A high-speed protection control method for a large amphibious aircraft

Abstract

The embodiment of the application discloses a high-speed protection control method for a large amphibious aircraft, comprising: after the aircraft enters a high-speed protection state, generating a high-speed protection pitch angle stabilizing instruction according to a current pitch angle of the aircraft, superimposing the high-speed protection pitch angle stabilizing instruction and a high-speed protection pitch angle instruction generated based on a pilot's driving intention to generate a high-speed protection pitch angle control instruction, converting the high-speed protection pitch angle control instruction into a high-speed protection overload instruction, and superimposing the high-speed protection overload instruction with a main flight control law instruction, so as to realize safe, efficient and stable high-speed protection control. The technical scheme provided by the embodiment of the application solves the problem that the aircraft pitch angle may be too large during the execution of the high-speed protection work by using the existing high-speed protection control mode, and the aircraft still flies at a large pitch angle after exiting the high-speed protection, which is not suitable for large amphibious aircraft and may endanger flight safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flight control, and in particular to a high-speed protection control method for a large amphibious aircraft. BACKGROUND

[0002] When designing the shape of a large amphibious aircraft, the landing and taking off on water are considered, and the lower part of the aircraft is usually designed as a ship body, and floaters are installed on both sides of the main wing. The flight resistance of this type of aircraft is greatly affected by the attitude. In addition, in order to reduce the water landing load, the weight of the amphibious aircraft is reduced as much as possible during design, so it is not equipped with a movable horizontal stabilizer, and the trimming and maneuvering of the aircraft are realized by the elevator.

[0003] The existing high-speed protection control method converts the high-speed protection command into a normal overload command to make the aircraft lift its head and slow down. During the high-speed protection process, the aircraft may have a too large pitch angle, and after exiting the high-speed protection, the aircraft still flies at a large pitch angle. For amphibious aircraft without movable horizontal stabilizers, the resistance is significantly greater than that of other aircraft, so when the aircraft flies at a large pitch angle, the speed decreases very quickly, and in the case of a short loss of ability of the pilot, the speed of the aircraft may decrease to the stall speed, which may endanger the safety of flight. SUMMARY

[0004] The purpose of the present application is to solve the above technical problems. The embodiments of the present application provide a high-speed protection control method for a large amphibious aircraft to solve the problem that the existing high-speed protection control method may cause the aircraft to have a too large pitch angle during the high-speed protection process, and the aircraft still flies at a large pitch angle after exiting the high-speed protection, which is not suitable for large amphibious aircraft and may endanger the safety of flight.

[0005] The technical solution of the present application is that the embodiments of the present application provide a high-speed protection control method for a large amphibious aircraft, which comprises:

[0006] After the aircraft enters the high-speed protection state, a high-speed protection pitch angle stabilization command is generated according to the current pitch angle of the aircraft. The high-speed protection pitch angle stabilization command is superimposed on the high-speed protection pitch angle command generated based on the pilot's driving intention to generate a high-speed protection pitch angle control command. After the high-speed protection pitch angle control command is converted into a high-speed protection overload command, it is superimposed on the main flight control law command of the aircraft, thereby realizing safe, efficient and stable high-speed protection control.

[0007] Optionally, in the high-speed protection control method for a large amphibious aircraft as described above, it comprises:

[0008] Step 1, filtering and correcting the corrected airspeed signal and the Mach number signal of the aircraft to obtain a predictive corrected airspeed prediction signal and a Mach number prediction signal, comparing them with the protection boundary speed threshold, and taking the greater one as the high-speed protection instruction;

[0009] Step 2, adjusting the high-speed protection instruction in real time according to the pilot's driving intention, and converting the speed protection instruction into a high-speed protection pitch angle instruction;

[0010] Step 3, after the aircraft enters the high-speed protection state, the generated high-speed protection pitch angle stability instruction is used to guide the aircraft to enter the stable pitch angle region, and after the high-speed protection state exits, the aircraft is controlled to fly safely at a stable pitch angle;

[0011] Step 4, generating a high-speed protection pitch angle control instruction according to the high-speed protection pitch angle instruction generated in step 2 and the high-speed protection pitch angle stability instruction generated in step 3, and after converting the high-speed protection pitch angle control instruction into a high-speed protection overload instruction, superimposing it with the main flight control law instruction of the aircraft.

