A method and system for processing aerodynamic noise of a helicopter rotor in forward flight

Abstract

The application provides a method for processing aerodynamic noise of a helicopter rotor in a forward flight state, and the method comprises the following steps: acquiring noise calculation parameters, blade load data, grid data and blade control quantity; processing the blade load data, the grid data and the blade control quantity to obtain a processing result; substituting the noise calculation parameters and the processing result into a noise calculation formula to obtain a contribution of each grid unit to total noise; superimposing the contribution of each grid unit to total noise to obtain a sound pressure time history of the entire rotor; and processing the sound pressure time history of the entire rotor to obtain a total sound pressure level of the rotor.

Description

Technical Field

[0001] This application belongs to the field of helicopter rotor aerodynamic noise analysis and control technology, and particularly relates to a method and system for processing helicopter rotor aerodynamic noise in forward flight state. Background Technology

[0002] The noise handling method in this technology involves transforming the blade mesh according to deformation during the noise calculation preparation stage before substituting it into the noise calculation program. This method is only applicable to hovering and cannot be extended to forward flight.

[0003] Because the blade mesh of this method has the same amount of deformation in all azimuth angles, it is impossible to realize that the blade mesh changes with the azimuth angle. This is completely inconsistent with the forward flight state, where different azimuth angles in the forward flight state have different blade deformations. Summary of the Invention

[0004] To address the aforementioned technical problems, in a first aspect, this application provides a method for processing aerodynamic noise of a helicopter rotor in forward flight, the method comprising:

[0005] Acquire noise calculation parameters, blade load data, mesh data, and blade control parameters;

[0006] The blade load data, grid data, and blade control parameters are processed to obtain the processing results;

[0007] Substituting the noise calculation parameters and processing results into the noise calculation formula, the contribution of each grid cell to the total noise is obtained;

[0008] The sound pressure time history of the entire rotor is obtained by summing the contributions of each grid cell to the total noise.

[0009] The total sound pressure level of the rotor is obtained by processing the sound pressure time history of the entire rotor.

[0010] Preferably, the process of processing the blade load data, grid data, and blade control parameters to obtain the processing result includes:

[0011] Process the blade load data to obtain the time derivative of the load data;

[0012] Process the grid data to obtain the center coordinates, normal vector, and area of ​​each grid cell;

[0013] The blade manipulation amount is processed to obtain the manipulation amount for each grid cell.

[0014] Preferably, the step of substituting the noise calculation parameters and processing results into the noise calculation formula to obtain the contribution of each grid cell to the total noise includes:

[0015] Substituting the noise calculation parameters, the manipulation amount of each grid cell, the time derivative of the load data, the center coordinates, normal vector, and area of ​​each grid cell into the noise calculation formula, we obtain the contribution of each grid cell to the total noise.

[0016] Preferably, the noise calculation parameters include rotor information and observation point information.

[0017] Preferably, the method further includes:

[0018] A three-dimensional blade surface mesh is drawn based on the blade shape parameters; wherein, the blade shape parameters include blade radius, airfoil distribution, chord length distribution, quarter chord point distribution, and torsion distribution.

[0019] Preferably, the method further includes:

[0020] The comprehensive analysis software for rotorcraft is configured based on rotor parameters. The configuration includes at least the overall rotor parameters, blade structure parameters, blade aerodynamic parameters, sensor arrangement and type, airframe weight, and center of gravity. The sensors include position sensors, lift sensors, drag sensors, and velocity sensors.

[0021] Preferably, the method further includes:

[0022] The target trim amount is determined based on the flight status, and then substituted into the comprehensive analysis software for rotorcraft to perform trim calculations. A flexible beam model is used to consider the elastic deformation of the blades.

[0023] The blade load data, as well as the torsional angle, flapping displacement, and oscillation displacement at each spanwise position in each azimuth direction, are extracted from the calculation results.

[0024] Preferably, the blade load data includes the distribution of the blade surface lift coefficient and drag coefficient.

[0025] Preferably, the method further includes:

[0026] The flapping displacement is converted into a flapping angle, and the oscillation displacement is converted into an oscillation angle; wherein, the torsion angle, flapping angle, and oscillation angle include the torsion and forward / backward sweep position of the blade itself.

[0027] Preferably, the method further includes:

[0028] By removing the influence of the blade's own parameters, we obtain the twist angle, flapping angle, and oscillation angle, which vary with the azimuth and spanwise positions, i.e., the blade control parameters.

