Ultra wide band (UWB) multi-reference positioning method for transformer internal inspection robot

Abstract

The invention discloses an ultra wide band (UWB) multi-reference positioning method for a transformer internal inspection robot, and the method comprises the steps: S100, arranging a plurality of UWB base stations at four corners above a target transformer and four corners below the target transformer, and nearby eight corners in total; s200, on the horizontal plane of the transformer, dividing the transformer into Sudoku; a part or all of the four transverse lines penetrate through a part of the at least four UWB base stations; s300, planning a cruising path of a submerged robot in the transformer in the nine-square, wherein the cruising path is a narrow area between a transformer winding and an outer wall; and S400, static positioning and dynamic positioning of the transformer internal inspection robot are realized by using the at least four UWB base stations and a UWB tag carried by the transformer internal inspection robot.

Description

Technical Field

[0001] The invention belongs to the field of transformer submersible robots, and in particular relates to an ultra-wideband (UWB) multi-reference positioning method for a transformer internal inspection robot. Background Art

[0002] In recent years, with the rapid development of industrial technology, robots have been used more and more widely in various fields. At present, robot technology has been applied to all aspects of the power system. Using robots to replace manual labor to carry out internal inspection of transformers can greatly improve on-site work efficiency, improve work quality, and reduce work risks. However, the robots currently used for internal inspection of oil-immersed transformers have the following problems: 1. The robot is too large and needs to enter through the hand hole at the bottom of the bushing, which is only suitable for specific types of transformers; 2. The internal environment of the oil-immersed transformer is complex, and the robot cannot be accurately positioned. It is difficult to recover the robot in the event of a robot failure, which can easily cause secondary damage to the transformer.

[0003] The problem is that the iron casing of the oil-immersed transformer has a serious shielding effect on electromagnetic signals. Conventional positioning methods cannot be applied to the positioning of the internal inspection robot inside the oil-immersed transformer, resulting in the internal inspection robot being unable to intuitively obtain position information when working inside the oil-immersed transformer. Summary of the invention

[0004] In view of this, the present invention discloses an ultra-wideband (UWB) multi-reference positioning method for a transformer internal inspection robot, comprising: S100, arranging a plurality of UWB base stations near four upper corners and four lower corners of a target transformer, a total of eight corners; At least four UWB base stations are arranged diagonally in multiple faces of the target transformer near four upper corners and four lower corners of the target transformer, a total of eight corners; S200, on the horizontal plane of the transformer, divide the transformer into nine squares; Among them, the Jiugong grid includes 4 parallel horizontal lines. Some or all of the four horizontal lines pass through a portion of the at least four UWB base stations; The Jiugong grid also includes 4 parallel vertical lines. Some or all of the four horizontal lines pass through the remaining part of the at least four UWB base stations; S300, planning a patrol path of the underwater robot inside the transformer in the nine-square grid, And the parade path is a narrow area between the transformer winding and the outer wall; S400: Implement static positioning and dynamic positioning of the transformer internal inspection robot by utilizing the at least four UWB base stations and the UWB tags carried by the transformer internal inspection robot itself.

[0005] Preferably, Measurements using diagonal arrangements or multiple base station distributions.

[0006] Preferably, Four UWB base stations are arranged diagonally.

[0007] Preferably, To ensure the accuracy of the UWB positioning system, a diagonal arrangement of at least four base stations should be adopted.

[0008] Preferably, If there are more than 4 base stations, a multi-base station dispersed deployment method is adopted.

[0009] Preferably, In order to solve the serious refraction of the signal propagation by the iron core, the following area division method is adopted: Divide the transformer into 9 areas.

[0010] Preferably, The patrol path of the submersible robot inside the transformer is in the narrow area between the transformer winding and the outer wall.

[0011] Preferably, The distance between the transformer winding and the shell of the submersible robot is determined by the camera carried by the submersible robot itself.

[0012] Preferably, After determining the distance between the transformer winding and the shell of the submersible robot, the positioning of the submersible robot can be achieved by simply calculating the two-dimensional coordinates of the submersible robot projected on its approach surface.

[0013] Preferably, Eight base stations are arranged outside the transformer's oil tank. When the underwater robot approaches a certain surface in the tank, it calls the data signal on the surface closest to it for calculation to eliminate the influence of the iron core and winding on the signal propagation process, thereby improving the accuracy of positioning.

