A ladder mark line-based magnetic suspension model roll angle measurement method and system

Abstract

The application discloses a kind of magnetic suspension model roll angle measurement method and system based on trapezoidal mark line.The system includes pose measurement sensor and trapezoidal mark line.The trapezoidal mark line is closed trapezoidal ring around pasting in model centroid, the width value of trapezoidal mark line parallel to model axis presents monotone linear variation, trapezoidal mark line is in geometric development state and presents trapezoidal with unequal base.During measurement, linear array CCD scans and detects the pixel serial number corresponding to two edge images of trapezoidal mark line formed by image;According to the difference of two edge corresponding pixel serial number, it can be solved that the roll angle of suspension model is combined with the preset geometric relation;The axial position of suspension model can be calculated by the mean value of two edge pixel serial number.The application realizes the integrated measurement of roll attitude and axial position by changing mark line configuration and solving method without changing hardware system, with the advantages of good compatibility, low cost, high measurement real-time.

Description

Technical Field

[0001] This invention relates to the field of magnetic suspension balance system technology, and in particular to a method and system for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines. Background Technology

[0002] Currently, in wind tunnel testing, when using a magnetic suspension balance system to suspend a suspended model without support, a pose measurement system based on a multi-linear CCD array arranged in an "H" shape is commonly employed, such as... Figure 1 As shown. In this process, symmetrical long strips and ring-shaped marker lines with a distinct color difference from the surface of the suspended model are typically designed and pasted onto the surface of the suspended model to detect and calculate the pose information of the suspended model. Current suspended models use black long strips and ring-shaped marker lines. The long strips are mainly imaged onto two vertically arranged CCDs (Cellular Digital Displays). Figure 1 The image is projected onto CCD1 and CCD2 in the image. The CCDs then detect the image edges of the marker lines to obtain pixel numbers. After pose calculation, the position information of the suspended model in space can be measured. Symmetrical ring marker lines are mainly imaged onto the horizontally arranged CCDs in the middle. Figure 1 The image is processed using a CCD (3) to detect the image edges of the marker lines, obtaining pixel numbers. After pose calculation, the axial position information of the suspended model in space can be measured. However, this commonly used method for measuring the pose of a suspended model in space can only measure the pose of five degrees of freedom (DOFs), and is incapable of measuring roll angles. Furthermore, if the suspended model rolls, and this roll angle is not measured to compensate for lateral and vertical position detection, the accuracy of the pose measurement for the five DDFs of freedom will be affected. Summary of the Invention

[0003] This invention provides a method and system for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines, in order to solve the technical problems mentioned in the background art.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] This invention provides a method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines, comprising the following steps:

[0006] S1. First, set the roll angle of the suspended model to 0 degrees in the initial state. In the initial state, obtain the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line imaged on the CCD photosensitive system along the axial direction of the suspended model, and record the pixel number difference between the two pixel numbers. ;

[0007] S2. After the suspended model rolls, in the current measurement state, obtain the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line imaged on the CCD sensor along the axial direction of the suspended model, and record the pixel number difference between the two pixel numbers in S2. ;

[0008] S3, Based on the pixel sequence difference , The roll angle of the suspension model in the current measurement state was calculated. .

[0009] Furthermore, the pixel number difference in S1 The calculation formula is as follows:

[0010] ;

[0011] in, , These are the pixel numbers corresponding to the two edges b and a of the trapezoidal marker line as imaged on the CCD photosensitive system in the initial state;

[0012] The pixel number difference in S2 The calculation formula is as follows:

[0013] ;

[0014] in, , These are the pixel numbers corresponding to the two edges b and a of the trapezoidal marker line as imaged on the CCD sensor system after the suspended model rolls.

[0015] Furthermore, the roll angle in S3 The calculation formula is:

[0016] .

[0017] Furthermore, after S3, it also includes:

[0018] S4. Based on the pixel number obtained in S2 and pixel number Calculate the average of the two pixel indices in S2. and based on the mean Calculate the axial position of the suspension model in the current measurement state.

[0019] Furthermore, the formula for calculating the axial position of the current measurement state in S4 is:

[0020] ;

[0021] in, This indicates the axial position of the suspension model in the current measurement state. This represents the calibrated mapping function from pixel number to actual spatial coordinate position.

