METHOD AND SYSTEM FOR REDUCING AERODYNAMIC LOADS EXERCISED ON AN AIRCRAFT BY ATMOSPHERIC TURBULENCE.
The aerodynamic load reduction system addresses the challenge of wind gust-induced loads by using sensor-derived control commands to adjust aircraft control surfaces, achieving up to 70% load reduction and improved comfort.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- AIRBUS OPERATIONS (SAS)
- Filing Date
- 2024-04-05
- Publication Date
- 2026-04-10
AI Technical Summary
Existing aircraft designs face challenges in effectively reducing aerodynamic loads and passenger discomfort caused by atmospheric turbulence, particularly wind gusts, while balancing structural resistance and weight to minimize fuel consumption.
An aerodynamic load reduction system using electronic circuitry detects atmospheric turbulence through sensors, calculates control commands based on vertical wind speed derivatives, and adjusts control surfaces to mitigate these loads, optimizing the load factor and passenger comfort.
The system significantly reduces aerodynamic loads by up to 70% and enhances passenger comfort by anticipating and counteracting wind gusts, allowing for a lighter aircraft structure and reduced fuel consumption.
Smart Images
Figure 00000017_0000 
Figure 00000017_0001 
Figure 00000017_0002
Abstract
Description
Title of the invention: Method and system for reducing aerodynamic loads exerted on an aircraft by atmospheric turbulence. technical field
[0001] The present invention relates to a method and a system for reducing loads exerted on an aircraft by atmospheric turbulence, and in particular by gusts of wind. STATE OF PRIOR ART
[0002] During flight, aircraft are often confronted with atmospheric turbulence (e.g., wind shear, wind gradients, free air turbulence, wake turbulence, air pockets, etc.). Atmospheric turbulence can include vertical and horizontal wind shear or wind gusts.
[0003] Wind gusts generate aerodynamic loads on the structure of aircraft, and in particular the wing (i.e., aircraft wings). In particular, wind gusts cause mechanical stresses on the aircraft structure, as well as discomfort for passengers (e.g., jolts felt when the aircraft passes through a wind gust zone) and a reduction in its aerodynamic performance in flight.
[0004] For economic and environmental reasons, reducing fuel consumption is a factor that must be taken into account in aircraft design. To this end, the aircraft structure must be able to withstand the aerodynamic loads exerted by wind gusts while being sufficiently light to limit fuel consumption.
[0005] One solution that allows for a compromise between reducing the load factor (i.e., increasing the aircraft structure's resistance to wind gusts) and reducing the aircraft's weight is the application of Gust Load Alleviation (GLA) strategies. A GLA strategy involves using aircraft sensors to provide control commands that allow the aircraft's control surfaces (e.g., inboard or outboard ailerons, elevators) to be deflected according to wind conditions. More specifically, sensors (e.g., aerodynamic data sensors, accelerometers, etc.) placed on the aircraft's fuselage or wings detect wind conditions and provide information on the aerodynamic loads exerted on the aircraft.This information is then transmitted to an aircraft avionics system for... triggering the deflection of the control surfaces at a specific angle, depending in particular on wind conditions. This makes it possible to create the aerodynamic forces and moments necessary to mitigate the additional aerodynamic load induced by wind gusts. The control surfaces are then used as control surfaces to reduce the aerodynamic loads induced by wind gusts.
[0006] Control commands for reducing wind gust loads can be established according to various well-known control laws. For example, a control law is known that is based on estimating the wind angle of attack using an angle-of-attack probe located at the nose of the aircraft. A control elevator and aileron command is then generated based on the wind angle of attack to reduce wind gust loads on the aircraft, primarily at the wing root.
