A dam underwater defect detection robot positioning method based on single-beacon ranging

Abstract

The application discloses a kind of dam underwater defect detection robot positioning methods based on single beacon ranging, it belongs to underwater robot navigation positioning technical field.The application solves the problem that due to the particularity of detection method and detection path of underwater dam detection robot when carrying out vertical dam surface detection, the existing underwater defect detection method in marine environment is no longer applicable.The application fully considers the characteristics of detection method and detection path of detection robot when carrying out vertical dam surface detection, and designs a method for realizing underwater positioning of robot by detection robot and single beacon, since only one acoustic beacon is needed, the complexity of positioning system and application cost are reduced.Furthermore, without obtaining heading information, speed information and previous time detection robot position information of detection robot, the data calculation amount is reduced, and the position calculation of detection robot at each time is highly independent.The method of the application can be applied to underwater robot positioning.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of underwater robot navigation and positioning, and particularly relates to a dam underwater defect detection robot positioning method based on single-beacon ranging. BACKGROUND

[0002] The relevant design specifications in China stipulate that the dam with a height of 70m or more is a high dam, the dam with a height of 200m or more is an extra-high dam, and the dam with a height of 300m or more is mostly a super-high dam. According to statistics, there are 588 high dams with a height of more than 70m, 223 high dams with a height of more than 100m, and 23 extra-high dams with a height of more than 200m in China, which is the country with the most high dams and the fastest development of large reservoirs in the world. Dam underwater defect detection is of great significance for the long-term safe operation and management of high dams and large reservoirs. With the wide application of underwater robots in various civil and military fields, underwater unmanned detection technology based on underwater robots has gradually become one of the most effective ways in dam detection field in addition to diver diving detection. At present, underwater unmanned detection technology mainly takes unmanned remote control underwater vehicles (ROV) as the carrier, and realizes underwater environment construction and dam defect detection by carrying related equipment to comb the underwater dam surface. In this process, the first problem to be solved is the navigation and positioning of underwater robots.

[0003] Due to the strong absorption shielding effect of electromagnetic waves by water medium, the underwater propagation distance of electromagnetic waves is very limited, and the global satellite navigation system (GNSS) is no longer applicable to underwater navigation. Sound waves become the main way of underwater information transmission, and underwater acoustic positioning technology has become an important means of underwater navigation and positioning.

[0004] The traditional underwater acoustic positioning system mainly includes long baseline (LBL) system and ultra-short baseline (USBL) system. The traditional long baseline and ultra-short baseline underwater acoustic positioning system has the characteristics of relatively complex structure, large number of beacons required, small coverage area, and low utilization efficiency, which cannot meet the long-time positioning demand; and the positioning technology based on single-beacon ranging can simplify the structure of the positioning system, reduce the calibration frequency, number and recovery cost of beacons, and improve the utilization efficiency of beacon nodes, which is the development trend of underwater navigation.

[0005] Due to the special needs of underwater dam detection robots when detecting the vertical dam surface, the application environment of dam underwater defect detection in water conservancy engineering is very different from that in marine engineering. Therefore, it is not feasible to simply transplant the underwater technology in marine environment to dam environment, and it is necessary to develop new technology to adapt to the special water environment of reservoir dam in a unique way. SUMMARY

[0006] The application aims to solve the problem that the positioning method of the underwater detection robot in the existing marine environment is no longer applicable due to the special needs of the underwater dam body detection robot when detecting the vertical dam surface, and proposes a dam underwater defect detection robot positioning method based on single-beacon ranging.

[0007] The technical scheme adopted by the application to solve the above technical problem is:

[0008] A dam underwater defect detection robot positioning method based on single-beacon ranging, the method specifically comprises the following steps:

[0009] Step one, after placing the beacon on the water surface, a navigation coordinate system with the center of the beacon as the origin O is established, and the position information (L0, λ0, d0) of the beacon in the geodetic coordinate system is obtained by calibrating the beacon, wherein L0 is the latitude of the beacon, λ0 is the longitude of the beacon, and d0 is the depth of the beacon;

[0010] Step two, after the detection robot sails to the action range of the beacon, the detection robot establishes acoustic communication with the beacon, obtains the distance information between the detection robot and the beacon, and controls the detection robot to sail to the beacon according to the obtained distance information;

[0011] The vertical line from the center of the beacon to the dam surface to be detected is drawn, and the detection robot is controlled to sail along the drawn vertical line to the dam surface to be detected, when the detection robot sails to position P, the distance information R0 between the detection robot and the beacon is obtained and recorded;

