A fuel model slice data compression system and method

Abstract

The present application relates to a kind of fuel model slice data compression system and method, can complete aircraft flight fuel center of gravity real-time fast effective calculation, tank model automation batch segmentation and the acquisition of center of gravity attribute, the auxiliary design and simulation of center of gravity control law of fuel transfer function.The present application includes fast segmentation and center of gravity attribute acquisition module, center of gravity real-time fast effective calculation module.Fast segmentation and center of gravity attribute acquisition module can complete the tank model processing and segmentation to the given aircraft tank scheme, obtain the mass characteristic data of each tank corresponding fuel model, finally obtain the fuel oil volume-weight center of gravity curve under different flight attitudes, and form database;Center of gravity real-time fast effective calculation can quickly carry out data extraction and analysis, establish the calculation model that meets the requirements of calculation accuracy and speed simultaneously, obtain aircraft tank fuel center of gravity, realize the basic information configuration of fuel transfer.

Description

Technical Field

[0001] This invention belongs to the field of aircraft fuel system technology, specifically relating to a fuel model slice data compression system and method. Background Technology

[0002] The range of changes in the fuel center of gravity during aircraft flight is a crucial aspect of aircraft center of gravity design. Due to the extreme complexity of aircraft fuel tanks, the aircraft's center of gravity changes in real time as fuel is consumed. The fuel weight and center of gravity under various flight attitudes are significant factors affecting flight quality and safety. Therefore, the range of changes in the fuel center of gravity during flight is a critical element in aircraft center of gravity design. However, given the complexity of aircraft fuel tanks, design specifications typically only provide data for a limited number of states, such as full fuel and half fuel, during level flight. To obtain more accurate center of gravity input for flight control and other systems, it is necessary to perform real-time, precise, and rapid calculations of the fuel weight and center of gravity of each fuel tank under arbitrary remaining fuel levels and arbitrary pitch and roll attitude angles during aircraft flight.

[0003] However, existing computing technologies cannot quickly calculate the fuel center of gravity in real time at any given state point (including the changing patterns of parameters such as aircraft attitude and fuel quantity in each fuel tank), and the difference between the calculated fuel center of gravity and the theoretical actual fuel center of gravity is relatively high, and the center of gravity calculation refresh rate time is also too long.

[0004] To address the issues of error constraints and low computational efficiency, a rapid compression calculation tool based on fuel model slice data was developed. This tool can effectively reduce data storage, save a significant amount of computational resources, greatly reduce the requirements for using CATIA software, and improve computational efficiency. Summary of the Invention

[0005] To overcome the technical problem of high requirements for models in traditional calculation methods, this invention provides a fuel model slice data compression system and method, which realizes automated batch slicing of aircraft fuel tank models, acquisition of center of gravity attributes, and real-time, fast and efficient calculation of the center of gravity, thereby enabling the configuration of basic information for fuel transfer.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A fuel model slice data compression system includes a rapid segmentation and center of gravity attribute acquisition module and a real-time fast and efficient center of gravity calculation module. The rapid segmentation and center of gravity attribute acquisition module performs fuel tank model processing and segmentation on a given aircraft fuel tank scheme to obtain the mass characteristic data of the fuel model corresponding to each fuel tank. Finally, it obtains the fuel quantity-weight center of gravity curves under different flight attitudes and forms a fuel mass characteristic database. The real-time fast and efficient center of gravity calculation module is used for fuel center of gravity calculation modeling of a single fuel tank and rapid and efficient calculation of the comprehensive fuel center of gravity of all fuel tanks. It quickly extracts and analyzes data, establishes a fuel center of gravity calculation model that simultaneously meets the requirements of calculation accuracy and speed, obtains the fuel center of gravity of the aircraft fuel tanks, and realizes the configuration of basic information for fuel transfer.

[0008] Furthermore, the difference between the calculated center of gravity of the fuel system and the theoretical actual center of gravity of the fuel system shall not exceed 10% of the range of changes in the center of gravity of the fuel system before and after fuel consumption; the center of gravity calculation refresh rate shall not exceed 0.2s.

[0009] Furthermore, the fast segmentation and centroid attribute acquisition module is specifically implemented as follows:

[0010] Based on the effective CATIA fuel model of the fuel tank, four calculation elements are input: sensor position, fuel pump position, drain valve position, and vent position, along with three attitude angles: pitch angle, roll angle, and yaw angle. The attitude angles are then calculated using the aircraft's actual flight attitude angles and three-axis overloads, and the fuel plane normal vector is represented as:

[0011]

[0012] Where, N x N y N z This indicates the aircraft's three-axis overload, where θ is the pitch angle and φ is the roll angle.

[0013] In the body coordinate system, the pitch angle θ and roll angle φ corresponding to the normal vector (A,B,C) are respectively:

[0014]

[0015] The fuel tank calculation model is then discretized into micro-elements according to the number of slices, and then sliced ​​from top to bottom. The fuel quantity, center of gravity, and mechanical properties are calculated and analyzed along the height direction, and stored according to different attitude angles to form fuel tank fuel quantity-center of gravity characteristic data.

