• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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    • 专利摘要:
    The invention relates to a method for correcting at least one calculation result of at least one flight characteristic of an airplane, in particular a drag coefficient Cx of the airplane, said calculation being based on measurements of flight and on values calculated from said measurements, the flight measurements being performed in at least one determined flight condition defining a given flight point, each flight condition being defined by particular values of flight parameters, said measurements and values being in particular: θmeasures the measured attitude of the aircraft and αmodels the incidence of the aircraft calculated by solving a lift equation and an aerodynamic model linking the incidence α of the aircraft to at least one flight parameter which is the lift coefficient Cz of the aircraft. The measurements of the θ measurement attitude are corrected by a Δθ0 attitude correction term which is a particular constant for each flight and the amodel calculated incidences are corrected by a correction term of incidence Δα (Cz ...). The terms of correction of attitude Δθ0 and incidence Δα (Cz ...), are computed under stress that the vertical wind WZ is on average practically nil.
    公开号:FR3031817A1
    申请号:FR1550308
    申请日:2015-01-15
    公开日:2016-07-22
    发明作者:Laurent Berdoulat
    申请人:Laurent Berdoulat；
    IPC主号:
    专利说明:

    [0001] The invention relates to a method for correcting the calculation of a flight characteristic of an aircraft by taking into account the vertical wind and a method for calculating the drag coefficient is also presented as an application of the method. It is implemented in aeronautics for the determination of aircraft characteristics. Among the characteristics of an airplane, the coefficient of drag, noted Cx, of the aircraft is important because, depending on the value of Cx, the aircraft can consume more or less fuel. It is therefore a characteristic of very important economic interest especially for commercial aircraft.
    [0002] If we can consider calculating the drag coefficient Cx by means of computer simulation, it remains nonetheless that it is from concrete flight measurements on the aircraft itself that we can obtain a result closest to reality given the number of elements that can influence the value of Cx. However, while some measures are becoming more precise thanks to modern means of measurement, there are others which are more difficult to obtain sufficiently precisely. This is particularly the case for the vertical wind to which the aircraft is subjected in flight. In addition, the accuracy of the measurements obtained can be high in relative and lower in absolute, there may also be measurement bias or even drifts in the measurements.
    [0003] In practice, so far, because of these limitations, the impact of the vertical wind in the calculations of airplane characteristics has not been taken into account or, at least, if we could have been interested the results that could have been obtained would not have been of sufficient precision to be used serenely. The present invention proposes to take into account the vertical wind with a method of correction of at least one result of calculation of at least one flight characteristic of an airplane, in particular a drag coefficient Cx of the airplane, said calculation being based on measurements in flight and on values calculated from said measurements, the flight measurements being performed in at least one determined flight condition defining a given flight point, each flight condition being defined by particular values of flight parameters, each flight point corresponding to a determined combination of flight parameter values and therefore to a specific flight condition, said measurements and values being in particular: ° measuring the measured attitude of the aircraft, a -model the incidence of the aircraft calculated by solving a lift equation and an aerodynamic model linking the incidence α of the aircraft to at least one flight parameter which is the e coefficient of lift Cz of the aircraft. According to the method of the invention: the measurement attitude measurements are corrected by an Aeo correction term and the effects calculated amodme are corrected by a correction term Aoc (Cz ...), and the terms of correction of attitude Aeo and incidence Acc (Cz ...), are computed under constraint that the vertical wind WZ is on average practically nil. The term "practically zero" means that the average wind must be set to be zero or at least to be the lowest value possible as a constraint in the calculations.