[0029] Secondly, this application also provides a helicopter rotor aerodynamic noise reduction system in forward flight state, the system comprising:

[0030] The acquisition module is used to acquire noise calculation parameters, blade load data, grid data, and blade control parameters.

[0031] The processing module is used to process the blade load data, grid data, and blade control parameters to obtain the processing results.

[0032] The calculation module is used to substitute the noise calculation parameters and processing results into the noise calculation formula to obtain the contribution of each grid cell to the total noise;

[0033] The superposition module is used to superimpose the contribution of each grid cell to the total noise to obtain the sound pressure time history of the entire rotor.

[0034] The processing module is also used to process the sound pressure time history of the entire rotor to obtain the total sound pressure level of the rotor.

[0035] Preferably, the processing module is further configured to process the blade load data to obtain the time derivative of the load data;

[0036] The processing module is also used to process the grid data to obtain the center coordinates, normal vector, and area of ​​each grid cell;

[0037] The processing module is also used to process the blade manipulation amount to obtain the manipulation amount for each grid cell.

[0038] Preferably, the calculation module is further configured to substitute the noise calculation parameters, the manipulation amount of each grid cell, the time derivative of the load data, the center coordinates, normal vector and area of ​​each grid cell into the noise calculation formula to obtain the contribution of each grid cell to the total noise.

[0039] Preferably, the noise calculation parameters include rotor information and observation point information.

[0040] Preferably, the system further includes:

[0041] The drawing module is used to draw a three-dimensional blade surface mesh based on the blade shape parameters; wherein, the blade shape parameters include blade radius, airfoil distribution, chord length distribution, quarter chord point distribution, and torsion distribution.

[0042] Preferably, the calculation module is further used to calculate and configure the comprehensive analysis software for the rotorcraft based on the rotor parameters. The configuration includes at least the overall rotor parameters, blade structure parameters, blade aerodynamic parameters, sensor arrangement and type, airframe weight, and center of gravity. The sensors include position sensors, lift sensors, drag sensors, and speed sensors.

[0043] Preferably, the calculation module is further used to determine the trim target amount based on the flight state, input it into the rotorcraft comprehensive analysis software for trim calculation, and use a flexible beam model to consider the blade elastic deformation.

[0044] The acquisition module is also used to extract blade load data from the calculation results, as well as the torsional angle, flapping displacement and oscillation displacement at each spanwise position in each azimuth.

[0045] Preferably, the blade load data includes the distribution of the blade surface lift coefficient and drag coefficient.

[0046] Preferably, the system further includes:

[0047] The conversion module is used to convert the flapping displacement into a flapping angle and the oscillation displacement into an oscillation angle; wherein the torsion angle, flapping angle, and oscillation angle include the torsion and forward / backward sweep position of the blade itself.

[0048] Preferably, the processing module is further used to process and remove the influence of the blade's own parameters to obtain the twist angle, flapping angle and oscillation angle that vary with the azimuth angle and spanwise position, i.e., the blade control amount.

[0049] The beneficial effects of this invention are:

[0050] This invention provides a method and system for calculating aerodynamic noise of a rotor in forward flight considering the elastic deformation of the blades, and can also calculate the hovering state. The calculation results are more accurate than those of the prior art. Attached Figure Description

[0051] Figure 1 A flowchart of rotor aerodynamic noise processing provided in the embodiments of this application;

[0052] Figure 2 This is a schematic diagram of a three-dimensional blade surface mesh provided in an embodiment of this application;

[0053] Figure 3 The torsion angle, flapping angle, and oscillation angle at each spanwise position in each azimuth direction are provided in the embodiments of this application;

[0054] Figure 4 A schematic diagram of the deformation distribution in the waving direction under level flight conditions with a forward ratio of 0.25, provided in an embodiment of this application.

[0055] Figure 5 The total noise cloud map of forward flight state obtained without considering blade deformation calculation is provided in the embodiments of this application;

[0056] Figure 6 The total noise cloud map of forward flight state obtained by the present invention considering blade deformation calculation is provided for the embodiments of this application;

[0057] Figure 7 The noise difference cloud map provided for embodiments of this application takes into account the blade deformation before and after the deformation. Detailed Implementation

[0058] In Embodiment 1 of this application, the provided solution includes the following:

[0059] (1) Draw a three-dimensional blade surface mesh based on the blade shape parameters.

