Intelligent adaptive quality characteristic acquisition method for tilt rotorcraft

Abstract

An intelligent adaptive quality characteristic acquisition method for a tilt rotorcraft comprises the steps that firstly, whether a target tilt rotorcraft adopts fuel oil as a power source or not is judged; according to whether the tilt rotorcraft adopts fuel oil as a power source or not and in combination with different influence factors and influence degrees thereof, the quality characteristic state of the tilt rotorcraft is subdivided into a plurality of unequal state categories, and corresponding quality characteristic data are collected for each state category; for the tilt rotorcraft in different states, measuring quality characteristic data; based on collected quality characteristic data corresponding to different states, a data fitting technology is used to construct a corresponding adaptive mathematical model.

Description

Technical Field

[0001] The present invention belongs to the field of mass center and moment of inertia measurement, and particularly relates to a method for measuring the mass characteristics, process, and computational mathematical model of a variable-structure large-scale tilt-rotor aircraft. Background Art

[0002] A tilt-rotor aircraft is a unique aircraft that combines vertical takeoff and landing capabilities with horizontal cruise capabilities. Its mass characteristics measurement system is crucial for ensuring the performance, safety, and reliability of the aircraft. During various stages such as vertical takeoff and landing, hovering, transition flight, and horizontal cruise, the tilt-rotor aircraft needs to maintain excellent stability and precise maneuverability. Therefore, accurate measurement of its mass characteristics is the key to ensuring the performance of the aircraft. The mass characteristics measurement system can monitor key parameters such as the weight, center of gravity position, moment of inertia, and product of inertia of the aircraft in real time, providing important data support for the design and optimization of the aircraft.

[0003] In the prior art, the acquisition of mass characteristics data mainly focuses on aircraft with traditional structures such as projectiles and fixed-wing aircraft. For aircraft with complex dynamic characteristics such as tilt-rotor aircraft, the methods for obtaining their mass characteristics data are still insufficient. Specifically, the current technology lacks a complete and systematic mass characteristics data measurement process. Most methods can only provide measurement results in a single state and do not comprehensively consider the dynamic changes in the mass characteristics of tilt-rotor aircraft in different flight states (such as vertical takeoff and landing, transition flight, horizontal cruise, etc.). In addition, the prior art also ignores the significant impact of fuel quantity changes on the mass characteristics data of the aircraft and fails to construct a mathematical model that can accurately reflect the relationship between fuel quantity changes and mass characteristics. Therefore, there is an urgent need in this field for a systematic measurement method and corresponding mathematical model solution that can comprehensively and accurately reflect the changes in the mass characteristics data of tilt-rotor aircraft in different states and consider the influence of fuel quantity changes. Summary of the Invention

[0004] To solve the above problems existing in the prior art, the present invention proposes an intelligent adaptive mass characteristics acquisition method applicable to tilt-rotor aircraft.

[0005] The present invention comprehensively covers fuel-type and non-fuel-type tilt-rotor aircraft, aiming to provide a detailed and systematic dynamic mass characteristics acquisition solution. Specifically, the present invention not only elaborates in detail the entire process from data acquisition to processing and analysis, but also includes an innovative solution for obtaining an adaptive mathematical model of the dynamic mass characteristics of tilt-rotor aircraft.

[0006] The present invention provides an intelligent adaptive mass characteristics acquisition method for tilt-rotor aircraft, and the method includes:

[0007] S1: First, for the target tiltrotor aircraft, determine whether it is a tiltrotor aircraft powered by fuel. According to whether the tiltrotor aircraft uses fuel as the power source, and in combination with different influencing factors and their influencing degrees, the mass characteristic state of the tiltrotor aircraft is subdivided into several state categories with unequal numbers, and corresponding mass characteristic data is collected for each state category;

[0008] S2: For the tiltrotor aircraft in different flight states, measure the mass characteristic data;

[0009] S3: Based on the collected mass characteristic data corresponding to different states, use data fitting technology to construct a corresponding adaptive mathematical model.

