CN111272380B - Wind shaft system self-calibration method for wind tunnel test model pose video measurement - Google Patents

Wind shaft system self-calibration method for wind tunnel test model pose video measurement Download PDF

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CN111272380B
CN111272380B CN202010110599.XA CN202010110599A CN111272380B CN 111272380 B CN111272380 B CN 111272380B CN 202010110599 A CN202010110599 A CN 202010110599A CN 111272380 B CN111272380 B CN 111272380B
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axis
model
wind
object space
test
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CN111272380A (en
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张征宇
王学渊
杨振华
魏锦宇
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High Speed Aerodynamics Research Institute of China Aerodynamics Research and Development Center
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High Speed Aerodynamics Research Institute of China Aerodynamics Research and Development Center
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
    • G01M9/06—Measuring arrangements specially adapted for aerodynamic testing
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
    • G01M9/02—Wind tunnels
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M9/00—Aerodynamic testing; Arrangements in or on wind tunnels
    • G01M9/08—Aerodynamic models

Abstract

The invention discloses a wind axis self-calibration method for video measurement of pose of a wind tunnel test model, which is characterized in that only three mark points are needed to be pasted on the model, based on the existing wind tunnel test process, after the model reference installation state with a zero attitude angle is completed, and in the absence of wind, a model attitude adjusting mechanism is controlled to support the model to do given attitude motion, so that the direction vectors of three coordinate axes of the wind axis in a camera object space can be accurately obtained, and the wind axis self-calibration of the video measurement of the pose of the test model is realized; and then based on the reference installation state and 3 mark points in the given state of the blowing test, calculating a translation and rotation matrix, and accurately solving the direction vector of the three axes of the model axis system in the given state of the blowing test in the object space of the camera, so that the model attitude and the deformation parameters under the aerodynamic force can be obtained. The invention saves labor and time, and does not need the traditional high-precision and high-cost multi-degree-of-freedom rotating platform and step calibration block, thereby having huge engineering application prospect.

Description

Wind shaft system self-calibration method for wind tunnel test model pose video measurement
Technical Field
The method relates to the technical field of wind tunnel tests based on machine vision and photogrammetry, in particular to a camera-based self-calibration method for video measurement of a wind shaft system of a test model pose.
Background
A high-speed wind tunnel test object (namely a test model) is generally connected with a posture adjusting mechanism of the model through a rod type cantilever beam bearing structure, and the posture parameters set by the posture adjusting mechanism are different from the actual posture of the test model due to insufficient supporting rigidity under the action of aerodynamic force. For example, the pneumatic load borne by the model during the 2.4 m transonic wind tunnel test can be up to 20 tons, and even a high-strength steel supporting mechanism can also generate obvious elastic deformation, so that the difference between the actual posture of the test model and the posture set by the model posture adjusting mechanism is caused.
Therefore, the attitude parameters of the wind tunnel test object (namely the test model) under the action of aerodynamic force are accurately measured, the torsion and bending deformation of the wing of the test model are mastered, and the corresponding relation between the actually measured aerodynamic data and the actually measured attitude and aerodynamic shape of the actually measured aerodynamic data is obtained, so that the method is a precondition for realizing model elastic influence correction of the high-speed wind tunnel test data and is also an inevitable requirement for verifying the CFD numerical simulation result based on the test data.
Although the Video Measurement (VM) technology has no special requirements on the design of the test model, the marking points are only needed to be pasted on the test model, and the collinear equation can be used for solving the three-dimensional coordinates of the marking points to obtain the deformation data of the wing wind tunnel test model, so that the method is favored by wind tunnel test mechanisms at home and abroad.
In the prior art, a camera calibration method commonly adopted by wind tunnel test mechanisms at home and abroad requires that three axes of a step calibration block coordinate system and three axes of a wind shaft system must be parallel (the direction of an X axis is reverse), so that the step calibration block can be positioned in a wind tunnel test section only by using a high-precision multi-degree-of-freedom rotating table, and at the moment, the three axes and the three axes of the wind shaft system must be parallel (the direction of the X axis is reverse), namely, a camera can be calibrated to the wind shaft system only by control point coordinates on the calibration block.
