A method for lateral asymmetry self-trim of large aircraft

Abstract

The application belongs to the technical field of aircraft flight control system design, and particularly relates to a large aircraft lateral and longitudinal asymmetric self-trimming method, an automatic trimming instruction storage module of a rudder and an automatic trimming instruction storage module of ailerons are respectively arranged; automatic trimming working condition rudder and aileron instruction values at multiple speed points in a speed range of the aircraft are obtained; a linear interpolation table is established according to the automatic trimming working condition rudder and aileron instruction values, linear interpolation calculation is performed, and the required rudder and aileron trimming instructions at the current indicated airspeed of the aircraft are obtained; the rudder and aileron trimming instructions are used to control the deflection of the rudder and aileron; the aircraft can be automatically trimmed in the lateral and longitudinal asymmetric state when the aircraft is in an artificial flight control mode, and the pilot's operation burden is reduced. The method does not need to modify any hardware part, and the lateral and longitudinal automatic trimming related function modules can be added on the basis of the existing flight control law architecture according to the method, so that the modification cost is saved.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft flight control system design, and in particular relates to a method for self-balancing asymmetric lateral and tack directions of large aircraft. Background Art

[0002] Due to the limited manufacturing technology level of large aircraft, it is impossible to achieve absolute symmetry of the aircraft's lateral and yaw structural shape, which will cause asymmetric lateral and yaw aerodynamic characteristics; in addition, under conditions such as fuel asymmetry, control surface sticking, and wing damage, the aircraft will also generate asymmetric torque, resulting in unexpected roll and yaw motions.

[0003] Modern fly-by-wire aircraft all have both automatic flight control and manual flight control modes. In the automatic flight control mode, certain operating modes of the automatic flight control system (such as heading / track keeping and horizontal navigation mode) can automatically balance lateral heading asymmetry.

[0004] However, when in manual flight control mode, most aircraft manual flight control systems (such as the Boeing B777) cannot automatically compensate for lateral and directional asymmetry because they do not use integrators for lateral and directional control. Balancing the aircraft relies solely on the pilot's manual control of the control surfaces, which greatly increases the pilot's operational burden.

[0005] Therefore, how to achieve automatic balancing of the aircraft is a problem that needs to be solved. Summary of the Invention

[0006] The purpose of this application is to provide a method for self-balancing asymmetric lateral and tack of large aircraft, so as to solve the problem in the prior art of relying on the pilot to manually control the control surfaces to balance the aircraft, which increases the operating burden of the pilot.

[0007] The technical solution of the present application is: a method for self-balancing asymmetric lateral and tack direction of a large aircraft, comprising:

[0008] A rudder automatic trim command storage module and an aileron automatic trim command storage module are respectively provided in the automatic flight rudder command channel and the aileron command channel; when the automatic flight control subsystem is disconnected, the automatic flight rudder command and the aileron command are respectively commands of the rudder automatic trim storage module and commands of the aileron automatic trim storage module;

[0009] Obtaining rudder automatic trim storage module instructions and aileron automatic trim storage module instructions: identifying the automatic trim working condition and recording the current automatic trim instruction value; the automatic trim instruction value includes the automatic trim working condition rudder and aileron automatic flight instruction values ​​at multiple speed points within the aircraft speed range;

[0010] The automatic trim working condition rudder and aileron command values ​​at multiple speed points within the aircraft speed range are obtained; a linear interpolation table is established based on the automatic trim working condition rudder and aileron command values, and the interpolation variable is the aircraft indicated airspeed; when the automatic flight control subsystem is disconnected, a linear interpolation calculation is performed based on the aircraft's current real-time aircraft indicated airspeed to obtain the rudder and aileron trim commands required at the current aircraft indicated airspeed, and the control surface deflection is controlled by the rudder and aileron trim commands.

[0011] Preferably, the instruction storage process of the automatic balancing instruction storage module is as follows: when the aircraft is in the automatic balancing working condition, the current real-time indicated airspeed of the aircraft is obtained and the current automatic balancing instruction value is recorded; when the aircraft is in the non-automatic balancing working condition, the instruction value is not recorded and the instruction value in the previous automatic balancing working condition calculation cycle is maintained.

[0012] Preferably, the rudder automatic trim instruction storage module and the aileron automatic trim instruction storage module both store trim instructions for different aircraft speeds under trim conditions, and the trim instructions are combined with selected aircraft speed points to form an interpolation table; the automatic trim instruction can be calculated according to the real-time speed of the aircraft through the interpolation table.