[0060] The blade shape parameters include blade radius, airfoil distribution, chord length distribution, quarter chord point distribution, and torsional distribution.

[0061] Specifically, airfoil generation software is used to generate two-dimensional coordinate points on the airfoil surface, the coordinate points are connected to generate a two-dimensional airfoil mesh, and one-dimensional station points distributed along the blade span are generated.

[0062] The generated two-dimensional airfoil surface mesh of the blade is arranged according to the airfoil distribution and the one-dimensional station point distribution law of the blade span, and scaled according to the chord length distribution law to obtain the mesh of each section along the blade span.

[0063] The root and tip of the propeller are folded to create an O-shaped tip.

[0064] Based on the distribution patterns of the rotor blade's twist angle (rotation) and 1 / 4 chord length position (translation) along the blade span, coordinate transformations are performed on the two-dimensional airfoil surface mesh and folded mesh at various positions along the blade span, ultimately generating a three-dimensional rotor blade surface mesh, as shown below. Figure 2 As shown.

[0065] The 1 / 4 chord length position consists of horizontal and vertical translations. The two-dimensional airfoil surface grid and folded grid of the blade section at each position along the blade span are translated in the plane of the blade section according to the translation.

[0066] Specifically, for rotors with complex tip shapes, the rotor tip shape is obtained using the following interpolation formula with chord length as the weighting coefficient.

[0067] θ1=|r-r1| / |r2-r1|

[0068] θ2=|r-r2| / |r2-r1|

[0069] CH(r) = C1·θ2 + C2·θ1

[0070] Coe1=|CH(r)-CH(r1)| / |CH(r1)-CH(r2)|

[0071] Coe2=|CH(r)-CH(r2)| / |CH(r1)-CH(r2)|

[0072] Where θ1 and θ2 are spanwise weighting coefficients, r1, r2, and r are the spanwise positions of the airfoil, C1 and C2 are the spanwise profile airfoil chord lengths, CH is the interpolated chord length, and Coe1 and Coe2 are the chord length weighting coefficients.

[0073] (2) Calculate the rotor blade control and blade surface load data for the helicopter's flight status; the flight status includes flight speed and flight path angle.

[0074] Specifically, the first step is to model the rotorcraft using comprehensive analysis software such as CAMRAD II based on the helicopter configuration parameters.

[0075] The helicopter configuration parameters include at least the overall rotor parameters (number of blades, hovering Mach number, rotation direction lights), blade structural parameters (torsion angle distribution, flapping stiffness, tumbling stiffness, torsional stiffness, etc.), blade aerodynamic parameters (chord length distribution, sweep angle distribution), sensor arrangement and type (position sensor, lift sensor, drag sensor, speed sensor, etc.), and airframe weight and center of gravity.

[0076] The flight status (flight speed, flight trajectory angle) is substituted into the comprehensive analysis software for rotorcraft for trim calculation. During this process, the aerodynamic / dynamic calculation of the rotor blade is performed using an elastic blade model to obtain the position information of each section of the rotor blade and the blade surface load data.

[0077] The positional information of each section of the rotor blade includes the torsional angle, flapping displacement, and flaring displacement at each spanwise position in each azimuth direction, such as... Figure 3 As shown; the blade surface load data includes the lift coefficient and drag coefficient at each spanwise position in all directions.

[0078] The positional information of each section of the rotor blade is further processed to obtain the control parameters of each section of the rotor blade.

[0079] Specifically, the flapping displacement is converted into flapping angle, and the flaring displacement is converted into flaring angle. At the same time, the position information of each section of the rotor blade, including the torsion angle, flapping angle, and flaring angle, includes the torsion and sweep position of the blade itself. Further processing is needed to remove the influence of the blade's own parameters, and finally the torsion angle, flapping angle, and flaring angle of each spanwise position in each azimuth angle are obtained. These quantities can be collectively referred to as the control quantities of each section of the rotor blade.

[0080] (3) Determine the noise calculation input parameters, including: helicopter flight speed, helicopter flight track angle, number of discrete points for calculating the time of one rotor rotation, number of rotor blades, rotor blade radius, blade chord length, hovering tip Mach number, and blade rotation direction.

[0081] (4) Generate observation points.