[0012] The position P satisfies: the vertical distance from the position P to the dam surface to be detected is equal to the detection distance of the detection robot;

[0013] Step three, the detection robot performs comb-shaped scanning detection on the vertical dam surface at a fixed distance from the vertical dam surface, at t1 moment in the comb-shaped scanning detection process, the position information of the detection robot at t1 moment is calculated according to the position information of the beacon in the geodetic coordinate system, the distance information R0, the dam surface azimuth information, the depth information of the detection robot at t1 moment, and the distance information between the detection robot and the beacon at t1 moment;

[0014] Step four, the position information of the detection robot calculated in step three and the position information of the detection robot output by the inertial navigation system are fused to obtain the final positioning information of the detection robot at t1 moment.

[0015] The application has the following beneficial effects:

[0016] (1) The present application is directed to the application environment of the underwater dam detection robot, fully considers the special needs of the detection robot when detecting the vertical dam surface, designs the detection method and detection path of the present application, and designs a method for realizing underwater positioning of the robot through the detection robot and a single beacon based on the detection method and detection path. Compared with the traditional acoustic positioning system, only one acoustic beacon is needed in the method of the present application, which reduces the complexity and application cost of the whole positioning system.

[0017] (2) Compared with the traditional single-beacon positioning method, the present application method does not need to obtain the heading information, speed information and previous time detection robot position information of the detection robot, which reduces the data calculation amount. At the same time, since the previous time detection robot position information is not needed, the position calculation output of the detection robot at each time in the present application method remains highly independent. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A flowchart of a dam underwater defect detection robot positioning method based on single-beacon ranging of the present application;

[0019] Figure 2 A schematic diagram of a two-dimensional coordinate system;

[0020] Figure 3 A schematic diagram of the minimum distance of the beacon distance comb-shaped scanning path;

[0021] Figure 4 A schematic diagram of the comb-shaped scanning detection process;

[0022] Figure 5 A coordinate conversion schematic diagram;

[0023] Figure 6 A two-dimensional coordinate system solving method schematic diagram. DETAILED DESCRIPTION

[0024] Specific implementation one: combined Figure 1 This embodiment describes a dam underwater defect detection robot positioning method based on single-beacon ranging, which specifically includes the following steps:

[0025] Step one, after placing the beacon on the water surface, a navigation coordinate system with the center of the beacon as the origin O is established, and the position information (L0, λ0, d0) of the beacon in the geodetic coordinate system is obtained by calibrating the beacon, wherein L0 is the latitude of the beacon, λ0 is the longitude of the beacon, and d0 is the depth of the beacon;

[0026] In the present application, the beacon is calibrated by the USBL system carried by the mother ship after the state of the water surface beacon is stable;

[0027] Step two, after the detection robot sails into the beacon action range, the detection robot and the beacon establish acoustic communication, the distance information between the detection robot and the beacon is obtained, and the detection robot is controlled to sail to the beacon according to the obtained distance information;

[0028] A perpendicular line is made from the beacon center to the dam surface to be detected (the dam surface itself is a vertical dam surface), and then the detection robot is controlled to sail from the beacon (i.e., the origin of the navigation coordinate system) along the perpendicular line to the dam surface to be detected, as shown in Figure 3 When the detection robot sails to position P, the distance information R0 between the detection robot and the beacon is obtained and recorded;

[0029] The position P satisfies: the vertical distance from the position P to the dam surface to be detected is equal to the detection distance of the detection robot;

[0030] Step three, as shown in Figure 4 The detection robot performs comb-shaped scanning detection on the vertical dam surface at a fixed distance from the vertical dam surface (the fixed distance here is the detection distance of the detection robot), at time t1 in the comb-shaped scanning detection process, the position information of the detection robot at time t1 is calculated according to the position information of the beacon in the geodetic coordinate system, the distance information R0, the dam surface azimuth information, the depth information of the detection robot at time t1, and the distance information between the detection robot and the beacon at time t1;

[0031] Step four, the position information of the detection robot calculated in step three and the position information of the detection robot output by the inertial navigation system are fused to obtain the final positioning information of the detection robot at time t1.

[0032] The method of the present application can obtain the positioning information at each time in the comb-shaped scanning detection process, and the single-beacon positioning system ends work when the detection robot completes the task and floats up or leaves the current beacon action range.