    [0004] In various embodiments of the invention, the following means can be used alone or in any technically possible combination, are employed: the term of correction of attitude Mo is a particular constant for each flight, the term of attitude correction 400 is variable, - the attitude correction term 3.00 comprises at least one particular constant for each flight, - the variable attitude correction term A00 is the sum of a particular constant for each flight and a linear variable of time, the linear variable of the time correcting a possible drift of the gyroscopes of the plane, zo - one makes measurements plane on a single flight, N = 1, - one repeats the flights to dispose of airplane measurements on a set of N flights, N being greater than one, - aircraft measurements are made under a given number M of different flight conditions, M being greater than or equal to one, 25 - each flight condition corresponds to at a flight point, the same flight point that can be found on different flights, - an airplane measurement corresponds to a given flight condition / given flight point, - the airplane measurements are recorded for the specified flight points of / flights, - the impact of the aircraft amodue is calculated by solving a lift equation and an aerodynamic model linking the incidence of the aircraft to the coefficient of lift Cz of the aircraft and, optionally, at one or more of the following flight parameters: a Mach speed of the airplane, a total mass m of the airplane, a position of the center of gravity CG of the airplane, - the term of attitude correction 400 is computed under constraint that for each flight, the average of the vertical wind WZ calculated for all the determined flight points of said flight is practically zero, - the incidence correction term Aoc, (Cz, ...) is calculated under the constraint that the average vertical wind WZ calculated for each conditi determined flight [Cz,] is practically zero, - the incidence of the model airplane is calculated by solving a lift equation and an aerodynamic model linking the incidence a, of the airplane to the coefficient of lift Cz of the aircraft and, optionally, one or more of the following flight parameters: a Mach speed of the aircraft, a total mass m of the aircraft, a CG center of gravity position of the aircraft; airplane, and the attitude correction term 400 is computed under the constraint that for each flight, the average of the vertical wind WZ calculated for all the determined flight points of said flight is practically zero, and the incidence correction term AOE (Cz,) is computed under the constraint that the average of the vertical wind WZ calculated for each determined flight condition [Cz, -] is practically zero, - a vertical wind WZ is computed by the aircraft by: WZ = VZgeom - TAS - sin (Omesure amodel + (3190 - where: VZgeom is the vertical velocity of the airplane in the terrestrial reference, positive upward, TAS is the true speed of the airplane in the aerodynamic reference, - in the case where only one flight is made and the number of measurements of the airplane is zo lower than a first threshold, we use by default an incidence correction term Act (Cz,) which is zero: Acx (Cz,) = 0, - in the case where a single flight is performed and the number of aircraft measurements is less than one first threshold, the vertical wind WZ is calculated by: WZ = VZgeom - TAS - sin (Omesure amodèle (MO)) 25 where: VZgéom is the vertical speed of the aircraft in the terrestrial reference, positive up, TAS is the true speed of the airplane in the aerodynamic reference, - in the case where only one flight is made, the aircraft measurements are made for are performed for a single flight condition / flight point, - in the case where a single flight is performed, the measurements had several flight conditions / flight points, - the first threshold is included in between three and ten aircraft measurements, - the first threshold is between three and five aircraft measurements, 35 - the first threshold is approximately ten aircraft measurements, - the first threshold is approximately five aircraft measurements, - the number of measurements airplane on a flight for the first threshold corresponds to all the airplane measurements for one or more flight conditions, - in the case where at least one flight is performed and the number of airplane measurements is greater than a second threshold, the Inc acceleration correction term (Cz, Mach, mass, CG, ...) is calculated by linear regression globally on all flights and decomposing by flight parameter Cz, Mach, mass, CG, ... with: (a A = 3, a0 + (Xi -) (Tel ') - aXi where Xi corresponds to each flight parameter Cz, Mach, mass, CG, ..., dWZ dWZ the constraint being that (-) which is the average of - axi dX; obtained by linear regression of WZ according to each flight parameter Xi on all the airplane measurements, ie practically zero, - the second threshold is greater than or equal to the first threshold, - the second threshold is between ten and one hundred aircraft measurements, - the number of airplane measurements on the flight or flights for the second threshold corresponds to the set of airplane measurements for several flight conditions, - in the case where at least one flight is performed and the number of airplane measurements is greater than one third threshold, the term of correction of incidence 3, a, (Cz, Mach, mass, CG, ...) is calculated by multi-variable polynomial regression globally on all the flights and by decomposing by parameter of flight Cz, Mach , mass, CG, ... with: AKX1, X2,) = Aao + (x, - (xi - xiref) - (x; - xief) ref (aA or a2Acr - + 4X, aXj) where each instance of indices i and j correspond to each flight parameter Cz, Mach, mass, CG, ... - the third threshold is greater than or equal to the second threshold, - the third threshold is between one hundred and one thousand aircraft measurements, - the third threshold is greater than one hundred aircraft measurements, - the number of airplane measurements on the flight or flights for the third threshold corresponds to all the airplane measurements. for several flight conditions, - the incidence correction term Act (Cz, ...) is calculated by interpolation in a table of values, - the terms of attitude correction 3.00 and incidence correction Acc (Cz, ...) are computed under the minimization constraint of Ep WZp2 where the index p characterizes the different airplane measurements made on all the flights by limiting itself to a given flight range, - the aircraft measurements are carried out in a simplifying flight configuration corresponding to a plane in stabilized flight with zero roll angle and with a stabilized engine speed. The invention also relates to a particular application of the consideration of the vertical wind with a method for calculating a drag coefficient Cx of an airplane based on measurements in flight and on values calculated from said measurements.