[0013] Preferably, the aircraft's automatic trim working condition judgment logic is as follows: after the aircraft takes off, when the radio altitude is greater than a certain height, the pilot will connect the automatic flight control subsystem. When the lateral mode of the automatic flight control subsystem is operating in heading / track holding or horizontal navigation mode, and the wings are level, it is judged that the aircraft is in an automatic trim working condition at this time; otherwise, it is in a non-automatic trim working condition.

[0014] Preferably, the specific method for recording the current automatic balancing instruction value is: when the aircraft is in the automatic balancing working state, speed points are selected at intervals of a certain value within the flight speed range of the aircraft, thereby selecting several speed points, and recording the aileron and rudder instructions when the aircraft speed reaches each speed point.

[0015] Preferably, the speed interval values ​​and speed points can be adaptively adjusted according to different aircraft.

[0016] Preferably, if the aircraft speed does not pass a certain speed point, the aileron and rudder instructions at the speed point that has not been passed are kept greater than the recorded values ​​of the control surface instructions at the next speed point of the speed point.

[0017] Preferably, recording the certain value at intervals specifically includes recording the rudder automatic trim storage module instructions and the aileron automatic trim storage module instructions at intervals of 50 km / h within the flight speed range.

[0018] Preferably, after the aircraft speed reaches each speed point and remains for 2 seconds, the current rudder automatic trim command and aileron automatic trim command are recorded and stored in the rudder automatic trim command storage module and the aileron automatic trim command storage module respectively.

[0019] Preferably, under automatic flight control, the rudder and aileron instructions generated by the automatic flight control subsystem will be superimposed with the instructions in the manual flight control subsystem to generate the final rudder instructions; the superimposed instructions include automatic flight rudder instructions, manual flight rudder instructions, manual flight aileron instructions and automatic flight aileron instructions.

[0020] The present invention proposes a method for automatically balancing lateral and tack asymmetry in large aircraft, enabling automatic balancing of lateral and tack asymmetry when the aircraft is in manual flight control mode, thereby reducing the pilot's operational burden. This method does not require any hardware modifications; rather, it can be used to add lateral and tack automatic trimming modules to the existing flight control law architecture, thus reducing modification costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions provided by this application, the following is a brief introduction to the accompanying drawings. Obviously, the accompanying drawings described below are only some embodiments of this application.

[0022] Figure 1 This is a schematic diagram of the overall process of this application;

[0023] Figure 2 This is a schematic diagram of the composition of the flight control system of a modern large aircraft for this application;

[0024] Figure 3 Add a schematic diagram of the automatic trim rudder and aileron command storage module to the basis of this application;

[0025] Figure 4 This is a logic diagram for determining the automatic trimming working condition identification for this application. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] A method for self-balancing the lateral and heading asymmetry of large aircraft, such as Figure 1 As shown, the following steps are included:

[0028] Step S100: The flight control system of a modern large aircraft is usually composed of an automatic flight control subsystem and a manual flight control subsystem. Under automatic flight control, the rudder and aileron commands generated by the automatic flight control subsystem are superimposed with the commands in the manual flight control subsystem to generate the final control surface commands. The superimposed commands include automatic flight rudder commands, manual flight rudder commands, manual flight aileron commands, and automatic flight aileron commands, such as Figure 2 .

[0029] Most aircraft in manual flight control mode do not use integral control in the lateral and heading control law, making automatic trimming impossible. Under automatic flight control, when operating in heading / track hold or horizontal navigation mode, the automatic flight control subsystem automatically trims the lateral and heading by controlling rudder and aileron deflections to maintain the target heading / track.

[0030] Get the automatic balancing rudder command, and set the rudder automatic balancing command storage module and the aileron automatic balancing command storage module in the automatic flight rudder command channel and the aileron command channel in the rudder command, respectively, such as Figure 3 When the automatic flight control subsystem is disconnected, the automatic flight rudder command and the aileron command are respectively the rudder automatic trim storage module command and the aileron automatic trim storage module command.

[0031] Step S200, obtaining the rudder automatic balancing storage module instructions and the aileron automatic balancing storage module instructions: identifying the automatic balancing working condition and recording the current automatic balancing instruction value; the automatic balancing instruction value includes the automatic balancing working condition rudder and aileron automatic flight instruction values ​​at multiple speed points within the aircraft speed range.