[0010] Preferably, step S1 includes:

[0011] S101: First, perform a determination of the power type of the tiltrotor aircraft to clarify whether it is a fuel-driven tiltrotor aircraft;

[0012] S102: If it is determined that the aircraft is a non-fuel tiltrotor aircraft, then when determining the factors affecting its performance, only the nacelle tilt angle is taken into consideration. Conversely, if the aircraft is a fuel tiltrotor aircraft, then two factors, namely the nacelle tilt angle and the fuel quantity, need to be considered simultaneously, and different influence levels are set for each factor. On this basis, the performance of each factor at different levels is recorded as the mass characteristic data of the tiltrotor aircraft under a specific state;

[0013] Preferably, step S102 includes:

[0014] When it is determined that the aircraft is a non-fuel tiltrotor aircraft, during the process of evaluating the influencing factors of the change in its mass characteristics, only the nacelle tilt angle is taken as a single consideration dimension. Specifically, the tiltrotor aircraft is divided into five different mass characteristic states according to different nacelle tilt angles, namely 0°, 15°, 30°, 60°, and 90°.

[0015] On the contrary, if the aircraft is a fuel tiltrotor aircraft, then two variables, namely the nacelle tilt angle and the fuel quantity, need to be considered comprehensively, and different influence levels are set for each variable. For the nacelle tilt angle variable, five levels of 0°, 15°, 30°, 60°, and 90° are set; for the fuel quantity variable, five levels of 0°, 15°, 30°, 60°, and 90° are set. Through the mutual combination of the five levels of these two variables, a total of 25 different combined states are formed. Accordingly, the fuel tiltrotor aircraft is divided into 25 different mass characteristic states.

[0016] Preferably, step S2 includes:

[0017] S201: Define and set the total number of experiments and their execution order. Subsequently, adjust the tiltrotor to the preset state one by one according to this order for accurate measurement of mass characteristics.

[0018] S202: When obtaining the mass characteristic data of the aircraft, measure and record the following parameters in sequence: mass, center of mass position, moment of inertia, and product of inertia. The acquisition of each data item must be strictly carried out in this order to ensure the accuracy and consistency of the data.

[0019] Preferably, step S202 includes:

[0020] S202-1: When performing the mass data determination process of the tiltrotor, use the three-point support method to determine its total mass. Tiltrotor total mass: M = M 1 +M 2 +M 3 (1);

[0021] Specifically, this determination process requires high-precision force sensors or force gauges as force measurement devices, which are accurately arranged at the three support points to measure the forces borne by these three support points respectively. Subsequently, the values collected by the force sensors at these three support points are summarized and processed to obtain the total mass of the tiltrotor. M 1 ,M 2 ,M 3 are the measurement values of the force sensors at the three support points;

[0022] S202-2: Execute the determination process of the center of mass data on the X-axis and Y-axis, using the unbalanced moment method. Suppose in the two-dimensional coordinate plane XOY, the specific operations are as follows: First, apply unbalanced moments to the X-axis and Y-axis respectively and measure the resulting moment effects; then, calculate the ratio of the moments generated on each axis to the corresponding forces, that is, using the principle of moment balance, to accurately obtain the position data of the center of mass in the X-axis and Y-axis directions:

[0023]

[0024] where X 1 ,X 2 ,X 3 ,Y 1 ,Y 2 ,Y 3 are the corresponding coordinate values in the coordinate plane XOY, M 1 ,M 2 ,M 3 are the measurement values of the three force sensors;

[0025] S202-3: Perform the centroid coordinate measurement process in the Z-axis dimension. Place the tilt-rotor aircraft to be measured in a horizontal position and measure the centroid position X in the X-axis direction in this state. 2 = Rcosβ(4);

[0026] Z-direction centroid of the object to be measured in the horizontal state: Z 0 = Rsinβ(5);

[0027] Subsequently, tilt the object to be measured to a predetermined angle α. The x-direction centroid of the object to be measured in the tilted state:

[0028] X 1 = Rcos(α + β) = Rcosαcosβ - Rsinαsinβ(6);

[0029] From the above formula, it can be obtained that:

[0030] S202-4: Perform the measurement process of the moment of inertia and the product of inertia. The UAV mass characteristic parameter measurement system uses the torsion pendulum method to measure the single-axis moment of inertia. Specifically, the torsion pendulum method accurately measures the swing period through an integrated high-precision photoelectric sensor. Based on the measured swing period, the system uses the following moment of inertia solution formula (or equivalent mathematical expression) to calculate the moment of inertia:

[0031]

[0032] In the formula: I is the moment of inertia of the test piece about the H axis; K is the torsional bar stiffness coefficient; ξ is the system viscous damping coefficient; T is the free torsional pendulum period of the system.

