Leveling mode control method, system, storage medium and terminal device of aircraft

Abstract

The application discloses a method and system for controlling a flattening mode of an aircraft, a storage medium and a terminal device. The method comprises: generating a first control signal based on a current estimated vertical speed and a current target vertical speed determined according to an aircraft flattening trajectory curve; determining a pitch control correction under the action of wind interference based on a current track speed of the aircraft and an approach table speed; generating a second control signal according to the pitch control instruction and the pitch control correction; determining a gain adjustment coefficient based on dynamic simulation, generating a comprehensive control signal based on the sum of the first control signal and the second control signal and the gain adjustment coefficient, and providing a flight command for realizing accurate tracking of a current flight path of the aircraft and the aircraft flattening trajectory curve according to the comprehensive control signal. The application can effectively solve the problems of unstable flattening trajectory, inaccurate speed control and inability to ensure soft landing of the aircraft under extreme weather conditions in the flattening mode of the aircraft.

Description

Technical Field

[0001] This invention relates to the field of automatic landing and leveling guidance technology for aircraft, and in particular to a leveling mode control method, system, storage medium, and terminal device for aircraft. Background Technology

[0002] The approach and landing phase of civil aircraft is the most accident-prone and complex phase of flight. Due to the low altitude and complex environment during this phase, the safety requirements for the aircraft are the highest, especially during terminal approach, where all aircraft states must be maintained with high precision until they touch down accurately at a designated point. According to EASA's CS-AWO, the probability of an aircraft's landing touchdown point being within 60 meters of the runway threshold is no more than 10%. -5 The probability that the landing point is more than 823m away from the runway threshold is no more than 10%. -6 The probability that the distance between the outer landing gear and the runway centerline exceeds 21m when the aircraft touches down is no more than 10%. -5 Furthermore, the sinking rate upon landing, i.e., the vertical velocity, must not exceed the ultimate load.

[0003] Automatic balancing is a fundamental function required for Category III landings. Category III landings involve an aircraft automatically completing a precise approach and landing under extreme weather conditions. To improve flight safety and reduce pilot workload, all advanced civilian aircraft worldwide possess Category III automatic landing capabilities. For Category IIIA landings, the decision altitude is below 30m (100ft) or there is no decision altitude, and the runway visual range is not less than 200m (700ft). The ICAO Category IIIA automatic approach and landing mode's automatic control system controls the aircraft to fly along the approach trajectory until the main landing gear touches down. The balancing function is considered complete when the main landing gear tires touch the runway surface or when a go-around begins. The aircraft then uses the automatic balancing system to complete the automatic landing, and the pilot takes over control of the aircraft after touchdown. The implementation method of automatic balancing should approximate the manual landing method as closely as possible and consider the following requirements:

[0004] a) The automatic leveling function should be activated smoothly, and there should be no abrupt changes in the control signal that could cause a dive.

[0005] b) The transition process of altitude, vertical velocity, and pitch angle should be monotonous.

[0006] c) The process of the aircraft entering the runway centerline should be a near-periodic process on the horizontal plane.

[0007] d) The landing heading deviation should not exceed 3° upon landing.

[0008] The leveling-out phase is a crucial step in the aircraft's control mode and logic transition. It's not just a change in control method, but also a critical element with significant implications for flight safety. Therefore, the precision requirements for the automatic leveling-out control system are extremely high. The leveling-out phase is typically very short, leaving little time for the autopilot system to make corrections. Thus, ensuring control accuracy, safety, and passenger comfort is paramount. It is urgent to address issues such as unstable leveling trajectories, inaccurate speed control leading to a less smooth landing, and improved resistance to wind interference under extreme weather conditions. Summary of the Invention

[0009] This invention provides a method, system, storage medium, and terminal device for controlling the leveling mode of an aircraft, which can effectively solve the problems of unstable leveling trajectory, inaccurate speed control, and inability to ensure smooth landing of the aircraft under extreme weather conditions in current leveling mode.

[0010] According to one aspect of the present invention, a method for controlling the leveling mode of an aircraft is provided, the method comprising: generating a current estimated vertical speed based on the aircraft's current radio altitude and normal overload change; generating a first control signal based on the current estimated vertical speed and a current target vertical speed determined according to the aircraft's leveling trajectory curve; determining the aircraft's pitch control target and generating a pitch control command based on the pitch control target; determining a pitch control correction amount under wind interference based on the aircraft's current track speed and approach airspeed; generating a second control signal according to the pitch control command and the pitch control correction amount; determining a gain adjustment coefficient based on dynamic simulation; generating a comprehensive control signal based on the sum of the first control signal and the second control signal and the gain adjustment coefficient; and providing a flight command command based on the comprehensive control signal to achieve precise tracking of the current aircraft flight path and the aircraft's leveling trajectory curve.

