Butterfly valve detection method and system based on underwater vehicle in pipeline

Abstract

A butterfly valve detection method based on an underwater vehicle in a pipeline, comprising: first directly acquiring a laser ring image emitted by an underwater vehicle to an inner wall of a water conveying pipeline (1); then taking the center of the image as the center of a laser circular ring (8), taking the center as a pole, and taking a line passing through the pole and coinciding with the horizontal axis in an image coordinate system as a polar axis; when an included angle between a certain laser point and the polar axis is a preset angle, determining projection coordinates of the laser point in the image coordinate system at the preset angle; and finally, comparing projection coordinates of the laser point at two adjacent moments to determine whether there is a butterfly valve (2) and a state of the butterfly valve (2). Further disclosed is a butterfly valve detection system based on an underwater vehicle in a pipeline.

Description

A butterfly valve detection method and system based on underwater vehicle in pipeline

[0001] This invention claims priority to Chinese patent application No. 202311575144.5 filed with the State Intellectual Property Office of China on November 24, 2023, entitled “A butterfly valve detection method and system based on underwater vehicle in pipeline”, the entire contents of which are incorporated by reference into this invention and constitute a part of this invention for all purposes. Technical Field

[0002] The present invention belongs to the technical field of underwater pipeline robots, and in particular relates to a butterfly valve detection method and system based on an underwater vehicle in a pipeline. Background Art

[0003] Pipeline transportation is the most common method of energy transportation today, with water, oil, and natural gas being the most common. Butterfly valves within pipelines are crucial devices for controlling the flow and direction of fluids within them. Their condition is crucial to the operation and maintenance of pipeline systems.

[0004] The inventors found that traditional pipeline monitoring technology mainly focuses on the outside of the pipeline, using monitoring equipment such as pressure sensors, flow meters and temperature sensors to monitor pipeline fluid parameters. These sensors can only provide the overall status of the pipeline fluid and cannot directly obtain information such as the position, opening degree and working status of the butterfly valve in the pipeline; the status of the butterfly valve is crucial to the operation and maintenance of the pipeline system. If there is a lack of real-time monitoring and detection of the butterfly valve in the pipeline, it may lead to unstable operation of the pipeline system and safety hazards; the existing detection technology cannot accurately obtain the status information of the butterfly valve, and maintenance personnel can only inspect and maintain the butterfly valve regularly or at regular intervals, which increases maintenance costs and workload, and poses a certain threat to the safety of the maintenance personnel themselves; the operation of the butterfly valve in an incorrect state may lead to energy waste of the pipeline fluid and increase the operating cost of the pipeline system.

[0005] Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes a butterfly valve detection method and system based on an underwater vehicle in a pipeline. The present invention can directly determine whether there is a butterfly valve at the detection position and the status of the butterfly valve, thereby achieving the purpose of directly detecting the position and status of the butterfly valve in the pipeline.

[0007] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a butterfly valve detection method based on an underwater vehicle in a pipeline, comprising:

[0009] Acquire an image of a laser ring emitted by an underwater vehicle onto the inner wall of a water pipeline;

[0010] The center of the image is used as the center of the laser ring; the center of the circle is used as the pole, and the line passing through the pole and coinciding with the horizontal axis of the image coordinate system is used as the polar axis;

[0011] When the angle between a certain laser point and the polar axis is a preset angle, determining the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle;

[0012] By comparing the projection coordinate values ​​of the laser point at two adjacent moments, the presence or absence of a butterfly valve and the state of the butterfly valve are determined.

[0013] Furthermore, if the projection coordinate values ​​at two adjacent moments are the same, it is determined that there is no butterfly valve in the current pipeline; otherwise, it is determined that there is a butterfly valve in the pipeline.

[0014] Furthermore, if the projection coordinate value at the current moment is less than the projection coordinate value at the previous moment, and as the underwater vehicle moves forward, the projection coordinate value at the current moment tends to 0, it is determined that the butterfly valve in the pipeline is in a closed state.

[0015] Furthermore, the preset angles are 0°, 90°, 180° and 270°.

[0016] Furthermore, if the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only at 0° and 180°, and as the underwater vehicle moves forward, the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve in the pipeline is in a horizontally open state.