[0022] A second aspect of the present invention also discloses a magnetic suspension model roll angle measurement system based on trapezoidal marker lines, configured to perform the above-described magnetic suspension model roll angle measurement method, the magnetic suspension balance system comprising:

[0023] At least one pose measurement sensor, including an imaging system and a CCD photosensitive system that are electrically connected to each other;

[0024] The trapezoidal marker line is configured as a closed loop marker line that is pasted around the center of gravity of the suspended model.

[0025] The trapezoidal marker line is constructed such that when it traverses the circumference of the suspended model, the geometric width of the trapezoidal marker line in the direction parallel to the axis of the suspended model changes monotonically and continuously in a linear manner, so that the trapezoidal marker line appears as a trapezoidal ring structure with unequal base lengths on the cylindrical surface unfolded geometry.

[0026] Furthermore, the pose measurement sensor is used to acquire an image containing the trapezoidal marker line and identify the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line imaged on the CCD photosensitive system along the axial direction of the suspended model.

[0027] Furthermore, the CCD photosensitive system determines the pixel number of edge a by detecting the falling edge corresponding to the edge of trapezoidal marker line image a in the image signal, and determines the pixel number of edge b by detecting the rising edge corresponding to the edge of trapezoidal marker line image b.

[0028] The beneficial effects of this invention are:

[0029] 1. This invention discloses a method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines. No additional hardware is required. By simply changing the ring marker lines and the measurement method, the roll angle of the suspension model and the axial position of the suspension model in the current measurement state can be measured. It has good compatibility with existing systems.

[0030] 2. This invention adds the measurement of roll attitude information, but does not affect the measurement of axial position information. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the "H"-shaped linear CCD array configuration in the background technology.

[0032] Figure 2 This is a schematic diagram showing the unfolded trapezoidal marker line in this invention;

[0033] Figure 3 This is a schematic diagram of the trapezoidal marker line at different roll angles in this invention;

[0034] Figure 4 This is a schematic diagram of the magnetic suspension balance system in this invention;

[0035] Figure 5 This is a partial cross-sectional view of the magnetic suspension balance system in this invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Pose measurement sensor; 11. Imaging system; 12. CCD photosensitive system;

[0038] 2. Trapezoidal marking lines;

[0039] 3. Suspended model;

[0040] 4. Lighting system;

[0041] 5. Vertical coil;

[0042] 6. Lateral coil;

[0043] 7. Axial coil;

[0044] 8. Iron core. Detailed Implementation

[0045] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many other different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0046] It should also be noted that in the embodiments of this application, the same reference numerals are used to represent the same component or part. For the same part in the embodiments of this application, the reference numerals may only be used to mark one part or component as an example. It should be understood that the reference numerals are also applicable to other identical parts or components.

[0047] Reference Figure 2 , Figure 4 and Figure 5 This application provides a method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines, comprising the following steps:

[0048] S1. First, set the roll angle of the suspended model 3 to 0 degrees in the initial state. In the initial state, obtain the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD photosensitive system 12 along the axial direction of the suspended model 3, and record the pixel number difference between the two pixel numbers. The suspended model 3 is suspended in the middle of the magnetic suspension balance system under the action of the vertical coil 5, lateral coil 6, and axial coil 7. There are four vertical coils 5 and four lateral coils 6, each with an iron core 8 inside. There are two axial coils 7, both of which are hollow coils. An illumination system 4 is installed on the magnetic suspension balance system to improve the imaging brightness of the CCD photosensitive system 12.

[0049] S2. After the suspended model 3 rolls, the pose measurement sensor 1 acquires an image containing the trapezoidal marker line 2 in real time. Then, in the current measurement state, the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD photosensitive system 12 along the axial direction of the suspended model 3 are obtained, and the pixel number difference between the two pixel numbers in S2 is recorded. ;

[0050] S3, Based on the pixel sequence difference , The roll angle of suspension model 3 in the current measurement state was calculated. .

[0051] In some embodiments, the pixel number difference in S1 The calculation formula is as follows:

[0052] ;

[0053] in, , These are the pixel numbers corresponding to the two edge ends b and a of the trapezoidal marker line 2 as imaged on the CCD photosensitive system 12 in the initial state;

[0054] The pixel number difference in S2 The calculation formula is as follows:

[0055] ;

[0056] in, , These are the pixel numbers corresponding to the two edges b and a of the trapezoidal marker line 2 as imaged on the CCD photosensitive system 12 after the suspended model 3 rolls.