[0011] Furthermore, determining the pitch control correction amount under wind interference based on the aircraft's current trajectory speed and approach airspeed includes: determining a first difference based on the difference between the aircraft's current trajectory speed and approach airspeed; and determining the pitch control correction amount under wind interference based on the first difference.

[0012] Further, determining the pitch control correction amount under wind interference based on the first difference includes: determining an estimated pitch control correction amount based on the first difference; determining whether the estimated pitch control correction amount exceeds a preset amplitude limit parameter; when the estimated pitch control correction amount does not exceed the preset amplitude limit parameter, using the estimated pitch control correction amount as the pitch control correction amount; when it is determined that the estimated pitch control correction amount exceeds the preset amplitude limit parameter, using the preset amplitude limit parameter as the pitch control correction amount.

[0013] Further, generating the second control signal based on the pitch control command and the pitch control correction includes: determining a first summation value based on the sum of the pitch control command and the pitch control correction; and determining the second control signal based on the first summation value.

[0014] Furthermore, determining the pitch control target of the aircraft and generating pitch control commands based on the pitch control target includes: obtaining the maximum leveling start altitude; determining the pitch control gain coefficient based on the maximum leveling start altitude and the current radio altitude of the aircraft; and determining the pitch control commands based on the pitch control gain coefficient and the pitch control target.

[0015] Further, determining the pitch control gain coefficient based on the maximum flattening start altitude and the aircraft's current radio altitude includes:

[0016] The current radio altitude of the aircraft is denoted as H. RA-LG Let the maximum starting height of the flattening be denoted as H. FLmax The pitch control gain coefficient is determined to be...

[0017] Furthermore, the step of generating the current estimated vertical velocity based on the aircraft's current radio altitude and normal overload change includes: filtering the radio altitude through a first filter to obtain a first filtering result; filtering the normal overload change through a second filter to obtain a second filtering result; and passing the first filtering result and the second filtering result through a preset first-order inertial element to generate the current estimated vertical velocity.

[0018] Further, the generation of the first control signal based on the current estimated vertical velocity and the current target vertical velocity determined according to the aircraft's flattened trajectory curve includes: based on Determine the current target's vertical velocity, where H represents the current target's vertical velocity. RA_LG H is the height from the lowest point of the aircraft's landing gear to the runway level. AS To flatten the height of the trajectory asymptote below the runway plane, T is the total time from the start of the flattening process to touchdown.

[0019] Determining the time constant T in the target's vertical velocity based on the aircraft's flattening trajectory curve includes: determining the asymptote of the flattening trajectory based on the aircraft's flattening trajectory curve. The asymptote of the flattened trajectory can be derived as follows:

[0020] T is the time constant of the target's vertical velocity, where H(0) is the starting height of the flattening relative to the asymptote of the flattening trajectory. fl(0) V is the flattening height of the aircraft relative to the runway plane at the initial flattening moment. Zfl(0) Vztdgiv is the vertical velocity latched by the flight control computer when the leveling mode is engaged, and Vztdgiv is the target vertical velocity at the moment of touchdown, which is determined based on flight quality requirements and the aircraft's ultimate load. The given leveling trajectory ends at the moment the main landing gear tires contact the runway surface.

[0021] The target's vertical velocity can be determined based on the time constant T.

[0022] A second difference is determined based on the difference between the current estimated vertical velocity and the current target vertical velocity;

[0023] The first control signal is determined based on the second difference.

[0024] According to another aspect of the present invention, a leveling-out mode control system for an aircraft is provided, comprising: a predicted vertical speed generation module for generating a current predicted vertical speed based on the aircraft's current radio altitude and normal overload change; a first control signal generation module for generating a first control signal based on the current predicted vertical speed and a current target vertical speed determined according to the aircraft's leveling-out trajectory curve; a pitch control command generation module for determining the aircraft's pitch control target and generating a pitch control command based on the pitch control target; a pitch control correction determination module for determining a pitch control correction under wind interference based on the aircraft's current trajectory speed and approach airspeed; a second control signal generation module for generating a second control signal according to the pitch control command and the pitch control correction; a comprehensive control signal generation module for determining a gain adjustment coefficient based on dynamic simulation and generating a comprehensive control signal based on the sum of the first control signal and the second control signal and the gain adjustment coefficient; and a flight command providing module for providing a flight command based on the comprehensive control signal to achieve accurate tracking of the current aircraft flight path and the aircraft's leveling-out trajectory curve.