[0033] Then the moment of inertia of the system is:

[0034] where T x is the swing period measured with the aircraft loaded, and T 0 is the swing period measured without the aircraft loaded; establish a right-handed coordinate system OXYZ with the table positioning center O as the coordinate origin, and establish a right-handed coordinate system OXYZ with the table positioning center O as the coordinate origin, and the OP axis is the torsional bar rotation axis. Then the moment of inertia of the object to be measured about the OP axis is:

[0035] I p = I XX cos 2 α + I YY cos 2 β + I ZZ cos 2 γ - 2I XY cosαcosβ - 2I YZ cosβcosγ - 2I XZcosαcosγ(10) where I XX ,I YY ,I ZZ ,I XY ,I YZ ,I XZ are respectively the three moments of inertia and three products of inertia of the object to be measured with respect to the coordinate system OXYZ, and α, β, and γ are respectively the angles between the three coordinate axes of the coordinate system of the object to be measured and the axis of the torsion bar. According to the above formula, the moments of inertia of the tilt-rotor aircraft in six attitudes can be obtained to calculate the moments of inertia and the data of the products of inertia with respect to the centroid.

[0036] Preferably, step S3 includes:

[0037] S301: Preliminary identification stage. First, determine the power type of the tilt-rotor aircraft to determine whether it is a fuel-driven type;

[0038] S302: According to the determination result of step S301, perform the following case-by-case processing:

[0039] If the determination result is that the tilt-rotor aircraft is not fuel-driven, the main factor affecting the mass characteristics of the aircraft is limited to the nacelle tilt angle. In this context, the least squares method is used as a mathematical tool for data processing to fit an adaptive mass characteristic equation for the aircraft.

[0040] If the determination result is that the tilt-rotor aircraft is fuel-driven, in addition to the nacelle tilt angle, the amount of fuel needs to be considered as a factor affecting the mass characteristics of the aircraft. For this type of situation, the experimental design method is used as a guide to design and implement a series of experiments, collect data, and then fit an adaptive mass characteristic equation applicable to the fuel-driven tilt-rotor aircraft.

[0041] The working principle of the present invention (the reason for the advantages of the present invention):

[0042] Power source determination and state subdivision: The present invention first determines whether the tilt-rotor aircraft uses fuel, which directly affects the data collection method. Based on this determination, combined with the influencing factors, the mass characteristic states of the tilt-rotor aircraft are subdivided into multiple categories to ensure the pertinence and comprehensiveness of data collection, laying a foundation for constructing a mathematical model.

[0043] Multi-state data measurement: The present invention measures the mass characteristic data of the tilt-rotor aircraft in different flight states (such as vertical takeoff and landing to horizontal cruise) to ensure the comprehensiveness and dynamics of the data, providing rich data support for model construction.

[0044] Full process of obtaining mass characteristics: The working principle of the present invention lies in providing a complete process for obtaining the mass characteristics of a tiltrotor aircraft (including mass, center of mass position, moment of inertia, and products of inertia data). It ensures the accurate measurement and calculation of the key mass characteristics of the tiltrotor aircraft, thus optimizing the design and performance evaluation processes.

[0045] Construction of an adaptive mathematical model: Based on the collected data, the present invention constructs an adaptive mathematical model to reflect the changes in the mass characteristics of the tiltrotor aircraft under different states and takes into account the influence of fuel quantity. The model can adaptively adjust parameters to improve the accuracy and robustness in the face of complex flight states.

[0046] The advantages of the present invention are:

[0047] Comprehensiveness and systematicness:

[0048] The invention proposes a detailed and systematic dynamic mass characteristic acquisition scheme, which comprehensively covers fuel-powered tiltrotor aircraft and non-fuel-powered tiltrotor aircraft, ensuring the wide applicability of the scheme.

[0049] Through power source determination and state subdivision, the invention subdivides the mass characteristic states of the tiltrotor aircraft into multiple specific state categories, providing a solid foundation for subsequent data collection and model construction, and ensuring the comprehensiveness and pertinence of the data.