Obviously, the conversion of the coordinate system measured by the VM camera to the wind axis system is laborious and troublesome, and is more difficult especially when the test section hole wall has an expansion angle (i.e. the airflow direction is not parallel to the test section hole wall).
Disclosure of Invention
The invention provides a wind axis system self-calibration method for video measurement of pose of a test model, which aims to overcome the defects of the prior art.
The purpose of the invention is realized by the following technical scheme:
the wind axis system self-calibration method for video measurement of the pose of the test model at least comprises the following steps:
s1: adjusting the pose parameters and the focal length of a camera outside the observation window of the wind tunnel to enable the imaging range of the camera to cover the motion range of the test model;
s2: three non-collinear mark points a, b and c are printed on the surface of the rigid area of the test model in a sticking mode;
s3: when the test model is in the ground state, the object space coordinates of the three mark points measured by the camera are respectively
Figure BDA0002389823850000021
Figure BDA0002389823850000022
And
Figure BDA0002389823850000023
s4: obtaining unit vectors in object space coordinate system in wingspan direction
Figure BDA0002389823850000024
S5: when the test model can independently adjust the sideslip angle, calculating to obtain the unit vector of the Z axis of the wind axis in the object space coordinate system
Figure BDA0002389823850000025
And based on unit vectors
Figure BDA0002389823850000026
And unit vector
Figure BDA0002389823850000027
Calculating to obtain the unit vector of the X-axis of the wind axis in the object space coordinate system
Figure BDA0002389823850000028
When the test model cannot independently adjust the sideslip angle, the roll angle of the test model is adjusted to obtain the object space of the X axis of the wind axis systemUnit vector in coordinate system
Figure BDA0002389823850000029
And based on unit vectors
Figure BDA00023898238500000210
And unit vector
Figure BDA00023898238500000211
Calculating to obtain a unit vector of a Z axis of a wind axis system in an object space coordinate system
Figure BDA00023898238500000212
S6: calculating longitudinal axis vector of model body shafting corresponding to given attitude t in wind tunnel test
Figure BDA00023898238500000213
To the transverse axis vector
Figure BDA00023898238500000214
And a rotation matrix RtTranslation matrix TtAnd deformation.
When the test model is in the ground state, taking the center of mass of the aircraft as the origin of the model body shafting and the longitudinal axis
Figure BDA00023898238500000215
Forward along the longitudinal axis of the aircraft model structure and
Figure BDA00023898238500000216
parallel (opposite direction), vertical axis
Figure BDA00023898238500000217
And
Figure BDA00023898238500000218
parallel, transverse axes
Figure BDA00023898238500000219
And
Figure BDA00023898238500000220
parallel, then wind tunnel incoming flow vector
Figure BDA00023898238500000221
Figure BDA00023898238500000222
Given a test attitude t in a wind tunnel test, the object space coordinates of three marking points measured based on a camera are respectively
Figure BDA00023898238500000223
And
Figure BDA00023898238500000224
can be obtained from
Figure BDA00023898238500000225
And
Figure BDA00023898238500000226
change to
Figure BDA00023898238500000227
And
Figure BDA00023898238500000228
of (3) a rotation matrix RtAnd translation matrix Tt。
Figure BDA00023898238500000229
I.e. for a given ith point on the model
Figure BDA00023898238500000230
Obtained by the above formula
Figure BDA00023898238500000231
Position at attitude t
Figure BDA00023898238500000232
Then
Figure BDA00023898238500000233
And
Figure BDA00023898238500000234
the difference of the coordinates of (2) is a point
Figure BDA00023898238500000235
Deformation corresponding to the posture t;
giving test attitude t, and longitudinal axis vector of model body axis system
Figure BDA00023898238500000236
And transverse axial vector
Figure BDA00023898238500000237
Is calculated as
Figure BDA0002389823850000031
S7: calculating the model attack angle alpha corresponding to the given test attitude t in the wind tunnel testtAnd angle of sideslip betat。
Wind tunnel incoming flow vector
Figure BDA0002389823850000032
Projection on the plane of the longitudinal axis and the vertical axis of the model body axis
Figure BDA0002389823850000033
Angle of attack of