[0014] In addition, the present invention also discloses a computer storage medium, wherein the storage medium includes computer instructions, and when the computer is run on the computer, the computer executes any of the methods described above.

[0015] Beneficial effects of the present invention: The present invention realizes a positioning method through UWB technology to provide real-time feedback on the position coordinates of a transformer internal inspection robot for reference by external operators, so as to facilitate efficient oil-immersed transformer fault detection through the transformer internal inspection robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a flow chart of an ultra-wideband (UWB) multi-reference positioning method for a transformer internal inspection robot in one embodiment of the present invention; Figure 2 It is a schematic diagram of measuring coordinates on the X-axis in a two-dimensional positioning method in the prior art; Figure 3 for Figure 2 A schematic diagram of measuring coordinates on the Y axis in a two-dimensional positioning method in the prior art is shown; Figure 4 It is a schematic diagram of measuring coordinates of the X-axis in the three-dimensional positioning method in the prior art; Figure 5 for Figure 4 A schematic diagram of measuring coordinates on the Y axis in a three-dimensional positioning method in the prior art is shown; Figure 6 for Figure 4 A schematic diagram of measuring coordinates on the Z axis in a three-dimensional positioning method in the prior art is shown; Figure 7 It is a schematic diagram of diagonally arranging four UWB base stations in one embodiment of the present invention; Figure 8 A schematic diagram of a further dispersed arrangement of multiple UWB base stations in another embodiment of the present invention; Fig. 9 This is a schematic diagram of a cruising path of a submersible robot inside a transformer in another embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make those skilled in the art understand the technical solution disclosed in the present invention, the following will be combined with the embodiments and related appended Figures 1 to 9 , the technical solutions of various embodiments are described, and the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Mentioning "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It will be understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0018] It should be noted that the submersible robot referred to in the present invention is a robot used to submerge in the oil tank of a transformer.

[0019] In one embodiment, see Figure 1 The present invention discloses an ultra-wideband (UWB) multi-reference positioning method for a transformer internal inspection robot, the method comprising the following steps: S100, arranging a plurality of UWB base stations near four upper corners and four lower corners of a target transformer, a total of eight corners; At least four UWB base stations are arranged diagonally in multiple faces of the target transformer near four upper corners and four lower corners of the target transformer, a total of eight corners; S200, on the horizontal plane of the transformer, divide the transformer into nine squares; Among them, the Jiugong grid includes 4 parallel horizontal lines. Some or all of the four horizontal lines pass through a portion of the at least four UWB base stations; The Jiugong grid also includes 4 parallel vertical lines. Some or all of the four horizontal lines pass through the remaining part of the at least four UWB base stations; S300, planning a patrol path of the underwater robot inside the transformer in the nine-square grid, And the parade path is a narrow area between the transformer winding and the outer wall; S400: Implement static positioning and dynamic positioning of the transformer internal inspection robot by utilizing the at least four UWB base stations and the UWB tags carried by the transformer internal inspection robot itself.

[0020] In another embodiment, S100, arranging a plurality of UWB base stations near four upper corners and four lower corners of a target transformer, a total of eight corners; At least four UWB base stations are arranged diagonally in multiple faces of the target transformer near four upper corners and four lower corners of the target transformer, a total of eight corners; S200, on the horizontal plane of the transformer, divide the transformer into nine squares; Among them, the Jiugong grid includes 4 parallel horizontal lines. Some or all of the four horizontal lines pass through a portion of the at least four UWB base stations; The Jiugong grid also includes 4 parallel vertical lines. Some or all of the four horizontal lines pass through the remaining part of the at least four UWB base stations; S300, planning a patrol path of the underwater robot inside the transformer in the nine-square grid, And the parade path is a narrow area between the transformer winding and the outer wall; S400: Implement static positioning and dynamic positioning of the transformer internal inspection robot by utilizing the at least four UWB base stations and the UWB tags carried by the transformer internal inspection robot itself.

[0021] It can be understood that planning the cruising path of the submersible robot inside the transformer in the nine-square grid includes the cruising paths at different transformer horizontal planes in the longitudinal direction, rather than just a cross-section of a fixed horizontal plane.