[0025] According to another aspect of the present invention, a storage medium is provided, wherein a plurality of instructions are stored therein, the instructions being adapted to be loaded by a processor to execute a leveling mode control method for any of the above-described aircraft.

[0026] According to another aspect of the present invention, a terminal device is provided, comprising a processor and a memory, the processor being electrically connected to the memory, the memory being used to store instructions and data, and the processor being used to execute steps in the leveling mode control method of any of the above-mentioned aircraft.

[0027] The advantages of this invention are as follows: the first control signal generates the current estimated vertical speed based on the aircraft's current radio altitude and normal overload change; the current estimated vertical speed is determined based on the current estimated vertical speed and the aircraft's normal overload change; the current estimated vertical speed signal is generated by two different sensors, and the influence of the aircraft's normal overload change on the current estimated vertical speed is considered, which can compensate for the delay of the vertical speed signal obtained from the radio altimeter; and by setting the pitch control correction, the impact of wind interference on the leveling mode is precisely controlled. Through the first control signal, the second control signal, and the comprehensive control signal determined based on the gain adjustment coefficient determined by dynamic simulation, precise control of the leveling trajectory can be ensured to guarantee the smoothness of the leveling process and the aircraft's gentle landing, and to ensure the ability to resist wind interference under extreme weather conditions. Attached Figure Description

[0028] The technical solution and other beneficial effects of the present invention will become apparent from the following detailed description of specific embodiments of the invention, in conjunction with the accompanying drawings.

[0029] Figure 1 A flowchart illustrating the steps of the flight leveling mode control method for an aircraft provided in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of the trajectory curve of an aircraft in accordance with an embodiment of the present invention.

[0031] Figure 3 This is a logic diagram of the flattening mode startup provided in an embodiment of the present invention.

[0032] Figure 4 This is a logic device diagram of a flight leveling mode control method provided in an embodiment of the present invention. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0035] See now Figure 1 , Figure 1 This is a flowchart illustrating the steps of a flight leveling mode control method for an aircraft provided in an embodiment of the present invention. The method includes:

[0036] Step S110: Generate the current estimated vertical speed based on the aircraft's current radio altitude and normal overload change.

[0037] For example, the current vertical speed is determined by the radio altitude obtained from the aircraft's radio altimeter and the changes in radio altitude at different times. In some embodiments, the current vertical speed can be obtained by aggregating the radio altitudes at different times to form the aircraft's trajectory and taking the derivative of the trajectory. The present invention does not limit the method of obtaining the current vertical speed from the radio altitude. After determining the current vertical velocity based on the radio altitude obtained from the aircraft's radio altimeter, the current vertical velocity is further corrected based on the change in normal overload, which is determined by the aircraft's inertial navigation system. The delay in the current vertical velocity signal determined by the radio altimeter is compensated by the acceleration signal directly determined by the aircraft's accelerometer. Specifically, the current reference vertical velocity is obtained by adding the current acceleration signal obtained from the change in normal overload to the current vertical velocity determined by the radio altimeter at a certain time scale. The sum of the two is used to obtain a current reference vertical velocity. After comparing and correcting the current vertical velocity with the current reference vertical velocity, the current estimated vertical velocity is obtained. Thus, the current estimated vertical velocity can compensate for the delay in the vertical velocity signal determined by the radio altimeter.

[0038] In some embodiments, step S110 further includes the following steps:

[0039] The radio altitude is filtered by a first filter to obtain a first filtering result.

[0040] For example, the first filter has a time constant of T. H Differential filter, time constant T HThere are two possible values, one for T when the flattening mode is activated. H1 When the flattening mode is not connected, the value T is taken. H2 T H2 >T H1 When not connected, the time constant is relatively large. Therefore, the control system's sensitivity to obstacles around the airport does not need to be too high before the aircraft passes the runway threshold. After the leveling mode is triggered and connected, the time constant T... H The value is relatively small to ensure that the control system has a high sensitivity to obstacles around the airport after the aircraft flies over the runway threshold.

[0041] The normal overload change is filtered by a second filter to obtain a second filtering result.