[0016] The center of mass data for each fuel tank is obtained based on the remaining fuel level and the input flight attitude parameters:

[0017] X cgfji ||Y cgfji ||Zcgfji =f j (W Fj余i ,T i )

[0018] Among them, W Fj余i T represents the remaining fuel level in the j-th fuel tank at time i; i Let T be the flight attitude at time i. i ={N xi N yi N zi ,θ i ,ψ i ,φ i};N xi For the overload component in the x-direction; N yi The overload component in the y-direction; N zi For the overload component in the z-direction; θ i Let ψ be the pitch angle of the aircraft at the i-th moment; i Let φ be the yaw angle of the aircraft at the i-th time moment; i Let X be the roll angle of the aircraft at the i-th moment; cgfji Y cgfji and Z cgfji The coordinates of the centroid of the j-th fuel tank in the x, y, and z directions are respectively, and f j (W Fj余i ,T i Its fuel quality characteristics are presented in the form of an M×N dimensional table, expressed as a multidimensional curve, and the data comes from a fuel quality characteristics database.

[0019] The instantaneous fuel system centroid is calculated as follows:

[0020]

[0021] Among them, X cgfi Y cgfi Z cgfi These are the centroid coordinates of the instantaneous fuel in the x, y, and z directions, respectively.

[0022] Furthermore, the real-time, fast, and efficient center of gravity calculation module is specifically implemented as follows:

[0023] For any overload state, all or part of f can be extracted from the database. j (W Fj余i ,T i The data was used to select initial reference state points through a heuristic search algorithm, and a cubic spline interpolation model of the centroid about the oil surface height was established. The interpolation model was then optimized using a simulated annealing algorithm, as detailed below:

[0024] (1) Parameter initialization, that is, setting the relevant input parameters, including reading the fuel center of gravity data file of the given fuel tank and setting the upper limit of the number of interpolation nodes;

[0025] (2) Data grouping, that is, the fuel quantity-fuel center of gravity data are divided into n groups according to different attitude angle combinations (θ,φ), and the fuel quantity-fuel center of gravity data under different attitudes are extracted respectively;

[0026] (3) Determine the initial interpolation node. That is, for the fuel quantity-fuel center of gravity data corresponding to the i-th group (i = 1, 2, ..., n) attitude angle, use a heuristic search algorithm to determine the initial interpolation node W0, and calculate the objective function E corresponding to the initial interpolation node. norm0 The objective function is taken as the 2-norm of the fuel center of gravity calculation error vector;

[0027] (4) Optimize the interpolation nodes. Based on the initial interpolation node W0, the simulated annealing algorithm is used to further optimize the interpolation nodes. The final interpolation node W is determined through the optimization structure of the inner and outer loops. * and objective function The inner loop generates new solutions and calculates and compares the increment ΔE of the objective function, while the outer loop avoids getting trapped in local minima by designing a cooling coefficient and eventually tends to the global optimum.

[0028] (5) Calculate the cubic spline interpolation coefficients; that is, the final interpolation node W output by the simulated annealing algorithm. * To find the optimal solution, calculate all output dimensions X. cg Y cg Z cg The corresponding cubic spline interpolation coefficients, where X cg Y cg Z cg These are the interpolation results in the x, y, and z directions of the final centroid fast calculation model;

[0029] (6) Save the output results, that is, automatically save the final interpolation nodes and interpolation coefficient calculation results, generate the corresponding file, and display all output dimensions X. cg Y cg Z cg Maximum calculation error result;

[0030] By obtaining the centroid data of the entire fuel system, a rapid calculation model for the fuel center of gravity of a single fuel tank can be derived, which can be expressed as:

[0031]

[0032] in, X cgfji Y cgfji Z cgfjiThe centroid coordinates after interpolation;

[0033] Finally, the combined center of gravity of the fuel system is calculated using the center of gravity calculation formula:

[0034]

[0035] Where X is the coordinate of the engine's fuel center of gravity in the x-direction, and W... j Let X be the optimal fuel tank capacity calculated for fuel tank j at a certain moment. j Let J be the coordinate of the center of gravity of fuel tank j in the x direction at this moment, and W be the remaining fuel capacity of the entire engine.

[0036] The present invention also provides a compression method for a fuel model slice data compression system, comprising the following steps:

[0037] Step S1, Inputting segmented data: Based on the CATIA fuel model of the fuel tank, input four calculation elements: sensor position, fuel pump position, drain valve position, and vent position, as well as three attitude angles: pitch angle, roll angle, and yaw angle.

[0038] Step S2, Segmentation Module Operation: The model data is processed digitally. For each fuel tank, a segmentation model, segmentation step size, and segmentation attitude angle are set. Then, the CATIA fuel model is called to perform segmentation, completing the slicing process of the fuel tank calculation model. After slicing, the fuel tank calculation model is discretized into micro-elements according to the number of slice layers. The fuel tank calculation model is then segmented from top to bottom according to the slices. Fuel quantity, center of gravity, and mechanical properties are calculated and analyzed along the height direction. The data is stored according to different attitude angles to form fuel quantity-center of gravity characteristic data of the fuel tank.