[0012] Optionally, in the high-speed protection control method of the large amphibious aircraft as described above, the step 1 comprises:

[0013] Step 11, calculating the corrected airspeed signal and the Mach number signal based on the aircraft's air data computer, and filtering through a high-pass filter to obtain a corrected airspeed rate signal and a Mach number rate signal;

[0014] Step 12, after superimposing the corrected airspeed rate signal and the Mach number rate signal with the corrected airspeed signal and the Mach number signal one by one, filtering out high-frequency noise through a low-pass filter to obtain a corrected airspeed prediction signal and a Mach number prediction signal with predictive characteristics;

[0015] Step 13, subtracting the corrected airspeed protection boundary threshold and the Mach number protection boundary threshold from the corrected airspeed signal and the Mach number signal with predictive characteristics one by one, and taking the greater one as the high-speed protection instruction after limiting the difference value through one-sided limiting.

[0016] Optionally, in the high-speed protection control method of the large amphibious aircraft as described above, the one-sided limiting of the difference value in step 13 comprises:

[0017] When the corrected airspeed difference value or the Mach number difference value is positive, the original corrected airspeed difference value or the Mach number difference value is output after one-sided limiting;

[0018] When the corrected airspeed difference value or the Mach number difference value is negative or 0, 0 is output after one-sided limiting.

[0019] Optionally, in the high-speed protection and control method for large amphibious aircraft as described above, step 2 includes:

[0020] The high-speed protection command is dynamically adjusted based on the displacement of the control stick to generate a high-speed protection pitch angle command, which gradually increases as the amount of push increases; when the control stick is in the neutral position, the high-speed protection pitch angle command remains at the command value of the control stick in the neutral position.

[0021] Optionally, in the high-speed protection and control method for large amphibious aircraft as described above, step 3 includes:

[0022] After the aircraft enters the high-speed protection state, a high-speed protection pitch angle stabilization command is generated based on the aircraft's current pitch angle. The high-speed protection pitch angle stabilization command gently guides the aircraft's pitch attitude into a stable pitch angle region. After the high-speed protection state is exited, the aircraft is controlled to fly safely with a stable pitch angle.

[0023] Optionally, in the high-speed protection and control method for large amphibious aircraft as described above, step 4 includes:

[0024] Step 41: The high-speed protection pitch angle command and the high-speed protection pitch angle stabilization command are superimposed and the difference is calculated with the pitch angle. The pitch angle difference is then low-pass filtered to generate the high-speed protection pitch angle control command.

[0025] Step 42: The high-speed protection pitch angle control command is converted into a high-speed protection overload command through gain, and the high-speed protection overload command is superimposed on the aircraft main control law command.

[0026] Optionally, the high-speed protection and control method for large amphibious aircraft described above also includes:

[0027] Determining whether an aircraft enters or exits high-speed protection mode includes:

[0028] By performing speed hysteresis on the corrected airspeed signal and Mach number signal respectively, speed protection start flag and Mach number protection start flag are obtained through processing logic. Then, based on the logical judgment of the speed protection start flag and Mach number protection start flag, the high-speed protection start flag is obtained. Thus, the entry or exit of high-speed protection state is determined according to the high-speed protection start flag.

[0029] The application has the beneficial effects that the embodiment of the application provides a high-speed protection control method for a large amphibious aircraft, after the aircraft enters a high-speed protection state, a high-speed protection pitch angle stabilizing instruction is generated according to a current pitch angle of the aircraft, a high-speed protection pitch angle control instruction is generated by superimposing the high-speed protection pitch angle stabilizing instruction and a high-speed protection pitch angle instruction generated based on a pilot's driving intention, and the high-speed protection pitch angle control instruction is converted into a high-speed protection overload instruction and superimposed with a main flight control law instruction, so as to realize safe, efficient and smooth high-speed protection control. The technical solution provided by the embodiment of the application can realize the speed perception of the pilot through the driving lever instruction speed. The high-speed protection instruction and the soft pitch angle stabilizing region guidance control are dynamically adjusted according to the driving intention of the pilot, so as to ensure that the high-speed protection control method provides safe, smooth and effective high-speed protection functions for the large amphibious aircraft.

[0030] In addition, the technical solution provided by the embodiment of the application controls not only the speed but also the pitch angle of the aircraft during the high-speed protection process. When the pilot manipulates, the driving lever instruction speed is greatly reduced, which reduces the burden of the pilot. When the pilot does not manipulate, the aircraft is automatically controlled to fly stably. Compared with the traditional high-speed protection control, the safety is effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the technical solutions of the application, and constitute a part of the specification, and are used to explain the technical solutions of the application together with the embodiments of the application, and do not constitute a limitation on the technical solutions of the application.

[0032] Figure 1 A flowchart of a high-speed protection control method for a large amphibious aircraft provided by the embodiment of the application is shown in the figure.