[0042] For example, the second filter has a time constant of T. nz The low-pass filter is then filtered by the second filter to obtain the second filtering result.

[0043] The first filtering result and the second filtering result are summed to generate the current estimated vertical velocity.

[0044] For example, the acceleration signal obtained by the accelerometer is fed back and added to the signal generated by the differential filtering of the radio altimeter to obtain the current estimated vertical velocity, so as to ensure that the current estimated vertical velocity can compensate for the delay of the vertical velocity signal determined by the radio altimeter.

[0045] Step S120: Generate a first control signal based on the current estimated vertical velocity and the current target vertical velocity determined according to the aircraft's flattened trajectory curve.

[0046] For example, Figure 2 This is a schematic diagram of the trajectory curve of an aircraft in accordance with an embodiment of the present invention, as shown below. Figure 2 As shown, the aircraft first flies along the glide path. When the leveling mode is triggered, the aircraft flies along the leveling path, thus entering the automatic landing leveling mode. The automatic landing leveling mode uses an exponential curve landing trajectory. The leveling trajectory calculation program starts from the moment the leveling mode is triggered. From the start of leveling, the vertical velocity commanded by the aircraft at each moment of descent is proportional to the current altitude. Based on this relationship, a schematic diagram of the leveling trajectory curve is obtained to show the aircraft's landing trajectory. According to the leveling trajectory curve, the aircraft's flight time and flight displacement curves are obtained. Therefore, based on the curve determined by the flight time and flight displacement, combined with the relationship between the motion moment and displacement, the vertical velocity at a certain motion moment can be determined, which is the aircraft's current target vertical velocity.

[0047] In some embodiments, generating the first control signal based on the current estimated vertical velocity and the current target vertical velocity determined according to the aircraft's flattened trajectory curve includes the following steps:

[0048] in accordance with Determine the current target's vertical velocity, where H represents the current target's vertical velocity. RA_LG H is the current radio altitude, which is the height from the lowest point of the aircraft's landing gear to the runway level. AS To flatten the height of the trajectory asymptote below the runway plane, T is the total time from the start of the flattening process to the touchdown.

[0049] For example, please refer to the schematic diagram of the aircraft's flattening trajectory curve. Based on the aircraft's flattening trajectory curve, H RA-LG H is the height from the lowest point of the landing gear to the runway level. It can be obtained from the aircraft's radio altitude and geometric data. RA_LG H AS It is the height at which the asymptote of the flattened trajectory is below the runway plane; assuming the target's vertical velocity at the given touchdown moment is V. ztdgiv Then the height H of the asymptote AS =-T·V ztdgiv Therefore, it is possible to obtain H AS After obtaining the value, substitute it into the above calculation formula to obtain the current target vertical velocity.

[0050] A second difference is determined based on the difference between the current estimated vertical velocity and the current target vertical velocity.

[0051] For example, the difference between the current estimated vertical velocity and the current target vertical velocity is calculated, and this difference is used as the second difference.

[0052] The first control signal is determined based on the second difference.

[0053] For example, let the current estimated vertical velocity be denoted as Let the current target's vertical velocity be... The target vertical acceleration increment is negatively correlated with the second difference, and is denoted as Δa. zgiv ,but Let Δa be the change in acceleration directly determined by the accelerometer of the aircraft. z Then, based on the target vertical acceleration increment Δa zgiv The change in acceleration Δa directly determined by the accelerometer of the aircraft z The difference is used to determine a third difference value, and based on this third difference value, a first control signal is determined. In some embodiments, the third difference value can be directly used as the first control signal. The acceleration change directly determined from the aircraft's accelerometer is introduced as Δa.z As the first control signal, the variable can reduce turbulence and improve dynamic accuracy.

[0054] Step S130: Determine the pitch control target of the aircraft and generate pitch control commands based on the pitch control target.

[0055] For example, the pitch control command generated based on the pitch control target is designed to change smoothly within a range not exceeding the pitch control target, so as to ensure the smoothness of the pitch angle change.

[0056] In some embodiments, determining the pitch control target of the aircraft and generating pitch control commands based on the pitch control target includes the following steps:

[0057] Obtain the maximum flattening start altitude, and determine the pitch control gain coefficient based on the maximum flattening start altitude and the current radio altitude of the aircraft.

[0058] For example, the maximum leveling start altitude is the altitude at which the aircraft triggers and enters leveling mode. The pitch control target is determined by the landing reference speed of the aircraft and the current center of gravity position of the aircraft. The correction of the pitch control target can adjust the vertical velocity at the ground and the longitudinal distance of the grounding point to ensure a smooth change in the pitch angle.