[0082] To analyze the aerodynamic noise radiation characteristics of helicopter rotors, the center of the rotor hub is typically used as the center of a sphere, and hemispheres of sound radiation, divided at equal angles along latitude and longitude lines, are taken as observation points. The distance between each observation point and the center of the hub is generally 5 to 20 times the rotor radius. Figure 4 As shown.

[0083] (5) Substitute the noise calculation input parameters, observation points, three-dimensional blade surface mesh, rotor blade control amount and blade surface load data into the noise calculation formula to solve the rotor noise sound pressure time history at the observation point.

[0084] The noise calculation formula is as follows:

[0085]

[0086]

[0087]

[0088] Where, p′ T p′ represents thickness noise. L Represents load noise, a0 represents the speed of sound in a undisturbed medium, ρ0 is the density, f = 0 is the blade surface equation, v is the velocity, [*] ret The variables within the parentheses take values ​​under the delay time; r is the distance between the source term and the observation point, L is the lift of the blade section, subscripts r and M are the projections along the propagation direction and the direction of the source surface motion Mach number, respectively, M is the source surface motion Mach number, dS represents the surface element of the blade, dl(y) is the distance between adjacent compact source points, and y is the radial position of the compact source point.

[0089] In Embodiment 2 of this application, when using the noise calculation formula to solve the time history of rotor noise sound pressure at the observation point, it is necessary to superimpose the contribution of all spanwise micro-elements of the blade to the rotor noise at the observation point. All spanwise micro-elements of the blade extract independent torsion angle, flapping angle and flaring angle from the torsion angle, flapping angle and flaring angle at each spanwise position of each azimuth angle. This is significantly different from the prior art and can take into account the influence of blade elastic deformation on rotor noise.

[0090] (6) Perform a Fourier transform on the sound pressure time history at the observation point to obtain the frequency domain information of the rotor noise. The effective sound pressure is obtained by calculating the root mean square value of the sound pressure time history at the observation point using the following formula.

[0091]

[0092] Where, p e For effective sound pressure, N is the number of time discrete points in one rotor revolution, and x(n) is the sound pressure value at each time discrete point.

[0093] The sound pressure level at the observation point is calculated using the following formula.

[0094]

[0095] Where SPL is the sound pressure level, p ref As a reference sound pressure level, 2 × 10⁻⁶ is typically used in air. -5 Pa.

[0096] (7) Transform the hemisphere into a conical projection with the positive Y-axis to obtain the Lambert projection of the acoustic radiation hemisphere.

[0097] In Embodiment 3 of this application, please refer to Figure 1-7 The solution provided in this application is as follows:

[0098] (1) Draw a three-dimensional blade surface mesh based on the blade shape parameters (blade radius, airfoil distribution, chord length distribution, quarter chord point distribution, and torsion distribution), such as Figure 2 .

[0099] (2) Calculate and configure the comprehensive analysis software for the rotorcraft based on the rotor parameters. The configuration content includes at least the overall rotor parameters, blade structure parameters, blade aerodynamic parameters, sensor arrangement and type (position sensor, lift sensor, drag sensor, speed sensor, etc.), airframe weight and center of gravity.

[0100] (3) Determine the trim target amount based on the flight status, substitute it into the rotorcraft comprehensive analysis software for trim calculation, and use a flexible beam model to consider the blade elastic deformation.

[0101] (4) Extract the blade load data, as well as the torsional angle, flapping displacement and oscillation displacement at each spanwise position in each azimuth direction from the calculation results;

[0102] (5) The swing displacement is converted into the swing angle, and the oscillation displacement is converted into the oscillation angle;

[0103] (6) At this time, the torsion angle, flapping angle and oscillation angle include the torsion and forward and backward sweeping position of the blade itself. Further processing is needed to remove the influence of the blade's own parameters, and finally the torsion angle, flapping angle and oscillation angle that vary with the azimuth angle and spanwise position are obtained. These quantities can be collectively referred to as blade control quantities.

[0104] (7) At this point, all preparation files for noise calculation are complete, including four parts: noise calculation input parameters (rotor information, observation point information), blade surface mesh (mesh coordinates), blade load data (blade surface lift coefficient, drag coefficient distribution), and blade control parameters. Then follow... Figure 1 The flowchart shown is used to calculate rotor noise.

[0105] (8) Process the grid data to obtain information such as the center coordinates, normal vector, and area of ​​each integral element; process the load data to obtain information such as the time derivative of the load.

[0106] (9) Extract the grid information and load information of a rotor.