Figure BDA0002389823850000034
And
Figure BDA0002389823850000035
the included angle of (A); a slip angle of
Figure BDA0002389823850000036
The included angle between the model body axis system and the plane where the vertical axis is located is calculated according to the formula
Figure BDA0002389823850000037
According to a preferred embodiment, in step S4, the unit vector
Figure BDA0002389823850000038
Obtained by the following steps:
s41, when the attack angle of the test model is adjusted to be (delta, 0, 0), the object space coordinates of the three mark points measured by the camera are respectively
Figure BDA0002389823850000039
And
Figure BDA00023898238500000310
s42, when the attack angle of the test model is adjusted to (-delta, 0, 0), the object space coordinates of the three mark points measured based on the camera are respectively
Figure BDA00023898238500000311
And
Figure BDA00023898238500000312
s43, based on the steps S41 and S42, the point a is calculated by the following calculation formula
Figure BDA00023898238500000313
Figure BDA00023898238500000314
S44, based on the step S43, respectively calculating to obtain the points b and c corresponding to the points b and c respectively
Figure BDA00023898238500000315
And
Figure BDA00023898238500000316
s45, taking
Figure BDA00023898238500000317
And
Figure BDA00023898238500000318
average value of (1) and unitization to obtain unit vector
Figure BDA00023898238500000319
According to a preferred embodiment, in step S5, when the test model can adjust the sideslip angle independently and the attack angle of the test model is adjusted to (0, Δ, 0), the object space coordinates of the three marked points measured by the camera are respectively (i) the object space coordinates
Figure BDA00023898238500000320
Figure BDA00023898238500000321
And
Figure BDA00023898238500000322
when the incidence angle of the model is adjusted to (0, -delta, 0) in the test, the object space coordinates of the three marked points are measured by the camera to be respectively
Figure BDA00023898238500000323
And
Figure BDA00023898238500000324
based on
Figure BDA00023898238500000325
Calculating a point
Figure BDA00023898238500000326
Respectively corresponding points b and c are calculated by the same method
Figure BDA00023898238500000327
And
Figure BDA00023898238500000328
get
Figure BDA00023898238500000329
And
Figure BDA00023898238500000330
the average value of the three is unitized to obtain the unit vector of the Z axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000331
And based on
Figure BDA00023898238500000332
Calculating to obtain a unit vector of the X axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000333
According to a preferred embodiment, in step S5, when the trial model cannot adjust the sideslip angle alone and the model attack angle is adjusted to (0, 0, Δ), the object space coordinates of the three marked points measured by the camera are respectively (0, 0, Δ)
Figure BDA00023898238500000334
And
Figure BDA0002389823850000041
when the attack angle of the model is adjusted to (0, 0, -delta), the object space coordinates of the three marking points measured by the camera are respectively
Figure BDA0002389823850000042
And
Figure BDA0002389823850000043
based on
Figure BDA0002389823850000044
Calculating a point
Figure BDA0002389823850000045
Respectively corresponding points b and c are calculated by the same method
Figure BDA0002389823850000046
And
Figure BDA0002389823850000047
get
Figure BDA0002389823850000048
And
Figure BDA0002389823850000049
the average value of the three is unitized to obtain the unit vector of the X axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000410
And based on unit vectors
Figure BDA00023898238500000411
And unit vector
Figure BDA00023898238500000412
Push button
Figure BDA00023898238500000413
Figure BDA00023898238500000414
Calculating to obtain a unit vector of a Z axis of a wind axis system in an object space coordinate system
Figure BDA00023898238500000415
The main scheme and the further selection schemes can be freely combined to form a plurality of schemes which are all adopted and claimed by the invention; in the invention, the selection (each non-conflict selection) and other selections can be freely combined. The skilled person in the art can understand that there are many combinations, which are all the technical solutions to be protected by the present invention, according to the prior art and the common general knowledge after understanding the scheme of the present invention, and the technical solutions are not exhaustive herein.