[0059] Based on the pitch control gain coefficient and the pitch control target, the pitch control command is determined.

[0060] For example, the pitch control command can be determined by the product of the pitch control gain coefficient and the pitch control target.

[0061] In some embodiments, determining the pitch control gain coefficient based on the maximum flattening start altitude and the aircraft's current radio altitude includes the following steps:

[0062] The current radio altitude of the aircraft is denoted as H. RA-LG Let the maximum starting height of the flattening be denoted as H. FLmax The pitch control gain coefficient is determined to be...

[0063] For example, the pitch control gain coefficient is To ensure a smooth change in the reference pitch angle, starting from the maximum leveling height, the pitch program controls the pitch angle to transition from 0 to the target attitude angle at ground contact, i.e., pitch control target.

[0064] Step S140: Based on the aircraft's current trajectory speed and approach airspeed, determine the pitch control correction amount under wind interference.

[0065] For example, the difference between the current flight path speed of the aircraft obtained from the inertial navigation system and the approach speed can be used as a characterization of the deviation between the current flight path speed and the approach speed given by the pilot from the automatic control system console, so as to correct the pitch angle under wind interference.

[0066] In some embodiments, determining the pitch control correction amount under wind interference based on the aircraft's current trajectory speed and approach airspeed includes the following steps:

[0067] The first difference is determined based on the difference between the aircraft's current trajectory speed and the approach description.

[0068] For example, the difference between the two can be used as the deviation between the current track speed and the approach speed given by the pilot from the automatic control system console, and determined as the first difference.

[0069] Based on the first difference, the pitch control correction amount under wind interference is determined.

[0070] For example, the pitch control correction under wind disturbance is generated using the first difference as a variable.

[0071] In some embodiments, determining the pitch control correction amount under wind interference based on the first difference includes the following steps:

[0072] Based on the mathematical simulation results under wind interference, the pitch control correction coefficient is determined.

[0073] For example, the pitch control correction coefficient is adjusted based on simulation and flight test to ensure that the pitch angle meets the pitch control target limit of the ground vertical velocity requirement under wind interference.

[0074] Based on the first difference and the pitch control correction coefficient, the estimated pitch control correction amount is determined.

[0075] For example, the estimated pitch control correction is related to the product of the pitch control correction coefficient and the first difference, and the estimated pitch control correction is the pitch correction under wind interference.

[0076] Determine whether the estimated pitch control correction is less than the preset amplitude limit parameter.

[0077] For example, by setting a preset amplitude limit parameter, the maximum value of the pitch control correction is limited, so that the wind interference-related correction has a certain amplitude limit.

[0078] When the estimated pitch control correction is less than the preset amplitude limit parameter, the estimated pitch control correction is used as the pitch control correction.

[0079] For example, using the estimated pitch control correction amount that is less than the preset amplitude limit parameter as the pitch control correction amount ensures that the pitch control correction amount meets the amplitude condition, making the aircraft more adaptable to changes in extreme weather conditions.

[0080] In some embodiments, when it is determined that the estimated pitch control correction amount is greater than a preset amplitude limit parameter, the preset amplitude limit parameter is used as the pitch control correction amount.

[0081] For example, the estimated pitch control correction amount that is greater than the preset amplitude limit parameter is discarded, and the preset amplitude limit parameter is used as the pitch control correction amount to ensure that the pitch control correction amount meets the amplitude condition, so that the aircraft can better adapt to changes in extreme weather conditions.

[0082] Step S150: Generate a second control signal based on the pitch control command and the pitch control correction.

[0083] For example, the pitch control command ensures a smooth change in the reference pitch angle. Starting from the maximum flattening height, the pitch program controls the pitch angle to transition from 0 to the target attitude angle at ground level, i.e., the pitch control target. The pitch control correction is the pitch correction under wind interference. Thus, in some embodiments, the second control signal can be set to be positively correlated with the pitch control command and the pitch control correction by a preset proportional coefficient.

[0084] In some embodiments, generating a second control signal based on the pitch control command and the pitch control correction includes the following steps:

[0085] The first summation value is determined based on the sum of the pitch control command and the pitch control correction.

[0086] For example, the sum of the pitch control command and the pitch control correction amount can be used as the first sum value. Alternatively, the first sum value can be set to be positively correlated with the sum of the pitch control command and the pitch control correction amount. This invention does not limit this.