[0057] In some embodiments, the roll angle in S3 The calculation formula is:

[0058] .

[0059] In some embodiments, the process after S3 further includes:

[0060] S4. Based on the pixel number obtained in S2 and pixel number Calculate the average of the two pixel indices in S2. and based on the mean Calculate the axial position of suspension model 3 in the current measurement state.

[0061] In some embodiments, the mean in S4 The formula for calculation is:

[0062] .

[0063] In some embodiments, the formula for calculating the axial position of the current measurement state in S4 is:

[0064] ;

[0065] in, This indicates the axial position of suspension model 3 in the current measurement state. This represents the calibrated mapping function from pixel number to actual spatial coordinate position.

[0066] The following describes the roll angle The calculation formula will be explained in detail below:

[0067] Reference Figure 2 , Figure 4 and Figure 5 In the initial state, the imaging area of ​​the trapezoidal marker line 2 on the CCD photosensitive system 12 is located at the bottom of the trapezoidal marker line 2, that is, the imaging area is 0mm away from the bottom edge of the trapezoidal marker line 2. In the initial state, the distance between the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD photosensitive system 12 along the axial direction of the suspended model 3 is... Meanwhile, the number of pixels occupied by the trapezoidal marker line 2 between the two opposite edges a and b along the axial direction of the suspended model 3 on the CCD photosensitive system 12 is... That is, the pixel number difference mentioned above. ;

[0068] Suspension Model 3 At time step, suspension model 3 generates roll angle. The rolling motion, in At time (corresponding to the current measurement state mentioned above), the distance between the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD photosensitive system 12 along the axial direction of the suspended model 3 is... The distance from the base of the trapezoidal marker line 2, as imaged on the CCD sensor system 12 along the axial direction of the suspended model 3, is... At the same time At any given moment, the number of pixels occupied by the trapezoidal marker line 2 between its two opposite edges a and b along the axial direction of the suspended model 3 on the CCD photosensitive system 12 is: That is, the pixel number difference mentioned above. ;

[0069] Using trapezoidal marker line 2 in The positional attributes at a given time can be used to construct the first relation, as follows:

[0070] ;

[0071] in, The length of the shorter side of the trapezoidal marker line 2; The perpendicular distance between the longer and shorter sides of the trapezoidal marker line 2; The radius of the suspended model 3;

[0072] Then, based on the initial state, the distance between the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD photosensitive system 12 along the axial direction of the suspended model 3 is... Pixel number difference and in At any given moment, the distance between the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD sensor system 12 along the axial direction of the suspended model 3 is... Pixel number difference The second relation can be constructed as follows:

[0073] ;

[0074] in, The width of each pixel in the axial direction of the suspended model 3 as imaged on the CCD photosensitive system 12 by the trapezoidal marker line 2;

[0075] After combining the first and second relations, a third relation can be obtained. This third relation allows us to calculate the suspension model 3 in... The roll angle at time t, the third relation is:

[0076] .

[0077] By observing the third relation, the roll angle can be found. Difference between pixel index and initial state ,as well as Pixel number difference at time 1 related.

[0078] Reference Figure 4 and Figure 5 In another aspect, the present invention provides a magnetic suspension model roll angle measurement system based on trapezoidal marker lines, configured or executing a magnetic suspension model roll angle measurement method, comprising:

[0079] At least one pose measurement sensor 1, including an imaging system 11 and a CCD photosensitive system 12 that are electrically connected to each other;

[0080] Trapezoidal marker line 2 is configured as a closed loop marker line that is pasted around the center of mass of the suspended model 3;

[0081] The trapezoidal marker line 2 is constructed such that when it traverses the circumference of the suspended model 3, the geometric width value of the trapezoidal marker line 2 in the direction parallel to the axis of the suspended model 3 changes monotonically and continuously in a linear manner, so that the trapezoidal marker line 2 appears as a trapezoidal ring structure with unequal base lengths on the cylindrical surface unfolded geometry.