[0039] Step S3, Center of Gravity Data Acquisition: Based on the remaining fuel level in each fuel tank and the input flight attitude parameters, acquire the instantaneous center of gravity position of each fuel tank, thereby obtaining the center of gravity data of the entire fuel system, and thus obtaining the center of gravity data of a single fuel tank:

[0040] X cgfji ||Y cgfji ||Z cgfji =f j (W Fj余i ,T i )

[0041] Among them, W Fj余i T represents the remaining fuel level in the j-th fuel tank at time i; i Let T be the flight attitude at time i. i ={N xi N yi N zi ,θ i ,ψ i ,φ i};N xiFor the overload component in the x-direction; N yi The overload component in the y-direction; N zi For the overload component in the z-direction; θ i Let ψ be the pitch angle of the aircraft at the i-th moment; i The i-th moment is the aircraft pitch angle; φ i Let X be the roll angle of the aircraft at the i-th moment. cgfji Y cgfji and Z cgfji The coordinates of the centroid of the j-th fuel tank in the x, y, and z directions are respectively, and f j (W Fj余i ,T i ) represents the fuel quality characteristics of the j-th fuel tank, in the form of an M×N dimensional table, expressed as a multidimensional curve, and its data comes from a fuel quality characteristic database;

[0042] The instantaneous fuel system centroid calculation is as follows:

[0043]

[0044] Among them, X cgfi Y cjfi Z cjfi These are the centroid coordinates of the instantaneous fuel in the x, y, and z directions, respectively.

[0045] Step S4, Modeling the Center of Gravity of Fuel in a Single Fuel Tank: For any overload state, all or part of the f values ​​can be extracted from the database. j (W Fj余i ,T i Using the data, an initial reference state point is selected through a heuristic search algorithm. A cubic spline interpolation model of the center of gravity with respect to the oil level is established. The interpolation model is then optimized using a simulated annealing algorithm to obtain a fast calculation model for the center of gravity of fuel in a single fuel tank, expressed as follows:

[0046]

[0047] in, X cgfi Y cjfi Z cjfi The centroid coordinates after interpolation;

[0048] Step S5, Calculation of the overall fuel center of gravity: Calculate the coordinates of the overall fuel center of gravity using the fuel center of gravity calculation formula:

[0049]

[0050] Where X is the coordinate of the engine's fuel center of gravity in the x-direction, and W... j Let X be the optimal fuel tank capacity calculated for fuel tank j at a certain moment. jLet J be the coordinate of the center of gravity of fuel tank j in the x direction at this moment, and W be the remaining fuel tank capacity of the entire engine;

[0051] The calculated results are saved in tabular form.

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] (1) The splitting process of this invention is simple and quick, and the rapid splitting has low requirements for the fuel tank design. The splitting module has been packaged into a macro plugin that can run on CATIA software. When using it, you can directly run it after importing the plugin. It can also manage and optimize the splitting data, and provide a basis for calculating the fuel quantity-mass characteristics in any state of fuel.

[0054] (2) The fuel center of gravity is obtained quickly and the modeling method is real-time and efficient. The cubic spline interpolation model and simulated annealing algorithm can reduce the consumption of computing resources while ensuring the accuracy of calculation and obtain the corresponding fuel quantity-mass characteristic curve.

[0055] (3) The calculation method is fast and convenient, with high calculation accuracy and strong real-time performance. The difference between the calculated center of gravity of the whole machine fuel and the theoretical actual center of gravity does not exceed 10% of the range of changes in the center of gravity before and after fuel consumption. The center of gravity calculation refresh rate is not higher than 0.2s.

[0056] This invention enables the slicing of general aircraft models, followed by rapid data segmentation and compression via a program. This effectively reduces data storage, saves significant computing resources, improves computational efficiency, and ultimately enables the configuration of basic information for fuel transfer. Attached Figure Description

[0057] Figure 1 This forms the overall logical framework of the present invention;

[0058] Figure 2 This is a theoretical diagram of the fuel segmentation model of the present invention;

[0059] Figure 3 The basic logic for establishing the fuel quality characteristic database of this invention is as follows;

[0060] Figure 4 This is the interface of the fuel quality characteristic segmentation module in this invention;

[0061] Figure 5 This is the fuel quality characteristic segmentation result file in this invention;

[0062] Figure 6 Database construction for this invention;

[0063] Figure 7 This is the calculation and modeling process for fuel quality characteristics in this invention;

[0064] Figure 8 The results of fuel center of gravity calculation modeling in this invention;

[0065] Figure 9 A basic interface for visualizing the simulation verification results of the control law based on fuel consumption sequence in this invention;

[0066] Figure 10 This is a basic interface for visualizing the simulation verification results of the control law based on fuel transfer in this invention.

[0067] Figure 11 This serves as the post-processing environment for the simulation results in this invention.