[0017] Furthermore, if the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only at 90° and 270°, and as the underwater vehicle moves forward, the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve in the pipeline is in a vertically open state.

[0018] Furthermore, determining the position of the underwater vehicle includes: obtaining a rotational angular velocity value of the underwater vehicle; integrating the rotational angular velocity value to obtain a rotation angle; removing the influence of gravity acceleration on the collected rotation angle to obtain an actual acceleration value; and determining the speed and position of the underwater vehicle during uniformly accelerated motion based on the actual acceleration value.

[0019] In a second aspect, the present invention further provides a butterfly valve detection system based on an underwater vehicle in a pipeline, comprising:

[0020] The data acquisition module is configured to: acquire an image of a laser ring emitted by the underwater vehicle onto the inner wall of the water pipeline;

[0021] The polar axis determination module is configured to: use the center of the image as the center of the laser ring; use the center as the pole; and use a line passing through the pole and coinciding with the horizontal axis of the image coordinate system as the polar axis;

[0022] The projection coordinate value determination module is configured to: when the angle between a certain laser point and the polar axis is a preset angle, determine the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle;

[0023] The state detection module is configured to determine whether there is a butterfly valve and the state of the butterfly valve by comparing the projection coordinate values ​​of the laser point at two adjacent moments.

[0024] In a third aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the butterfly valve detection method based on an underwater vehicle in a pipeline as described in the first aspect.

[0025] In a fourth aspect, the present invention also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the butterfly valve detection method based on an underwater vehicle in a pipeline as described in the first aspect are implemented.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention first directly obtains a laser ring image emitted by an underwater vehicle onto the inner wall of a water pipeline; then, the center of the image is used as the center of the laser ring; the center of the circle is used as the pole, and a line passing through the pole and coinciding with the horizontal axis in the image coordinate system is used as the polar axis; when the angle between a certain laser point and the polar axis is a preset angle, the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle is determined; finally, by comparing the projection coordinate values ​​of the laser point at two adjacent moments, it is determined whether a butterfly valve exists and the status of the butterfly valve; the presence or absence of a butterfly valve at the detection position and the status of the butterfly valve can be directly determined, thereby achieving the purpose of directly detecting the position and status of the butterfly valve in the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the specification of this embodiment are used to provide a further understanding of this embodiment. The schematic embodiments and descriptions of this embodiment are used to explain this embodiment and do not constitute an improper limitation on this embodiment.

[0029] FIG1 is a schematic diagram of the underwater vehicle in the pipeline according to the present invention;

[0030] FIG2 is a laser halo of the underwater vehicle in the present invention when there is no butterfly valve;

[0031] FIG3 shows the illumination of the laser halo by the underwater vehicle when the butterfly valve is just detected to be closed;

[0032] FIG4 shows the illumination of the laser light ring when the butterfly valve is closed and the underwater vehicle stops according to the present invention;

[0033] FIG5 shows the illumination of the laser ring when the underwater vehicle just detects the opening of the horizontal butterfly valve in the present invention;

[0034] FIG6 is a diagram showing the illumination of the laser ring before the underwater vehicle adjusts its posture when the horizontal butterfly valve is detected to be open in the present invention;

[0035] FIG7 shows the illumination of the laser ring when the underwater vehicle just detects that the vertical butterfly valve is opened in the present invention;

[0036] FIG8 is a diagram showing the illumination of the laser ring before the underwater vehicle adjusts its posture after detecting that the vertical butterfly valve is opened in the present invention;

[0037] FIG9 is a flow chart of a specific embodiment of the present invention;

[0038] Among them, 1. Pipeline; 2. Butterfly valve; 3. Underwater vehicle shell; 4. Ultrasonic radar; 5. Inertial navigation system; 6. Infrared camera; 7. Laser source with conical mirror; 8. Laser ring. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0041] Example 1:

[0042] Traditional pipeline monitoring technology primarily focuses on the exterior of the pipeline, using monitoring devices such as pressure sensors, flow meters, and temperature sensors to monitor pipeline fluid parameters. These sensors can only provide an overall picture of the pipeline fluid status and cannot directly obtain information such as the position, opening degree, and operating status of the butterfly valve within the pipeline. The pipeline here can be understood as a water pipeline.

