Satellite cable bending radius measuring method and system

Abstract

The invention provides a satellite cable bending radius measuring method and system. The satellite cable bending radius measuring method comprises the steps that a plurality of measuring devices are arranged on the periphery of a satellite cable laying path; acquiring the laying path of the cable on the satellite deck and the image information of the measuring device; analyzing the image information to obtain two-dimensional coordinates of the measuring device and the cable path in a plane reference system; converting the two-dimensional coordinate of the cable into a space coordinate under a cabin coordinate system by using a projection matrix method; and solving the bending radius of the cable through a least square fitting method. The measuring device is used as a reference system and needs to be input into image information together with the cable. By adopting the method, bending radius information extraction can be carried out on the cable image shot at any visual angle, effective interpretation of cable network image data is greatly improved, a certain engineering significance is provided for quality control of the bending radius of the satellite cable network, and reliable operation of a satellite power supply and distribution link is greatly guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of satellite overall circuit products, and in particular to a method and system for measuring the bending radius of a satellite cable. Background Art

[0002] The cable wiring environment on satellites is very complex and is limited by factors such as cabin structure, installation space, and electromagnetic compatibility. The cable bending radius will inevitably be less than the minimum bending radius. When the cable is twisted and deformed to a certain extent, internal stress will be generated. The physical and electrical properties of the cable will be damaged under the action of stress for a long time. In addition, excessive bending of the cable may cause loose connections of connectors, damage to the insulation layer and shielding wire, and even breakage of internal wires, resulting in hidden faults such as poor information transmission, susceptibility to electromagnetic interference or poor contact, which will introduce huge hidden dangers to the on-orbit operation of the spacecraft.

[0003] At present, the contact method is generally used to measure the bending radius of the cable. However, in engineering practice, in order to improve the operability of the bending radius measurement inspection process, a quick lookup table is generally formed based on the measured data or a standard pallet is made for rapid measurement. However, this measurement method is extremely labor-intensive and the measurement accuracy is not high.

[0004] Patent document CN108072310A (application number: 201711231702.0) discloses a cable bending radius measuring device and detection method, including a fixed bracket, a retractable scale and a rotating shaft, the rotating shaft fixes the fixed bracket and the retractable scale together, and the fixed bracket and the retractable scale rotate around the rotating shaft. The retractable scale includes three hollow square cubes, namely an upper scale, a middle scale and a lower scale, and the outer diameters of the upper scale, the middle scale and the lower scale increase; the upper scale can be retracted into the middle scale, and the middle scale can be retracted into the lower scale, and the upper scale, the middle scale and the lower scale are all marked with scale lines. Summary of the invention

[0005] In view of the defects in the prior art, an object of the present invention is to provide a method and system for measuring the bending radius of a satellite cable.

[0006] A satellite cable bending radius measurement method provided by the present invention comprises:

[0007] Step S1: setting up a number of measuring devices at preset positions around the satellite cable laying path;

[0008] Step S2: Acquire the cable laying path on the satellite cabin board and the image information of the measuring device;

[0009] Step S3: parsing the image information to obtain the two-dimensional coordinates of the measuring device and the cable path in the plane reference system;

[0010] Step S4: using a projection matrix combined with characteristic boundary conditions to transform the two-dimensional coordinates of the cable path into spatial coordinates in the cabin coordinate system;

[0011] Step S5: Based on the spatial coordinates of the cable path in the cabin coordinate system, the cable bending radius is obtained by a least square fitting method.

[0012] Preferably, the measuring device is a cubic structure formed by three planes intersecting vertically, and image recognition points are arranged on each plane according to a preset rule;

[0013] The measuring device can be placed in any area of ​​the satellite.

[0014] Preferably, when acquiring the image information of the cable laying path on the satellite cabin board and the measuring device, the angle of the measuring device is adjusted so that more identification points and cables are included in the image.