[0068] Figure 12 This is a post-processing of simulation results for the control law based on fuel consumption sequence used in this invention;

[0069] Figure 13 This is a post-processing of simulation results using the control law based on fuel transfer in this invention. Detailed Implementation

[0070] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0071] like Figure 1 As shown, the fuel model slice data compression system of the present invention consists of a fast segmentation and center of gravity attribute acquisition module 1 and a real-time fast and effective center of gravity calculation module 2.

[0072] The rapid segmentation and center of gravity attribute acquisition module 1 is a macro plugin developed based on VBA language that can run within CATIA and CAA software. It can perform fuel tank model processing and model segmentation for a given aircraft fuel tank scheme, obtain the mass characteristic data of the fuel model corresponding to each fuel tank, and finally obtain the fuel quantity-weight center of gravity curve under different flight attitudes, and form a fuel mass characteristic database.

[0073] The real-time, fast, and efficient center of gravity calculation module 2 includes two aspects: single fuel tank center of gravity calculation modeling and comprehensive fuel center of gravity calculation for all fuel tanks. It can perform single fuel tank center of gravity calculation modeling based on a fuel quality characteristic database and calculation accuracy and time constraints, obtaining a fuel center of gravity calculation model. Finally, it combines the remaining fuel in each tank and flight attitude to achieve rapid fuel center of gravity calculation and generate fuel center of gravity characteristic data. The difference between the calculated overall fuel center of gravity and the theoretical actual fuel center of gravity does not exceed 10% of the range of changes in fuel center of gravity before and after fuel consumption; the center of gravity calculation refresh rate is no higher than 0.2 seconds.

[0074] This invention also provides a method for compressing fuel model slice data, specifically including the following steps:

[0075] Step S1, Inputting segmented data: such as Figure 2 As shown, based on the valid CATIA fuel model for the fuel tank, four calculation elements are input: sensor position, fuel pump position, drain valve position, and vent position, along with three attitude angles: pitch angle, roll angle, and yaw angle. The vent is located at the top of the fuel tank; there is no more fuel above the vent, so the fuel level can be calculated up to this point. A fuel tank may have multiple sensors; the position of each sensor can be determined by two three-dimensional coordinates. Figure 2 The diagram shows the first sensor 1 and the second sensor 2; the fuel level in the tank above the fuel pump represents the available fuel level; the fuel level above the drain valve represents the discharge fuel level. Figure 2 As can be seen from this, the amount of fuel that can be emitted = the amount of fuel available + the amount of fuel that cannot be used.

[0076] The attitude angles can be calculated from the actual flight attitude angles of the aircraft and the three-axis overload, and the oil plane normal vector can be expressed as:

[0077]

[0078] Where N x N y N z This indicates the aircraft's three-axis overload, where θ is the pitch angle and φ is the roll angle.

[0079] In the body coordinate system, the pitch angle θ and roll angle φ corresponding to the normal vector (A,B,C) are respectively:

[0080]

[0081] Specifically, the handling methods for different attitude angles are as follows:

[0082] The rotation matrix around the x-axis is as follows:

[0083]

[0084] The rotation matrix around the y-axis is as follows:

[0085]

[0086] The rotation matrix around the z-axis is as follows:

[0087]

[0088] The yaw attitude angle is ψ, and the rotation sequence is defined as follows: 1. Around the z-axis (yaw angle); 2. Around the y-axis (pitch angle); 3. Around the x-axis (roll angle). The old coordinate system is O-xyz, and the new coordinate system is O'-x'y'z'.

[0089] The following matrices can be used to achieve mutual transformation:

[0090]

[0091]

[0092] The fuel tank calculation model is then discretized into micro-elements according to the number of slices, and the slices are divided from top to bottom. The fuel quantity, center of gravity, and mechanical properties are calculated and analyzed along the height direction, and stored according to different attitude angles to form fuel tank fuel quantity-center of gravity characteristic data.

[0093] Step S2, Segmentation Module Operation: After slicing, the original fuel tank calculation model will be discretized into infinitesimal elements according to the number of slice layers, and then segmented from top to bottom according to the slices. The segmentation interface is as follows: Figure 4 As shown, by loading an effective cutting model that includes sensor placement, fuel pump, drain valve, and vent location, and setting the cutting step size and cutting conditions, the software automatically calls CATIA to cut the corresponding model after configuration. Figure 3 The basic logic for establishing a fuel quality characteristic database is implemented, capable of processing fuel tank information to construct a fuel model, and then segmenting the fuel quality characteristic model according to fuel tank operating conditions, ultimately forming the fuel quality characteristic database. The generated result file is as follows: Figure 5 As shown, Figure 6 A database built for data.