The invention has the beneficial effects that: different from the method for converting an object space coordinate system into a wind axis system by using the existing VM (virtual machine), the method is free from a traditional multi-degree-of-freedom rotating table and a step calibration block, only three mark points are needed to be pasted and printed on the model, based on the existing wind tunnel test process, after the model reference installation state with a zero attitude angle is completed, and in the absence of wind, the model attitude adjusting mechanism is controlled to support the model to perform given attitude motion, so that the direction vectors of three coordinate axes of the wind axis system in a camera object space can be accurately obtained, and the wind axis system self-calibration of the test model attitude video measurement is realized; and then based on the reference installation state and 3 marking points in the given state of the blowing test, calculating a translation and rotation matrix, and accurately solving the direction vector of the three axes of the model axis system in the given state of the blowing test in the camera object space, namely obtaining the posture and deformation parameters of the test model under aerodynamic force. The method saves labor and time, does not need a traditional high-precision and high-cost multi-degree-of-freedom rotating table and a step calibration block (and expensive storage cost thereof), is particularly suitable for a working environment in which the wall of the test section has an expansion angle (namely the air flow direction is not parallel to the wall of the test section), and quickly realizes the self-calibration of the wind axis system for the video measurement of the pose of the test model at low cost, thereby having huge engineering application prospect.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that, in order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments.
Thus, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In addition, it should be noted that, in the present invention, if the specific structures, connection relationships, position relationships, power source relationships, and the like are not written in particular, the structures, connection relationships, position relationships, power source relationships, and the like related to the present invention can be known by those skilled in the art without creative work on the basis of the prior art.
Examples
The invention discloses a wind shaft system self-calibration method for wind tunnel test model pose video measurement, which at least comprises the following steps:
step S1: and adjusting the pose parameters and the focal length of the camera outside the observation window of the wind tunnel to enable the imaging range to cover the motion range of the test model. And (3) obtaining distortion parameters of the camera optical system by adopting a mature machine vision and photogrammetry method, and finishing camera correction.
Preferably, a wind tunnel three-dimensional coordinate system is established in the wind tunnel test space. The direction of the wind tunnel airflow is made to be the X-axis direction, and the machine body axis of the test model is the same as the X-axis direction. The spanwise direction of the test model is the Y-axis direction. The direction perpendicular to the plane formed by the X axis and the Y axis is the Z axis direction.
Step S2: and sticking and printing three non-collinear mark points a, b and c on the surface of the rigid area of the test model.
Step S3: when the test model is in the ground state, the object space coordinates of the three mark points measured by the camera are respectively
Figure BDA0002389823850000051
And
Figure BDA0002389823850000052
when the test model is in the ground state, that is, when the model posture is (0, 0, 0).
Step S4: obtaining unit vectors in object space coordinate system in wingspan direction
Figure BDA0002389823850000053
Preferably, in step S4, the unit vector
Figure BDA0002389823850000054
Obtained by the following steps:
s41, when the attack angle of the test model is adjusted to be (delta, 0, 0), the object space coordinates of the three mark points measured by the camera are respectively
Figure BDA0002389823850000055
And
Figure BDA0002389823850000056
s42, when the attack angle of the test model is adjusted to (-delta, 0, 0), the object space coordinates of the three mark points measured based on the camera are respectively
Figure BDA0002389823850000057
And
Figure BDA0002389823850000058
s43, based on the steps S41 and S42, the point a is calculated by the following calculation formula
Figure BDA0002389823850000059
Figure BDA00023898238500000510
S44, based on the step S43, respectively counting according to the same principleCalculate the corresponding points b and c
Figure BDA00023898238500000511
And
Figure BDA00023898238500000512
s45, taking
Figure BDA00023898238500000513
And
Figure BDA00023898238500000514
average value of (1) and unitization to obtain unit vector
Figure BDA00023898238500000515
Step S51: when the test model can independently adjust the sideslip angle, calculating to obtain the unit vector of the Z axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000516
And based on unit vectors
Figure BDA00023898238500000517
And unit vector
Figure BDA00023898238500000518
Calculating to obtain the unit vector of the X-axis of the wind axis in the object space coordinate system