[0007] However, it is desirable to provide a solution that improves the effectiveness of existing strategies for alleviating loads due to wind gusts. In particular, it is desirable to provide a strategy for alleviating loads due to wind gusts that optimizes the reduction of the load factor and improves passenger comfort. Description of the invention
[0008] A method for reducing the aerodynamic loads exerted on an aircraft in flight by atmospheric turbulence is proposed herein, said method being implemented by an aerodynamic load reduction system in the form of electronic circuitry, said method comprising: (i) detection of atmospheric turbulence, and (ii) a reduction of aerodynamic loads, said detection comprising the following steps: - receiving from a measuring system information representative of a current vertical wind speed, - compare said current vertical wind speed to a predetermined threshold, - determine the presence of atmospheric turbulence if said current vertical wind speed exceeds a predetermined threshold, said reduction of aerodynamic loads including: - estimate a first derivative of said current vertical wind speed, - calculate a steering command at least from the first derivative of said current vertical wind speed, - provide said control command for a deflection of at least one control surface of the aircraft according to said control command, said reduction of aerodynamic loads being executed when said current vertical wind speed is greater than the predetermined threshold, otherwise said detection is repeated.
[0009] Advantageously, it is possible to reduce the aerodynamic load factor exerted on the aircraft. By thus reducing the load factor, it is possible to obtain a gain in the structural mass of the aircraft, but also to improve passenger comfort when the aircraft passes through an area of atmospheric turbulence.
[0010] According to a particular embodiment, said steering command is expressed according to the following equation: . / / / \ / Lnf \ \ (M)\ / / \ / L„f \ A / «(o \ ] With: Jl- H; ; v—J / - representing a gain for optimizing the reduction of the wind gust load factor; - Cm^ corresponding to a moment gradient in effect of pitch velocity variation of the complete aircraft expressed at an aerodynamic center in effect of angle of attack; - Cmq corresponding to a moment gradient in effect of pitch velocity of the complete aircraft expressed at the aerodynamic center in effect of angle of attack; - Cm* corresponding to a moment gradient in effect of variation of the complete aircraft expressed at the aerodynamic focus in effect of the angle of attack; - Cm^ corresponding to a moment gradient in the effect of steering of said at least one control surface of the complete aircraft expressed at the aerodynamic focus in effect of angle of attack; - V representing the actual speed of the aircraft; - Lref corresponding to a reference length; - Ta representing the travel time of the wind from the nose of the aircraft to the aerodynamic focus in terms of angle of attack; - u(t) corresponding to the current vertical wind speed at time t; - il(f) corresponding to the first derivative of the current vertical wind speed u(t); " «( / ) corresponding to a second derivative of the current vertical wind speed u(t).
[0011] According to a particular embodiment, the gain Kw,inrfest is expressed according to the following equation: \ and the optimized steering order is then expressed according to the following equation ^wind — A Cn^Cm^ / : s Cm'“ \ f Lref j W 1 , I Cmv \ f Lref j 2 । f V ^mnd-opt ' \ \ Cmsq ] ' V / J \ V / [ y Cm^ / \ Cnï^Crn^ / ' /
[0012] According to a particular embodiment, said detection of the presence of atmospheric turbulence and said reduction of aerodynamic loads are repeated at a predetermined frequency (At).
[0013] According to a particular embodiment, the measurement system includes a light detection and telemetry system configured to obtain said information representative of the current vertical wind speed.
[0014] According to a particular embodiment, the measurement system comprises a set of incidence probes configured to measure an angle of incidence of the wind from which said information representative of the current vertical wind speed is obtained.
[0015] Also proposed here is a system for reducing the aerodynamic loads exerted on an aircraft in flight by atmospheric turbulence, said system comprising electronic circuitry configured to: (i) perform a detection of atmospheric turbulence, and (ii) perform a reduction of aerodynamic loads, said detection comprising the following steps: - to receive information from a measurement system that is representative of a current vertical wind speed, - compare said current vertical wind speed to a predetermined threshold, - determine the presence of atmospheric turbulence if said current vertical wind speed exceeds a predetermined threshold, said reduction of aerodynamic loads including: - estimate a first derivative of said current vertical wind speed, - calculate a steering command at least from the first derivative of said current vertical wind speed, - provide said steering command for a steering of at least one control surface of the aircraft according to said steering command, said reduction of aerodynamic loads being executed when said current vertical wind speed is above the predetermined threshold, otherwise said detection is repeated.