[0022] About the existing technology: Conventional positioning methods cannot be applied to the positioning of internal inspection robots inside oil-immersed transformers. Figure 2 The figure shows a schematic diagram of a UWB two-dimensional positioning method in the prior art. The actual coordinates are (1.74, 3.42) / m. In the environment inside the transformer, the measurement error is relatively large.

[0023] The actual coordinate value of the X-axis measurement is 1.74m. Figure 2 The Y-axis is shown to be in a stable range at 1.26m, with a large fluctuation range, with the maximum value reaching 1.80m and the minimum value reaching 1.05m. It can be seen that ordinary UWB two-dimensional positioning has a large error.

[0024] See also Figure 3 , The actual measured coordinate of the Y axis is 3.42m. As can be seen from the figure, the Y axis is in a stable range within the range of 3.51m, and the fluctuation range is large, with the maximum value reaching 4.03m and the minimum value reaching 3.01m. The data with a measurement quantity between 200-350 also shows that the existing technology deviates greatly from the stable value.

[0025] In three-dimensional positioning, the actual coordinates are (1.785, 3.46, 1.01) / m. The actual coordinate errors of the measuring robot inside the transformer are large. For further information, see Figure 4 shown.

[0026] The actual coordinate of the X-axis is 1.785m, while the image stability value is about 1.67m. The fluctuations between the measurement quantities in each group are large, with the maximum value reaching 2.50m and the minimum value reaching 1.06m. The measurement has a large error.

[0027] See also Figure 5 , The actual coordinate of the Y axis is 3.46m, the stable value is about 3.30m, the maximum value reaches 4.12m, and the minimum value reaches 2.51m.

[0028] See also Figure 6 , the actual coordinate of the Z axis is 1.01m, and the stable value is around 1m, but it fluctuates greatly up and down.

[0029] Therefore, the above prior art precisely reflects the problems faced by conventional positioning including conventional UWB positioning methods in this field.

[0030] In order to solve the serious shielding effect of the iron shell of the oil-immersed transformer on the electromagnetic signal, the present invention adopts a diagonal arrangement or multi-base station distribution measurement method, such as Figure 7 shown.

[0031] Figure 7 It shows how four UWB base stations are arranged diagonally.

[0032] See also Figure 8 , which further illustrates the distributed deployment of multiple UWB base stations. Figure 8 The blue solid origin of the UWB base station represents the UWB base station, which means that the above figure illustrates the situation of 8 UWB base stations. To ensure the accuracy of the UWB positioning system, a diagonal arrangement method of at least 4 base stations should be adopted; if there are more than 4 base stations, a multi-base station dispersed arrangement method should be adopted.

[0033] For further information, see Fig. 9 In order to solve the serious refraction of the iron core for signal propagation, the following area division method is adopted: The transformer is divided into nine areas. The patrol path of the submersible robot inside the transformer is in the narrow area between the transformer winding and the outer wall. Therefore, it can rely on the camera it carries to determine the distance between the transformer winding and the outer shell. The robot can be positioned by simply calculating the two-dimensional coordinates of the robot projected on its approach surface.

[0034] After the signal propagates through the iron core and windings, the amplitude is significantly attenuated and the arrival time of the direct signal wave is difficult to determine. Therefore, 8 base stations are arranged outside the oil tank of the transformer. When the underwater robot approaches a certain surface in the oil tank, it calculates by calling the data signal on the surface closest to it. This eliminates the influence of the iron core and winding on the signal propagation process and improves the accuracy of positioning.

[0035] Furthermore, those skilled in the art know that: There is a common problem with UWB positioning. When the distance is too close, the multipath effect will reduce the accuracy of the measurement. The propagation speed of waves in oil is lower than that in air.

[0036] In another embodiment, according to the inventor's practice, UWB positioning technology must ensure a distance of at least 5m in the air to be accurate, while in oil it only requires a distance of at least 3m.

[0037] This means that when arranging a base station outside the transformer tank, in order to reduce the impact of multipath effects and improve positioning accuracy, the distance between the base station and the transformer should be kept at least 3 meters, especially considering that the oil in the tank will slow down the propagation of the signal.