Figure BDA0002389823850000061
Preferably, in step S51, when the test model is capable of adjusting the sideslip angle alone and the attack angle of the test model is adjusted to (0, Δ, 0), the object space coordinates of the three marked points measured by the camera are respectively (i) the side slip angle, the attack angle, and the attack angle are (0, Δ, 0)
Figure BDA0002389823850000062
And
Figure BDA0002389823850000063
when the incidence angle of the model is adjusted to (0, -delta, 0) in the test, the object space coordinates of the three marked points are measured by the camera to be respectively
Figure BDA0002389823850000064
And
Figure BDA0002389823850000065
based on
Figure BDA0002389823850000066
Calculating a point
Figure BDA0002389823850000067
Respectively corresponding points b and c are calculated by the same method
Figure BDA0002389823850000068
And
Figure BDA0002389823850000069
get
Figure BDA00023898238500000610
And
Figure BDA00023898238500000611
the average value of the three is unitized to obtain the unit vector of the Z axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000612
And based on
Figure BDA00023898238500000613
Calculating to obtain a unit vector of the X axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000614
Step S52: when the test model can not be adjusted independentlyWhen the sideslip angle is adjusted, the roll angle of the test model is adjusted to obtain the unit vector of the X axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000615
And based on unit vectors
Figure BDA00023898238500000616
And unit vector
Figure BDA00023898238500000617
Calculating to obtain a unit vector of a Z axis of a wind axis system in an object space coordinate system
Figure BDA00023898238500000618
Preferably, in the step S52, when the test model cannot adjust the sideslip angle alone,
when the attack angle of the model is adjusted to (0, 0, delta), the object space coordinates of the three mark points measured by the camera are respectively
Figure BDA00023898238500000619
Figure BDA00023898238500000620
And
Figure BDA00023898238500000621
when the attack angle of the model is adjusted to (0, 0, -delta), the object space coordinates of the three marking points measured by the camera are respectively
Figure BDA00023898238500000622
Figure BDA00023898238500000623
And
Figure BDA00023898238500000624
based on
Figure BDA00023898238500000625
Calculating a point
Figure BDA00023898238500000626
Respectively corresponding points b and c are calculated by the same method
Figure BDA00023898238500000627
And
Figure BDA00023898238500000628
get
Figure BDA00023898238500000629
And
Figure BDA00023898238500000630
the average value of the three is unitized to obtain the unit vector of the X axis of the wind axis in the object space coordinate system
Figure BDA00023898238500000631
And based on unit vectors
Figure BDA00023898238500000632
And unit vector
Figure BDA00023898238500000633
Push button
Figure BDA00023898238500000634
Calculating to obtain a unit vector of a Z axis of a wind axis system in an object space coordinate system
Figure BDA00023898238500000635
S6: calculating longitudinal axis vector of model body shafting corresponding to given attitude t in wind tunnel test
Figure BDA00023898238500000636
To the transverse axis vector
Figure BDA00023898238500000637
And a rotation matrix RtTranslation matrix TtAnd deformation.
When the test model is in the ground state, taking the center of mass of the aircraft as the origin of the model body shafting and the longitudinal axis
Figure BDA00023898238500000638
Forward along the longitudinal axis of the aircraft model structure and
Figure BDA00023898238500000639
parallel (opposite direction), vertical axis
Figure BDA00023898238500000640
And
Figure BDA00023898238500000641
parallel, transverse axes
Figure BDA00023898238500000642
And
Figure BDA00023898238500000643
parallel, then wind tunnel incoming flow vector
Figure BDA00023898238500000644
Figure BDA00023898238500000645
Given a test attitude t in a wind tunnel test, the object space coordinates of three marking points measured based on a camera are respectively
Figure BDA00023898238500000646
And
Figure BDA00023898238500000647
can be obtained from
Figure BDA00023898238500000648
And
Figure BDA00023898238500000649
change to
Figure BDA00023898238500000650
And
Figure BDA00023898238500000651
of (3) a rotation matrix RtAnd translation matrix TtI.e. by
Figure BDA0002389823850000071
For a given ith point on the model
Figure BDA0002389823850000072
Obtained by the above formula
Figure BDA0002389823850000073
Position at attitude t
Figure BDA0002389823850000074
Then
Figure BDA0002389823850000075
And
Figure BDA0002389823850000076
the difference of the coordinates of (2) is a point
Figure BDA0002389823850000077
Deformation corresponding to the posture t; giving test attitude t, and longitudinal axis vector of model body axis system
Figure BDA0002389823850000078
And transverse axial vector
Figure BDA0002389823850000079
Is calculated as
Figure BDA00023898238500000710
S7: calculating the model attack angle alpha corresponding to the given test attitude t in the wind tunnel testtAnd angle of sideslip betat。
Wind tunnel incoming flow vector
Figure BDA00023898238500000711
Projection on the plane of the longitudinal axis and the vertical axis of the model body axis
Figure BDA00023898238500000712
Angle of attack of
Figure BDA00023898238500000713
And
Figure BDA00023898238500000714
the included angle of (A); a slip angle of
Figure BDA00023898238500000715