[0016] Also proposed here is an aircraft comprising an aerodynamic load reduction system as described above according to one embodiment.
[0017] A computer program product is also proposed, comprising instructions that cause a processor to execute the process described above in any of its embodiments when said instructions are executed by the processor. A storage medium for storing such instructions is also proposed. Brief description of the drawings
[0018] The features of the invention mentioned above, as well as others, will become clearer upon reading the following description of at least one exemplary embodiment, said description being made in relation to the accompanying drawings, among which:
[0019] [Fig-1] schematically illustrates, in side view, an aircraft equipped with a system of reduction of aerodynamic loads, according to an embodiment;
[0020] [Fig.2] schematically illustrates the aerodynamic load reduction system, according to a particular embodiment;
[0021] [Fig.3] schematically illustrates an example of a hardware platform enabling to implement, in the form of electronic circuitry, the aerodynamic load reduction system according to one embodiment; and
[0022] [Fig.4] schematically illustrates the steps of a load reduction process aerodynamic forces exerted on an aircraft, executed by the aerodynamic load reduction system, according to an embodiment.
[0023] DETAILED DESCRIPTION OF IMPROVEMENTS
[0024] The general principle of the following disclosure relates to a method and system for reducing aerodynamic loads exerted on an aircraft by atmospheric turbulence, and in particular by wind gusts. To this end, information representative of the vertical wind speed is obtained in real time from a measurement system comprising sensors positioned on the aircraft. This information is then transmitted to the aerodynamic load reduction system for the calculation of a control command based on a first derivative and, optionally, a second derivative of the vertical wind speed. This calculated control command allows for real-time deflection of the control surfaces (e.g., elevators and / or ailerons) to reduce aerodynamic loads by pitching the aircraft down or up to counteract the effects of the gust.
[0025] Fig. 1 schematically illustrates, in side view, an aircraft 100 equipped with an aerodynamic load reduction system 101, according to one embodiment.
[0026] According to the embodiment of [Fig.1], the aerodynamic load reduction system 101 (also referred to hereafter as load reduction system 101) is an electronic device on board the aircraft 100. For example, the load reduction system 101 is part of an electronic circuitry of the avionics of the aircraft 100. For example, the load reduction system 101 is integrated into a flight control computer, denoted CCV.
[0027] The load reduction system 101 is schematically and globally illustrated in [Fig.2], according to one embodiment.
[0028] The load reduction system 101 is configured to receive information representative of the vertical wind speed. This information is transmitted by a measurement system SYS_MES of the aircraft 100 comprising sensors configured to measure wind conditions (e.g., vertical wind speed, angle of attack, etc.). In one example, the sensors are a set of angle-of-attack probes positioned at the nose of the aircraft 100 and / or a light detection and ranging system, also known as LIDAR (Light Detection and Ranging).
[0029] The load reduction system 101 is further configured to estimate a first derivative and, optionally, a second derivative of the vertical wind speed obtained from said information in order to calculate a control command. The load reduction system 101 is further configured to provide this control command to the flight control controller (FCC). The flight control controller (FCC) is configured to control the movement, via actuators (not shown in [Fig. 2]), of the aircraft control surfaces 100, such as the two outer ailerons (denoted SCI and SC2), the two inner ailerons (denoted SC3 and SC4), and / or the two elevators (denoted SC5 and SC6).In particular, the CCV flight control controller is configured to transmit the rudder command calculated by the load reduction system 101 to the actuators which then deflect one or a combination of the SCI to SC6 control surfaces at a particular angle.
[0030] The load reduction system 101 is also configured to receive various other information from other avionics systems of the aircraft 100 (not shown in [Fig. 2]). This information includes, for example, information concerning the altitude of the aircraft 100, the actual speed of the aircraft 100 (i.e., the aircraft's ground speed), etc.
[0031] Fig. 3 schematically illustrates an example of a hardware platform for implementing, in the form of electronic circuitry, the charge reduction system 101, according to one embodiment.