[0038] Specifically, if you plan to arrange 8 base stations outside the transformer oil tank, and hope that when the robot approaches a certain surface, it can call the data signal on the surface closest to it for calculation to eliminate the influence of the iron core and winding on the signal propagation process, then the distance between each base station and the transformer should be kept at least 3 meters to ensure the accuracy of positioning.

[0039] In another embodiment, Advanced signal processing algorithms are used to identify and suppress multipath effects and improve positioning accuracy.

[0040] Assume that there is a UWB positioning system with 8 base stations, and the target object is located at an unknown position P(x, y, z) in space. The positions of the base stations are ; The following is a corresponding method for suppressing multipath effects, comprising the following steps: Step 1: Signal preprocessing Signal preprocessing can include removing noise and interference, usually using filters.

[0041] Step 2: Identification of multipath effects For each base station B i , the correlation function of the signal can be calculated:

[0042] Then find the delay time corresponding to the first peak , which represents the time of the direct signal; Where s(t) is the received signal, is its complex conjugate; Step 3: Time Difference of Arrival Estimation Once the time of the direct signal is determined , calculate the time difference of arrival (TDoA) for subsequent positioning calculation. Assume that base station B1 is used as the reference base station, and other base stations The TDoA relative to B1 is ,

[0043] Step 4: Positioning calculation Use TDoA data to calculate the target location.

[0044] Given a TDoA value , establish the following set of equations to solve the target position P(x,y,z):

[0045] Where c is the speed of light; An exemplary solution method includes: Construct the residual vector r; For each base station B i , i=2,3,…,8, calculate the corresponding residual: - + ; calculate ; Use nonlinear optimization methods (such as gradient descent, Newton's method, etc.) to solve the minimum value of J.

[0046] Thus, through the above steps, the optimal position P(x, y, z) can be obtained, thereby improving the accuracy of UWB positioning.

[0047] In addition, in one embodiment, the present invention also discloses a computer storage medium, wherein the storage medium includes computer instructions, and when the computer is run on the computer, the computer executes any of the methods described above.

[0048] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An ultra-wideband (UWB) multi-reference positioning method for a transformer internal inspection robot, comprising: S100, arranging a plurality of UWB base stations near four upper corners and four lower corners of a target transformer, a total of eight corners; S200, dividing the transformer into nine-square grids on a horizontal plane of the transformer; wherein the nine-square grid includes four parallel horizontal lines, and some or all of the four horizontal lines pass through a portion of the at least four UWB base stations; the nine-square grid also includes four parallel vertical lines, and some or all of the four horizontal lines pass through a remaining portion of the at least four UWB base stations; S300, planning a patrol path of the underwater robot inside the transformer in the nine-square grid; S400: Implement static positioning and dynamic positioning of the transformer internal inspection robot by utilizing the at least four UWB base stations and the UWB tags carried by the transformer internal inspection robot itself.

2. The method according to claim 1, wherein: Measurements using diagonal arrangements or multiple base station distributions.

3. The method according to claim 2, wherein: Four UWB base stations are arranged diagonally.

4. The method according to claim 2, wherein: To ensure the accuracy of the UWB positioning system, a diagonal arrangement of at least four base stations should be adopted.

5. The method according to claim 2, wherein: If there are more than 4 base stations, a multi-base station dispersed deployment method is adopted.

6. The method according to claim 1, wherein: In order to solve the serious refraction of the signal propagation by the iron core, the following area division method is adopted: Divide the transformer into 9 areas.

7. The method according to claim 6, wherein: The patrol path of the submersible robot inside the transformer is in the narrow area between the transformer winding and the outer wall.

8. The method according to claim 7, wherein: The distance between the transformer winding and the shell of the submersible robot is determined by the camera carried by the submersible robot itself.

9. The method according to claim 8, wherein: After determining the distance between the transformer winding and the shell of the submersible robot, the positioning of the submersible robot can be achieved by simply calculating the two-dimensional coordinates of the submersible robot projected on its approach surface.

10. The method according to claim 1, wherein: Eight base stations are arranged outside the transformer's oil tank. When the underwater robot approaches a certain surface in the tank, it calls the data signal on the surface closest to it for calculation to eliminate the influence of the iron core and winding on the signal propagation process, thereby improving the accuracy of positioning.

11. A computer storage medium, wherein: The storage medium includes computer instructions, which, when executed on a computer, enable the computer to execute the method according to any one of claims 1 to 10.

Images