[0032] Preferably, the instruction storage process of the automatic balancing instruction storage module is as follows: when the aircraft is in the automatic balancing working condition, the current real-time indicated airspeed of the aircraft is obtained and the current automatic balancing instruction value is recorded; when the aircraft is in the non-automatic balancing working condition, the instruction value is not recorded and the instruction value in the previous automatic balancing working condition calculation cycle is maintained.

[0033] Preferably, the rudder automatic trim command storage module and the aileron automatic trim command storage module both store trim commands for different aircraft speeds under trim conditions, and the trim commands are combined with selected aircraft speed points to form an interpolation table. The automatic trim command can be calculated based on the real-time aircraft speed using the interpolation table.

[0034] Preferably, the automatic trim working condition judgment logic of the aircraft is as follows: after the aircraft takes off, when the radio altitude is greater than a certain altitude, such as 60m, the pilot will turn on the automatic flight control subsystem. When the lateral mode of the automatic flight control subsystem is working in the heading / track holding mode or the horizontal navigation mode, and the wings are level (the roll angle is within ±1°), it is judged that the aircraft is in the automatic trim working condition at this time; otherwise, it is in the non-automatic trim working condition, such as Figure 4 .

[0035] Preferably, the specific method for recording the current automatic trim command value is as follows: when the aircraft is in the automatic trim state, select speed points at regular intervals within the aircraft's flight speed range, thereby selecting several speed points, and record the aileron and rudder commands when the aircraft reaches each speed point. The speed interval value and speed points can be adaptively adjusted according to different aircraft.

[0036] Preferably, the rudder and aileron automatic trim memory module commands are recorded at intervals of 50 km / h within the flight speed range. For example, if the aircraft speed range is 300 km / h to 500 km / h, then when the aircraft speed reaches 300±5 km / h, 350±5 km / h, 400±5 km / h, 450±5 km / h, and 500±5 km / h (±5 km / h is the speed point determination error range) and remains within this range for 2 seconds, the current rudder and aileron commands are recorded and stored in the rudder and aileron automatic trim command storage modules, respectively. The speed intervals and speed points can be adjusted adaptively based on different aircraft, but the overall concept remains the same.

[0037] If the aircraft's speed does not pass through a certain speed point, the aileron and rudder commands for that speed point remain greater than the recorded values ​​for the control surface commands at the speed point immediately following that speed point. For example, if the aircraft does not pass through 300 km / h during auto-trim, the stored aileron and rudder values ​​for 300 km / h remain the same as those for 350 km / h. If the aircraft does not pass through 300 km / h and 350 km / h during auto-trim, the stored aileron and rudder values ​​for 300 km / h and 350 km / h remain the same as those for 450 km / h, and so on. This is because the higher the aircraft speed, the greater the control surface efficiency, and the smaller the required trim angle. For example, the trim angle at 300 km / h is greater than that at 350 km / h. If the aileron and rudder commands for the speed point not passed through are kept smaller than the recorded values ​​for that speed point, the resulting trim angle will be larger, causing "over-trim" and undesirable aircraft response. Therefore, the aileron and rudder commands at the speed points that have not been passed are kept greater than the recorded values ​​of the control surface commands at the speed points to achieve "under-trim" control and ensure that the aircraft responds as expected.

[0038] Step S300 obtains rudder and aileron command values ​​for automatic trim at multiple speed points within the aircraft speed range, such as rudder and aileron command values ​​for automatic trim at 300 km / h, 350 km / h, 400 km / h, 450 km / h, and 500 km / h, as shown in Table 1. The values ​​in Table 1 are for illustration only and may vary for different aircraft.

[0039] Table 1 Examples of stored auto-trim rudder and aileron command values ​​at speed points

[0040]

[0041] A linear interpolation table is created based on the rudder and aileron command values ​​in the automatic trim condition, with the aircraft's indicated airspeed as the interpolation variable. When the automatic flight control subsystem is disconnected, a linear interpolation calculation is performed based on the aircraft's current, real-time indicated airspeed to determine the rudder and aileron trim commands required at the current indicated airspeed. These rudder and aileron trim commands are used to control control surface deflection, ensuring lateral trim control of the aircraft under manual flight control.

[0042] In summary, the above design enables automatic lateral and directional trimming of aircraft in manual flight control mode, reducing the pilot's operational burden. This method does not require any hardware modifications. By adding automatic lateral and directional trimming modules to the existing flight control law architecture, this approach can reduce modification costs.