[0033] Figure 2 A working principle schematic diagram of a high-speed protection control method for a large amphibious aircraft provided by the embodiment of the application is shown in the figure.

[0034] Figure 3 A control effect schematic diagram of a high-speed protection control method for a large amphibious aircraft provided by the embodiment of the application is shown in the figure. DETAILED DESCRIPTION

[0035] In order to make the objects, technical solutions and advantages of the application clearer, the embodiments of the application will be described in detail below with reference to the drawings. It should be explained that, in the case of no conflict, the embodiments and features in the embodiments in the application can be combined with each other at will.

[0036] As explained in the background section, the flight drag of large amphibious aircraft is greatly affected by attitude. Furthermore, due to the design requirement of minimizing aircraft weight, this type of aircraft is not equipped with a movable horizontal stabilizer; trim and maneuvering are achieved solely through elevators. If existing high-speed protection control methods are used to perform high-speed protection operations on large amphibious aircraft, excessive pitch angles may occur, and the aircraft may continue to fly at a large pitch angle even after exiting high-speed protection. This is unsuitable for large amphibious aircraft and could potentially jeopardize flight safety.

[0037] To address the aforementioned problems, embodiments of the present invention provide a high-speed protection control method for large amphibious aircraft, specifically a high-speed and Mach number protection control method that can realize the speed commanded by the pilot's control stick and improve safety and comfort during and after the protection process.

[0038] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0039] This invention provides a high-speed protection and control method for large amphibious aircraft, specifically a technical solution for high-speed and Mach number protection and control of large amphibious aircraft. The implementation method of the high-speed protection and control method provided by this invention is as follows:

[0040] After the aircraft enters high-speed protection mode, a high-speed protection pitch angle stabilization command is generated based on the aircraft's current pitch angle. This command is then superimposed with a high-speed protection pitch angle command generated based on the pilot's flight intentions to generate a high-speed protection pitch angle control command. This control command is then converted into a high-speed protection overload command and superimposed with the aircraft's main flight control law command to achieve safe, efficient, and stable high-speed protection control.

[0041] like Figure 1 The diagram shown is a flowchart of a high-speed protection and control method for a large amphibious aircraft according to an embodiment of the present invention. This high-speed protection and control method may include the following steps:

[0042] Step 1: After filtering and correcting the aircraft airspeed and Mach number signals, obtain predictive airspeed and Mach number prediction signals. Compare these with the protection boundary speed thresholds and take the larger one as the high-speed protection command.

[0043] Step 2: Adjust the high-speed protection command in real time according to the pilot's flight intentions, and convert the speed protection command into a high-speed protection pitch angle command;

[0044] Step 3, after the aircraft enters the high-speed protection state, the generated high-speed protection pitch angle stabilizing instruction is used to guide the aircraft to enter the stable pitch angle region; and after the high-speed protection state is exited, the aircraft is controlled to fly at a stable pitch angle safely.

[0045] Step 4, the high-speed protection pitch angle control instruction is generated according to the high-speed protection pitch angle instruction generated in step 2 and the high-speed protection pitch angle stabilizing instruction generated in step 3, and after the high-speed protection pitch angle control instruction is converted into a high-speed protection overload instruction, the high-speed protection overload instruction is superimposed with the aircraft main flight control law instruction.

[0046] As shown in Figure 2 Fig. 1 is a schematic diagram of the working principle of a high-speed protection control method of a large amphibious aircraft provided by an embodiment of the present application. As shown in Figure 2 Fig. 2, the implementation process of step 1 in the embodiment of the present application includes the following steps:

[0047] Step 11, based on the corrected airspeed signal and the corrected Mach number signal obtained by the aircraft air data computer, the corrected airspeed signal and the Mach number signal are filtered through a high-pass filter to obtain a corrected airspeed rate of change signal and a Mach number rate of change signal.

[0048] Step 12, after the corrected airspeed rate of change signal and the Mach number rate of change signal are superimposed with the corrected airspeed signal and the Mach number signal one by one, the high-frequency noise is filtered out through a low-pass filter to obtain a corrected airspeed prediction signal and a Mach number prediction signal with prediction characteristics, which are used to judge the flight state of the aircraft when entering the high-speed protection, such as accelerating dive or slow entry.

[0049] Step 13, the corrected airspeed prediction signal and the Mach number prediction signal with prediction characteristics are subtracted from the corrected airspeed protection boundary threshold and the Mach number protection boundary threshold one by one, and the greater one is taken as the high-speed protection instruction through one-sided amplitude limiting processing.