[0043] In response to the above-mentioned problems existing in traditional pipeline monitoring technology, as shown in Figure 1, this embodiment provides a butterfly valve detection method based on an underwater vehicle in a pipeline. First, a laser ring image emitted by the underwater vehicle to the inner wall of the water pipeline is directly obtained; then, the center of the image is used as the center of the laser ring 8; the center of the circle is used as the pole, and the line passing through the pole and coinciding with the horizontal axis in the image coordinate system is used as the polar axis; when the angle between a certain laser point and the polar axis is a preset angle, the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle is determined; finally, by comparing the projection coordinate values ​​of the laser point at two adjacent moments, it is determined whether there is a butterfly valve 2 and the status of the butterfly valve 2; it can be directly determined whether there is a butterfly valve 2 and the status of the butterfly valve 2 at the detection position, thereby achieving the purpose of directly detecting the position and status of the butterfly valve 2 in the pipeline 1.

[0044] In this embodiment, an underwater vehicle is used to replace workers entering pipeline 1 for inspection. Optionally, the underwater vehicle is equipped with an inertial navigation system 5, a visual system, a propulsion system, and a ranging and obstacle avoidance system. The inertial navigation system 5 may include a fiber optic gyroscope and an accelerometer, which fuse sensor data to obtain information about the underwater vehicle's speed. The visual system may include a laser transmitter with a conical mirror and a camera that cooperates with the laser transmitter. The laser transmitter generates a conical laser, which illuminates the inner wall of pipeline 1 to form a laser ring. The camera is used to obtain the position information of the laser ring and construct a three-dimensional point cloud map. The laser ring position information is calculated from the image captured by the camera to determine the presence and status of butterfly valve 2. The ranging and obstacle avoidance system may use an ultrasonic radar 4 to obtain the distance between the underwater vehicle and the inner wall of pipeline 1, which is used to maintain the underwater vehicle's flight in the center of pipeline 1 and adjust its posture. As shown in FIG1 , the underwater vehicle in this embodiment may include an underwater vehicle shell 3, an ultrasonic radar 4 arranged on the underwater vehicle shell 3, an inertial navigation system 5, an infrared camera 6, and a laser source 7 with a conical mirror, etc. Other settings of the underwater vehicle can be achieved through conventional settings and will not be described in detail here.

[0045] In this embodiment, the attitude output equation of the underwater vehicle is first constructed, and the kinematic equation is used to obtain the precise position information of the vehicle. Then, a laser transmitter generates a conical laser, which is irradiated onto the inner wall of the pipe 1 to form a laser ring. A camera is used to obtain the position information of the laser ring and construct a three-dimensional point cloud image. Finally, the camera is used to detect changes in the laser ring in the image to determine the type and status of the butterfly valve 2 in the pipe 1. As shown in Figure 9, the specific steps are as follows:

[0046] S1. Obtain the precise position of the underwater vehicle:

[0047] S1.1. Establish the fiber optic gyroscope model and accelerometer model in the world coordinate system. Define the raw data collected by the fiber optic gyroscope at time k as the three-axis rotation angular velocity value w k =[wkX w kY w kZ ] T , define the original data collected by the accelerometer at time k as the three-axis acceleration value a k =[a kX a kY a kZ ] T .

[0048] Among them, w kX , w kY , w kZ Respectively represent the angular velocity values ​​of rotation on the X, Y, and Z axes at time k; a kX , a kY , a kZ Respectively represent the acceleration values ​​on the X, Y, and Z axes at time k.

[0049] S1.2, the rotation angular velocity value w k Integrate to get the rotation angle at time k:

[0050] Use the current rotation angle Remove the influence of gravity acceleration g on the acquisition and get the actual acceleration value a′ k =[a′ kX a′ kY a′ kZ ] T .

[0051] S1.3. Assume that the underwater vehicle is in uniform acceleration motion during the time period from k-1 to k. Then the velocity v of the underwater vehicle at time k is k and position p k is: v k =[v kX v kY v kZ ] T =v k-1 +a′ k Δt

[0052] Where Δt = t k -t k-1 is the time interval from time k-1 to time k; v k and p k are the velocities and positions of the three axes in the world coordinate system at time k.