[0033] In order to cope with the special needs of the underwater dam detection robot in the vertical dam detection, the present application designs the corresponding detection method and detection path.

[0034] In terms of detection method design, the present application fully considers the complexity of the underwater environment and the limitations of sound wave propagation, especially in vertical dam detection, a comb-shaped scanning detection mode is adopted. This mode can ensure that the robot covers a larger detection area within a fixed detection distance, ensures that no defects may be missed, and improves the overall detection accuracy and efficiency.

[0035] In terms of detection path design, the present application plans the shortest path from the beacon to the dam surface for the detection robot, and during the detection process, the robot maintains a fixed detection distance and keeps a parallel motion trajectory to the dam surface. This path design helps to ensure that the robot always maintains a proper distance from the dam surface, avoiding the impact of distance fluctuations on detection accuracy. At the same time, the path planning simplifies the positioning algorithm, making the positioning calculation at each moment more accurate and stable.

[0036] Such design combines the particularity of underwater environment and the demand of dam detection, ensuring the accuracy and efficiency of detection.

[0037] Specific implementation method two: Different from the specific implementation method one, the navigation coordinate system takes the north direction as the positive direction of the x n axis, the east direction as the positive direction of the y n axis, and the ground direction as the positive direction of the z n axis.

[0038] The other steps and parameters are the same as those in the specific implementation method one.

[0039] Specific implementation method three: Different from the specific implementation method one or two, the specific process of step three is as follows:

[0040] Step three one, the distance between the detection robot at time t1 and the beacon is recorded as L1, and the depth of the detection robot at time t1 is recorded as d1, which is obtained by the depth gauge. According to d0 and d1, the depth difference Ah between the detection robot and the beacon at time t1 is calculated;

[0041] Step three two, the projection distance R1 of the distance L1 in the two-dimensional coordinate system xoy is calculated according to the depth difference Ah;

[0042] The origin of the two-dimensional coordinate system xoy is the center of the beacon, the x n axis direction is the same as the x n axis direction of the navigation coordinate system, and the y axis direction is the same as the x

[0043] axis direction of the navigation coordinate system;

[0044] Step three three, the included angle a1 between the perpendicular line from the beacon to the dam surface and the line connecting the beacon and the detection robot at time t1 is calculated according to the projection distance R1 and the distance information R0; Figure 2 Step three four, the position (x1, y1) of the detection robot at time t1 in the two-dimensional coordinate system xoy is calculated according to the projection distance R1, the dam surface azimuth angle, and the included angle a1, as shown in

[0045] The other steps and parameters are the same as those in the specific implementation method one or two.

[0046] Specific implementation four: the difference between this embodiment and one of the specific implementations one to three is that the depth difference between the robot and the beacon at t1 is:

[0047] Δh=d1-d0

[0048] The other steps and parameters are the same as one of the specific implementations one to three.

[0049] Specific implementation five: in combination with Figure 5 This embodiment is described. The difference between this embodiment and one of the specific implementations one to four is that the specific process of step three two is:

[0050]

[0051] The other steps and parameters are the same as one of the specific implementations one to four.

[0052] Specific implementation six: the difference between this embodiment and one of the specific implementations one to five is that the dam surface azimuth angle information is the angle between the perpendicular line of the dam surface and the north direction, and the dam surface azimuth angle is recorded as θ.

[0053] The other steps and parameters are the same as one of the specific implementations one to five.

[0054] In the present application, the dam surface azimuth angle information can be obtained by the dam operation management department.

[0055] Specific implementation seven: the difference between this embodiment and one of the specific implementations one to six is that the specific process of step three three is:

[0056] α1=arccos(R0 / R1)

[0057] The other steps and parameters are the same as one of the specific implementations one to six.

[0058] Specific implementation eight: in combination with Figure 6 This embodiment is described. The difference between this embodiment and one of the specific implementations one to seven is that the specific process of step three four is:

[0059]

[0060] The other steps and parameters are the same as one of the specific implementations one to seven.

[0061] Specific implementation nine: the difference between this embodiment and one of the specific implementations one to eight is that the specific process of step four is:

[0062] The position information of the detection robot at t1 is processed:

[0063]

[0064] Among them, R M is the radius of curvature of the meridian, and R N is the radius of curvature of the prime vertical;

[0065] Taking the position information (L1, λ1, d1) of the inspection robot in the geodetic coordinate system at time t1 as the observation quantity, and taking the position information of the inspection robot output by the inertial navigation system at time t1 as the state quantity, using a non-linear filtering method to fuse the observation quantity and the state quantity, and taking the fusion result as the corrected position information of the inspection robot at time t1, that is, obtaining the final positioning information of the inspection robot.