[0094] Step S3, Center of Gravity Data Acquisition: Based on the remaining fuel level in each fuel tank and the input flight attitude parameters, obtain the instantaneous center of gravity position of each fuel tank, thereby obtaining the center of gravity data of the entire fuel system, and thus the center of gravity data of a single fuel tank:

[0095] X cgfji ||Y cgfji ||Z cgfji =f j (W Fj余i ,T i )

[0096] Among them, W Fj余i T represents the remaining fuel level in the j-th fuel tank at time i; i Let T be the flight attitude at time i. i ={N xi N yi N zi ,θ i ,ψ i ,φ i};N xi For the overload component in the x-direction; N yi The overload component in the y-direction; N zi For the overload component in the z-direction; θ i Let ψ be the pitch angle of the aircraft at the i-th moment; i Let φ be the yaw angle of the aircraft at the i-th time moment; i Let X be the roll angle of the aircraft at the i-th moment. cgfji Y cgfji and Z cgfji The coordinates of the centroid of the j-th fuel tank in the x, y, and z directions are respectively, and f j (W Fj余i ,T i ) represents the fuel quality characteristics of the j-th fuel tank, in the form of an M×N dimensional table, expressed as a multidimensional curve, and its data comes from a fuel quality characteristic database.

[0097] The instantaneous fuel system centroid calculation is as follows:

[0098]

[0099] Among them, X cgfi Y cjfi Z cjfi These are the centroid coordinates of the instantaneous fuel in the x, y, and z directions, respectively.

[0100] Step S4, Modeling the Center of Gravity of Fuel in a Single Fuel Tank: For any overload state, all or part of the f values ​​can be extracted from the database. j (W Fj余i ,T i Using the data, an initial reference state point is selected through a heuristic search algorithm. A cubic spline interpolation model of the center of gravity with respect to the oil level is established. The interpolation model is then optimized using a simulated annealing algorithm. The resulting fast calculation model for the center of gravity of fuel in a single fuel tank can be expressed as follows:

[0101]

[0102] in, X cgfji Y cgfji Z cgfji The centroid coordinates after interpolation.

[0103] Selection of calculation points and generation of calculation models, such as Figure 7 As shown, the initialization and optimization of calculation point selection are first performed based on the fuel quality characteristic database, and a calculation model is generated based on the constraints of calculation accuracy and recalculation time.

[0104] Specifically, after selecting the calculation points, a cubic spline interpolation calculation model is established, with the vertical centroid X as the reference point. cgfi For example, if the number of fuel level data points in the fuel tank is n, and the data storage allowed by the hardware constraints is m, then the determined (m / 4+1) calculation points form m / 4 segmented intervals. Each segmented interval can be described as a cubic polynomial:

[0105] X cg (W)=a k +b k (WW k )+c k (WW k ) 2 +d k (WW k ) 3 k = 0, 1, ..., m / 4

[0106] Among them, a k ,b k ,c k ,d k There are m parameters to be solved, which can be calculated based on the second-order continuity equation and boundary conditions for each node. cg W is the longitudinal center of gravity of the fuel. k Let W be the remaining fuel level in fuel tank k stage. A rapid center of gravity calculation model is established with the longitudinal center of gravity X of fuel tank j as the reference point. cgfji For example, the piecewise linear interpolation method is described as follows:

[0107] For a given set of inputs (W, θ, φ), first determine the intervals θ and φ corresponding to the interpolation nodes. L ≤θ≤θ H φ L ≤φ≤φ H For the four posture combinations (θ) L ,φ L ), (θ L ,φ H ), (θ H ,φ L ), (θ H ,φ H The longitudinal center of gravity X of the fuel under four attitude combinations was calculated using a cubic spline interpolation model. cg1 X cg2 Xcg3 X cg4 Where θ is the pitch angle and φ is the roll angle. L =θ min θ is the minimum pitch angle. H =θ max The maximum pitch angle φ L =φ min For the minimum roll angle, φ H =φ max This represents the maximum roll angle. Therefore:

[0108] X cg1 =cubic_interp(θ) L ,φ L )

[0109] X cg2 =cubic_interp(θ) L ,φ H )

[0110] X cg3 =cubic_interp(θ) H ,φ L )

[0111] X cg4 =cubic_interp(θ) H ,φ H )

[0112] Where cubic_interp(·) is a cubic spline interpolation polynomial, and the polynomial coefficients correspond to different pose combinations.

[0113] For X cg1 ,X cg2 ,X cg3 ,X cg4 Two-dimensional linear interpolation of θ and φ is performed. First, θ is kept constant, and linear interpolation of φ is performed to obtain the longitudinal fuel center of gravity coordinates when the pitch angle reaches its minimum value. Longitudinal fuel center of gravity coordinates at maximum value

[0114]

[0115]

[0116] By keeping φ constant and performing linear interpolation on θ, we can obtain:

[0117]

[0118] X calculated from the above formula cg This is the interpolation result output by the final centroid fast calculation model.

[0119] Based on the above method for generating the fuel center of gravity calculation model, the main program for interpolation model calculation was developed. The specific steps are as follows:

[0120] (1) Parameter initialization. This involves setting the relevant input parameters, including reading the fuel center of gravity data file of the given fuel tank and setting the upper limit of the number of interpolation nodes.

[0121] (2) Data grouping. The fuel quantity-fuel center of gravity data are divided into n groups according to different attitude angle combinations (θ,φ), and the fuel quantity-fuel center of gravity data under different attitudes are extracted respectively.