[0053] In step S1.1, a world coordinate system is established. The center of the pipeline inspection port is set as the coordinate origin and coincides with the center of the underwater vehicle. The forward direction of the underwater vehicle is the Z axis and the direction of the earth's gravity is the Y axis. The world coordinate system O is determined according to the right-hand coordinate system. W -XYZ.

[0054] The underwater vehicle can also be called a robot. Optionally, four ultrasonic radars 4 are installed in a circle behind the robot body, with a difference of 90° between two adjacent ultrasonic radars 4. The installation direction of the ultrasonic radar 4 is perpendicular to the surface of the pipe 1, so that when it detects the inner wall of the pipe 1, the ultrasonic radar 4 is detecting the inner wall of the pipe 1; a fiber optic gyroscope and an accelerometer are installed at the middle end of the robot body; a laser transmitter with a conical mirror is installed at the front of the robot, and a camera that cooperates with the laser transmitter is installed above the laser transmitter.

[0055] S2. Build a 3D point cloud map of pipeline 1:

[0056] S2.1. Before the underwater vehicle begins to construct the three-dimensional point cloud map of Pipeline 1, determine whether the underwater vehicle's visual system has been calibrated. If the camera has not been calibrated, first perform the calibration operation step S2.5. If the calibration is completed, start constructing the three-dimensional point cloud map of Pipeline 1.

[0057] S2.2. Place a checkerboard calibration plate in front of the camera and calibrate the camera using the Zhang Zhengyou calibration method. Calculate the projection error based on the actual pixel coordinates and the calculated pixel coordinates. Repeatedly iterate the camera's internal and external parameters and distortion parameters until convergence. This completes the camera calibration.

[0058] S2.3. After calibration, use the ultrasonic radar 4 to detect whether the aircraft is located at the center of the pipeline 1. If it is, proceed to the following steps. Otherwise, adjust the position of the aircraft. After adjustment, repeat this step.

[0059] S2.4. When the vehicle moves forward in pipe 1, the laser transmitter emits laser light to illuminate the inner wall of pipe 1, forming a laser ring.

[0060] S2.5. De-noise the laser ring image projected onto the inner wall of pipeline 1 captured by infrared camera 6 using median filtering. Use a circle detection algorithm to detect the laser ring in the image, calculate the depth information of the laser ring, and integrate the underwater vehicle position information to construct a point cloud map of pipeline 1.

[0061] In step S2.2, the infrared camera 6 is calibrated as follows:

[0062] S2.2.1. Establish the camera coordinate system, with the optical center of the camera as the origin of the coordinate system and the Z C The axis is perpendicular to the imaging plane and points to the front of the camera, X CAxis and Y C The axis is parallel to the world coordinate system. The transformation relationship from the world coordinate system to the camera coordinate system is as follows:

[0063] Among them, X p , Y p , Z p is the position coordinate of P in the world coordinate system; X C , Y C , Z C is the coordinate of P in the camera coordinate system; R and T represent the rotation matrix and translation matrix between the world coordinate system and the camera coordinate system respectively.

[0064] S2.2.2. Establish an image coordinate system. The origin of the image coordinate system is the intersection of the camera optical axis and the imaging plane. The x-axis is horizontally to the right, and the y-axis is vertically downward. The conversion relationship between the image coordinate system and the camera coordinate system is as follows:

[0065] The coordinates of point P in the image coordinate system are (x, y); f represents the focal length of the camera.

[0066] From this we can deduce the transformation relationship between the world coordinate system and the image coordinate system:

[0067] S2.2.3. The camera has nonlinear distortion, which can be corrected using the following formula:

[0068] in, k1, k2 are the distortion parameters of the camera; x′, y′ are the coordinates of the distorted image, and x and y are the coordinates of the ideal image.

[0069] S3. As shown in FIG. 2 to FIG. 8 , the change of the laser ring is detected in the projected image to determine the type and status of the butterfly valve 2 in the pipeline 1:

[0070] S3.1. The infrared camera 6 captures an image with the image center as the center of the laser ring 8. The image polar coordinate system is established with the center as the pole and the polar axis coinciding horizontally to the right with the positive x-axis in the image coordinate system.