[0050] Dynamic adaptability:

[0051] The invention measures the mass characteristic data of the tiltrotor aircraft under different flight states, can capture the dynamic changes in the mass characteristics of the tiltrotor aircraft, and provides rich data support for subsequent model construction.

[0052] The constructed adaptive mathematical model can adaptively adjust parameters according to the data under different states to more accurately describe the changes in the mass characteristics of the tiltrotor aircraft, improving the accuracy and robustness of the model.

[0053] Consideration of the influence of fuel quantity change:

[0054] Compared with the prior art, the invention not only considers the changes in the mass characteristics of the tiltrotor aircraft under different flight states, but also particularly emphasizes the influence of fuel quantity change on the mass characteristics.

[0055] By constructing a mathematical model that can reflect the relationship between fuel quantity change and mass characteristics, the invention provides more accurate data support for the design and optimization of the aircraft.

[0056] Improvement of flight performance and safety:

[0057] The invention provides an important basis for the design and optimization of aircraft by accurately measuring the mass characteristic data of tiltrotors, which helps to improve the performance and safety of the aircraft.

[0058] Real-time monitoring of key parameters such as the weight, center of gravity position, and moment of inertia of the aircraft can ensure that the aircraft maintains excellent stability and precise controllability in various stages such as vertical takeoff and landing, hovering, transitional flight, and horizontal cruising.

[0059] Promote technological development:

[0060] The proposal and application of this invention will promote the development of tiltrotor mass characteristic measurement technology, providing new ideas and methods for research and application in related fields.

[0061] With the continuous progress of technology and the expansion of the application scope, this invention is expected to play a greater role in the aviation field, providing more comprehensive and accurate data support for the design and optimization of aircraft. Brief Description of the Drawings

[0062] Figure 1 It is a schematic flow diagram of a method for obtaining the intelligent adaptive mass characteristics of a tiltrotor of the present invention;

[0063] Figure 2 It is a schematic flow diagram for obtaining the mass characteristics in the tiltrotor state;

[0064] Figure 3 It is a schematic diagram for determining the centroid coordinates in the Z-axis dimension in S202-3;

[0065] Figure 4 It is a schematic diagram of the angular relationship between the rotation axis OP and each coordinate in S202-4;

[0066] Figure 5 It is a schematic diagram of the transition process of the tiltrotor nacelle angle change;

[0067] Figure 6 It is a schematic diagram of the device for measuring the mass characteristics of a tiltrotor in the embodiment;

[0068] Figure 7 It is a schematic diagram of the turntable measurement points on the device for measuring the mass characteristics of a tiltrotor in the embodiment;

[0069] Figure 8a It is a schematic diagram of the horizontal attitude of the device for measuring the mass characteristics of a tiltrotor in the embodiment; Figure 8b It is a schematic diagram of the inclined attitude of the device for measuring the mass characteristics of a tiltrotor in the embodiment. Detailed Description of the Invention

[0070] The present invention will be further described below in conjunction with the drawings and embodiments.

[0071] This embodiment provides a method for obtaining the intelligent adaptive mass characteristics of a tiltrotor aircraft, including the following steps:

[0072] S1: First, for the target tiltrotor aircraft, determine whether it is a tiltrotor aircraft powered by fuel. According to whether the tiltrotor aircraft uses fuel as the power source, and combining different influencing factors and their influencing degrees, the mass characteristic states of the tiltrotor aircraft are subdivided into several state categories with different numbers, and corresponding mass characteristic data are collected for each state category;

[0073] Specifically, step S1 includes the following steps:

[0074] S101: First, perform the determination of the power type of the tiltrotor aircraft to clarify whether it is a fuel-driven tiltrotor aircraft; in this embodiment, the specific operation of step S101 is: According to the judgment, this tiltrotor aircraft is a non-fuel-driven tiltrotor aircraft;

[0075] S102: If it is determined that the aircraft is a non-fuel tiltrotor aircraft, then when determining the factors affecting its performance, only the nacelle tilt angle is included in the consideration range. On the contrary, if the aircraft is a fuel tiltrotor aircraft, then two factors, namely the nacelle tilt angle and the fuel quantity, need to be considered simultaneously, and different influence levels are set for each factor. On this basis, the performances of each factor at different levels are recorded as the mass characteristic data of the tiltrotor aircraft under specific states;

[0076] In this embodiment, the specific operation of step S102 is: When it is determined that the aircraft is a non-fuel tiltrotor aircraft, during the process of evaluating the influencing factors of the change in its mass characteristics, only the nacelle tilt angle is used as a single consideration dimension. Specifically, the tiltrotor aircraft is divided into five different mass characteristic states according to different nacelle tilt angles, namely 0°, 15°, 30°, 60°, and 90°.