[0087] The second control signal is determined based on the first sum value.

[0088] For example, the result of the first summation can be used as the second control signal, or the second control signal can be set to be positively correlated with the result of the first summation; the present invention does not limit this.

[0089] Step S160: Determine the gain adjustment coefficient based on dynamic simulation, and generate a comprehensive control signal based on the sum of the first control signal and the second control signal and the gain adjustment coefficient.

[0090] For example, the flattening dynamics are significantly improved by combining the first and second control signals. Based on the gain adjustment coefficient and the sum of the first and second control signals to generate a comprehensive control signal, the control law for the elevator channel in this control mode consists of two parts: a closed-loop control loop determined by the first control signal and an open-loop control loop determined by the second control signal. The closed-loop control loop corrects the approach trajectory and ensures the aircraft has a given vertical velocity upon landing, guaranteeing a smooth landing and not exceeding structural load limits. The open-loop control loop ensures the aircraft flies along the planned path.

[0091] In some embodiments, determining the time constant T in the target's vertical velocity based on the flattened trajectory curve of the aircraft includes the following steps:

[0092] The asymptote of the flattening trajectory is determined based on the flattening trajectory curve of the aircraft. The asymptote of the flattened trajectory can be derived as follows:

[0093] T is the time constant of the target's vertical velocity, where H(0) is the starting height of the flattening relative to the asymptote of the flattening trajectory. fl(0) V is the flattening height of the aircraft relative to the runway plane at the initial flattening moment. Zfl(0) Vztdgiv is the vertical velocity latched by the flight control computer when the leveling mode is engaged, and Vztdgiv is the target vertical velocity at the moment of touchdown, which is determined based on flight quality requirements and the aircraft's ultimate load. The given leveling trajectory ends at the moment the main landing gear tires contact the runway surface.

[0094] For example, the initial leveling height of the aircraft relative to the runway plane at the initial leveling moment depends on the signal command to enter the automatic leveling mode. This signal command is derived from the judgment logic of the automatic leveling mode activation. After entering the automatic leveling mode, the aircraft performs leveling landing according to the planned flight path and speed command.

[0095] Figure 3 Here is a logic diagram of the flattening mode startup provided in an embodiment of the present invention, as follows: Figure 3 As shown, in some embodiments, the judgment logic for starting the leveling mode is as follows: 1. The leveling start height is greater than the landing gear ground clearance, where the leveling start height Hfl(0) = -KVz × (vertical velocity at the initial leveling moment - target vertical velocity at the given ground contact moment); 2. The leveling start height is greater than 10m and less than 16m; where the parameter KVz = T, T is a time constant value, generally taken as 4~6s. Therefore, the flight control computer decides to level the aircraft by monitoring the vertical velocity and altitude of the aircraft at the current moment in real time, and stores the leveling height and vertical velocity at this moment. The height at the leveling moment is the leveling start height.

[0096] Step S170: Based on the integrated control signal, provide a flight command to accurately track the current flight path of the aircraft with the trajectory curve of the aircraft.

[0097] For example, the integrated control signal is directly used as an input signal to the flight control computer to provide flight command commands that enable precise tracking of the current flight path of the aircraft with the flattened trajectory curve of the aircraft.

[0098] Figure 4 This is a logic diagram of a flight vehicle leveling mode control method provided in an embodiment of the present invention. The landing gear ground clearance H is obtained by data correction based on the current radio altitude of the flight vehicle. RA-LG The system employs a differential filter to filter the aircraft's normal overload change obtained from the inertial navigation system (INS), multiplies it by gravitational acceleration, and then filters it through a low-pass filter. Differential filtering of the landing gear ground clearance is combined with low-pass filtering of the INS' vertical acceleration to generate the current estimated vertical velocity. The current target vertical velocity is calculated using an exponentially flattened trajectory function; the difference between the two is the target vertical acceleration increment. The vertical acceleration change monitored in real-time by the INS, which is directly determined by the aircraft's accelerometers, is compared with the target vertical acceleration increment to form the control signal for the closed-loop control loop. Open-loop control is used to programmatically control the pitch attitude, ensuring the aircraft flies along the planned path. Deviations between the aircraft's approach trajectory velocity and indicated airspeed are corrected, enhancing the robustness of open-loop control against wind interference. The sum of the open-loop control signal and the closed-loop control signal, multiplied by a gain adjustment coefficient, yields the control command for the automatic leveling mode. The current estimated vertical velocity signal is generated by two different sensors, and the influence of the aircraft's normal overload variation on the current estimated vertical velocity is considered. This can compensate for the delay of the vertical velocity signal obtained through the radio altimeter. Furthermore, by setting the pitch control correction, the impact of wind interference on the leveling mode is precisely controlled. Through the first control signal, the second control signal, and the comprehensive control signal determined based on the gain coefficient determined by dynamic simulation, precise control of the leveling trajectory can be ensured to guarantee the smoothness of the leveling process and the aircraft's gentle grounding, as well as the ability to resist wind interference under extreme weather conditions.