[0071] S3.2. Use the following formula to express the position information of a laser point in the laser ring at time k: D = [xy θ t k ] T

[0072] Where x and y represent the projected coordinates of the laser point in the laser ring in the image coordinate system; θ is the angle between the laser point and the polar axis in the image polar coordinate system; and T represents time.

[0073] When the robot first enters the water, it records the current time t0, as well as the x and y values ​​corresponding to when θ is equal to 0°, 90°, 180°, and 270°, respectively. The four sets of recorded values ​​are saved as the corresponding state when there is no butterfly valve 2.

[0074] S3.3. If the projection coordinate values ​​at two adjacent moments are the same, it is determined that there is no butterfly valve 2 in the current pipeline 1; otherwise, it is determined that there is butterfly valve 2 in the pipeline 1. Specifically, during the robot's forward movement, the x and y values ​​corresponding to the time θ at time k equal to 0°, 90°, 180°, and 270° are recorded, and compared with the corresponding x and y values ​​recorded at time k-1. If D k Record the four sets of x and y values ​​and D k-1 If the four sets of x and y values ​​are the same, it is determined that there is no butterfly valve 2 in the current pipeline 1.

[0075] S3.4 If D k Record the four sets of x and y values ​​and D k-1 If the four sets of x and y values ​​are different, it is considered that there is a butterfly valve 2 in pipeline 1, and the status of butterfly valve 2 is judged.

[0076] If the projection coordinate value at the current moment is less than the projection coordinate value at the previous moment, and as the underwater vehicle moves forward, the projection coordinate value at the current moment tends to 0, then it is determined that the butterfly valve 2 in the pipeline 1 is in the closed state. Specifically, if D k The four sets of x and y values ​​are all less than D k-1 Record four sets of x and y values, and as the underwater vehicle moves forward, D k If the values ​​of the four groups of x and y recorded in the are all approaching 0, it is determined that the butterfly valve 2 in the current pipeline 1 is in the closed state, and the underwater vehicle stops moving forward.

[0077] If the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only at 0° and 180°, and as the underwater vehicle moves forward, the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve 2 in the pipeline 1 is in the horizontal open state. Specifically, if D k The four sets of x and y values ​​recorded in the table are only related to D when θ is equal to 0° and 180°. k-1 When θ is equal to 0° and 180°, the recorded values ​​of x and y are different, and as the underwater vehicle moves forward, D k When θ is equal to 0° and 180°, the recorded values ​​of x and y all tend to 0, which means that the butterfly valve 2 in the current pipeline 1 is in a horizontally open state. The underwater vehicle posture is adjusted and the underwater vehicle moves upward to pass through the butterfly valve 2.

[0078] If the projection coordinate values ​​at the current moment are not equal to the projection coordinate values ​​at the previous moment only at 90° and 270°, and as the underwater vehicle moves forward, the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve 2 in the pipeline 1 is in the vertical open state. Specifically, if D k The four sets of x and y values ​​recorded in the table are only related to D when θ is equal to 90° and 270°. k-1 When θ is equal to 90° and 270°, the recorded values ​​of x and y are different, and as the underwater vehicle moves forward, D k When θ is equal to 90° and 270°, the recorded values ​​of x and y all tend to 0, which means that the butterfly valve 2 in the current pipeline 1 is in the vertically open state. The posture of the underwater vehicle is adjusted, and the underwater vehicle moves to the left to pass through the butterfly valve 2.

[0079] Example 2:

[0080] This embodiment provides a butterfly valve detection system based on an underwater vehicle in a pipeline, comprising:

[0081] The data acquisition module is configured to: acquire an image of a laser ring emitted by the underwater vehicle onto the inner wall of the pipeline;

[0082] The polar axis determination module is configured to: use the center of the image as the center of the laser ring; use the center as the pole; and use a line passing through the pole and coinciding with the horizontal axis of the image coordinate system as the polar axis;

[0083] The projection coordinate value determination module is configured to: when the angle between a certain laser point and the polar axis is a preset angle, determine the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle;

[0084] The state detection module is configured to determine whether there is a butterfly valve and the state of the butterfly valve by comparing the projection coordinate values ​​of the laser point at two adjacent moments.