[0032] The hardware platform comprises, connected by a communication bus 310, a processor or CPU (Central Processing Unit) 301; a RAM (Random-Access Memory) 302; a read-only memory 303, for example of the ROM (Read Only Memory) or EEPROM (Electrically-Erasable Programmable ROM) type, such as a Flash memory; a storage unit, such as a HDD (Hard Disk Drive) 304, or a storage media reader, such as an SD (Secure Digital) card reader; and a COM interface manager 305.
[0033] The COM 305 interface manager allows the load reduction system 101 to interact with other avionics systems of the aircraft 100 such as the SYS_MES measurement system.
[0034] The processor 301 is capable of executing instructions loaded into RAM 302 from ROM 303, external memory, a storage medium (such as an SD card), or a communication network. When the hardware platform is powered on, the processor 301 is capable of reading instructions from RAM 302 and executing them. These instructions form a computer program causing the processor 301 to implement all or part of the steps, processes, or, more broadly, the operating sequences of the aircraft described herein.
[0035] All or part of the steps, processes, and operations described herein can thus be implemented in software form by executing a set of instructions by a programmable machine, for example, a DSP (Digital Signal Processor) or a microcontroller, or implemented in hardware form by a dedicated machine or electronic component (chip) or a dedicated set of electronic components (chipset), for example, an FPGA (Field Programmable Gate Array) or ASIC (Application-Specific Integrated Circuit). Generally speaking, the load reduction system 101 comprises electronic circuitry adapted and configured to implement all or part of the operations, processes, and steps described herein.
[0036] The steps of a method for reducing aerodynamic loads exerted on the aircraft 100 by atmospheric turbulence, such as wind gusts, are shown in diagram form in relation to [Fig. 4], according to one embodiment. All or part of this method for reducing aerodynamic loads is implemented by the load reduction system 101 described above.
[0037] The method for reducing aerodynamic loads comprises: - detection of atmospheric turbulence, such as wind gusts. This detection of atmospheric turbulence includes steps 401 and 402; - a reduction of aerodynamic loads comprising steps 403 to 405.
[0038] From the start of the flight of aircraft 100, during step 401, the load reduction system 101 receives, in real time, from a SYS_MES measurement system, information representative of the current vertical wind speed, denoted u(t), at time t in a particular geographical area. This particular geographical area corresponds to a measurement range zone of the sensors of the SYS_MES measurement system.
[0039] According to one embodiment, the SYS_MES measurement system transmits to the load reduction system 101 information representing the current vertical wind speed u(t) at a predetermined frequency. In one example, this frequency is less than 500 ms.
[0040] In one embodiment, the SYS_MES measurement system comprises a plurality of sensors corresponding to a set of angle-of-attack probes positioned at the nose of the aircraft 100. Atmospheric turbulence, and in particular a gust of wind, causes the angle-of-attack measurement of these probes to vary. The current vertical wind speed u(t) is then determined by a wind estimator device, also included in the SYS_MES measurement system, from the angle of attack measured at time t by the angle-of-attack probes and the actual speed of the aircraft 100.
[0041] According to this embodiment, the geographical area corresponds to the measurement range area of the angle-of-attack probes, i.e. the area corresponding to the current position of the aircraft 100 during flight.
[0042] Alternatively or additionally, the SYS_MES measurement system includes a sensor corresponding to a LIDAR that directly measures the current vertical wind speed u(t) as described in the Applicant's patent application FR2 883 983. In particular, the LIDAR directly measures the current vertical wind speed u(t) in a geographical area corresponding to a measurement range zone located on the trajectory of the aircraft 100 in flight, upstream of the aircraft 100's current position, in its direction of travel. It is thus possible to anticipate the aerodynamic load that will be exerted on the aircraft 100 by the wind gusts present in this geographical area when the aircraft 100 reaches said area.
[0043] The load reduction system 101 also obtains from other avionics systems of aircraft 100, information representative of the actual speed of aircraft 100, denoted V.
[0044] During step 402, the load reduction system 101 compares the current vertical wind speed u(t) to a predetermined threshold, denoted S. If the current vertical wind speed u(t) is greater than the predetermined threshold S, then the load reduction system 101 repeats step 401 (step 402, with a result of "no"); otherwise, step 403 is performed (step 402, with a result of "yes"). Applying this threshold prevents the aerodynamic load reduction from being triggered by weak wind gusts.