    [0005] In said method, the correction method of the invention is used in order to calculate the drag coefficient Cx by a calculation formula taking into account the vertical wind, said calculation formula including a term of aerodynamic slope aero with yaero = (Omesure + MO) (amodel Aa (Cz, ...)). Advantageously, the drag coefficient Cx is calculated by: idvgeom + acorious .exer ° + FG.cos (eniesure + Aeo + caiago-RD.cos (Yaero) dt Cx = CZ-tan (v aero) qScos (yetero) where Yaero is the aerodynamic slope Vgeom is the velocity vector in the terrestrial reference, exa ° is the standardized vector collinear to the aerodynamic velocity vector, exhaled "is the normed vector resulting from the projection on the horizontal plane of the vector exaer °, m is the mass of the aircraft, FG is the gross thrust of the engines, RD is the engine catch, stall is the vertical stall angle of the engines relative to the axis of the aircraft, q is the reference dynamic pressure , S is the reference surface of the aircraft, acorious is the Coriolis acceleration due to the rotation of the Earth.
    [0006] The invention may also relate to a computer program comprising program code instructions recorded on a computer readable medium and for performing the methods of the invention. The present invention, without it being so far limited, will now be exemplified with the following description of embodiments and implementation in connection with: Figure 1 which shows a diagram of an aircraft with different axes essentially concerning angles and speeds in flight as well as a decomposition of the wind vector, and Figure 2 which represents a diagram of an aircraft with different axes essentially concerning the forces involved during a flight. We will now describe the principle underlying the invention with the calculation of the vertical wind WZ and then describe an application to calculate the drag coefficient Cx. For the sake of simplicity, it will be assumed in the following that there is no drifting of the gyroscopes of the aircraft during the flight and therefore a term of correction of attitude Mo will be used which is a particular constant for each flight. However, the invention can be implemented with an attitude correction term Mo which is a linearly variable variable as a function of time during each flight to take into account a possible drift of the gyroscopes of the aircraft. The term "aircraft measurement" corresponds to the measurement of a set of 15 parameters of the aircraft, for example the geometric speed, the aerodynamic speed, the attitude, etc. for a certain duration. In order to be able to take into account the vertical wind in order to be able to correct the airplane measurements and / or the values resulting from calculations from the airplane measurements, it is proposed to calculate the vertical wind WZ from airplane attitude measurements, 20 measurements of vertical speed in a terrestrial reference and an aerodynamic model linking the incidence of the aircraft to at least the coefficient of lift Cz of the aircraft. In the following, the following notations are used: W which is the wind vector, WX which is the horizontal component of the wind, positive forward, in ms-1, 25 WZ which is the vertical component of the wind, positive towards the high, in ms-1, E [X] which is the expectation of the variable X, (X) which is the average value of X, Cz which is the coefficient of lift of the plane, Cx which is the coefficient of drag of the plane, 30 0 which is the plane plate in radian, which is the incidence plane in radian, Y aero which is the aerodynamic slope in radian, TAS which is the true speed of the plane in the landmark aerodynamic, in ms-1, Vgeom which is the speed vector in the terrestrial reference, in ms-1, 35 VZgeom which is the vertical speed of the plane in the terrestrial reference, positive upwards, in ms-1, VZ aero which is the vertical speed of the plane in the aerodynamic landmark, positive upwards, in ms-1, exaero which is the standardized vector colinear to the velocity vector ie aerodynamics TAS, ee'r ° which is the norm vector normal to the aerodynamic real velocity vector TAS, in the vertical plane, directed upwards, exahér ° which is the normalized vector resulting from the projection on the horizontal plane of the vector eer ° , m which is the total mass of the airplane, in kg, FG which is the gross thrust of the engines, in N, RD which is the trapping catch of the engines, in N, wedging which is the vertical wedging angle of the engines relative to the aircraft axis, in radian, q which is the reference dynamic pressure, in Pa, S which is the reference surface of the aircraft, in m2, g which is the gravitational acceleration, in ms; 2, acorious which is the acceleration of Coriolis, in ms-2, CG which is the position of the center of gravity, in m or% of aerodynamic average chord, Re which is the Reynolds number obtained for a reference length of one meter (parameter without dimension) corresponding to the flight conditions of the aircraft, and Altitude which is the altitude of e the plane, in m. It should be noted here that the flight parameter CG is the position of the center of gravity for information purposes because this parameter is not used directly in the calculations of the vertical wind, but it can however intervene in the aerodynamic model of the aircraft in particular according to the accuracy of the model or the choice of its formulation. It is the same for the Altitude and Re flight parameters that can be used in the aerodynamic model of the aircraft. Figures 1 and 2 allow to visualize some of these notations in relation to the aircraft whose characteristics one wants to determine / calculate. In order to be able to calculate the vertical wind, it is necessary to know exactly the plane attitude measured, and to have a precise model which makes it possible to know the incidence of the plane at any moment. For this, we transform a zero vertical wind hypothesis on average, into two sub-hypotheses: vertical wind is zero on average per flight, and zero vertical wind on average for each flight condition.
