channel instruction ELE_NM_INT at the triggering moment is recorded and expressed as the following formula: ELE_NM_INT=KI*(errori+error*ts) Wherein, KI is the integral channel control gain, KI=3; errori is the error between the expected value and the actual value at the moment before the trigger point; error is the error between the expected value and the actual value at the trigger moment; ts is the sampling step size.

5. The method according to claim 1, wherein: In the event of non-command deviation in the integrator, the command limiter module is used to ensure that the integral channel command does not exceed the range that the aircraft control system can handle; When the integral channel instruction causes the offset instruction component ELE_FLARE_OFFSET to stop at the most unfavorable position due to non-instructional reasons, the amplitude of the relevant instruction will be limited by the instruction limit module, which is expressed as the following formula:

6. The method according to claim 5, characterized in that: The command limit module adopts a limit range of -5 degrees to 5 degrees, that is, LIM_UP = 5 degrees, LIM_DN = -5 degrees.

7. The method according to any one of claims 1 to 6, characterized in that: The initial command value ELE_FLARE_FADER0 passes through a fader module to form the real-time control surface control command component ELE_FLARE_FADER. Starting at the moment of entering the leveling control law, the initial command value ELE_FLARE_FADER0 is gradually faded to zero within a specified time to reduce the transient caused by the aircraft mode switching. The fader module uses linear fade logic with a fade time of ΔT = 5 seconds, which is expressed as the following formula: ELE_FLARE_FADER=ELE_FLARE_FADER0*f(t) Among them, the function f(t) is the fade function, which adopts linear fade logic. The specific formula is as follows: Wherein, t is the real time starting from the triggering moment t=0 to enter the leveling state.

8. The method according to any one of claims 1 to 6, characterized in that: The elevator control command for the flare control law is given by the following formula: ELE_CMD=ELE_FLARE_FWD+ELE_FLARE_OFFSET+ELE_FLARE_FADER Among them, ELE_FLARE_FWD is the forward control channel command; ELE_FLARE_OFFSET is the rudder offset command; ELE_FLARE_FADER is the real-time command generated by the command transition link.

Images