[0045] During the reduction of aerodynamic loads, in a step 403, the load reduction system 101 estimates a first derivative denoted and, optionally a second derivative denoted of the current vertical wind speed u(t).
[0046] Indeed, according to one embodiment, it is possible to consider the second derivative of the current vertical wind speed u(t) as negligible (i.e., an approximation according to which the second derivative is substantially zero) in order to simplify the calculation of equation EQ1 below.
[0047] The load reduction system 101 calculates, during a step 404, a control input, providing a deflection angle for a control surface. This control input is calculated from the first derivative and advantageously the second derivative of the current wind speed u(t) in order to deflect one or a combination of the control surfaces SCI to SC6 at a suitable deflection angle to reduce aerodynamic loads. Furthermore, the deflection angle is adapted to the nature of the control surface. Indeed, the control input depends on the nature of the control surface; that is, it differs depending on whether the control surface corresponds to an inboard aileron, an outboard aileron, or an elevator.
[0048] This control command, denoted , is expressed according to equation EQ1 below:
[0049] It ) (—f ) ( - ) + q —sç— )(-14-))
[0050] with:
[0051] Kwind representing a gain allowing an optimization of the reduction of the wind gust load factor (in English);
[0052] Cm^ corresponding to the gradient of the "pitch velocity variation moment" of the complete aircraft 100 expressed at the "aerodynamic center of effect at angle of attack". The aerodynamic center of effect at angle of attack (or "neutral point" in English) being the point of reduction of the forces acting at angle of attack. Cmq corresponding to the gradient of "pitch velocity effect moment" of the complete aircraft 100 expressed at the "aerodynamic focus in angle of attack effect", dimensionless. Cm* corresponds to the gradient of "moment in effect of change of angle of attack" of the complete aircraft 100 expressed at the "aerodynamic focus in effect of angle of attack", dimensionless. Cm^ corresponding to the gradient of "steering moment effect of a given control surface" of the complete aircraft 100 expressed at the "aerodynamic focus effect of incidence", dimensionless. V represents the actual speed of aircraft 100, that is, the speed of aircraft 100 relative to the ground and expressed in meters per second. Lref corresponds to the reference length. This parameter is classically used in flight mechanics equations and is expressed in meters. Ta represents the travel time of the wind from the nose of the aircraft 100 to the "aerodynamic focus in effect of angle of attack" and is expressed in seconds. The term u(t) is the vertical wind speed at time t, expressed in meters per second. The term is the first derivative of the vertical wind speed u(t). It represents the vertical wind speed expressed in meters per second squared at time t. The term is the second derivative of the vertical wind speed u(t). It is the vertical wind speed expressed in meters per second cubed, at time t.
[0053] This equation EQ1 of the order of control as a function of the derivative The first and, optionally, the second derivative of the vertical wind speed at time t results from a coupling between a lift and aerodynamic moment equation of a quasi-static linear model of flight mechanics. This coupling leads to a single equation expressed as a function of the vertical wind speed at time t as input and the control surfaces (i.e., elevator and / or inboard and / or outboard ailerons). This coupling eliminates the direct component of the vertical wind, leaving only the components corresponding to the first derivative and, where applicable, the second derivative of the vertical wind speed at time t. Indeed, as described above, in a particular embodiment, it is possible to approximate the second derivative and consider it negligible.
[0054] In order to optimize the reduction of the wind gust load factor and thus improve passenger comfort, the gain is applied to equation EQ1 above. Indeed, by writing the expression for the load factor with respect to the vertical wind speed, it is possible to demonstrate that there is a particular or optimal gain, which makes it possible to cancel the static gain of the transfer function with respect to the vertical wind speed at time t, which has the effect of reducing the load factor at the aircraft's center of gravity 100.