[0077] Specifically, step S2 includes the following steps:

[0078] S201: Define and set the total number of experiments and their implementation order, and then adjust the tiltrotor aircraft to the preset state one by one according to this order for accurate measurement of mass characteristics;

[0079] In this embodiment, the specific operation of step S201 is: Considering that the aircraft is a tiltrotor aircraft without fuel, its nacelle tilt angle is set as the only evaluation parameter. Accordingly, five mass characteristic data collection operations are carried out in sequence according to the working state order of the tiltrotor aircraft with nacelle tilt angles of 0°, 15°, 30°, 60°, and 90°, and both the data collection and the conversion of the nacelle angle follow this established order.

[0080] S202: When obtaining the mass characteristics data of the aircraft, the following parameters shall be measured and recorded in sequence: mass, center of mass position, moment of inertia, and product of inertia. The acquisition of each item of data shall be strictly carried out in this order to ensure the accuracy and consistency of the data.

[0081] Specifically, step S202 includes the following steps:

[0082] S202-1: When performing the mass data measurement process of the tiltrotor aircraft, the three-point support method is adopted to determine its total mass. The total mass of the tiltrotor aircraft: M = M 1 +M 2 +M 3 (1);

[0083] In this embodiment, the specific operation of step S202-1 is as follows: Specifically, this measurement process requires high-precision force sensors or dynamometers to be equipped as force measurement devices, and these devices are precisely arranged at the three support points to measure the forces borne by these three points respectively. Subsequently, the values collected by these three force sensors are summarized and processed to obtain the total mass of the tiltrotor aircraft. M 1 ,M 2 ,M 3 are the values of the three force sensors; To calculate the actual measured weight, that is, net load = total loaded weight - empty load weight, the following steps need to be performed: First, collect the data records of the three sensors under no-load conditions, and then collect the data records of the three sensors under the condition of loading the tiltrotor aircraft.

[0084] S202-2: Perform the determination process of the center of mass data on the X-axis and Y-axis. The unbalanced moment method is adopted. Suppose in the two-dimensional coordinate plane XOY, the specific operation is as follows: First, apply unbalanced moments to the X-axis and Y-axis respectively and measure the resulting moment effects; then, by calculating the ratio of the moments generated on each axis to the corresponding forces, that is, using the principle of moment balance, accurately obtain the position data of the center of mass in the X-axis and Y-axis directions

[0085] where X 1 ,X 2 ,X 3 ,Y 1 ,Y 2 ,Y 3 are the corresponding coordinate values in the coordinate plane XOY, M 1 ,M 2 ,M 3 are the values of the three force sensors;

[0086] Table 1

[0087]

[0088] S202-3: Perform the centroid coordinate measurement process in the Z-axis dimension. Place the tilt-rotor aircraft to be measured in a horizontal position and measure its centroid position in the X-axis direction in this state: X 2 = Rcosβ (4);

[0089] The Z-direction centroid of the object to be measured in the horizontal state: Z 0 = Rsinβ (5);

[0090] Subsequently, tilt the object to be measured to a predetermined angle α. The x-direction centroid of the object to be measured in the tilted state:

[0091] X 1 = Rcos(α + β) = Rcosαcosβ - Rsinαsinβ (6);

[0092] From the above formula, it can be obtained that:

[0093] In this embodiment, the specific operations of steps S202-2 and S202-3 are as follows:

[0094] Synchronously collect data of the following four states: the aircraft loading state, the aircraft loading and tilting state, the turntable no-load state, and the turntable tilting state. For the data collected in the above-mentioned states, apply the formula net load = total loading weight - no-load weight for calculation. Finally, based on the processed data, deduce and obtain the mass centroid parameters of the tilt-rotor aircraft.

