A self-flowing water pipeline leak detection device positioning correction method

Abstract

The application discloses a self-flow type water pipeline leakage detection device positioning correction method, belongs to the pipeline leakage positioning field, and relates to a spherical detector which is loaded with a strapdown inertial navigation module and rotates with the water flow in the water pipeline. The method comprises the following steps: S1, determining the first translational speed of the spherical detector in the water pipeline by using an inertial navigation algorithm; S2, determining the second translational speed of the spherical detector according to the real-time rolling speed of the spherical detector and a previously established relationship between the rolling speed and the second translational speed of the spherical detector, wherein the relationship is obtained by fitting analysis on the relationship between the rolling speed and the translational speed of the spherical detector; and S3, correcting the first translational speed by using the second translational speed, and calculating the pipeline leakage position according to the corrected first translational speed. The method can further improve the positioning accuracy of the pipeline leakage point.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of pipeline leakage positioning, and more particularly relates to a self-flow type water pipeline leakage detection device positioning correction method. BACKGROUND

[0002] The water pipeline network is the artery of urban water supply. Regularly detecting the pipeline leakage, timely finding and accurately positioning the tiny defects and hidden dangers can effectively avoid the occurrence of major leakage accidents, improve the pipeline maintenance efficiency, and save the economic cost.

[0003] The positioning accuracy of the pipeline leakage point directly affects the repair workload and determines the time cost and economic cost of the repair. The micro-mechanical (MEMS) inertial navigation is widely used in unmanned driving, emergency rescue, commercial electronic products and other fields in recent years due to its advantages of light weight and low cost. However, the large noise error and poor stability of the micro-mechanical (MEMS) inertial navigation will cause the positioning error to gradually increase with the accumulation of time, and the accurate positioning of the pipeline leakage point cannot be performed. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a self-flow type water pipeline leakage detection device positioning correction method, thereby solving the technical problem that the prior art cannot accurately position the pipeline leakage.

[0005] To achieve the above-mentioned purpose, according to the first aspect of the present application, a self-flow type water pipeline leakage detection device positioning correction method is provided, the detection device is a spherical detector carrying a strapdown inertial navigation module and rotating with the water flow in the water pipeline, and the method comprises:

[0006] S1, determining the first translational velocity of the spherical detector in the water pipeline by using an inertial navigation algorithm;

[0007] S2, determining the second translational velocity of the spherical detector according to the real-time rolling speed of the spherical detector and a previously established relationship between the rolling speed of the spherical detector and the second translational velocity; wherein the relationship is obtained by fitting analysis on the relationship between the rolling speed of the spherical detector and the second translational velocity;

[0008] S3, correcting the first translational velocity by using the second translational velocity, and calculating the pipeline leakage position according to the corrected first translational velocity.

[0009] According to the second aspect of the present application, a self-flow type water pipeline leakage detection device positioning correction system is provided, comprising: a computer readable storage medium and a processor;

[0010] The computer readable storage medium is used for storing executable instructions;

[0011] The processor is configured to read the executable instructions stored in the computer readable storage medium and execute the method according to the first aspect.

[0012] According to a third aspect of the present application, a computer readable storage medium is provided, which stores computer instructions for causing a processor to execute the method according to the first aspect.

[0013] In general, the above technical solutions conceived by the present application can achieve the following beneficial effects compared with the prior art:

[0014] The present application takes into account the defect that the inertial navigation technology gradually increases the cumulative error over time in practical application, and proposes a self-flowing water pipeline leakage detection device positioning correction method, which uses the rotation speed of the axis-rolling spherical detector to calculate the second translational speed thereof, and uses the inertial navigation algorithm to calculate the first translational speed of the spherical detector drifting in the water pipeline to fuse the data, so as to correct the first translational speed and obtain the optimal estimation value of the translational speed, which is brought into the position updating equation to correct the positioning error, and can further improve the positioning accuracy of the leakage point. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A self-flowing water pipeline leakage detection device positioning correction method flowchart is provided for the embodiments of the present application.

[0016] Figure 2 A pipeline center section water flow speed schematic diagram is provided for the embodiments of the present application.

[0017] Figure 3 One of the external shape schematic diagrams of the spherical detector is provided for the embodiments of the present application.

[0018] Figure 4 The second external shape schematic diagram of the spherical detector is provided for the embodiments of the present application.