    [0007] The basis of the invention is therefore based on the assumption that the average vertical wind WZ experienced by an aircraft in flight is zero. We can then write: E [WZ] = 0. We can translate this hypothesis in two ways: - For a sufficiently long flight, including the course is not limited to a too limited geographical area, we can assume that: (WZ) 1.01 = O. This can be extended to a set of flights: (WZ) i = 0 with i an index whose instances correspond to each of the different flights. - For a flight point defined by a determined combination of values of a set of flight parameters [Macho, Czo, mass °, CG0, ...], if sufficient airplane / recording measurements under these same conditions of flight determined flights have been made, potentially on several flights, and that these aircraft / recordings measurements can be considered as decorrelated, we can then assume that: (WZ (Macho, Czo, mass °, CGo, ...)) = 0 A based on these assumptions, and using the aircraft's flight measurements, in particular the attitude 0 and the vertical speed VZgeom in the terrestrial frame, we can re-align the aerodynamic model making it possible to establish the relationship between the lift coefficient Cz (a, Mach, mass, CG, ...) of the aircraft and its incidence a. From the model recalé and using always the same measures, it is then possible to calculate the vertical wind, for each moment of the flight compatible with the aerodynamic model used. It should be noted that an engine model of the aircraft is also used for the calculation of the FG and RD values, which are involved in the calculation of the lift coefficient Cz, and especially in the calculation of the drag coefficient CX.
    [0008] By taking into account this vertical wind in the propulsion equation, the computation of the drag from the measurements is made more precise and more robust. We will now give examples of calculation of the vertical wind that are not limiting. In order to simplify the explanations, it is assumed here that the aircraft is in a flight configuration that corresponds to a stabilized flight with a zero roll angle and with a stabilized engine speed. The vertical wind WZ can be calculated from measurements in flight and values calculated from said measurements, in particular from ° measurement, VZgeom, amodel Where amodel is the incidence of the aircraft calculated from an equation of lift and an aerodynamic model linking the aircraft lift coefficient to this incidence. From the following relations: WZ = VZgeom - VZaero VZaero = TAS - sin (v, aero) and 0 = a + Yaero we obtain: WZ = VZgeom TAS - sin (0measurement - amodel) The amodue incidence resulting from the aerodynamic model is obtained by applying a levitation equation that can be chosen according to the desired accuracy. For example, one can use the following equation of levitation: dVz - geom (VZgeomy V zq TAS Cx TAS mdt VZgeom geoin + FG - Si11 (0m'u '+ rigging) - RD m - (g + aeoriolis' ez TAS ge with eom z which is a normed vector, vertical in the terrestrial reference, directed upwards.This equation assumes a weak vertical wind typical of what is encountered in a calm atmosphere. To establish the relationship between the coefficient of lift Cz at the angle α of the airplane can be more or less precise, as an example of a simple relation: Cz = Czo + Cza - a, and more complex relation: Cz = Czo (CG, Mach) + Cza (CG, Mach) - a + .ACzNL (a, Mach) Each aircraft manufacturer predefines its aerodynamic model and the flight condition (s) in which it is In practice, the predefined flight conditions in question make it possible to predefine a flight domain in which the model is valid. The corresponding flight condition (s) for the airplane measurements for the purpose of calculating the characteristics of the airplane will therefore be available. In general, a simplifying flight configuration is associated with these predefined flight conditions: stabilized flight airplane with zero roll angle, stabilized engine speed. It is assumed from experience that the aircraft attitude measurement may be biased and this bias is different from one flight to another, but remains constant during each flight. The error of the model Cz (a, Mach, mass, CG, ...) for the coefficient of lift is equivalent to an error Aa (Cz, Mach, mass, CG, ...). The relation v aero = ° measure - amodel thus becomes Yaero = (0measure + MO) - (amodele Aa (Cz, Mach, mass, CG, ...)). Hence WZ = VZgeom - TAS - sin (Omesure amodel (3 ^ 00 -, Aa (Cz, Mach, Mass, CG, ...))) Assuming that for each flight, the average vertical wind encountered by the aircraft is approximately zero, and the If the bias of the attitude measurement can vary from one flight to another, we will determine L00 (flight) so as to have (WZ) voii = 0, so for each index flight j, with i = [1..N] and N> = 1, in the case of a set of N 30 flights. According to the density of the airplane measurements obtained / recorded in a flight range corresponding to flight parameter values [Macho, Czo, masseo, CGo, ...] predefined for the aerodynamic model used, for example 0.4 <Cz <0.5 and 0.8 <Mach <0.85, we can apply more or less precise methods to correct the incidence model. It is recalled that the constraint imposed for the calculations is to have for every point of flight: (WZ (Cz, Mach, mass, CG, ...)) = 0. This last condition can be declined in different ways according to the density airplane measurements in the considered flight domain. These determinations are made by setting the set of variables (3,0031 <i <NN being the number of flights (index i) and: a A - to% and (ct aX) (where Q is the number of variables on which depends the incidence) if i 1 <i <Q one opts for a correction of the linear type (the plane measurements are obtained for several flight conditions / flight points in order to be able to carry out at least a linear regression), OU - & ï, ( a Act) a2Aa etc ... (Q being the number of variables whose axi) 1 <i <Q '(axiax) 1 <i <Q, 1 <j <Q' depends on the incidence) if we opt for a correction of multivariable polynomial type OR - Glak (Cz, Mach, mass, CG, ...)) (where P is the number of data points between which interpolated) if a correction obtained by interpolation in a data table is chosen. This is typically done through the use of optimization methods. The constraint being to have at the end: Vi E ftl, N]], (WZ (vol i)) = 0 and - Vi E ft1, Q, (az) = 0 if a linear correction has been chosen aXi OR aliVZ - Vi EQ]], (axi) = 0, v (i, j) E (a2wz .axiax / = 0, etc ... if a multi-variable polynomial correction has been chosen OR - Vk E [0,9, (WZ (condition k)) = 0 if an interpolation correction in a table of values has been chosen According to the number of variables of the correction model (Q + 1 variables a Aa for the linear correction (- for example), it It is necessary to have a certain number of airplane measurements made under conditions compatible with the hypotheses of the engine and aerodynamic models, therefore, in general, with a zero roll angle, and a stabilized engine speed. This number obviously depends on the uncertainty of each measurement as well as on the desired precision. n 5 parameter given measured. For a given flight point, during the same flight or during different flights, it is possible to perform one or more catches / recordings of the values of the various measured parameters and therefore, for each take / record of flight point available several measurements each corresponding to a measurement of a given parameter. It will be recalled that the term "aircraft measurement" 10 corresponds to the set of measurements of the parameters necessary for the application of this method, measurements recorded for each measurement phase. It is understood that if the number of aircraft measurements for each flight is high and the density of aircraft measurements in the flight range is high, the better the accuracy of the results, always respecting the predefined flight conditions for the models and in particular the aerodynamic model. The measurements are typically recorded for later use with deferred calculations of the characteristics of the aircraft. If, preferably, the calculations are made in deferred time in order to be able to collate the measurements and possible values collected during the flight and previous flights, one can envisage progressive calculations, in real time, during each flight, and which will therefore gradually refine as each flight. In practice, the measurements are obtained during measurement phases which each last a certain time which can depend on many factors. A measurement phase can thus last between a few seconds and a few minutes. The calculations are carried out in a programmable computer / computer which receives data input including the measurements and any calculated values recorded during the flight. These data are identified in time and possibly by flight, a particular flight can however be found according to its time registration. The flight conditions can be determined a priori, possibly recorded with the data, or determined a posteriori on the recorded data. In fact, the flight conditions can be determined a priori, for example the pilot deciding that he has entered particular flight conditions, these conditions possibly being recorded with the corresponding data. They can be determined a posteriori automatically from the measurements and recorded values corresponding to flight parameters [Macho, Czo, mass °, CG 0, ...], the programmable computer / computer classifying the measurements and values by conditions. and keeping those that can be used for calculations, including those respecting the predefined flight conditions for the models and, if necessary, the predefined simplified flight configuration. Some of the calculated values can be measured during real-time measurements and can be saved and others can be calculated later from the recorded measurements. Thus, when it is indicated that for the recorded flight points of the flight (s) measurements and values calculated from said measurements are recorded, this is considered equivalent to a recording of the measurements and subsequent calculations of values calculated from said recorded measurements.