[0050] It should be noted that the difference value in this step 13 is processed by one-sided amplitude limiting, which includes the following two cases:

[0051] When the corrected airspeed difference value or the Mach number difference value is positive, the original corrected airspeed difference value or the Mach number difference value is output after one-sided amplitude limiting processing;

[0052] When the corrected airspeed difference value or the Mach number difference value is negative or 0, 0 is output after one-sided amplitude limiting processing.

[0053] In the embodiment of the present application, the specific embodiment mode of the above-mentioned step 2 can include:

[0054] According to the displacement of the driving rod, the high-speed protection instruction is dynamically adjusted, a high-speed protection pitch angle instruction is generated, and the high-speed protection pitch angle instruction is gradually increased with the increase of the push rod amount, so that the flight speed can be effectively protected when the pilot performs a maneuvering action.

[0055] It should be noted that when the pull rod or the driving rod is in the neutral position, the high-speed protection pitch angle instruction is maintained at the instruction value of the neutral position of the driving rod.

[0056] In the embodiment of the application, the specific embodiment mode of step 3 can include:

[0057] When the high-speed protection function is activated, that is, after the aircraft enters the high-speed protection state, a high-speed protection pitch angle stable instruction is generated according to the current pitch angle of the aircraft, the high-speed protection pitch angle stable instruction is used to gently guide the pitch attitude of the aircraft into the stable pitch angle region, and the aircraft is controlled to fly at a stable pitch angle after the high-speed protection state is exited.

[0058] In actual application, the designer designs the corresponding high-speed protection pitch angle stable instruction for different aircrafts according to the trim angle of attack and the resistance characteristics of the aircraft, so as to adapt to different aircrafts. In the initial stage of entering the high-speed protection state, the instruction is used to gently guide the pitch attitude of the aircraft into the stable pitch angle region, so as to reduce the speed increasing trend. Since the aircraft has entered the stable pitch angle region before exiting, the aircraft can be controlled to fly at a stable pitch angle after the high-speed protection state is exited.

[0059] The implementation process of step 4 in the embodiment of the application includes the following steps:

[0060] In step 41, the high-speed protection pitch angle instruction and the high-speed protection pitch angle stable instruction are superimposed, and then the pitch angle is subtracted, the pitch angle difference is low-pass filtered to generate a high-speed protection pitch angle control instruction.

[0061] In step 41, the low-pass filter can filter out the instruction transient caused by the internal switch switching of the control form.

[0062] In step 42, the high-speed protection pitch angle control instruction is converted into a high-speed protection overload instruction through a gain, and the high-speed protection overload instruction is superimposed with the main control law instruction of the aircraft. The gain is selected according to the ratio of the difference between the negative overload limit value of the aircraft and the difference between the speed protection threshold value and the speed limit boundary of the aircraft, so that the maximum limit speed corresponding to the maximum rod displacement can be provided by the pilot through the driving rod instruction speed, and the safe, smooth and effective high-speed protection function of the large amphibious aircraft can be provided.

[0063] The high-speed protection control method of the large amphibious aircraft provided in the embodiment of the application adopts a control method based on the corrected airspeed and the Mach number protection of the aircraft, and has the following innovative points:

[0064] 1. In steps 1 and 2 of the technical solution provided in the embodiments of the present invention, by converting the speed command into a high-speed protection pitch angle command, not only is the overload limited during the high-speed protection process, but the aircraft can also be controlled to prevent large pitch angles when recovering from high speed, and fly with a stable pitch angle when exiting high-speed protection, which greatly improves flight safety and reduces the safety hazards of the aircraft flying with a large attitude after the pilot is temporarily disabled.

[0065] 2. In step 3 of the technical solution provided in this embodiment of the invention, the smooth pitch angle stable region guidance and control technology: by adjusting the pitch angle control command in real time according to the aircraft's current pitch angle, when the pilot does not perform any operation, the aircraft can be smoothly controlled to move towards the target pitch angle stable region, and ultimately maintain flight at the target stable pitch angle. When the pilot performs maneuvering operations, this technology can dynamically adjust the control command according to the aircraft's real-time pitch angle response, so that the aircraft response is consistent with the pilot's control intention. Figure 1 This reduces the transients caused by pitch angle stabilization region guidance control.

[0066] 3. In step 2 of the technical solution provided in this embodiment of the invention, the high-speed protection pilot intent recognition technology specifically employs the following: Pilot intent is recognized through the aircraft control stick displacement signal; the high-speed protection command is dynamically adjusted based on the pilot's intent. After entering high-speed protection, the greater the pilot's push of the control stick, the more obvious the pilot's intention to accelerate the aircraft, and the higher the high-speed protection command becomes; as the pilot gradually reduces the push of the control stick, the high-speed protection command also dynamically decreases. This technology ensures that during pilot maneuvering, the aircraft response matches the pilot's expectations without significant overload transients.