[0015] Preferably, the step S3 comprises: using an image recognition algorithm to analyze the image information to obtain the two-dimensional coordinates of the identification point on the measuring device and the two-dimensional coordinates of the cable trajectory.

[0016] Preferably, the step S4 comprises:

[0017] Step S4.1: The spatial coordinates of the identification points on the measuring device form a reference pose matrix B = (b1, b2, b3), and the two-dimensional coordinates of the identification points on the measuring device in the image form a matrix K = (k1, k2, k3), and the projection matrix P′ is obtained;

[0018] P′=(k1,k1,k3)B -1 =KB -1

[0019] Step S4.2: Calculate the spatial coordinate b in the cabin coordinate system based on the projection coordinate k of a point on the cable obtained from the image information;

[0020] P′b=k;

[0021] Step S4.3: Based on characteristic boundary conditions, including that the cable laying plane and the plane where the measuring device is placed are coincident, parallel or perpendicular, the spatial coordinates of the cable trajectory are solved.

[0022] Preferably, the step S5 comprises: obtaining the spatial coordinates of the cable segment trajectory according to the circle equation (x-x0) 2 +(y-y0) 2 =R 2 Perform the least squares fitting to obtain the cable bending radius R; where (x ， y) represents the spatial coordinates of the cable trajectory; (x 0，y0) coordinates of the center of the circle.

[0023] A satellite cable bending radius measurement system provided by the present invention comprises:

[0024] Module M1: When a number of measuring devices are set at preset positions around the satellite cable laying path, image information of the cable laying path on the satellite cabin board and the measuring devices is obtained;

[0025] Module M2: Analyze the image information to obtain the two-dimensional coordinates of the measuring device and the cable path in the plane reference system;

[0026] Module M3: Use the projection matrix combined with characteristic boundary conditions to transform the two-dimensional coordinates of the cable path into spatial coordinates in the cabin coordinate system;

[0027] Module M4: Based on the spatial coordinates of the cable path in the cabin coordinate system, the cable bending radius is obtained by the least squares fitting method.

[0028] Preferably, the measuring device is a cubic structure formed by three planes intersecting vertically, and image recognition points are arranged on each plane according to a preset rule;

[0029] The measuring device can be placed in any area of ​​the satellite;

[0030] When acquiring the cable laying path on the satellite cabin board and the image information of the measuring device, the angle of the measuring device is adjusted so that more identification points and cables are included in the image.

[0031] Preferably, the module M2 comprises: using an image recognition algorithm to analyze image information to obtain the two-dimensional coordinates of the identification point on the measuring device and the two-dimensional coordinates of the cable trajectory.

[0032] Preferably, the module M3 comprises:

[0033] Module M3.1: The spatial coordinates of the identification points on the measuring device form a reference pose matrix B = (b1, b2, b3), and the two-dimensional coordinates of the identification points on the measuring device in the image form a matrix K = (k1, k2, k3), and the projection matrix P′ is obtained;

[0034] P′=(k1,k1,k3)B -1 =KB -1

[0035] Module M3.2: Calculate the spatial coordinates b in the cabin coordinate system based on the projection coordinates k of a point on the cable obtained from the image information;

[0036] P′b=k;

[0037] Module M3.3: Solve the spatial coordinates of the cable trajectory based on characteristic boundary conditions, including the coincidence, parallelism or perpendicularity between the cable laying plane and the plane where the measuring device is placed;

[0038] The module M4 comprises: obtaining the spatial coordinates of the cable segment trajectory according to the circle equation (x-x0) 2 +(y-y0) 2 =R 2 Perform the least squares fitting to obtain the cable bending radius R; where (x ， y) represents the spatial coordinates of the cable trajectory; (x 0， y0) coordinates of the center of the circle.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The present invention can calculate the bending radius of cable laying image data taken from any viewing angle. As a non-contact measurement method, it does not require complex measuring equipment and only requires the arrangement of measuring devices around the satellite, which reduces the calculation complexity and improves the detection accuracy and efficiency.