[0107] (10) Take out an integral element, and at the same time take out the grid information of the element and its load information at each azimuth angle, and store it in a temporary array.

[0108] (11) Take out a blade and calculate the starting position coordinates of the observation point.

[0109] (12) Take out a physical time and use Newton's method to iteratively solve for the delay time.

[0110] (13) The load information and micro-element motion law (manipulation amount) at the delay time are obtained from the temporary array formed in step (10) by interpolation.

[0111] (14) Obtain the motion information of the infinitesimal element through the motion law of the blade and the coordinate transformation formula.

[0112] (15) The contribution of the extracted micro-element to the total noise is calculated using the noise calculation formula.

[0113]

[0114]

[0115]

[0116] Where, p′ T p′ represents thickness noise. L Represents load noise, a0 represents the speed of sound in a undisturbed medium, ρ0 is the density, f = 0 is the blade surface equation, v is the velocity, [*] ret The variables within the parentheses take values ​​under the delay time; r is the distance between the source term and the observation point, L is the lift of the blade section, subscripts r and M are the projections along the propagation direction and the direction of the source surface motion Mach number, respectively, M is the source surface motion Mach number, dS represents the surface element of the blade, dl(y) is the distance between adjacent compact source points, and y is the radial position of the compact source point.

[0117] (16) Determine if this is the last physical time. If yes, remove the next blade; otherwise, repeat steps (11) to (16).

[0118] (17) Determine if this is the last blade. If yes, take out the next integral element; otherwise, repeat steps (11) to (17).

[0119] (18) Determine if it is the last integral element. If yes, take out the next rotor; otherwise, repeat steps (11) to (18).

[0120] (19) Determine if this is the last rotor. If yes, the sound pressure time history at the observation point has been calculated. If not, repeat steps (11) to (19).

[0121] (20) Perform Fourier transform on the time history of sound pressure to obtain the frequency domain information of noise.

[0122] (21) Output the settlement results.

[0123] In Embodiment 4 of this application, a method for processing aerodynamic noise of a helicopter rotor in forward flight state is provided. The method includes: acquiring noise calculation parameters, blade load data, grid data, and blade control parameters; processing the blade load data, grid data, and blade control parameters to obtain a processing result; substituting the noise calculation parameters and processing result into a noise calculation formula to obtain the contribution of each grid cell to the total noise; superimposing the contributions of each grid cell to the total noise to obtain the sound pressure time history of the entire rotor; and processing the sound pressure time history of the entire rotor to obtain the total sound pressure level of the rotor. Simultaneously, this application also provides an aerodynamic noise processing system for a helicopter rotor in forward flight state; the calculation results of this application are more accurate.

Claims

1. A method for processing aerodynamic noise of a helicopter rotor in forward flight state, characterized in that, The method includes: Acquire noise calculation parameters, blade load data, mesh data, and blade control parameters; The blade load data, grid data, and blade control parameters are processed to obtain the processing results; Substituting the noise calculation parameters and processing results into the noise calculation formula, the contribution of each grid cell to the total noise is obtained; The sound pressure time history of the entire rotor is obtained by summing the contributions of each grid cell to the total noise. The total sound pressure level of the rotor is obtained by processing the sound pressure time history of the entire rotor.

2. The method according to claim 1, characterized in that, The process of processing the blade load data, grid data, and blade control parameters to obtain the processing result includes: Process the blade load data to obtain the time derivative of the load data; Process the grid data to obtain the center coordinates, normal vector, and area of ​​each grid cell; The blade manipulation amount is processed to obtain the manipulation amount for each grid cell.

3. The method according to claim 2, characterized in that, The step of substituting the noise calculation parameters and processing results into the noise calculation formula to obtain the contribution of each grid cell to the total noise includes: Substituting the noise calculation parameters, the manipulation amount of each grid cell, the time derivative of the load data, the center coordinates, normal vector, and area of ​​each grid cell into the noise calculation formula, we obtain the contribution of each grid cell to the total noise.

4. The method according to claim 3, characterized in that, The noise calculation parameters include rotor information and observation point information.

5. The method according to claim 4, characterized in that, The method further includes: A three-dimensional blade surface mesh is drawn based on the blade shape parameters; wherein, the blade shape parameters include blade radius, airfoil distribution, chord length distribution, quarter chord point distribution, and torsion distribution.