    [0009] We can consider the case of a very low density of aircraft measurements. This is for example the case if we do a flight, then we have: N = 1, and with only a few measurements plane, whether for: - a single condition of flight / point of flight, ie M = 1 with for example 3 to 5 aircraft measurements, or - several flight conditions / flight points, for example M = 3 to 5 with a single aircraft measurement per flight point. It is understood that this very low density of aircraft measurements may correspond to other combinations of number of flight points / flight conditions and number of measurement (s) plane per point of flight / flight condition during a flight 20 unique. So, in this case of very low density of aircraft measurements, we only correct the MB attitude bias because in such a case, Acto and other corrective terms can be considered null. Indeed, in this case, there are not enough airplane measurements to correct the incidence model. So there is only one correction term: 25 to use and the formula of the vertical wind becomes: WZ = VZgeom - TAS sin (Omesure amodèle (Lx0 0)) - In the case of a density of plane measurements average, for example between a dozen and a few hundred aircraft measurements in total in the flight field considered, we can impose the constraint (-aawxz) = 0 using linear regressions, 30 for each Xi which is here a flight parameter, Xi can be the Mach, the Cz, etc., the variables being (-a). We then have a correction of the type: aXct =) Ei (Xi - Xiref - (a a X) In the case of a high plane density of measurements, for example several hundreds to several thousand measurements plane in the considered flight domain The precision of the results can be increased by multi-variable polynomial regression with a correction of the form: Aa (X1, X2, ...) = Aao + (xi - xiref) - the A c; t aXi) +) f- (x .- Xrje) (a2'12 I aXiaXi where j and j are the indices for the parameters [Mach, Cz, etc.] This computation is aWZ based on the constraints: = 0, (a2wz = 0 and so immediately up to the order aXt dXidXj (wanted, with Xi and Xj the flight parameters Mach, Cz, etc. and the variables are the e.Lr) and the (a2a) and possibly others if the order the polynomial is greater than axi axiaxi 2. Alternatively, it is also possible to directly modify the values of the data tables of the model Cz (a, Mach, mass, CG, ...), for example by minimizing Ep wzp2. The modif ication of the table of Cz is equivalent to interpolating in a table pek (Cz, Mach, mass, CG, ...)) 1 <k <p Indeed and as explained above, the goal, with the optimization of N + P terms of correction (3,00i.) 1 <i <N and (Aak (Cz, Mach, mass, CG, ...)) 1 <k <p where N characterizes the number of flights and P characterizes the number of flight conditions / flight points from the data table, is to have Vi E (WZ (flight i)) = 0, 15 Vk E (WZ (condition k)) = O. The N + P correction terms (M ° 3 and 1 <i <N (Aak (Cz, Mach, mass, CG, ...)) can be obtained by minimizing Ep wzp2 on the set of measurements, the index p characterizing the different measurements plane carried out on all the flights and the whole of a determined flight domain. In this interpolated method in a data table, the airplane measurements are made in the flight range defined by the boundaries of the table. These aircraft measurements can therefore be performed under different conditions from one another, the important thing being the number of aircraft measurements in relation to the number of variables of the calculation. The latter variant amounts to transforming the two conditions that are the zero average per flight and the zero average per flight condition into one: the minimization of Ep wzp2. With the various preceding methods, it is therefore possible to calculate the corrections to be made to the attitude and the incidence and therefore to the calculation of the vertical wind or even to calculated measurements or values or other characteristics of the airplane on the basis of the same principles. Thus, it becomes possible in particular to rely on the vertical wind calculated at each instant by the formula: WZ = VZgeom - TAS sin (amodel Omesure (3 ^ 00 - Aa (Cz, Mach, mass, CG, ...))) We will now describe an application to a calculation of a characteristic of the aircraft which is its drag coefficient Cx.
    [0010] The application to the airplane of the fundamental principle of the dynamics in the terrestrial reference, projected according to the vector exhaled "gives: CXmesure aCoriolis e aero xh + FG - cos (Omesure + zO0 + rigging) - RD - cos (y aero) ClIgeom -111 'Cit - S cos (y aero) - Cz - tan (y, aero) with: Yaero = (Omesure + Mo) - (amodele Aa (Cz, Mach, mass, CG, ...)).