[0067] 4. In step 4 of the technical solution provided in this embodiment of the invention, the control stick command speed technology specifically employs the following: the conversion gain from the high-speed protective pitch angle control command to the overload command is matched and adjusted with the aircraft's maximum negative overload value to ensure that the overload command generated by the high-speed protective pitch angle control command at the maximum speed limit is consistent in magnitude and opposite in direction to the overload command generated by the pilot pushing the control stick. After completing the gain matching according to different aircraft models, the control stick speed control function can be realized, enhancing the pilot's speed perception.

[0068] 5. This embodiment of the invention also employs speed information prediction technology: by performing high-pass filtering on the corrected airspeed and its Mach number, adding it to the corrected airspeed or Mach number, and then performing low-pass filtering, a low-noise speed signal with predictive information is obtained. When the aircraft dives into high-speed protection with a large acceleration, this technology can control the aircraft to perform deceleration maneuvers in advance to prevent the aircraft speed from exceeding the maximum flight speed. At the same time, it increases the long-period damping of the aircraft to prevent pitch oscillation caused by speed response overshoot.

[0069] 6. This embodiment of the invention also employs a dual protection technology for corrected airspeed and Mach number: by simultaneously processing the corrected airspeed and Mach number signals to generate either a speed protection command or a Mach number protection command, and performing logical judgment on the two protection commands to achieve dual protection for both the corrected airspeed and Mach number. This protects the corrected airspeed at low altitudes and the Mach number at high altitudes, effectively improving flight safety.

[0070] 7. This embodiment of the invention also employs dual control command protection technology: to prevent control command saturation caused by signal abrupt changes due to atmospheric sensor instability or signal transmission in the flight control system, dual safety boundary protection is adopted. First-level limiting is applied to noise-sensitive signals such as corrected airspeed and Mach number prediction signals, while second-level limiting is applied to corrected airspeed protection commands and Mach number protection commands. This technology can effectively prevent command saturation caused by signal errors.

[0071] 8. In this embodiment of the invention, mode switching transient suppression technology is also employed: by applying hysteresis processing to the corrected airspeed signal and Mach number signal, a relatively stable state signal is obtained, preventing frequent jumps in the high-speed protection activation signal start-up flag caused by atmospheric disturbances and signal transmission. Simultaneously, at the command generation end, the signal is processed to obtain a smooth command, preventing abrupt changes in the control signal.

[0072] This invention provides a high-speed protection control method for large amphibious aircraft. After the aircraft enters a high-speed protection state, a high-speed protection pitch angle stabilization command is generated based on the aircraft's current pitch angle. This command is then superimposed with a high-speed protection pitch angle command generated based on the pilot's intentions to generate a high-speed protection pitch angle control command. This control command is then converted into a high-speed protection overload command and superimposed with the aircraft's main flight control law command, thereby achieving safe, efficient, and stable high-speed protection control. Using the technical solution provided in this invention, pilots can control speed via the control stick, enhancing speed perception. Dynamically adjusting the high-speed protection command and gentle pitch angle stabilization zone guidance control based on the pilot's intentions ensures that this high-speed protection control method provides safe, smooth, and effective high-speed protection for large amphibious aircraft.

[0073] Furthermore, by adopting the technical solution provided in the embodiments of the present invention, not only is the speed controlled during high-speed protection, but the pitch angle of the aircraft is also controlled. When the pilot is operating, the speed of the control stick command is greatly reduced, which significantly reduces the pilot's burden. When the pilot is not operating, the aircraft can be automatically controlled to fly stably. Compared with traditional high-speed protection control, this effectively improves safety.

[0074] The technical scheme provided by the embodiment of the application is verified by multiple test pilots, and it is unanimously considered that the application has a remarkable effect on improving the high-speed protection safety of large amphibious aircraft.

[0075] The embodiment of the application provides a large amphibious aircraft high-speed protection control method.