[0019] Figure 5 The coordinate change schematic diagram when the axis-rolling spherical detector advances. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0021] According to the detection position, the pipeline leakage detection method can be divided into pipeline external indirect detection method and pipeline internal detection method; the pipeline internal detection ball is a new pipeline leakage detection technology, which is a kind of unpowered self-flowing pipeline leakage detection device, does not need external driving, can move with water flow, and adopts spherical structure to easily pass through the interface and the elbow. The detection ball adopts the sound wave detection method to identify the leakage, the operation is simple, and the technology is reliable; the combined navigation mode taking the micro mechanical (MEMS) inertial navigation as the core and combining the global satellite navigation system (GNSS) is adopted, the volume is light, and the price is low. However, the noise error and poor stability of the micro mechanical (MEMS) inertial navigation will cause the positioning error to gradually increase with the accumulation of time, and the micro mechanical (MEMS) inertial navigation cannot be directly applied to the pipeline leakage positioning alone.

[0022] Based on this, in order to further improve the positioning accuracy of pipeline leakage, the self-flowing water pipeline leakage detection device positioning correction method provided by the embodiment of the present application is combined with the special environment of the detection ball in the water pipeline, the detection device is a spherical detector carrying a strapdown inertial navigation module and rotating around the axis under the action of water flow in the water pipeline, as shown in Figure 1 , comprising:

[0023] S1, the inertial navigation algorithm is used to determine the first translational velocity of the spherical detector in the water pipeline.

[0024] Specifically, the self-flowing water pipeline leakage detection device positioning correction method provided by the embodiment of the present application, wherein the detection device is a spherical detector (hereinafter also referred to as a detection ball) carrying a strapdown inertial navigation module and rotating around the axis under the action of water flow in the water pipeline.

[0025] The detection ball adopts the sound wave detection method and the combined navigation mode taking the micro mechanical (MEMS) inertial navigation as the core and combining the global satellite navigation system (GNSS) to carry out leakage detection and positioning, and a high-precision strapdown inertial navigation module is carried inside. The strapdown inertial navigation module can be a six-axis strapdown inertial navigation module, or a nine-axis strapdown inertial navigation module, or a more-axis strapdown inertial navigation module.

[0026] The inertial navigation algorithm is used to solve the first translational velocity of the detection ball drifting in the water pipeline.

[0027] The inertial navigation solution is to deduce the navigation information at this moment from the navigation information at the last moment, including attitude updating, speed updating and position updating. Specifically, it is to build the differential relationship between the current moment navigation information and the last moment navigation information, and the motion input (angular velocity, acceleration).

[0028] The strapdown inertial navigation is fixed with the carrier (i.e. the detection ball) when working, therefore, the navigation information is solved first to determine the attitude matrix , that is, to establish a mathematical platform. The attitude matrix differential equation is as follows:

[0029]

[0030] wherein represents the attitude transformation matrix from the carrier coordinate system to the navigation coordinate system, b represents the carrier coordinate system, and n represents the navigation coordinate system, represents the anti-symmetric matrix of the angular velocity.

[0031] The attitude matrix is directly multiplied and decomposed:

[0032]

[0033] wherein:

[0034]

[0035]

[0036] The two-subsample compensation algorithm of conic motion is adopted:

[0037]

[0038] m represents the current time, φ represents the equivalent rotation vector, M RV represents the conversion of the equivalent rotation vector to the attitude matrix, and Δθ represents the angular increment output by the gyroscope.

[0039] The change is very small in a short time, so The angular increment in T m can be approximated.

[0040] In specific calculation, the equivalent rotation vector is often converted into a quaternion, and the quaternion is solved. Since the quaternion, the equivalent rotation vector, and the attitude transformation matrix all essentially represent the detection ball attitude, only the forms are different, and they can be converted into each other. Therefore, solving the quaternion Q (q0, q1, q2, q3) also solves the attitude transformation matrix , which is the mathematical platform in the strapdown inertial navigation system.

[0041] The specific force equation reflects the relationship between the measurement value (specific force) of the accelerometer in the inertial navigation system and the navigation parameters (velocity):

[0042]

[0043] wherein represents the output of the accelerometer, and respectively represent the anti-symmetric matrix of the rotation angular velocity of the earth system relative to the inertial system and the navigation system relative to the earth system, and g n (t) represents the gravitational acceleration at time t.

[0044] The specific force equation contains the accelerometer measurement value (specific force), the Coriolis force correction term, the centripetal force correction term and the gravity term. The equation is discretized and updated as follows:

[0045]

[0046] wherein, is the first translational velocity of the ball in the water pipeline, is the fast-changing part of the velocity, containing the specific force increment, the navigation system rotation correction, the rotation effect compensation and the rowing effect compensation, is the slow-changing part.