    [0011] It may be noted that the term Cz - tanCvaero. 1 involves the calculated vertical wind. This formula is given as an example and it is understood that it is possible to calculate this coefficient of drag Cx with other formulas based on the application of the fundamental principle of dynamics, especially in a slightly different reference. These formulas are based on the fact that the deviation ACx = CXmesure CXmodel obtained for each measurement comes partly from the inaccuracy of the measurements, and partly from the model error. If it is assumed that the measurements contain noise but are unbiased, 15 for any flight point defined by a set of flight parameters [Cz, Mach, mass, CG, Re, altitude, ...] having particular values and for which enough uncorrelated records have been made, then: (ACx (Cz, Mach, mass, CG, Re, altitude, = 0 By the same type of approach and logic as for the setting of Mo and it is possible to readjust the drag model by correcting 20 Cxmodel (Cz, Mach, mass, CG, Re, altitude, ...) to verify the previous equation, thus, depending on the density of the available aircraft measurements will be able to choose between several means of calculation of the correction to be made on the incidence: constant, linear regressions, multi-variable polynomial regressions or even interpolation in tables of data.
    [0012] In the end, therefore, a complete aerodynamic base (lift and drag coefficients) is obtained, corrected on the results of flight tests.
    权利要求:
    Claims (10)
    [0001]
    REVENDICATIONS1. Method for correcting at least one result of calculation of at least one flight characteristic of an airplane, in particular of a drag coefficient Cx of the airplane, said calculation being based on measurements in flight and on values calculated from said measurements, the flight measurements being performed in at least one determined flight condition defining a given flight point, each flight condition being defined by particular values of flight parameters, each flight point corresponding to a combination determined from flight parameter values and therefore to a determined flight condition, said measurements and values being in particular: ° measures the measured attitude of the aircraft, a -models the incidence of the airplane calculated by resolution of a lift equation and an aerodynamic model linking the incidence cx. of the aircraft to at least one flight parameter which is the coefficient of lift Cz of the aircraft, characterized in that: the measurements of the measurement base are corrected by a correction term Aeo and the incidences calculated amodue are corrected by an incidence correction term AOE (Cz ...), and in that the terms of attitude correction 400 and Acx incidence (Cz ...), are computed under constraint that the vertical wind WZ is on average virtually zero.
    [0002]
    2. Method according to claim 1, characterized in that the incidence of the amodme aircraft is calculated by solving a levitation equation and an aerodynamic model linking the incidence α. of the aircraft at the lift coefficient Cz of the aircraft and, optionally, at one or more of the following flight parameters: a Mach speed of the aircraft, a total mass m of the airplane, a center position of gravity CG of the aircraft, and in that: the attitude correction term 400 is computed under the constraint that for each flight, the average of the vertical wind WZ calculated for all the determined flight points of said flight is practically zero , and the incidence correction term AOE (Cz, ...) is computed under the constraint that the average of the vertical wind WZ calculated for each determined flight condition [Cz, ...] is practically zero.
    [0003]
    3. Method according to claim 2, characterized in that calculates a vertical wind WZ undergone by the aircraft by: WZ = VZ - sin (Omesure geom - TAS amodel (A00 - Aa (Cz, ...))) where: VZgeom is the vertical speed of the aircraft in the terrestrial reference, positive up, TAS is the true speed of the aircraft in the aerodynamic reference.
    [0004]
    4. Method according to claim 2 or 3, characterized in that in the case where a single flight is performed and the number of aircraft measurements is less than a first threshold, is used by default an incidence correction term 3.0c (Cz,) which is zero: 3.0c (Cz,) = O.
    [0005]
    5. Method according to claim 2 or 3, characterized in that in the case where at least one flight is performed and the number of measurements is greater than a second threshold, the Acx incidence correction term (Cz, Mach, mass, CG, ...) is calculated by linear regression globally on all flights and decomposing by flight parameter Cz, Mach, mass, CG, ... with: = Acto + (Xi - Xiref) - where Xi corresponds at each flight parameter, Cz, Mach, mass, CG, ..., dWZ the stress then being that (az), which is the average of obtained by d X id X i linear regression of WZ according to each flight parameter Xi on the set of measures, practically nil.
    [0006]
    6. Method according to claim 2 or 3, characterized in that in the case where at least one flight is performed and the number of airplane measurements is greater than a third threshold, the incidence correction term 3, a, (Cz, Mach, mass, CG, ...) is computed by multi-variable polynomial regression globally on all flights and decomposed by flight parameter Cz, Mach, mass, CG, ... with: (a A a aXi (xi - xiref) - (x; - xief) axax) + --- WHERE 30 each instance of indices i and j corresponds to each flight parameter Cz, Mach, mass, CG, ... ia Aa aXi = Aao + (xi - xiref) -
    [0007]
    7. Method according to claim 1 or 2, characterized in that the Aeo attitude correction and Act (Cz,) correction terms are calculated under a minimization constraint of Ep WZp2 where the index p characterizes the different aircraft measurements taken on all flights by limiting themselves to a specific flight area.