[0076] Referring to Figure 2 The principle diagram of the large amphibious aircraft high-speed protection control method is shown in the screenshot, and the method provided by the embodiment can include the following steps:

[0077] Step one:

[0078] On the one hand, the processing method of the corrected airspeed signal is:

[0079] 1. The corrected airspeed signal is subjected to high-pass filtering processing to obtain a corrected airspeed change rate signal, which can reduce the noise caused by directly obtaining a differential signal;

[0080] 2. The corrected airspeed change rate signal is subjected to amplitude limiting and multiplied by a corrected airspeed prediction gain to obtain a corrected airspeed prediction signal. The amplitude limiting link ensures the safety of the corrected airspeed change rate signal, and the corrected airspeed change rate signal is subjected to limited authority processing to prevent the possibility of control command saturation caused by signal mutation due to unstable atmospheric sensor or signal transmission in the flight control system. The corrected airspeed prediction gain can be selected according to the long-period damping characteristics of the aircraft itself and the speed interval of the high-speed protection;

[0081] 3. The corrected airspeed signal and the corrected airspeed prediction signal are added and then subtracted from the airspeed protection starting speed to obtain a corrected airspeed protection original control command. The airspeed protection starting speed is usually slightly greater than the maximum maneuvering limit speed of the aircraft, and the system automatically helps the aircraft to exit the overspeed state after fully prompting the pilot;

[0082] 4. The corrected airspeed protection original control command is subjected to low-pass filtering and amplitude limiting processing to obtain a corrected airspeed protection command. The speed response period of the aircraft is relatively long, and the frequency is relatively low, so the cut-off frequency of the selected low-pass filter can be appropriately reduced to further reduce high-frequency signal noise and improve signal quality. The amplitude limiter is designed to ensure safety and prevent the phenomenon of command saturation caused by signal errors;

[0083] On the other hand, the processing method of the Mach number signal is:

[0084] 5. The Mach number signal is subjected to high-pass filtering processing to obtain a corrected Mach number change rate signal, which can reduce the noise caused by directly obtaining a differential signal;

[0085] 6. The Mach number prediction signal is obtained by limiting the Mach number rate of change signal and multiplying it by the Mach number prediction gain. The limiting ensures the safety of the Mach number rate of change signal, and limits the possibility of control command saturation caused by signal mutation due to unstable atmospheric sensors or signal transmission in the flight control system. The Mach number prediction gain can be selected according to the long-period damping characteristics of the aircraft itself and the speed range of the high-speed protection;

[0086] 7. The Mach number protection original control command is obtained by adding the Mach number signal and the Mach number prediction signal and then subtracting the Mach number protection start speed. The normal airspeed protection start speed is slightly greater than the maximum maneuvering limit speed of the aircraft, and the system automatically helps the aircraft to exit the overspeed state after fully prompting the pilot;

[0087] 8. The Mach number protection command is obtained by low-pass filtering and limiting the Mach number protection original control command and then multiplying it by the Mach number conversion gain. The Mach number conversion gain converts the control command for the Mach number into a control command of the same order of magnitude as the corrected airspeed control command.

[0088] After completing the processing of the corrected airspeed signal and the corrected Mach number signal respectively, the corrected airspeed protection command and the Mach number protection command are obtained, and then the following operations are performed

[0089] 9. The speed protection control command is obtained by taking the greater of the corrected airspeed protection command and the Mach number protection command. Through the greater value logic, simultaneous protection of the corrected airspeed and the Mach number is realized, and the greater value is the high-speed protection command.

[0090] Step two:

[0091] 1. The high-speed protection pitch angle command is obtained by multiplying the high-speed protection command by the stick dynamic adjustment gain. The stick dynamic adjustment gain is adjusted in real time according to the stick displacement, and the pilot's driving intention is recognized by processing the stick displacement signal. If the stick displacement is in a positive large position, it means that the pilot still wants the aircraft to gain speed, and a larger gain should be used to protect the speed of the aircraft at this time; if the stick displacement is in a positive small position, it means that the pilot expects the aircraft to slowly pitch down to increase speed, and the gain should be reduced at this time to prevent the aircraft from quickly exiting the high-speed protection state, which is inconsistent with the pilot's expectation; if the stick displacement is near the neutral position, it means that the pilot considers that the automatic exit from the high-speed state at this time meets his expectation; if the stick displacement is in a negative position, it means that the pilot has an active intention to exit the high-speed state, and the dynamic adjustment gain remains at the gain when the stick is in the neutral position, helping the pilot to exit the high-speed protection state. By dynamically adjusting the speed protection control command, strong speed protection is provided during the pilot's stick pushing process, the aircraft response is smooth during the stick pulling process, and the pilot is assisted in exiting the high-speed protection state during the stick pulling process.

[0092] Step three:

[0093] 1. The corrected airspeed signal is passed through a speed hysteresis loop to obtain a speed protection start flag, and the specific logic is as follows:

[0094] (1) When the corrected airspeed signal is greater than the start threshold VW1, the speed protection start flag is set to TRUE;

[0095] (2) When the corrected airspeed signal is less than the exit threshold VW0, the speed protection start flag is set to FALSE;

[0096] (3) When the corrected airspeed signal is greater than or equal to the exit threshold VW0 and less than or equal to the start threshold VW1, the speed protection start flag takes the previous value.