[0122] (3) Determine the initial interpolation node. For the fuel quantity-fuel center of gravity data corresponding to the attitude angle of the i-th group (i = 1, 2, ..., n), a heuristic search algorithm is used to determine the initial interpolation node W0, and the objective function E corresponding to the initial interpolation node is calculated. norm0 The objective function is taken as the 2-norm of the fuel center of gravity calculation error vector, which is a global performance indicator for measuring the calculation error.

[0123] (4) Optimize interpolation nodes. Based on the initial interpolation node W0, the simulated annealing algorithm is used to further optimize the interpolation nodes. The final interpolation node W is determined through the optimization structure of inner and outer loops. * and objective function The inner loop generates new solutions and calculates and compares the increment ΔE of the objective function, while the outer loop avoids getting trapped in local minima by designing a cooling coefficient and eventually tends to the global optimum.

[0124] (5) Calculate the cubic spline interpolation coefficients. The final interpolation node W output by the simulated annealing algorithm is used. * To find the optimal solution, calculate all output dimensions X. cg Y cg Z cg The corresponding cubic spline interpolation coefficients.

[0125] (6) Save the output results. The system automatically saves the final interpolation nodes and interpolation coefficient calculation results, generates a corresponding Excel file, and displays the output X. cg Y cg Z cg Maximum calculation error result.

[0126] Step S5, Calculation of the overall fuel center of gravity: Calculate the coordinates of the overall fuel center of gravity using the fuel center of gravity calculation formula:

[0127]

[0128] Where X is the coordinate of the engine's fuel center of gravity in the x-direction, and W... j Let X be the optimal fuel tank capacity calculated for fuel tank j at a certain moment.j Let J be the coordinate of the center of gravity of fuel tank j in the x direction at this moment, and W be the remaining fuel capacity of the entire engine.

[0129] The calculated results are as follows Figure 8 As shown, the data is saved in a table format for easy reuse and comparison later.

[0130] Taking the calculation of the aircraft's center of gravity in the x-direction as an example, according to mission requirements, the upper limit of the absolute error in the overall fuel center of gravity calculation is δ = 1% MAC, and the upper limit of the relative error in the calculation of the weight of a single fuel tank is 2.5%. The constraint of the overall center of gravity calculation error will determine the accuracy requirement of the calculation model for the center of gravity of a single fuel tank.

[0131] Let the upper limit of the absolute error in calculating the center of gravity of a single fuel tank be δ0. Assuming that the weight of a single fuel tank is relatively independent of the center of gravity calculation, we can obtain:

[0132]

[0133] in,

[0134] Right now:

[0135]

[0136] Where X is the coordinate of the aircraft's center of gravity in the x-direction, and W... j Let X be the optimal fuel tank capacity calculated for fuel tank j at a certain moment. j Let J be the coordinate of the center of gravity of fuel tank j in the x direction at this moment, and W be the remaining fuel capacity of the entire engine.

[0137] To estimate the requirement for δ0, the following assumptions can be made about the aircraft fuel tank:

[0138] Assume each fuel tank has approximately the same fuel weight, and there are a total of 6 fuel tanks; since most of the fuel tanks are located near the aircraft's center of gravity, let |X j -X| is generally no more than 3000mm; MAC is approximately 5000mm.

[0139] Then we can obtain:

[0140]

[0141] Based on the above estimates, the accuracy of the calculation model for the center of gravity of a single fuel tank, δ0, should not exceed 2δ (if δ0 = δ is required), which can roughly meet the accuracy requirements for the overall center of gravity calculation of fuel. More accurate accuracy estimates can be calculated based on the actual model's fuel tank layout information, fuel tank capacity information, and fuel consumption sequence.

[0142] The following verifies the calculation accuracy:

[0143] For the rapid calculation model of fuel center of gravity, all original data points of fuel tanks 1, 2, 3, 4, L, and R of a certain type of aircraft were selected as test data, with the longitudinal center of gravity X... cg The accuracy of the fuel center of gravity calculation model is verified using an example. The center of gravity calculation errors are summarized below:

[0144]

[0145] The test results above show that this fuel center of gravity calculation model is effective in all output dimensions X. cg Y cg Z cg All of these methods demonstrate high computational accuracy. The verification results for the six fuel tanks show that the fuel center of gravity calculation model obtained using this algorithm has high accuracy. Compared with the original data, the average calculation error of the fuel center of gravity for each fuel tank is <0.3mm, the maximum calculation error is <3.6mm, and the maximum combined calculation error is <2.0mm. Furthermore, compared with the heuristic search algorithm, the combinatorial optimization algorithm can further optimize the interpolation nodes, improve the accuracy of the center of gravity calculation model, and verify the algorithm's superiority and effectiveness.

[0146] The following verifies the calculation speed:

[0147] Using the above input conditions as the object, a real-time center of gravity calculation was performed 3000 times on a personal computer for a fuel system containing 6 fuel tanks. The total time was 316.096 seconds, and the average calculation time for the fuel system was 0.105 seconds per calculation.