[0099] Another embodiment of the present invention provides a leveling-out mode control system for an aircraft, comprising: a predicted vertical speed generation module for generating a current predicted vertical speed based on the aircraft's current radio altitude and normal overload change; a first control signal generation module for generating a first control signal based on the current predicted vertical speed and a current target vertical speed determined according to the aircraft's leveling-out trajectory curve; a pitch control command generation module for determining the aircraft's pitch control target and generating a pitch control command based on the pitch control target; a pitch control correction determination module for determining a pitch control correction under wind interference based on the aircraft's current trajectory speed and approach airspeed; a second control signal generation module for generating a second control signal according to the pitch control command and the pitch control correction; a comprehensive control signal generation module for determining a gain adjustment coefficient based on dynamic simulation and generating a comprehensive control signal based on the sum of the first and second control signals and the gain adjustment coefficient; and a flight command provision module for providing a flight command based on the comprehensive control signal to achieve accurate tracking of the current aircraft flight path and the aircraft's leveling-out trajectory curve.

[0100] According to another aspect of the present invention, a storage medium is provided, wherein a plurality of instructions are stored therein, the instructions being adapted to be loaded by a processor to execute a leveling mode control method for any of the above-described aircraft.

[0101] According to another aspect of the present invention, a terminal device is provided, comprising a processor and a memory, the processor being electrically connected to the memory, the memory being used to store instructions and data, and the processor being used to execute steps in the leveling mode control method of any of the above-mentioned aircraft.

[0102] The first control signal of this invention generates the current estimated vertical speed based on the aircraft's current radio altitude and normal overload change. The current estimated vertical speed is determined jointly based on the current estimated vertical speed and the aircraft's normal overload change. This current estimated vertical speed signal is generated by two different sensors, and the influence of the aircraft's normal overload change on the current estimated vertical speed is considered. This compensates for the delay in the vertical speed signal obtained from the radio altimeter. Furthermore, by setting pitch control corrections, the impact of wind interference on the leveling-off mode is precisely controlled. Through the first control signal, the second control signal, and the comprehensive control signal determined based on the gain adjustment coefficient determined by dynamic simulation, precise control of the leveling-off trajectory can be ensured, guaranteeing smoothness during the leveling-off process and a gentle landing of the aircraft, while also ensuring resistance to wind interference under extreme weather conditions.

[0103] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0104] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A method for controlling the leveling mode of an aircraft, characterized in that, The method includes: The current estimated vertical speed is generated based on the aircraft's current radio altitude and normal overload change. The first control signal is generated based on the current estimated vertical velocity and the current target vertical velocity determined according to the aircraft's flattened trajectory curve; The aircraft's pitch control target is adjusted based on the aircraft's approach and landing speed and center of gravity position; the maximum leveling start altitude is obtained; and the aircraft's current radio altitude is recorded as... The maximum starting height for leveling is denoted as The pitch control gain coefficient is determined to be... Based on the pitch control gain coefficient and the pitch control target, determine the pitch control command; Based on the aircraft’s current trajectory speed and approach airspeed, determine the pitch control correction amount under wind interference; A second control signal is generated based on the pitch control command and the pitch control correction. The gain adjustment coefficient is determined based on dynamic simulation, and a comprehensive control signal is generated based on the sum of the first control signal and the second control signal and the gain adjustment coefficient. Based on the integrated control signals, flight command commands are provided to achieve precise tracking of the current flight path of the aircraft with the flattened trajectory curve of the aircraft.

2. The aircraft leveling mode control method according to claim 1, characterized in that, The determination of pitch control corrections under wind interference based on the aircraft's current trajectory speed and approach airspeed includes: The first difference is determined based on the difference between the aircraft's current trajectory speed and its approach indicated speed; Based on the first difference, the pitch control correction amount under wind interference is determined.