[0043] Finally, it should be noted that the drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures can refer to common designs. In the absence of conflicts, the same embodiment and different embodiments of the present invention can be combined with each other.

[0044] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for self-balancing asymmetric lateral and tack direction of a large aircraft, characterized by: include: A rudder automatic trim command storage module and an aileron automatic trim command storage module are respectively provided in the automatic flight rudder command channel and the aileron command channel; When the automatic flight control subsystem is disconnected, the automatic flight rudder command and the aileron command are respectively the rudder automatic trim storage module command and the aileron automatic trim storage module command; Obtaining rudder automatic trim storage module instructions and aileron automatic trim storage module instructions: identifying the automatic trim working condition and recording the current automatic trim instruction value; the automatic trim instruction value includes the automatic trim working condition rudder and aileron automatic flight instruction values ​​at multiple speed points within the aircraft speed range; The automatic trim working condition rudder and aileron command values ​​at multiple speed points within the aircraft speed range are obtained; a linear interpolation table is established based on the automatic trim working condition rudder and aileron command values, and the interpolation variable is the aircraft indicated airspeed; when the automatic flight control subsystem is disconnected, a linear interpolation calculation is performed based on the aircraft's current real-time aircraft indicated airspeed to obtain the rudder and aileron trim commands required at the current aircraft indicated airspeed, and the control surface deflection is controlled by the rudder and aileron trim commands.

2. The large aircraft asymmetric lateral and heading self-balancing method according to claim 1, characterized in that: The instruction storage process of the automatic balancing instruction storage module is as follows: when the aircraft is in the automatic balancing condition, the current real-time indicated airspeed of the aircraft is obtained and the current automatic balancing instruction value is recorded; when the aircraft is in the non-automatic balancing condition, the instruction value is not recorded and the instruction value in the previous automatic balancing condition calculation cycle is maintained.

3. The large aircraft asymmetric lateral and heading self-balancing method according to claim 2, characterized in that: The rudder automatic trim command storage module and the aileron automatic trim command storage module both store trim commands for different aircraft speeds under trim working conditions, and form an interpolation table by combining the trim commands with selected aircraft speed points; The automatic trim command can be calculated based on the real-time speed of the aircraft through the interpolation table.

4. The large aircraft asymmetric lateral and heading self-balancing method according to claim 1, characterized in that: The aircraft's automatic trim working condition judgment logic is as follows: After the aircraft takes off, when the radio altitude is greater than a certain height, the pilot will connect the automatic flight control subsystem. When the lateral mode of the automatic flight control subsystem is working in heading / track hold or horizontal navigation mode, and the wings are level, the aircraft is judged to be in automatic trim working condition; otherwise, it is in non-automatic trim working condition.

5. The large aircraft asymmetric lateral and heading self-balancing method according to claim 1, characterized in that: The specific method for recording the current automatic balancing command value is as follows: when the aircraft is in the automatic balancing state, select speed points at certain intervals within the aircraft's flight speed range, thereby selecting several speed points, and record the aileron and rudder commands when the aircraft speed reaches each speed point.

6. The large aircraft asymmetric lateral and heading self-balancing method according to claim 5, characterized in that: The speed interval values ​​and speed points can be adaptively adjusted according to different aircraft.

7. The large aircraft asymmetric lateral and heading self-balancing method according to claim 5, characterized in that: If the aircraft speed does not pass a certain speed point, the aileron and rudder commands at the speed point that has not been passed will remain greater than the control surface command record value at the next speed point after that speed point.

8. The large aircraft asymmetric lateral and heading self-balancing method according to claim 5, characterized in that: Specifically, the certain value at each interval is as follows: within the flight speed range, the rudder automatic trim storage module command and the aileron automatic trim storage module command are recorded at each interval of 50 km / h.

9. The large aircraft asymmetric lateral and heading self-balancing method according to claim 8, characterized in that: After the aircraft speed reaches each speed point and remains at that speed for 2 seconds, the current rudder automatic trim command and aileron automatic trim command are recorded and stored in the rudder automatic trim command storage module and the aileron automatic trim command storage module respectively.

10. The large aircraft asymmetric lateral and heading self-balancing method according to claim 1, characterized in that: Under automatic flight control, the rudder and aileron commands generated by the automatic flight control subsystem will be superimposed with the commands in the manual flight control subsystem to generate the final rudder commands; the superimposed commands include automatic flight rudder commands, manual flight rudder commands, manual flight aileron commands and automatic flight aileron commands.

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