[0148] The following is an analysis of data storage requirements:

[0149] Compared to database interpolation, using a rapid fuel center of gravity calculation model can significantly reduce data storage and effectively lower storage complexity. The total storage volume of the original data from the six test fuel tanks is compared with that of the calculation model below:

[0150]

[0151] As shown in the table above, the rapid calculation model for the center of gravity of fuel can significantly reduce the amount of data stored. The data storage of the center of gravity calculation model accounts for only 6% to 20% of the original data, and the data storage of some fuel tanks is reduced by more than 90%, which greatly saves storage space.

[0152] Step S7, Dynamic Demonstration: Enter the simulation results visualization module through "Simulation Result Visualization". The interactive visualization panel of simulation results provides a comprehensive and clear visualization environment for simulation results, presenting intuitive dynamic charts to visualize flight status, aircraft weight and center of gravity, fuel tank and fuel pump status, fuel transfer control law status, etc., and providing visualization interfaces for simulation results under two different control laws. Then, enter the simulation results post-processing environment through "Simulation Result Post-processing". After exporting the simulation results as *.csv format, post-processing of the entire simulation process data can be performed. The software defaults to directly supporting the MATLAB environment for data post-processing. Finally, directly execute SimPlot.m to plot parameters such as the overall aircraft center of gravity, fuel center of gravity, and front and rear limits of the center of gravity as charts. Figure 9 A basic interface is provided for visualizing the simulation verification results of the control law based on fuel consumption sequence. Figure 10 A basic interface for visualizing the simulation verification results of the control law based on fuel transfer is provided. Figure 11 This serves as the post-processing environment for simulation results. Taking a specific test sample as an example... Figure 12 To utilize the simulation results of the control law based on fuel consumption sequence, Figure 13 The simulation results are based on the control law of fuel transfer.

[0153] The parts of this invention not described in detail are well-known in the field.

[0154] The above description is only a part of the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A fuel model slice data compression system, characterized in that: The system includes a rapid segmentation and center of gravity attribute acquisition module (1) and a real-time rapid and effective center of gravity calculation module (2). The rapid segmentation and center of gravity attribute acquisition module (1) completes the processing and segmentation of the fuel tank model for a given aircraft fuel tank scheme, obtains the mass characteristic data of the fuel model corresponding to each fuel tank, and finally obtains the fuel quantity-weight center of gravity curve under different flight attitudes, and forms a fuel mass characteristic database. The real-time rapid and effective center of gravity calculation module (2) is used for the calculation and modeling of the fuel center of gravity of a single fuel tank and the rapid and effective calculation of the comprehensive fuel center of gravity of all fuel tanks. It quickly extracts and analyzes data, establishes a fuel center of gravity calculation model that meets the requirements of calculation accuracy and speed, obtains the fuel center of gravity of the aircraft fuel tank, and realizes the configuration of basic information for fuel transfer. The real-time rapid and effective center of gravity calculation module (2) specifically implements the following functions: for any overload state, it extracts all or part of the data from the database. The data is used to select an initial reference state point through a heuristic search algorithm, establish a cubic spline interpolation model of the center of gravity with respect to the oil level height, and optimize the interpolation model using a simulated annealing algorithm. The difference between the calculated center of gravity of the whole engine fuel and the theoretical actual center of gravity of the fuel does not exceed 10% of the range of change of the center of gravity of the fuel before and after fuel consumption; the center of gravity calculation refresh rate is not higher than 0.2s.

2. The fuel model slice data compression system according to claim 1, characterized in that: The fast segmentation and centroid attribute acquisition module (1) is implemented as follows: Based on the effective CATIA fuel model of the fuel tank, four calculation elements are input: sensor position, fuel pump position, drain valve position, and vent position, along with three attitude angles: pitch angle, roll angle, and yaw angle. The attitude angles are then calculated using the aircraft's actual flight attitude angles and three-axis overloads, and the fuel plane normal vector is represented as: in, , , This indicates that the aircraft is overloaded in three directions. For pitch angle, This refers to the roll angle; Normal vector in body coordinate system Corresponding pitch angle and roll angle They are respectively: ， The fuel tank calculation model is then discretized into micro-elements according to the number of slices, and then sliced ​​from top to bottom. The fuel quantity, center of gravity, and mechanical properties are calculated and analyzed along the height direction, and stored according to different attitude angles to form fuel tank fuel quantity-center of gravity characteristic data. The center of mass data for each fuel tank is obtained based on the remaining fuel level and the input flight attitude parameters: in, This represents the remaining fuel level in the j-th fuel tank at time i. Let i be the flight attitude at time i. ; The overload component is in the x-direction; The overload component is in the y-direction; The overload component is in the z-direction; Let i be the aircraft pitch angle at time i; Let i be the aircraft yaw angle at time i; Let i be the roll angle of the aircraft at time i; , and These are the j-th fuel tanks. The centroid coordinates of the direction, Its fuel quality characteristics, in the form of The table is presented in the form of a multi-dimensional curve, and its data comes from a fuel quality characteristics database. The instantaneous fuel system centroid is calculated as follows: ； ； in, Instantaneous fuel at The coordinates of the centroid in the direction.