3. The aircraft leveling mode control method according to claim 2, characterized in that, The step of determining the pitch control correction amount under wind interference based on the first difference includes: Based on the mathematical simulation results under wind interference, the pitch control correction coefficient is determined; Based on the first difference and the pitch control correction coefficient, the estimated pitch control correction amount is determined; Determine whether the estimated pitch control correction exceeds the preset amplitude limit parameter; When the estimated pitch control correction amount does not exceed the preset amplitude limit parameter, the estimated pitch control correction amount is used as the pitch control correction amount; when it is determined that the estimated pitch control correction amount exceeds the preset amplitude limit parameter, the amplitude limit parameter is used as the pitch control correction amount.

4. The aircraft leveling mode control method according to claim 1, characterized in that, The step of generating a second control signal based on the pitch control command and the pitch control correction includes: The first summation value is determined based on the sum of the pitch control command and the pitch control correction. The second control signal is determined based on the first sum value.

5. The flight leveling mode control method for an aircraft according to claim 1, characterized in that, The generation of the current estimated vertical velocity based on the aircraft's current radio altitude and normal overload change includes: The radio altitude is filtered through a first filter to obtain a first filtering result; The normal overload change is filtered by a second filter to obtain a second filtering result. The first and second filtering results are passed through a preset first-order inertial element to generate the current estimated vertical velocity.

6. The aircraft leveling mode control method according to claim 1, characterized in that, The generation of the first control signal based on the current estimated vertical velocity and the current target vertical velocity determined according to the aircraft's flattened trajectory curve includes: The vertical velocity of the current target can be determined based on the exponentially flattened trajectory curve. ,in The current target's vertical velocity, The height of the lowest point of the aircraft's landing gear from the runway level. To level the height of the trajectory asymptote below the runway plane, The time constant of the target's vertical velocity represents the total time from the start of the flattening process to grounding. Based on the time constant Determine the target's vertical velocity; A second difference is determined based on the difference between the current estimated vertical velocity and the current target vertical velocity; The first control signal is determined based on the second difference.

7. The flight leveling mode control method for an aircraft according to claim 6, characterized in that, The time constant in the vertical velocity of the target is determined based on the flattened trajectory curve of the aircraft. ,include: The asymptote of the flattening trajectory is determined based on the flattening trajectory curve of the aircraft. ; The asymptote of the flattened trajectory is derived as follows ; Let be the time constant of the target's vertical velocity, where The starting height for flattening is relative to the asymptote of the flattening trajectory. The flattening height of the aircraft relative to the runway plane at the initial flattening moment. The vertical speed latched by the flight control computer when the leveling mode is activated. The target vertical velocity at the moment of touchdown is determined based on flight quality requirements and the aircraft's ultimate load, given the moment when the flattening trajectory ends at the moment the main landing gear tires contact the runway surface.

8. A leveling mode control system for an aircraft, characterized in that, include: The estimated vertical velocity generation module is used to generate the current estimated vertical velocity based on the aircraft's current radio altitude and normal overload change; The first control signal generation module is used to generate a first control signal based on the current estimated vertical velocity and the current target vertical velocity determined according to the flattened trajectory curve of the aircraft. The pitch control command generation module is used to determine the pitch control target of the aircraft and generate pitch control commands based on the pitch control target; The pitch control correction determination module is used for: adjusting the pitch control target of the aircraft based on the aircraft's approach and landing speed and center of gravity position; obtaining the maximum leveling start altitude; and recording the aircraft's current radio altitude as... The maximum starting height for leveling is denoted as The pitch control gain coefficient is determined to be... Based on the pitch control gain coefficient and the pitch control target, determine the pitch control command; The second control signal generation module is used to generate a second control signal based on the pitch control command and the pitch control correction amount. The integrated control signal generation module is used to determine the gain adjustment coefficient based on dynamic simulation, and to generate an integrated control signal based on the sum of the first control signal and the second control signal and the gain adjustment coefficient. The flight command providing module is used to provide flight command commands based on the integrated control signals to achieve precise tracking of the current flight path of the aircraft with the flattened trajectory curve of the aircraft.

9. A storage medium, characterized in that, The storage medium stores multiple instructions, which are adapted to be loaded by a processor to execute the leveling mode control method for the aircraft according to any one of claims 1 to 7.

10. A terminal device, characterized in that, It includes a processor and a memory, the processor being electrically connected to the memory, the memory being used to store instructions and data, and the processor being used to execute the steps in the flattening mode control method for the aircraft according to any one of claims 1 to 7.

Images