[0095] S202-4: Perform the measurement process of the moment of inertia and the product of inertia. The unmanned aircraft mass characteristic parameter measurement system uses the torsion pendulum method to measure the single-axis moment of inertia. Specifically, the torsion pendulum method accurately measures the swing period through an integrated high-precision photoelectric sensor. Based on the measured swing period, the system uses the following moment of inertia solution formula (or equivalent mathematical expression) to calculate the moment of inertia:

[0096] In the formula: I is the moment of inertia of the test piece about the H axis; K is the torsional bar stiffness coefficient; ξ is the system viscous damping coefficient; T is the free torsion pendulum period of the system.

[0097] Then the moment of inertia of the system is:

[0098] where T x is the swing period measured with the aircraft loaded, and T 0 is the swing period measured without the aircraft loaded; establish a right-handed coordinate system OXYZ with the table positioning center O as the coordinate origin. Establish a right-handed coordinate system OXYZ with the table positioning center O as the coordinate origin, and the OP axis is the torsional bar rotation axis. Then the moment of inertia of the object to be measured about the OP axis is:

[0099] I p = I XX cos 2 α + I YY cos 2 β + I ZZ cos 2 γ - 2I XY cosαcosβ - 2I YZ cosβcosγ - 2I XZ cosαcosγ (10) where I XX ,I YY ,I ZZ ,I XY ,I YZ ,I XZ are respectively the three moments of inertia and three products of inertia of the object under test with respect to the coordinate system OXYZ, and α, β, γ are respectively the angles between the three coordinate axes of the object coordinate system to be measured and the torsion bar rotation axis. According to the above formula, the moments of inertia of the tilt-rotor aircraft in six attitudes can be obtained to calculate the moment of inertia and the data of the product of inertia with respect to its center of mass.

[0100] In this embodiment, the specific operation of step S202-4 is as follows: The present invention relates to a method for measuring the moment of inertia, which mainly relies on the combination of a turntable device and an inclination device to achieve the purpose of attitude transformation. Specifically, the implementation steps are as follows:

[0101] Select measurement points: First, several state measurement points are selected on the turntable device, and these measurement points respectively correspond to the positions of 0°, 45°, 90°, 180°, and 270°.

[0102] Horizontal inertia measurement: When the inclination device is not activated and the turntable remains in a horizontal state, the inertia measurements of no-load and load are simultaneously performed at the above five positions. This step ensures that the inertia data of the turntable at different angles can be accurately obtained without external interference.

[0103] Inclined inertia measurement: Subsequently, the turntable is tilted to 15° by using the inclination device, and the inertia data is measured again at the above five positions in the no-load and load states. This step aims to evaluate the influence of the load on the moment of inertia and obtain the inertia data in the inclined state.

[0104] Data repeated acquisition: When performing state acquisition, for each position of the rotation period, four groups of data are repeatedly acquired to improve the accuracy and reliability of the data. Subsequently, three groups of similar data are selected from each group of four groups of data for averaging, and the obtained average value is used as the periodic data of this measurement state.

[0105] Table 2

[0106]

[0107] Data processing: Consider the data at the 0° and 180° positions as data at the same position. Similarly, consider the data at the 90° and 270° positions as data at the same position. This processing step simplifies the subsequent calculation process based on the symmetry principle of the moment of inertia.

[0108] Moment of inertia calculation: Finally, substitute the processed data into the moment of inertia calculation formula to obtain the corresponding moment of inertia and products of inertia data.

[0109] Table 3

[0110]

[0111] Specifically, step S3 includes the following steps:

[0112] S301: Preliminary identification stage. First, determine the power type of the tiltrotor aircraft to determine whether it is a fuel-driven type;

[0113] In this embodiment, the specific operation of step S301 is:

[0114] According to the judgment, this tiltrotor aircraft is a non-fuel-driven tiltrotor aircraft;

[0115] S302: According to the judgment result of step S301, perform the following case-by-case processing:

[0116] If the judgment result is a non-fuel-driven tiltrotor aircraft, the main factor affecting the mass characteristics of the aircraft is limited to the nacelle tilt angle. In this context, use the least squares method as a mathematical tool for data processing to fit an adaptive mass characteristic equation for the aircraft.

[0117] If the judgment result is a fuel-driven tiltrotor aircraft, in addition to the nacelle tilt angle, the fuel quantity also needs to be considered as a factor affecting the mass characteristics of the aircraft. For such cases, use the experimental design method as a guide to design and implement a series of experiments, collect data, and then fit an adaptive mass characteristic equation applicable to the fuel tiltrotor aircraft.