[0041] 2. The present invention can improve the effective interpretation of cable network image data, has certain engineering significance for the quality control of the bending radius of the satellite cable network, and greatly ensures the reliable operation of the satellite power supply and distribution link. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0043] Figure 1 The figure is a flow chart of the method for measuring the bending radius of a satellite cable.

[0044] Figure 2 This is a physical diagram of the design of the measuring device.

[0045] Figure 3 Schematic diagram of the arrangement of measuring devices inside the satellite.

[0046] Figure 4 This is the calculation flow chart of the satellite cable bending radius measurement system.

[0047] Figure 5 This is the processing result diagram of the satellite cable bending radius measurement system. DETAILED DESCRIPTION

[0048] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0049] Example 1

[0050] A satellite cable bending radius measurement method provided by the present invention comprises:

[0051] Step 1: Set up a number of measuring devices around the satellite cable laying path. The measuring devices, as reference systems in subsequent image information, should be arranged around the cable laying path in the satellite cabin as much as possible;

[0052] Step 2: Obtain the image information of the cable laying path on the satellite cabin board and the measuring device;

[0053] Step 3: Analyze the image information to obtain the two-dimensional coordinates of the measuring device and the cable path in the plane reference system;

[0054] Step 4: Use the projection matrix combined with the characteristic boundary condition method to transform the two-dimensional coordinates of the cable into the spatial coordinates in the cabin coordinate system;

[0055] Step 5: Calculate the cable bending radius using the least squares fitting method.

[0056] In this embodiment, image recognition points are arranged on the measuring device according to certain rules, so that the subsequent measuring system can automatically recognize these measuring points, and the cubic design structure can be placed in any area in the satellite cabin.

[0057] In this embodiment, the captured image information needs to include the measured cable object and the measuring device. Considering the complexity of the satellite cabin space environment, the measuring device should be properly adjusted when acquiring the image to ensure that as many identification points as possible on the measuring device are included in the image.

[0058] In this embodiment, the color of the image recognition point on the measuring device is complementary to the color of the device body, and the color of the cable body is complementary to the color of the satellite cabin body. The image recognition algorithm in the measuring system can more accurately identify the image recognition point on the measuring device and the trajectory path of the cable.

[0059] In this embodiment, the satellite cable bending radius measurement system uses a projection matrix combined with a characteristic boundary condition method to transform the two-dimensional coordinates of the cable into spatial coordinates in a cabin coordinate system, including:

[0060] Step 4.1: Simplifying boundary conditions, including but not limited to making the cable laying plane coincident, parallel or perpendicular to the plane where the measuring device is placed to form characteristic boundary conditions;

[0061] Step 4.2: Combining the spatial coordinate set of the image recognition points on the measuring device and the two-dimensional coordinate set of the recognition points obtained by the image recognition algorithm to form a projection matrix;

[0062] Step 4.3: Combining the projection matrix with the characteristic boundary conditions to form an inverse projection matrix;

[0063] Step 4.4: Convert the two-dimensional cable trajectory coordinates into spatial coordinates in the cabin coordinate system by reverse projection.

[0064] The present invention also provides a satellite cable bending radius measurement system, which can be implemented by executing the process steps of the satellite cable bending radius measurement method, that is, those skilled in the art can understand the satellite cable bending radius measurement method as a preferred implementation of the satellite cable bending radius measurement system.

[0065] Example 2

[0066] Embodiment 2 is a preferred embodiment of Embodiment 1

[0067] like Figure 1 As shown, a satellite cable bending radius measurement method provided by the present invention comprises the following steps:

[0068] Step 1: Set up a number of measuring devices around the satellite cable laying path. The measuring devices, as reference systems in subsequent image information, should be arranged around the cable laying path in the satellite cabin as much as possible;

[0069] Step 2: Obtain the image information of the cable laying path on the satellite cabin board and the measuring device;

[0070] Step 3: Analyze the image information to obtain the two-dimensional coordinates of the measuring device and the cable path in the plane reference system;

[0071] Step 4: Use the projection matrix combined with the characteristic boundary condition method to transform the two-dimensional coordinates of the cable into the spatial coordinates in the cabin coordinate system;

[0072] Step 5: Calculate the cable bending radius using the least squares fitting method.