6. The method according to claim 5, characterized in that, The method further includes: The comprehensive analysis software for rotorcraft is configured based on rotor parameters. The configuration includes at least the overall rotor parameters, blade structure parameters, blade aerodynamic parameters, sensor arrangement and type, airframe weight, and center of gravity. The sensors include position sensors, lift sensors, drag sensors, and velocity sensors.

7. The method according to claim 6, characterized in that, The method further includes: The target trim amount is determined based on the flight status, and then substituted into the comprehensive analysis software for rotorcraft to perform trim calculations. A flexible beam model is used to consider the elastic deformation of the blades. The blade load data, as well as the torsional angle, flapping displacement, and oscillation displacement at each spanwise position in each azimuth direction, are extracted from the calculation results.

8. The method according to claim 7, characterized in that, The blade load data includes the distribution of the blade surface lift coefficient and drag coefficient.

9. The method according to claim 8, characterized in that, The method further includes: The flapping displacement is converted into a flapping angle, and the oscillation displacement is converted into an oscillation angle; wherein, the torsion angle, flapping angle, and oscillation angle include the torsion and forward / backward sweep position of the blade itself.

10. The method according to claim 9, characterized in that, The method further includes: By removing the influence of the blade's own parameters, we obtain the twist angle, flapping angle, and oscillation angle, which vary with the azimuth and spanwise positions, i.e., the blade control parameters.

11. A helicopter rotor aerodynamic noise reduction system in forward flight state, characterized in that, The system includes: The acquisition module is used to acquire noise calculation parameters, blade load data, grid data, and blade control parameters. The processing module is used to process the blade load data, grid data, and blade control parameters to obtain the processing results. The calculation module is used to substitute the noise calculation parameters and processing results into the noise calculation formula to obtain the contribution of each grid cell to the total noise; The superposition module is used to superimpose the contribution of each grid cell to the total noise to obtain the sound pressure time history of the entire rotor. The processing module is also used to process the sound pressure time history of the entire rotor to obtain the total sound pressure level of the rotor.

12. The system according to claim 11, characterized in that, The processing module is also used to process the blade load data to obtain the time derivative of the load data; The processing module is also used to process the grid data to obtain the center coordinates, normal vector, and area of ​​each grid cell; The processing module is also used to process the blade manipulation amount to obtain the manipulation amount for each grid cell.

13. The system according to claim 12, characterized in that, The calculation module is also used to substitute the noise calculation parameters, the manipulation amount of each grid cell, the time derivative of the load data, the center coordinates, normal vector and area of ​​each grid cell into the noise calculation formula to obtain the contribution of each grid cell to the total noise.

14. The system according to claim 13, characterized in that, The noise calculation parameters include rotor information and observation point information.

15. The system according to claim 14, characterized in that, The system also includes: The drawing module is used to draw a three-dimensional blade surface mesh based on the blade shape parameters; wherein, the blade shape parameters include blade radius, airfoil distribution, chord length distribution, quarter chord point distribution, and torsion distribution.

16. The system according to claim 15, characterized in that, The calculation module is also used to calculate and configure the comprehensive analysis software for the rotorcraft based on the rotor parameters. The configuration includes at least the overall rotor parameters, blade structure parameters, blade aerodynamic parameters, sensor arrangement and type, airframe weight and center of gravity; wherein the sensors include position sensors, lift sensors, drag sensors and speed sensors.

17. The system according to claim 16, characterized in that, The calculation module is also used to determine the trim target amount based on the flight status, input it into the rotorcraft comprehensive analysis software for trim calculation, and use a flexible beam model to consider the elastic deformation of the blades. The acquisition module is also used to extract blade load data from the calculation results, as well as the torsional angle, flapping displacement and oscillation displacement at each spanwise position in each azimuth.

18. The system according to claim 17, characterized in that, The blade load data includes the distribution of the blade surface lift coefficient and drag coefficient.

19. The system according to claim 18, characterized in that, The system also includes: The conversion module is used to convert the flapping displacement into a flapping angle and the oscillation displacement into an oscillation angle; wherein the torsion angle, flapping angle, and oscillation angle include the torsion and forward / backward sweep position of the blade itself.

20. The system according to claim 19, characterized in that, The processing module is also used to process and remove the influence of the blade's own parameters to obtain the twist angle, flapping angle and oscillation angle that vary with the azimuth angle and spanwise position, i.e., the blade control amount.

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