[0118] In this embodiment, the specific operation of step S302 is:

[0119] If the determination result is a non-fuel-driven tiltrotor aircraft, the main factor affecting the mass characteristics of the aircraft is limited to the nacelle tilt angle. Mass characteristic data at five different nacelle angles (specifically 0°, 15°, 30°, 60°, 90°) are obtained. Subsequently, the least squares method is used to fit these data in order to accurately depict the variation law of the mass characteristics of the tiltrotor aircraft during the entire tilting process. Through the above method, the present invention realizes the effective prediction and acquisition of the mass characteristics of the tiltrotor aircraft within the full tilting range.

[0120] Least squares calculation: Obtain the mass characteristic observation data points (x 1 , y 1 ), (x 2 , y 2 ), (x 3 , y 3 ), (x 4 , y 4 )...(x n , y n ), and hope to find a mass characteristic model y = β 0 + β 1 x(10) (linear model) such that the difference between the model prediction value and the actual observation value is minimized, where x i is the i-th angle and y i is the corresponding mass characteristic data.

[0121] Find a set of parameters β 0 and β 1 such that the sum of the squares of the errors between all the observed values and the model prediction values is minimized. The sum of the squares of the errors S is defined as:

[0122] Find the minimum β 0 and β 1 such that S is minimized;

[0123]

[0124] where, ∑(x i y i ) represents the sum of all x i y i , ∑x i represents the sum of all x i , Σy i represents the sum of all y i , and Σxi 2 represents the sum of all xi 2 .

[0125] Once β 1 is obtained, β 0 can be calculated by the following formula: where y is the average value of y i and is the average value of x which is the average value of x i .

[0126] Obtain the quality characteristic model y = β 0 + β 1 x (linear model), and obtain the model of the quality characteristic with respect to the nacelle tilt angle (including data on the center of mass, moment of inertia, and product of inertia in total)

[0127] The content described in the embodiments of this specification is only an enumeration of the implementation forms of the inventive concept. The protection scope of the present invention should not be regarded as limited to the specific forms stated in the embodiments. The protection scope of the present invention also extends to equivalent technical means that can be conceived by those skilled in the art based on the inventive concept of the present invention.

Claims

1. A method for obtaining intelligent adaptive quality characteristics of a tiltrotor aircraft, characterized in that: The following steps are involved: S1: First, for the target tiltrotor, determine whether it is a tiltrotor that uses fuel as a power source; based on whether the tiltrotor uses fuel as a power source and in combination with different influencing factors and their degree of influence, subdivide the mass characteristic state of the tiltrotor into a number of state categories of varying numbers, and collect corresponding mass characteristic data for each state category; S2: Measure mass characteristic data for tiltrotor aircraft in different states; S3: Based on the collected quality characteristic data corresponding to different states, the data fitting technology is used to construct the corresponding adaptive mathematical model.

2. According to claim 1, a tiltrotor aircraft intelligent adaptive quality characteristic acquisition method is characterized in that: Step S1 includes: S101: First, determine the power type of the tiltrotor aircraft to determine whether it is a fuel-driven tiltrotor aircraft; S102: If the aircraft is determined to be a non-fuel tiltrotor, only the nacelle tilt angle is taken into consideration when determining the factors affecting its performance. On the contrary, if the aircraft is a fuel tiltrotor, both the nacelle tilt angle and the amount of fuel are considered, and different impact levels are set for each factor. On this basis, the performance of each factor at different levels is recorded as the mass characteristic data of the tiltrotor in a specific state.

3. According to claim 2, a method for obtaining intelligent adaptive quality characteristics of a tiltrotor aircraft is characterized in that: Step S2 includes: S201: clarifying and setting the total number of experiments and the order of their implementation, and then adjusting the tiltrotor aircraft to a preset state one by one according to the order, so as to accurately measure the mass characteristics; S202: When acquiring the aircraft mass characteristic data, measure and record the following parameters in sequence: mass, center of mass position, moment of inertia, and product of inertia; the acquisition of each data must be strictly performed in this order to ensure the accuracy and consistency of the data.