The included angle between the model body axis system and the plane where the vertical axis is located is calculated according to the formula
Figure BDA00023898238500000716
In conclusion, different from the method for converting an object space coordinate system into a wind axis system by using the existing VM, the method only needs to print three mark points on the model in a sticking way, and based on the existing wind tunnel test process, after the model reference installation state with the attitude angle of zero is completed, and when no wind exists, the model attitude adjusting mechanism is controlled to support the model to do given attitude motion, so that the direction vectors of three coordinate axes of the wind axis system in the camera object space can be accurately obtained, and the self-calibration of the wind axis system for the video measurement of the attitude of the test model can be realized; and then based on the reference installation state and 3 marking points in the given state of the blowing test, calculating a translation and rotation matrix, and accurately solving the direction vector of the three axes of the model axis system in the given state of the blowing test in the camera object space, namely obtaining the posture and deformation parameters of the test model under aerodynamic force. The method saves labor and time, does not need a traditional high-precision and high-cost multi-degree-of-freedom rotating table and a step calibration block (and expensive storage cost thereof), is particularly suitable for a working environment in which the wall of the test section has an expansion angle (namely the air flow direction is not parallel to the wall of the test section), and quickly realizes the self-calibration of the wind axis system for the video measurement of the pose of the test model at low cost, thereby having huge engineering application prospect.
The foregoing basic embodiments of the invention and their various further alternatives can be freely combined to form multiple embodiments, all of which are contemplated and claimed herein. In the scheme of the invention, each selection example can be combined with any other basic example and selection example at will. The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (4)

1. The method for automatically calibrating the wind axis system for video measurement of the pose of the test model is characterized by at least comprising the following steps:
s1: adjusting the pose parameters and the focal length of a camera outside the observation window of the wind tunnel to enable the imaging range of the camera to cover the motion range of the test model;
s2: three non-collinear mark points a, b and c are printed on the surface of the rigid area of the test model in a sticking mode;
s3: when the test model is in the ground state, namely the attack angle, the sideslip angle and the roll angle of the test model are all zero, the object space coordinates of the three mark points measured by the camera are respectively
Figure FDA0003309527100000011
And
Figure FDA0003309527100000012
s4: obtaining unit vectors in object space coordinate system in wingspan direction
Figure FDA0003309527100000013
S5: when the test model can independently adjust the sideslip angle, calculating to obtain the unit vector of the Z axis of the wind axis in the object space coordinate system
Figure FDA0003309527100000014
And based on unit vectors
Figure FDA0003309527100000015
And unit vector
Figure FDA0003309527100000016
Calculating to obtain the unit vector of the X-axis of the wind axis in the object space coordinate system
Figure FDA0003309527100000017
When the test model cannot independently adjust the sideslip angle, the roll angle of the test model is adjusted to obtain the unit vector of the X axis of the wind axis in the object space coordinate system
Figure FDA0003309527100000018
And based on unit vectors
Figure FDA0003309527100000019
And unit vector
Figure FDA00033095271000000110
Calculating to obtain a unit vector of a Z axis of a wind axis system in an object space coordinate system
Figure FDA00033095271000000111
S6: calculating longitudinal axis vector of model body shafting corresponding to given attitude t in wind tunnel test
Figure FDA00033095271000000112
To the transverse axis vector
Figure FDA00033095271000000113
And a rotation matrix RtTranslation matrix TtAnd deforming;
the object space coordinates of the three mark points measured based on the camera are respectively
Figure FDA00033095271000000114
And
Figure FDA00033095271000000115
can obtain the product
Figure FDA00033095271000000116
I.e. for a given ith point on the model
Figure FDA00033095271000000117
Obtained by the above formula
Figure FDA00033095271000000118
Position at attitude t
Figure FDA00033095271000000119
Then
Figure FDA00033095271000000120
And
Figure FDA00033095271000000121
the difference of the coordinates of (2) is a point
Figure FDA00033095271000000122
Deformation corresponding to the posture t; while
Figure FDA00033095271000000123
S7: calculating the model attack angle alpha corresponding to the given test attitude t in the wind tunnel testtAnd angle of sideslip betatWind tunnel incoming flow vector
Figure FDA00033095271000000124
Projection on the plane of the longitudinal axis and the vertical axis of the model body axis
Figure FDA00033095271000000125
Then
Figure FDA00033095271000000126
Wherein
Figure FDA00033095271000000127
Is the longitudinal axis vector.