[0066] Other steps and parameters are the same as those in any one of the specific embodiments one to eight.

[0067] Specific Embodiment Ten: The difference between this embodiment and any one of the specific embodiments one to nine is that the non-linear filtering method is a Kalman filter or a particle filter method.

[0068] Other steps and parameters are the same as those in any one of the specific embodiments one to nine.

[0069] The non-linear filtering method adopted in this embodiment includes, but is not limited to, a Kalman filter or a particle filter method.

[0070] Embodiment

[0071] As Figure 1 shown, this embodiment proposes a positioning method for a dam underwater defect detection robot based on single beacon ranging, which specifically includes the following steps one to four. The following is an explanation of steps one to four:

[0072] Step One: After deploying the beacon on the water surface, establish a navigation coordinate system with the center of the beacon as the origin O, and the north direction of the navigation coordinate system is the positive direction of the x n axis, the east direction is the positive direction of the y n axis, and the downward direction is the positive direction of the z n axis;

[0073] After the state of the water surface beacon is stable, use the USBL system carried by the mother ship to calibrate the beacon; determine the position information (L0, λ0, d0) of the beacon in the geodetic coordinate system by taking the mean value. Among them, L0 is the latitude of the beacon, λ0 is the longitude of the beacon, and d0 is the depth of the beacon;

[0074] Step Two: When the inspection robot sails into the range of the beacon, establish acoustic communication between the inspection robot and the beacon, obtain the distance information between the inspection robot and the beacon, and control the inspection robot to sail towards the beacon according to the obtained distance information;

[0075] A vertical line is made from the beacon center to the dam surface to be detected, and then the detection robot is controlled to navigate from the beacon (i.e., the origin of the navigation coordinate system) along the vertical line to the dam surface to be detected, as shown in Figure 3 When the vertical distance from the detection robot to the vertical dam surface to be detected is equal to the detection distance of the detection robot, the distance information R0 between the detection robot and the beacon is obtained and recorded;

[0076] Step three, as shown in Figure 4 , the detection robot performs comb-shaped scanning detection on the vertical dam surface at a fixed distance from the vertical dam surface (the fixed distance here is the detection distance of the detection robot), the distance between the detection robot and the beacon at time t1 is recorded as L1, and the depth of the detection robot at time t1 is recorded as d1, the depth d1 is obtained by a depth gauge, and the depth difference Ah of the detection robot from the beacon at time t1 is calculated according to d0 and d1:

[0077] Ah = d1 - d0

[0078] As shown in Figure 2 , a two-dimensional coordinate system xoy is established with the beacon center as the origin, the x-axis direction being the same as the x n -axis direction of the navigation coordinate system, and the y-axis direction being the same as the x n -axis direction of the navigation coordinate system, the projection distance R1 of the distance L1 in the two-dimensional coordinate system xoy is calculated according to the depth difference Ah;

[0079]

[0080] According to the projection distance R1 and the distance information R0, the included angle a1 between the vertical line from the beacon to the dam surface and the line connecting the beacon and the detection robot at time t1 is calculated;

[0081] a1 = arccos (R0 / R1)

[0082] According to the projection distance R1, the dam surface azimuth angle, and the included angle a1, the position (x1, y1) of the detection robot in the two-dimensional coordinate system xoy at time t1 is calculated;

[0083]

[0084] Step four, the detection robot position information calculated in step three is processed:

[0085]

[0086] wherein R M is the meridian curvature radius, and R N is the prime vertical curvature radius;

[0087] The position information (L1, λ1, d1) of the detection robot in the earth coordinate system at the time t1 is taken as an observation, the position information of the detection robot output by the inertial navigation system at the time t1 is taken as a state, a nonlinear filtering method such as Kalman filtering or particle filtering is used to fuse the observation and the state, and the fusion result is taken as the corrected position information of the detection robot at the time t1, that is, the final positioning information of the detection robot is obtained.

[0088] The method of the embodiment can obtain the positioning information at each time during the detection process, and the single-beacon positioning system stops working when the detection robot completes the task and floats up or leaves the current beacon action range.