4. A tiltrotor aircraft intelligent adaptive quality characteristic acquisition method according to claim 3, characterized in that: Step S202 includes: S202-1: When executing the mass data determination process of the tiltrotor aircraft, the three-point support method is used to determine its total mass. The total mass of the tiltrotor aircraft is: M = M1 + M2 + M3 (1) Specifically, the measurement process is equipped with high-precision force sensors or dynamometers as force measuring devices, which are precisely arranged on three supporting points to measure the forces borne by the three supporting points respectively; then, the values ​​collected by the three force sensors are summarized and processed to obtain the total mass of the tiltrotor aircraft; M1, M2, M3 are the measurement values ​​of the force sensors on the three supporting points; S202-2: Execute the process of measuring the X-axis and Y-axis centroid data, using the unbalanced moment method, set in the two-dimensional coordinate plane XOY, and the specific operations are as follows: First, apply unbalanced moments to the X-axis and Y-axis respectively, and measure the torque effect generated thereby; then, by calculating the ratio of the torque generated on each axis to the corresponding force, that is, using the moment balance principle, accurately obtain the position data of the centroid in the X-axis and Y-axis directions: Among them, X1, X2, X3, Y1, Y2, Y3 are their corresponding coordinate values ​​on the coordinate plane XOY; S202-3: Execute the Z-axis dimension centroid coordinate measurement process, place the tiltrotor aircraft under test in a horizontal position, and measure its centroid position in the X-axis direction in this state: X2=Rcosβ(4); The Z-center of gravity of the object under test in the horizontal state: Z0 = Rsinβ(5); Then, the object to be measured is tilted to a predetermined angle α, and the x-center of gravity of the object to be measured in the tilted state is: X1=Rcos(α+β)=Rcosαcosβ-Rsinαsinβ(6); According to the above formula, we can get: S202-4: Execute the moment of inertia and product of inertia measurement process. The drone mass characteristic parameter measurement system uses the torsion pendulum method to measure the single-axis moment of inertia. Specifically, the torsion pendulum method accurately measures the swing period through an integrated high-precision photoelectric sensor. Based on the measured swing period, the system uses the following moment of inertia solution formula (or equivalent mathematical expression) to calculate the moment of inertia: Where, I is the moment of inertia of the specimen about the H axis; K is the torsion bar stiffness coefficient; ξ is the system viscous damping coefficient; T is the free torsion period of the system; The moment of inertia of the system is: Among them, T x is the swing period measured by the loaded aircraft, T0 is the swing period measured by the unloaded aircraft; The right-handed coordinate system OXYZ is established with the table positioning center O as the coordinate origin. The OP axis is the torsion bar axis, and the moment of inertia of the object being measured around the OP axis is: p =I XX cos 2 α+I YY cos 2 β+I ZZ cos 2 γ-2I XY cosαcosβ-2I YZ cosβcosγ-2I XZ cosαcosγ(10)where I XX , I YY , I ZZ , I XY , I YZ , I XZ are the three moments of inertia and three products of inertia of the object to be measured relative to the coordinate system OXYZ, α, β, γ are the angles between the three coordinate axes of the coordinate system of the object to be measured and the torsion bar axis, respectively. According to the above formula, the moment of inertia of the tiltrotor aircraft in six postures can be obtained to obtain the moment of inertia and product of inertia data relative to the center of mass.

5. According to claim 3, a tiltrotor aircraft intelligent adaptive quality characteristic acquisition method is characterized in that: Step S3 includes: S301: Initial identification stage, firstly, determining the power type of the tiltrotor aircraft to determine whether it is a fuel-driven type; S302: According to the determination result of step S301, the following processing is performed: If the result of the determination is that the aircraft is a non-fuel-driven tiltrotor aircraft, the main factor affecting the mass characteristics of the aircraft is limited to the nacelle tilt angle; in this case, the least square method is used as a mathematical tool to perform data processing to fit the adaptive mass characteristic equation for the aircraft; If the result is a fuel-driven tiltrotor aircraft, then the factors affecting the mass characteristics of the aircraft, in addition to the nacelle tilt angle, also need to take into account the amount of fuel. For such cases, the experimental design method is used as a guide to design and implement a series of experiments, collect data, and then fit the adaptive mass characteristic equation suitable for the fuel-driven tiltrotor aircraft.

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