[0097] 2. The Mach number signal is passed through a Mach number hysteresis loop to obtain a Mach number protection start flag, and the specific logic is as follows:

[0098] (1) When the Mach number signal is greater than the start threshold MW1, the Mach number protection start flag is set to TRUE;

[0099] (2) When the Mach number signal is less than the exit threshold MW0, the Mach number protection start flag is set to FALSE;

[0100] (3) When the Mach number signal is greater than or equal to the exit threshold MW0 and less than or equal to the start threshold MW1, the Mach number protection start flag takes the previous value.

[0101] 3. The high-speed protection start flag is determined by the speed protection start flag and the Mach number protection start flag, and the specific logic is as follows:

[0102] (1) The speed protection start flag is TRUE, or;

[0103] (2) The Mach number protection start flag is TRUE.

[0104] 4. The high-speed protection pitch angle stability command is determined according to the high-speed protection start flag, and the specific logic is as follows:

[0105] (1) When the high-speed protection start flag is TRUE, the pitch angle stability command is taken as the high-speed protection pitch angle stability command;

[0106] (2) When the high-speed protection start flag is FALSE, 0 is taken as the high-speed protection pitch angle stability command.

[0107] The selection of the pitch angle stability instruction should be adjusted according to the real-time pitch angle of the aircraft, so as to ensure that the aircraft response is soft and meets the expectation of the pilot, and the pitch angle stability instruction should not be greater than the real-time pitch angle of the aircraft by 5 degrees. When the value is too large, the aircraft response may produce a transient state when the aircraft initially enters the pitch angle; and when the value is too small, the aircraft may not be protected from exceeding the limit speed when the aircraft dives at a large attitude to enter the high-speed protection. The final pitch angle stability instruction of the aircraft should be selected according to the trim angle of attack and the resistance characteristic curve of the aircraft.

[0108] Step four:

[0109] 1. The high-speed protection pitch angle control instruction is obtained by subtracting the sum of the high-speed protection pitch angle instruction and the high-speed protection pitch angle stability instruction from the pitch angle of the aircraft.

[0110] 2. The high-speed protection overload instruction is obtained by multiplying the low-pass filtered high-speed protection pitch angle control instruction by an overload conversion gain. The low-pass filtering is to reduce the instruction mutation caused by the switching of the high-speed protection start switch, so that the aircraft response is smooth and free of transient states. The overload conversion gain should be matched and adjusted with the maximum negative overload value of the aircraft, and the matching principle should be that the overload instruction generated by the high-speed protection pitch angle control instruction at the maximum limit speed is consistent with the maximum limit negative overload instruction of the aircraft. After the gain matching is completed, the speed control function of the control stick can be realized during the high-speed protection process, and the speed perception of the pilot is enhanced.

[0111] 3. The high-speed protection overload instruction is connected to the C* main flight control law, and the high-speed protection control method of the large amphibious aircraft provided by the embodiment of the present application is realized.

[0112] As shown in Figure 3 , it is a control effect schematic diagram of the high-speed protection control method of the large amphibious aircraft provided by the embodiment of the present application. As shown in Figure 3 The simulation curve shows that initially, the aircraft is trimmed to fly at 430Km / h, and the limit speed of the aircraft is 495Km / h. The pilot pushes the control stick to 80% of the stroke at the 4th second and maintains for 26s, and releases the control stick at the 30th second. As shown in the figure, the flight speed of the aircraft is effectively limited within the limit speed, and when the position of the control stick remains constant, the speed of the aircraft is also stabilized at the instruction speed, realizing the speed instruction of the control stick. After the aircraft exits the high-speed protection, the aircraft is automatically stabilized to fly at a pitch angle of 3 degrees. The aircraft response is smooth throughout the process, which meets the expectation of the pilot.

[0113] The technical scheme provided by the embodiment of the present application has been verified by a plurality of test pilots, and they all agree that the present application has a remarkable effect on improving the safety of high-speed protection of large amphibious aircraft.