[0055] In a particular embodiment, the reduction of the wind gust load factor is optimized to improve passenger comfort. For this, the gain must be greater than or equal to one. Thus, in order to minimize the maximum value of the wind gust load factor in the low-frequency wind gust range, the gain is expressed according to the following equation EQ2:
[0056] „ Cn^ \ ^wind H Cn^-Cm^ /
[0057] Thus, the optimized steering order, denoted Can be expressed according to the equation EQ3 below:
[0058] / ~ \ [ Le / ] \ / Ufi \ / ( Cm^ \ l / Le / / Ü(t) \ ^windopA^ ~ 1%¾ PV ' HV ' + \2\Cm^ / \ Cn^Cm^ / \ K / / \ V /
[0059] Initial simulations show a significant effect on reducing the load factor of wind gusts at the aircraft's center of gravity 100, on the order of 30% for discrete gusts. Using the optimal gain expression mentioned above, this reduction reaches up to 70%, again for discrete gusts, but with an increase in the control order (i.e., an increase in the absolute value of the steering angle of the control surfaces SCI to SC6).
[0060] During a step 405, the load reduction system 101 provides the CCV flight control computer in real time with the control command calculated according to equation EQ1 or the optimized control command calculated according to equation EQ3. The CCV flight control computer then commands actuators of the control surfaces SCI to SC6 to deflect one or a combination of these control surfaces SCI to SC6 by a deflection angle depending on the current vertical wind speed u(t) and the nature of the control surface to be deflected.
[0061] In a particular embodiment, when the SYS_MES measurement system includes a LIDAR, it is possible for the load reduction system 101 to transmit the control command before the aircraft 100 encounters wind gusts detected in the geographical area located along the aircraft 100's trajectory, upstream of the aircraft 100 in its direction of travel. This control command is sent at a predetermined activation time that takes into account the current position, mass, and inertia of the aircraft 100. Furthermore, this predetermined activation time also takes into account transmission delays within the various avionics systems of the aircraft 100, so that the control command does not produce the opposite effect to that desired, namely, the reduction of the load factor.This makes it possible to steer either or a combination of the SCI to SC6 control surfaces in an earlier and smoother manner, thus improving passenger comfort.
[0062] According to one embodiment, at the end of step 405, the load reduction system 101 reiterates the detection of atmospheric turbulence and then, if necessary, the reduction of atmospheric loads, as described previously. In other words, the calculation of the control command is performed iteratively by a control loop of predetermined frequency, denoted At (for example, At < 500 ms). Thus, at each of the instants t0, t0 + At, t0 + 2At, t0 + 3At... the load reduction system 101 calculates the control commands. When the vertical wind speed u(t) is below the predetermined threshold S, then the steering order to counter the gust is zero (i.e., no steering of the control surfaces SCI to SC6).
Claims
1. Demands A method for reducing the aerodynamic loads exerted on an aircraft (100) in flight by atmospheric turbulence, said method being implemented by an aerodynamic load reduction system (101) in the form of electronic circuitry, said method comprising: (i) detection of atmospheric turbulence, and (ii) reduction of aerodynamic loads, said detection comprising the following steps: - receive from a measurement system (SYS_MES) information representative of a current vertical wind speed (u(t)), - compare said current vertical wind speed (u(t)) to a predetermined threshold (S), - determine the presence of atmospheric turbulence if said current vertical wind speed (u(t)) is greater than a predetermined threshold (S), said reduction of aerodynamic loads including: - estimating a first derivative of said current vertical wind speed (u(t)), - calculate a steering command at least from the first derivative of said current vertical wind speed (u(t)), - provide said steering command for a deflection of at least one aircraft control surface (100) as a function of said steering command, said reduction of aerodynamic loads being executed when said current vertical wind speed (u(t)) is greater than the predetermined threshold (S), otherwise said detection is repeated, characterized in that said steering command is expressed according to the following equation (EQ1): x i- i HA) / w \ (With: - representing a gain for optimizing the reduction of the wind gust load factor; - Cm^ corresponding to a moment gradient in effect of variation of pitch velocity of the aircraft (100) complete expressed at an aerodynamic focus in effect of angle of attack; - Cm^ corresponding to a complete pitch velocity moment gradient of the aircraft (100) expressed at the aerodynamic center in terms of angle of attack; - Cm* corresponding to a complete angle of attack moment gradient of the aircraft (100) expressed at the aerodynamic center in terms of angle of attack; - Cm^ corresponding to a complete steering moment gradient of said at least one control surface of the aircraft (100) expressed at the aerodynamic center in terms of angle of attack; - V representing an actual speed of the aircraft (100); - Lref corresponding to a reference length; - Ta representing the wind travel time from the nose of the aircraft (100) to the aerodynamic center in terms of angle of attack; - u(t) corresponding to the current vertical wind speed at time t; - ù(t) corresponding to the first derivative of the current vertical wind speed u(t); " u(t) corresponding to a second derivative of the current vertical wind speed u(t).