[0073] like Figure 2-Figure 5 As shown, each step in this embodiment is discussed in detail:

[0074] In step 1, the measuring device is formed into a cubic structure by three planes intersecting vertically. Image recognition points are arranged on each plane according to a certain rule, so that the subsequent measurement system can automatically recognize these measurement points. The cubic design structure can be placed in any area of ​​the satellite.

[0075] In step 2, the measuring device should be placed as close to the satellite cable as possible, and the angle of the measuring device should be adjusted appropriately before acquiring the image to ensure that as many identification points and cables on the device as possible are included in the image;

[0076] In step 3, a two-dimensional plane coordinate system is established with the captured image, and the image recognition algorithm in the measurement system will automatically extract the two-dimensional coordinates of the identification points on the measurement device and the two-dimensional coordinates of the cable trajectory;

[0077] In step 4, the cable bending radius measurement system designed by the present invention uses a projection matrix combined with a characteristic boundary condition method to convert the two-dimensional coordinates of the cable into spatial coordinates in the cabin coordinate system. The implementation principle includes:

[0078] The spatial coordinates of the identification points on the measuring device constitute the reference pose matrix B = (b1, b2, b3), and the two-dimensional coordinates of the identification points on the measuring device in the image constitute the matrix K = (k1, k2, k3), and the projection matrix P' is obtained by combining the following formula:

[0079] P′=(k1,k1,k3)B -1 =KB -1

[0080] Further, the projection coordinate k of a certain point on the cable segment is obtained from the image, and its spatial coordinate b in the cabin coordinate system can be obtained by solving the non-homogeneous linear equation system P′b=k;

[0081] In addition, considering that the non-secondary linear equations have countless solutions, the boundary conditions need to be substituted to determine the unique spatial coordinate b of a point on the cable segment. Here, the cable laying plane and the plane where the measuring device is placed can be coincident, parallel or perpendicular to form a characteristic boundary condition. The spatial coordinates of the cable segment trajectory can be solved by substituting them.

[0082] After obtaining the spatial coordinates of the cable segment trajectory in step 5, follow the circle equation (x-x0) 2 +(y-y0) 2 =R 2 The cable bending radius R is obtained by performing least square fitting.

[0083] Those skilled in the art know that, in addition to implementing the system, device and its various modules provided by the present invention in a purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers and embedded microcontrollers by logically programming the method steps. Therefore, the system, device and its various modules provided by the present invention can be considered as a hardware component, and the modules included therein for implementing various programs can also be considered as structures within the hardware component; the modules for implementing various functions can also be considered as both software programs for implementing the method and structures within the hardware component.

[0084] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for measuring the bending radius of a satellite cable, characterized in that: include: Step S1: setting up a number of measuring devices at preset positions around the satellite cable laying path; Step S2: Acquire the cable laying path on the satellite cabin board and the image information of the measuring device; Step S3: parsing the image information to obtain the two-dimensional coordinates of the measuring device and the cable path in the plane reference system; Step S4: using a projection matrix combined with characteristic boundary conditions to transform the two-dimensional coordinates of the cable path into spatial coordinates in the cabin coordinate system; Step S5: Based on the spatial coordinates of the cable path in the cabin coordinate system, the cable bending radius is obtained by a least square fitting method.

2. The satellite cable bending radius measurement method according to claim 1, characterized in that: The measuring device is a cubic structure formed by three planes intersecting vertically, and image recognition points are arranged on each plane according to a preset rule; The measuring device can be placed in any area of ​​the satellite.

3. The satellite cable bending radius measurement method according to claim 1, characterized in that: When acquiring the cable laying path on the satellite cabin board and the image information of the measuring device, the angle of the measuring device is adjusted so that more identification points and cables are included in the image.