[0114] Although the present application has been described with reference to the above embodiments, the contents are only the embodiments for facilitating the understanding of the present application, and are not intended to limit the present application. Any modification and change in the form and details of the embodiments can be made by any person skilled in the art without departing from the spirit and scope of the present application. The patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A high-speed protection and control method for a large amphibious aircraft, characterized in that, include: After the aircraft enters the high-speed protection state, a high-speed protection pitch angle stabilization command is generated based on the aircraft's current pitch angle. The high-speed protection pitch angle stabilization command is superimposed with the high-speed protection pitch angle command generated based on the pilot's flight intention to generate a high-speed protection pitch angle control command. After the high-speed protection pitch angle control command is converted into a high-speed protection overload command, it is superimposed with the aircraft's main flight control law command to achieve a safe, efficient, and stable high-speed protection control function. The high-speed protection and control method for the large amphibious aircraft includes: Step 1: After filtering and correcting the aircraft airspeed and Mach number signals, obtain predictive airspeed and Mach number prediction signals. Compare these with the protection boundary speed thresholds and take the larger one as the high-speed protection command. Step 2: Adjust the high-speed protection command in real time according to the pilot's flight intentions, and convert the high-speed protection command into a high-speed protection pitch angle command; Step 3: After the aircraft enters the high-speed protection state, the generated high-speed protection pitch angle stabilization command is used to guide the aircraft into the stable pitch angle region; and after the high-speed protection state is exited, the aircraft is controlled to fly safely at a stable pitch angle. Step 4: Generate a high-speed protection pitch angle control command based on the high-speed protection pitch angle stabilization command generated in Step 2 and the high-speed protection pitch angle control command generated in Step 3. Then, after converting the high-speed protection pitch angle control command into a high-speed protection overload command, superimpose it with the aircraft's main flight control law command.

2. The high-speed protection and control method for large amphibious aircraft according to claim 1, characterized in that, Step 1 includes: Step 11: Based on the aircraft air data computer, the corrected airspeed signal and Mach number signal are acquired, and the corrected airspeed rate of change signal and Mach number rate of change signal are obtained by filtering through a high-pass filter. Step 12: After superimposing the corrected airspeed rate of change signal and the Mach number rate of change signal with the corrected airspeed signal and the Mach number signal in a one-to-one correspondence, the high-frequency noise is filtered out by a low-pass filter to obtain the corrected airspeed prediction signal and the Mach number prediction signal with prediction characteristics. Step 13: The difference between the corrected airspeed signal and the Mach number signal with predictive characteristics and the corrected airspeed protection boundary threshold and the Mach number protection boundary threshold is calculated one-to-one. The difference is then processed by unilateral amplitude limiting, and the larger difference is taken as the high-speed protection command.

3. The high-speed protection and control method for large amphibious aircraft according to claim 2, characterized in that, Step 13 involves processing the difference using unilateral limiting, including: When the corrected airspeed difference or Mach number difference is positive, the original corrected airspeed difference or Mach number difference is output after single-sided limiting processing. When the corrected airspeed difference or Mach number difference is negative or 0, the output is 0 after single-sided limiting.

4. The high-speed protection and control method for large amphibious aircraft according to claim 2, characterized in that, Step 2 includes: The high-speed protection command is dynamically adjusted based on the displacement of the control stick to generate a high-speed protection pitch angle command, which gradually increases as the amount of push increases; when the control stick is in the neutral position, the high-speed protection pitch angle command remains at the command value of the control stick in the neutral position.

5. The high-speed protection and control method for large amphibious aircraft according to claim 4, characterized in that, Step 3 includes: After the aircraft enters the high-speed protection state, a high-speed protection pitch angle stabilization command is generated based on the aircraft's current pitch angle. The high-speed protection pitch angle stabilization command gently guides the aircraft's pitch attitude into a stable pitch angle region. After the high-speed protection state is exited, the aircraft is controlled to fly safely with a stable pitch angle.

6. The high-speed protection and control method for large amphibious aircraft according to claim 5, characterized in that, Step 4 includes: Step 41: The high-speed protection pitch angle command and the high-speed protection pitch angle stabilization command are superimposed and the difference is calculated with the pitch angle. The pitch angle difference is then low-pass filtered to generate the high-speed protection pitch angle control command. Step 42: The high-speed protection pitch angle control command is converted into a high-speed protection overload command through gain, and the high-speed protection overload command is superimposed on the aircraft main control law command.

7. The high-speed protection and control method for a large amphibious aircraft according to any one of claims 1 to 6, characterized in that, Also includes: Determining whether an aircraft enters or exits high-speed protection mode includes: By performing speed hysteresis on the corrected airspeed signal and Mach number signal respectively, speed protection start flag and Mach number protection start flag are obtained through processing logic. Then, based on the logical judgment of the speed protection start flag and Mach number protection start flag, the high-speed protection start flag is obtained. Thus, the entry or exit of high-speed protection state is determined according to the high-speed protection start flag.

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