3. The fuel model slice data compression system according to claim 2, characterized in that: The specific implementation of the real-time fast and efficient center of gravity calculation module (2) is as follows: (1) Parameter initialization, that is, setting the relevant input parameters, including reading the fuel center of gravity data file of the given fuel tank and setting the upper limit of the number of interpolation nodes; (2) Data grouping, i.e., based on different combinations of attitude angles Divide the fuel quantity-fuel center of gravity data into n groups, and extract the fuel quantity-fuel center of gravity data under different postures. (3) Determine the initial interpolation nodes, that is, for the fuel quantity-fuel center of gravity data corresponding to the i-th attitude angle, use a heuristic search algorithm to determine the initial interpolation nodes. And calculate the objective function corresponding to the initial interpolation nodes. The objective function is taken as the 2-norm of the fuel center of gravity calculation error vector; where i=1,2,…,n; (4) Optimize the interpolation nodes, that is, at the initial interpolation nodes Based on this, the simulated annealing algorithm is used to further optimize the interpolation nodes, and the final interpolation nodes are determined through the optimization structure of inner and outer loops. and objective function The inner loop generates a new solution and calculates and compares the increment of the objective function. The external circulation system avoids getting stuck in local minima and eventually tends to the global optimum by designing the cooling coefficient; (5) Calculate the cubic spline interpolation coefficients; that is, the final interpolation nodes output by the simulated annealing algorithm. To find the optimal solution, calculate all output dimensions. The corresponding cubic spline interpolation coefficients, where The final fast calculation model of the center of gravity is respectively in Interpolation results in direction; (6) Save the output results, that is, automatically save the final interpolation nodes and interpolation coefficient calculation results, generate the corresponding files, and display all output dimensions. Maximum calculation error result; By obtaining the centroid data of the entire fuel system, a rapid calculation model for the fuel center of gravity of a single fuel tank can be derived, which can be expressed as: in, , , They are respectively , , The centroid coordinates after interpolation; Finally, the combined center of gravity of the fuel system is calculated using the center of gravity calculation formula: Where X is the coordinate of the engine's fuel center of gravity in the x-direction, and W... j X represents the optimal remaining fuel level of fuel tank j calculated at a certain moment. j Let J be the coordinate of the center of gravity of fuel tank j in the x direction at this moment, and W be the remaining fuel capacity of the entire engine.

4. A compression method for a fuel model slice data compression system according to any one of claims 1-3, characterized in that, Includes the following steps: Step S1, Inputting segmented data: Based on the CATIA fuel model of the fuel tank, input four calculation elements: sensor position, fuel pump position, drain valve position, and vent position, as well as three attitude angles: pitch angle, roll angle, and yaw angle. Step S2, Segmentation Module Operation: The model data is processed digitally. For each fuel tank, a segmentation model, segmentation step size, and segmentation attitude angle are set. Then, the CATIA fuel model is called to perform segmentation, completing the slicing process of the fuel tank calculation model. After slicing, the fuel tank calculation model is discretized into micro-elements according to the number of slice layers. The fuel tank calculation model is then segmented from top to bottom according to the slices. Fuel quantity, center of gravity, and mechanical properties are calculated and analyzed along the height direction. The data is stored according to different attitude angles to form fuel quantity-center of gravity characteristic data of the fuel tank. Step S3, Center of Gravity Data Acquisition: Based on the remaining fuel level in each fuel tank and the input flight attitude parameters, acquire the instantaneous center of gravity position of each fuel tank, thereby obtaining the center of gravity data of the entire fuel system, and thus obtaining the center of gravity data of a single fuel tank: in, This represents the remaining fuel level in the j-th fuel tank at time i. Let i be the flight attitude at time i. ; The overload component is in the x-direction; The overload component is in the y-direction; The overload component is in the z-direction; Let i be the aircraft pitch angle at time i; Let i be the aircraft yaw angle at time i; Let i be the roll angle of the aircraft at time i; , and These are the j-th fuel tanks. The centroid coordinates of the direction, Let the fuel quality characteristic of the j-th fuel tank be in the form of: The table is presented in the form of a multi-dimensional curve, and its data comes from a fuel quality characteristics database. The instantaneous fuel system centroid calculation is as follows: ； ； ； in, Instantaneous fuel at The coordinates of the centroid in the direction; Step S4, Modeling the Center of Gravity of Fuel in a Single Fuel Tank: For any overload state, all or part of the data can be extracted from the database. The data, using a heuristic search algorithm to select initial reference state points, establishes a cubic spline interpolation model of the center of gravity with respect to the oil level, and optimizes the interpolation model using a simulated annealing algorithm, resulting in a fast calculation model for the center of gravity of fuel in a single fuel tank, expressed as follows: in, They are respectively The centroid coordinates after interpolation; Step S5, Calculation of the overall fuel center of gravity: Calculate the coordinates of the overall fuel center of gravity using the fuel center of gravity calculation formula: Where X is the coordinate of the engine's fuel center of gravity in the x-direction, and W... j X represents the optimal remaining fuel level of fuel tank j calculated at a certain moment. j Let J be the coordinate of the center of gravity of fuel tank j in the x direction at this moment, and W be the remaining fuel tank capacity of the entire engine; The calculated results are saved in tabular form.

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