[0089] The above calculation examples of the present application are only used to illustrate the calculation model and the calculation process of the present application, and are not used to limit the embodiments of the present application. Based on the above description, other different forms of changes or variations can be made by those skilled in the art, and all the embodiments cannot be exhausted here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A method for locating an underwater defect detection robot for dams based on single beacon ranging, characterized in that, The method specifically includes the following steps: Step 1: After deploying the beacon on the water surface, establish an origin point with the beacon's center as the reference point. The navigation coordinate system is established by calibrating the beacon to obtain its position information in the geodetic coordinate system. ,in, It is the latitude of the beacon. It is the longitude of the beacon. It refers to the depth of the beacon; Step 2: After the detection robot navigates into the beacon's effective range, it establishes acoustic communication with the beacon to obtain distance information between the robot and the beacon. Based on this distance information, the robot is then controlled to navigate towards the beacon. Draw a perpendicular line from the beacon center to the dam surface to be inspected, then control the inspection robot to travel from the beacon along the drawn perpendicular line towards the dam surface. When the inspection robot reaches the designated position... At the same time, the distance information between the detection robot and the beacon is obtained and recorded. ; The location Satisfy: Location The vertical distance to the dam surface to be inspected is equal to the inspection distance of the inspection robot; Step 3: The inspection robot performs a comb-like scan of the vertical dam surface at a fixed distance. During the comb-like scan inspection process... At any given time, based on the beacon's position and distance information in the geodetic coordinate system... , dam face azimuth information Continuously monitor robot depth information and The distance between the robot and the beacon is constantly monitored to calculate the robot's detection capabilities. Location information at any given time; Step 4: Fuse the robot position information calculated in Step 3 with the robot position information output by the inertial navigation system to obtain the robot's position in... The final location information at any given moment.

2. The method for locating an underwater defect detection robot for dams based on single beacon ranging according to claim 1, characterized in that, The navigation coordinate system is oriented north-south. The positive direction of the axis, with east as the reference direction. The positive direction of the axis, with the Earth's direction as the reference point. Positive direction of the axis.

3. The method for locating an underwater defect detection robot for dams based on single beacon ranging according to claim 1, characterized in that, The specific process of step three is as follows: Step 31, The distance between the robot and the beacon is constantly monitored and recorded as follows: ,Will The depth of the robot is constantly monitored and recorded as follows: ,according to and Calculation in At any given moment, detect the depth difference between the robot and the beacon. ; Step 3.2, based on depth difference Calculate distance In a two-dimensional coordinate system Projection distance below ; The two-dimensional coordinate system The origin is the beacon center. Axis direction relative to navigation coordinate system The axes are in the same direction. Axis direction relative to navigation coordinate system The axes are in the same direction; Step 33: Based on the projection distance and distance information Calculate the perpendicular line from the beacon to the dam surface and... The angle between the time beacon and the detection robot connection ; Steps three and four: Based on the projection distance azimuth and included angle of dam face ,calculate Constantly monitor the robot in a two-dimensional coordinate system The lower position .

4. The method for locating an underwater defect detection robot for dams based on single beacon ranging according to claim 3, characterized in that, The above At any given time, the depth difference between the detection robot and the beacon is: 。 5. The method for locating a robot for underwater defect detection in dams based on single beacon ranging according to claim 3, characterized in that, The specific process of step three-two is as follows: 。 6. The method for locating an underwater defect detection robot for dams based on single beacon ranging according to claim 3, characterized in that, The azimuth information of the dam face is the angle between the vertical line of the dam face and the north direction, and the azimuth of the dam face is denoted as... .

7. The method for locating an underwater defect detection robot for dams based on single beacon ranging according to claim 3, characterized in that, The specific process of step 33 is as follows: 。 8. A method for locating a robot for underwater defect detection in dams based on single beacon ranging, as described in claim 6, is characterized in that... The specific process of steps three and four is as follows: 。 9. A method for locating a robot for underwater defect detection in dams based on single beacon ranging, as described in claim 3, is characterized in that... The specific process of step four is as follows: For the inspection robot The location information at any given time is processed: Among them, is the radius of curvature of the meridian, is the radius of curvature of the prime vertical; Will Continuously monitor the robot's position information in the geodetic coordinate system As an observation, The robot's position information output by the inertial navigation system at any given time is used as a state variable. A nonlinear filtering method is used to fuse the observed data and the state variable, and the fusion result is used as the corrected state variable. The robot's position information is detected at any time, thus obtaining the robot's final positioning information.

10. A method for locating an underwater defect detection robot for dams based on single beacon ranging, as described in claim 9, is characterized in that... The nonlinear filtering method is either Kalman filtering or particle filtering.

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