    [0008]
    8. Method according to one of the preceding claims, characterized in that the aircraft measurements are carried out in a simplifying flight configuration corresponding to a plane in stabilized flight with zero roll angle and with a stabilized engine speed.
    [0009]
    9. A method for calculating a drag coefficient Cx of an airplane based on in-flight measurements and on values calculated from said measurements, characterized in that the correction method of one any one of the preceding claims for calculating the drag coefficient Cx by a calculation formula taking into account the vertical wind, said calculation formula including an aerodynamic slope term v aero with v aero = (0th dimension -A ° 0) (amodel
    [0010]
    10. Method according to claim 9, characterized in that the drag coefficient Cx is calculated by: m. (Diffleon, dt + acoriolis exer ° + Fo-cos (measurement + A80 + cala9e) -RD .cos (Yaéro) qscos (Yaéro) Where Yaero is the aerodynamic slope Vgepm is the velocity vector in the terrestrial reference, eer ° is the standardized vector collinear to the aerodynamic velocity vector, e xéro is the normed vector resulting from the projection on the horizontal plane of the vector eer °, m is the mass of the airplane, FG is the gross thrust of the engines, RD is the trailing catch of the engines, setting is the angle of vertical setting of the engines with respect to the axis of the airplane, q is the reference dynamic pressure, S is the reference surface of the aircraft, acoriolis is the acceleration of Coriolis Cx = Cz - tan (Yaéro)
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    同族专利:
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    US10502755B2|2019-12-10|
    FR3031817B1|2018-05-25|
    US20170356925A1|2017-12-14|
    WO2016113511A1|2016-07-21|
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    DE102009060327A1|2009-12-23|2011-06-30|Airbus Operations GmbH, 21129|Airplane with a control device|CA2999761A1|2015-09-22|2017-03-30|Ohio University|Loss-of-control prevention and recovery flight controller|
    CN106168529B|2016-07-27|2018-06-26|江西洪都航空工业集团有限责任公司|A kind of wind tunnel test methods for correcting aircraft rigid body lift coefficient|
    US10592636B2|2017-03-17|2020-03-17|General Electric Company|Methods and systems for flight data based parameter tuning and deployment|
    US10768201B2|2017-06-12|2020-09-08|The Boeing Company|System for estimating airspeed of an aircraft based on a drag model|
    US11066189B2|2018-12-07|2021-07-20|The Boeing Company|Flight control system for determining estimated dynamic pressure based on lift and drag coefficients|
    US11003196B2|2018-12-07|2021-05-11|The Boeing Company|Flight control system for determining a common mode pneumatic fault|
    US11029706B2|2018-12-07|2021-06-08|The Boeing Company|Flight control system for determining a fault based on error between a measured and an estimated angle of attack|
    CN111122901B|2019-12-31|2021-11-02|中国航空工业集团公司西安飞机设计研究所|Attack angle error automatic detection method and correction system thereof|
    CN111273056A|2020-04-02|2020-06-12|山东创惠电子科技有限责任公司|Attack angle observation method of high-speed aircraft without adopting altitude measurement|
    CN112729760B|2021-01-20|2021-10-19|中国科学院力学研究所|Pneumatic lift and pneumatic resistance coefficient combined measurement method|
    CN113221479B|2021-05-08|2022-02-01|北京航空航天大学|Unmanned aerial vehicle dynamics modeling method considering rainfall weather|
    CN113281531A|2021-05-20|2021-08-20|北京科技大学|Method and device for measuring current wind speed and direction of unmanned aerial vehicle|
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1550308|2015-01-15|
    FR1550308A|FR3031817B1|2015-01-15|2015-01-15|METHOD OF CORRECTING THE CALCULATION OF A FLIGHT CHARACTERISTIC OF A PLANE BY TAKING INTO ACCOUNT OF THE VERTICAL WIND, METHOD OF CALCULATING THE COEFFICIENT OF TRAINING|FR1550308A| FR3031817B1|2015-01-15|2015-01-15|METHOD OF CORRECTING THE CALCULATION OF A FLIGHT CHARACTERISTIC OF A PLANE BY TAKING INTO ACCOUNT OF THE VERTICAL WIND, METHOD OF CALCULATING THE COEFFICIENT OF TRAINING|
    US15/543,829| US10502755B2|2015-01-15|2016-01-15|Method for correcting the calculation of a flight characteristic of an aeroplane by taking vertical wind into account, method for calculating the drag coefficient|
    PCT/FR2016/050072| WO2016113511A1|2015-01-15|2016-01-15|Method for correcting the calculation of a flight characteristic of an aeroplane by taking vertical wind into account, method for calculating the drag coefficient|
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