[0085] The working method of the system is the same as the butterfly valve detection method based on the underwater vehicle in the pipeline in Example 1, and will not be repeated here.

[0086] Example 3:

[0087] This embodiment provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the steps of the butterfly valve detection method based on an underwater vehicle in a pipeline described in Example 1 are implemented.

[0088] Example 4:

[0089] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the butterfly valve detection method based on an underwater vehicle in a pipeline described in Example 1 are implemented.

[0090] The above description is merely a preferred embodiment of this embodiment and is not intended to limit this embodiment. Those skilled in the art will readily appreciate that this embodiment may be modified and varied in various ways. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this embodiment shall be within the scope of protection of this embodiment.

Claims

1. A butterfly valve detection method based on an underwater vehicle in a pipeline, characterized in that: include: Acquire a laser ring image emitted by an underwater vehicle onto the inner wall of a water pipeline; The center of the image is taken as the center of the laser ring; the center of the circle is taken as the pole, and the line passing through the pole and coinciding with the horizontal axis in the image coordinate system is taken as the polar axis; When the angle between a certain laser point and the polar axis is a preset angle, determining the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle; By comparing the projection coordinate values ​​of the laser point at two adjacent moments, it is determined whether there is a butterfly valve and the state of the butterfly valve; specifically: If the projection coordinate values ​​at two adjacent moments are the same, it is determined that there is no butterfly valve in the current pipeline; otherwise, it is determined that there is a butterfly valve in the pipeline; wherein the preset angles are 0°, 90°, 180° and 270°; If the projection coordinate value at the current moment is less than the projection coordinate value at the previous moment, and as the underwater vehicle moves forward, the projection coordinate value at the current moment tends to 0, then it is determined that the butterfly valve in the pipeline is in a closed state; If the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only when the underwater vehicle moves forward at 0° and 180°, and the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve in the pipeline is in a horizontal open state; If the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only at 90° and 270°, and as the underwater vehicle moves forward, the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve in the pipeline is in a vertically open state.

2. A butterfly valve detection method based on an underwater vehicle in a pipeline as claimed in claim 1, characterized in that: Determining the position of the underwater vehicle includes: obtaining the rotation angular velocity value of the underwater vehicle; integrating the rotation angular velocity value to obtain the rotation angle; removing the influence of gravity acceleration on the collected rotation angle to obtain the actual acceleration value; and determining the speed and position of the underwater vehicle when performing uniform acceleration motion according to the actual acceleration value.

3. A butterfly valve detection system based on an underwater vehicle in a pipeline, characterized in that: The steps of implementing the butterfly valve detection method based on an underwater vehicle in a pipeline as described in any one of claims 1-2 include: The data acquisition module is configured to: acquire a laser ring image emitted by the underwater vehicle to the inner wall of the water pipeline; The polar axis determination module is configured to: use the center of the image as the center of the laser ring; use the center of the circle as the pole, and use the line passing through the pole and coinciding with the horizontal axis in the image coordinate system as the polar axis; The projection coordinate value determination module is configured to: when the angle between a certain laser point and the polar axis is a preset angle, determine the projection coordinate value of the laser point in the image coordinate system corresponding to the preset angle; The state detection module is configured to: determine whether there is a butterfly valve and the state of the butterfly valve by comparing the projection coordinate values ​​of the laser point at two adjacent moments; specifically: If the projection coordinate values ​​at two adjacent moments are the same, it is determined that there is no butterfly valve in the current pipeline; otherwise, it is determined that there is a butterfly valve in the pipeline; wherein the preset angles are 0°, 90°, 180° and 270°; If the projection coordinate value at the current moment is less than the projection coordinate value at the previous moment, and as the underwater vehicle moves forward, the projection coordinate value at the current moment tends to 0, then it is determined that the butterfly valve in the pipeline is in a closed state; If the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only when the underwater vehicle moves forward at 0° and 180°, and the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve in the pipeline is in a horizontal open state; If the projection coordinate value at the current moment is not equal to the projection coordinate value at the previous moment only at 90° and 270°, and as the underwater vehicle moves forward, the projection coordinate values ​​at the current moment all tend to 0, then it is determined that the butterfly valve in the pipeline is in a vertically open state.

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