[0082] In some embodiments, the pose measurement sensor 1 is used to acquire an image containing the trapezoidal marker line 2 and identify the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line 2 imaged on the CCD photosensitive system 12 along the axial direction of the suspended model 3.

[0083] In some embodiments, the CCD photosensitive system 12 determines the pixel number of edge a by detecting the falling edge of the image signal corresponding to the edge a of the trapezoidal marker line 2, and determines the pixel number of edge b by detecting the rising edge of the image signal corresponding to the edge b of the trapezoidal marker line 2.

[0084] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines, characterized in that, The roll angle measurement system of the magnetic suspension model is used. The magnetic suspension model roll angle measurement system includes: a magnetic suspension balance system and a magnetic suspension model (3). The magnetic suspension model (3) is suspended in the middle of the magnetic suspension balance system under the action of the vertical coil (5), lateral coil (6) and axial coil (7) of the magnetic suspension balance system; there are four vertical coils (5) and four lateral coils (6), each with an iron core (8) on the inside; there are two axial coils (7), both of which are hollow coils. At least one pose measurement sensor (1), including an imaging system (11) and a CCD photosensitive system (12) that are electrically connected to each other. The trapezoidal marker line (2) is configured as a closed loop marker line that is pasted around the center of mass of the magnetic suspension model (3); Among them, the trapezoidal marker line (2) is constructed as follows: when traversing the circumference of the magnetic suspension model (3), the geometric width value of the trapezoidal marker line (2) in the direction parallel to the axis of the magnetic suspension model (3) changes monotonically and continuously, so that the trapezoidal marker line (2) appears as a trapezoidal ring structure with unequal base lengths on the cylindrical surface unfolded geometry. Specifically, the following steps are included: S1. First, set the roll angle of the magnetic suspension model (3) to 0 degrees in the initial state. In the initial state, obtain the pixel numbers corresponding to the two edges a and b of the trapezoidal marker line (2) on the CCD photosensitive system (12) along the axial direction of the magnetic suspension model (3), and record the pixel number difference between the two pixel numbers. ; S2. After the magnetic suspension model (3) rolls, under the current measurement state, obtain the pixel numbers corresponding to the two opposite edges a and b of the trapezoidal marker line (2) imaged on the CCD photosensitive system (12) along the axial direction of the magnetic suspension model (3), and record the pixel number difference between the two pixel numbers in S2. ; S3, Based on the pixel sequence difference , The roll angle of the magnetic suspension model (3) in the current measurement state was calculated. ; The pixel number difference in S1 The calculation formula is as follows: ； in, , These are the pixel numbers corresponding to the two edge ends b and a of the trapezoidal marker line (2) imaged on the CCD photosensitive system (12) in the initial state; The pixel number difference in S2 The calculation formula is as follows: ； in, , These are the pixel numbers corresponding to the two edges b and a of the trapezoidal marker line (2) as imaged on the CCD photosensitive system (12) after the magnetic suspension model (3) rolls. The roll angle in S3 The calculation formula is: 。 2. The method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines according to claim 1, characterized in that, Following S3, the following also includes: S4. Based on the pixel number obtained in S2 and pixel number Calculate the average of the two pixel indices in S2. and based on the mean Solve the axial position of the magnetic suspension model (3) in the current measurement state.

3. The method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines according to claim 2, characterized in that, The formula for calculating the axial position of the current measurement state in S4 is: ； in, This indicates the axial position of the magnetic suspension model (3) in the current measurement state. This represents the calibrated mapping function from pixel number to actual spatial coordinate position.

4. The method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines according to claim 3, characterized in that, The pose measurement sensor (1) is used to acquire an image containing the trapezoidal marker line (2) and identify the pixel numbers corresponding to the two edges a and b of the trapezoidal marker line (2) on the CCD photosensitive system (12) along the axial direction of the magnetic suspension model (3).

5. The method for measuring the roll angle of a magnetic suspension model based on trapezoidal marker lines according to claim 4, characterized in that, The CCD photosensitive system (12) determines the pixel number of the edge a by detecting the falling edge of the image a corresponding to the edge a of the trapezoidal marker line (2) in the image signal, and determines the pixel number of the edge b by detecting the rising edge of the image b corresponding to the edge b of the trapezoidal marker line (2).

Images