2. A method according to claim 1, wherein the gain K^.^ is expressed according to the following equation (EQ2): \ and the optimized control order is then expressed according to the following equation (EQ3):
3. A method according to any one of claims 1 or 2, wherein said detection of the presence of atmospheric turbulence and said reduction of aerodynamic loads are repeated at a predetermined frequency (At).
4. A method according to any one of claims 1 to 3, wherein said measurement system (SYS_MES) comprises a light detection and ranging system (LIDAR) configured to obtain said information representative of the current vertical wind speed (u(t)).
5. A method according to any one of claims 1 to 4, wherein said measuring system (SYS_MES) comprises a set of incidence probes configured to measure an angle of incidence
6. of the wind from which said information representative of the current vertical wind speed (u(t)) is obtained. A system for reducing aerodynamic loads exerted on an aircraft (100) in flight by atmospheric turbulence, said system comprising electronic circuitry configured to: (i) perform atmospheric turbulence detection, and (ii) perform a reduction of aerodynamic loads, said detection comprising the following steps: - receive from a measurement system (SYS_MES) information representative of a current vertical wind speed (u(t)), - compare said current vertical wind speed (u(t)) to a predetermined threshold (S), - determine the presence of atmospheric turbulence if said current vertical wind speed (u(t)) is greater than a predetermined threshold (S), said reduction of aerodynamic loads including: - estimating a first derivative of said current vertical wind speed (u(t)), - calculate a steering command at least from the first derivative of said current vertical wind speed (u(t)), - provide said steering command for a deflection of an aircraft control surface (100) as a function of said steering command, said reduction of aerodynamic loads being executed when said current vertical wind speed (u(t)) is greater than the predetermined threshold (S), otherwise said detection is repeated, characterized in that said steering command is expressed according to the following equation (EQ1): =K^\ ( ( -c^- + ( — J (—) ) (- ) ) - KvvW representing a gain for optimizing the reduction of the wind gust load factor; - Cm^ corresponding to a moment gradient in effect of variation of pitch velocity of the aircraft (100) complete expressed at an aerodynamic focus in effect of angle of attack; - Cm^ corresponding to a complete pitch velocity moment gradient of the aircraft (100) expressed at the aerodynamic focus in angle of attack effect; - Cm^ corresponding to a moment gradient in effect of variation of the aircraft's angle of attack (100) expressed at the aerodynamic center in effect of angle of attack; - Cm^ corresponding to a moment gradient in effect of steering of said at least one control surface of the aircraft (100) complete expressed at the aerodynamic center in effect of angle of attack; - V representing an actual speed of the aircraft (100); - Lref corresponding to a reference length; - Ta representing a travel time of the wind from a nose of the aircraft (100) to the aerodynamic center in effect of angle of attack; - u(t) corresponding to the current speed of the vertical wind at time t; -ù(t) corresponding to the first derivative of the current speed of the vertical wind u(t); - corresponding to a second derivative of the current speed of the vertical wind u(t).
7. Aircraft (100) comprising an aerodynamic load reduction system (101) according to claim 6.
8. Product computer program, comprising instructions causing a processor to execute the method according to any one of claims 1 to 5, when said instructions are executed by the processor.
9. Storage medium, storing a computer program comprising instructions causing a processor to execute the method according to any one of claims 1 to 5, when said instructions are read and executed by the processor.