2. The test model pose video measurement wind axis system self-calibration method as claimed in claim 1, wherein in step S4, unit vector is used
Figure FDA0003309527100000021
Obtained by the following steps:
s41, when the attack angle of the test model is adjusted to be (delta, 0, 0), the object space coordinates of the three mark points measured by the camera are respectively
Figure FDA0003309527100000022
And
Figure FDA0003309527100000023
s42, when the attack angle of the test model is adjusted to (-delta, 0, 0), the object space coordinates of the three mark points measured based on the camera are respectively
Figure FDA0003309527100000024
And
Figure FDA0003309527100000025
s43, based on the steps S41 and S42, the point a is calculated by the following calculation formula
Figure FDA0003309527100000026
Figure FDA0003309527100000027
S44, based on the step S43, respectively calculating to obtain the points b and c corresponding to the points b and c respectively
Figure FDA0003309527100000028
And
Figure FDA0003309527100000029
s45, taking
Figure FDA00033095271000000210
And
Figure FDA00033095271000000211
average value of (1) and unitization to obtain unit vector
Figure FDA00033095271000000212
3. The method for self-calibration of the wind axis system for video measurement of the pose of the test model as claimed in claim 1, wherein in the step S5, when the test model can independently adjust the sideslip angle,
when the attack angle of the test model is adjusted to (0, delta, 0), the object space coordinates of the three marking points measured by the camera are respectively
Figure FDA00033095271000000213
And
Figure FDA00033095271000000214
when the incidence angle of the model is adjusted to (0, -delta, 0) in the test, the object space coordinates of the three marked points are measured by the camera to be respectively
Figure FDA00033095271000000215
And
Figure FDA00033095271000000216
based on
Figure FDA00033095271000000217
Calculating a point
Figure FDA00033095271000000218
Respectively corresponding points b and c are calculated by the same method
Figure FDA00033095271000000219
And
Figure FDA00033095271000000220
get
Figure FDA00033095271000000221
And
Figure FDA00033095271000000222
the average value of the three is unitized to obtain the unit vector of the Z axis of the wind axis in the object space coordinate system
Figure FDA00033095271000000223
And based on
Figure FDA00033095271000000224
Calculating to obtain a unit vector of the X axis of the wind axis in the object space coordinate system
Figure FDA00033095271000000225
4. The method for self-calibration of the wind axis system of the video measurement of the pose of the test model as claimed in claim 1, wherein in the step S5, when the test model can not independently adjust the sideslip angle,
when the attack angle of the model is adjusted to (0, 0, delta), the object space coordinates of the three mark points measured by the camera are respectively
Figure FDA00033095271000000226
Figure FDA00033095271000000227
And
Figure FDA00033095271000000228
when the attack angle of the model is adjusted to (0, 0, -delta), the object space coordinates of the three marking points measured by the camera are respectively
Figure FDA00033095271000000229
Figure FDA00033095271000000230
And
Figure FDA00033095271000000231
based on
Figure FDA00033095271000000232
Calculating a point
Figure FDA00033095271000000233
Respectively calculating the points b and c respectivelyShould be that
Figure FDA00033095271000000234
And
Figure FDA00033095271000000235
get
Figure FDA0003309527100000031
And
Figure FDA0003309527100000032
the average value of the three is unitized to obtain the unit vector of the X axis of the wind axis in the object space coordinate system
Figure FDA0003309527100000033
And based on unit vectors
Figure FDA0003309527100000034
And unit vector
Figure FDA0003309527100000035
Push button
Figure FDA0003309527100000036
Calculating to obtain a unit vector of a Z axis of a wind axis system in an object space coordinate system
Figure FDA0003309527100000037
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