4. The satellite cable bending radius measurement method according to claim 1, characterized in that: The step S3 includes: using an image recognition algorithm to analyze image information to obtain the two-dimensional coordinates of the identification point on the measuring device and the two-dimensional coordinates of the cable trajectory.

5. The satellite cable bending radius measurement method according to claim 1, characterized in that: The step S4 comprises: Step S4.1: The spatial coordinates of the identification points on the measuring device form a reference pose matrix B = (b1, b2, b3), and the two-dimensional coordinates of the identification points on the measuring device in the image form a matrix K = (k1, k2, k3), and the projection matrix P′ is obtained; P′=(k1,k1,k3)B -1 =KB -1 Step S4.2: Calculate the spatial coordinate b in the cabin coordinate system based on the projection coordinate k of a point on the cable obtained from the image information; P′b=k; Step S4.3: Based on characteristic boundary conditions, including that the cable laying plane and the plane where the measuring device is placed are coincident, parallel or perpendicular, the spatial coordinates of the cable trajectory are solved.

6. The satellite cable bending radius measurement method according to claim 1, characterized in that: The step S5 comprises: obtaining the spatial coordinates of the cable segment trajectory according to the circle equation (x-x0) 2 +(y-y0) 2 =R 2 Perform the least squares fitting to obtain the cable bending radius R; where (x ， y) represents the spatial coordinates of the cable trajectory; (x 0， y0) coordinates of the center of the circle.

7. A satellite cable bending radius measurement system, characterized in that: include: Module M1: When a number of measuring devices are set at preset positions around the satellite cable laying path, image information of the cable laying path on the satellite cabin board and the measuring devices is obtained; Module M2: Analyze the image information to obtain the two-dimensional coordinates of the measuring device and the cable path in the plane reference system; Module M3: Use the projection matrix combined with characteristic boundary conditions to transform the two-dimensional coordinates of the cable path into spatial coordinates in the cabin coordinate system; Module M4: Based on the spatial coordinates of the cable path in the cabin coordinate system, the cable bending radius is obtained by the least squares fitting method.

8. The method for measuring the bending radius of a satellite cable according to claim 7, characterized in that: The measuring device is a cubic structure formed by three planes intersecting vertically, and image recognition points are arranged on each plane according to a preset rule; The measuring device can be placed in any area of ​​the satellite; When acquiring the cable laying path on the satellite cabin board and the image information of the measuring device, the angle of the measuring device is adjusted so that more identification points and cables are included in the image.

9. The satellite cable bending radius measurement system according to claim 7, characterized in that: The module M2 includes: using an image recognition algorithm to analyze image information to obtain the two-dimensional coordinates of the identification point on the measuring device and the two-dimensional coordinates of the cable trajectory.

10. The satellite cable bending radius measurement system according to claim 7, characterized in that: The module M3 comprises: Module M3.1: The spatial coordinates of the identification points on the measuring device form a reference pose matrix B = (b1, b2, b3), and the two-dimensional coordinates of the identification points on the measuring device in the image form a matrix K = (k1, k2, k3), and the projection matrix P′ is obtained; P′=(k1,k1,k3)B -1 =KB -1 Module M3.2: Calculate the spatial coordinates b in the cabin coordinate system based on the projection coordinates k of a point on the cable obtained from the image information; P′b=k; Module M3.3: Solve the spatial coordinates of the cable trajectory based on characteristic boundary conditions, including the coincidence, parallelism or perpendicularity between the cable laying plane and the plane where the measuring device is placed; The module M4 comprises: obtaining the spatial coordinates of the cable segment trajectory according to the circle equation (x-x0) 2 +(y-y0) 2 =R 2 Perform the least squares fitting to obtain the cable bending radius R; where (x ， y) represents the spatial coordinates of the cable trajectory; (x 0， y0) coordinates of the center of the circle.

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