[0047] In an optional embodiment, the shell surface of the spherical detector is uniformly provided with an additional member for increasing the difference in the thrust force received by the spherical detector on the side close to the central axis of the pipeline and on the side close to the pipe wall, so that the spherical detector rotates along the axis in the water pipeline.

[0048] It can be understood that the water flow impact in the pipeline will generate a thrust force on the side of the spherical detector close to the central axis of the pipeline and on the side close to the pipe wall. The presence of the additional member can change the impact force of the water flow impact on the detection ball (i.e. the thrust force received by the detection ball).

[0049] In an optional embodiment, the additional member is a protrusion or a recess uniformly distributed along the outer surface of the spherical detector.

[0050] In an optional embodiment, the protrusion or the recess is in the shape of a circular arc and is formed by two arcs with different curvatures.

[0051] Specifically, the positioning correction method of the self-flowing water pipeline leakage detection device provided by the embodiment of the present application is provided, wherein the detection device is a spherical detector rotating along the axis in the water pipeline. The rotation of the spherical detector along the axis can be realized by using the existing technology, for example, by reasonably increasing the weight of the spherical detector. Preferably, the rotation of the spherical detector along the axis can also be realized by using the method provided by the present application: according to the pressure distribution on the surface of the detection ball in the pipeline and the fluid flow speed characteristics, a special surface fluid shape is designed for the spherical detector, so that the detection ball stably rolls along the axis under the impact of the water flow in the pipeline.

[0052] The water flow in the pipeline impacts the detection ball, and the pressure on the spherical surface of the detection ball will change, i.e. it will first decrease and then increase along the direction of the water flow, the decreasing amount is greater than the increasing amount, and the pressure upstream of the detection ball is greater than the pressure downstream. Under the action of the pressure difference, the water flow generates a thrust force on the detection ball. The water flow speed near the end of the detection ball close to the central axis of the pipeline is fast, and the flow speed near the end close to the pipe wall is slow, as shown in FIG. 1. Figure 2 As shown in FIG. 2, the thrust force of the water flow on the detection ball increases with the increase of the water flow speed in the pipeline, and the relationship is a quadratic function, which can be fitted by a quadratic function.

[0053] The flow velocity difference between the ball near the central axis of the pipeline and the water flow near the pipe wall causes the thrust on the end near the central axis of the pipeline to be always greater than the thrust on the end near the pipe wall, so that the detection ball is prone to axial rolling along the water flow direction. Based on this, the structure of the detection ball or the shape of the fluid is reasonably designed to make the axial rolling movement of the detection ball more stable.

[0054] According to the surface pressure distribution of the detection ball and the flow velocity characteristics, the target axis of the axial rotation is taken as the axis, and the same circular arc fluid patterns are uniformly processed on the surface of the detection ball shell. The convex patterns can be processed outward or the concave patterns can be processed inward. Each pattern is composed of a convex shape surrounded by two circular arcs with different radii. The closer to the central vertical surface of the rotating shaft, the wider the cross section of the pattern, and the overall is excessively smooth.

[0055] That is, in combination with the special environment of the water delivery pipe network, the detection ball shape as shown in Figures 3-4 is designed. Figure 3 is a detection ball shape in the water flow direction. Figure 4 is a detection ball shape perpendicular to the water flow direction. The target axis of the axial rotation is taken as the axis, and the circular arc fluid patterns are uniformly processed on the surface of the detection ball metal shell. The convex patterns can be processed outward or the concave patterns can be processed inward. Each pattern is composed of a shape surrounded by two circular arcs with different radii. The closer to the central vertical surface of the rotating shaft, the wider the cross section of the pattern, and the overall is excessively smooth.

[0056] Among them, Figures 3-4 The schematic shape is a convex circular arc pattern. The pattern is in the shape of a circular arc and is surrounded by two arcs with different curvatures. The curvature of the upper arc is smaller than that of the lower arc. The farther away from the axis, the wider the cross section of the pattern, and the closer to the axis, the narrower the cross section. The special fluid pattern can make the detection ball roll stably along the axis.

[0057] The detection ball drifts in the water delivery pipeline and works suspended at the bottom of the pipeline. The water flow speed near the central axis of the pipeline is large, the resistance on the large side of the concave circular arc pattern impacted by the ball is large, and a large thrust is generated. The water flow speed near the pipe wall is small, the flow is divided to both ends along the side streamline shape, the resistance on the surface of the detection ball is small, and a small thrust is generated. The difference between the thrusts on the upper and lower ends of the detection ball impacted by the water flow makes the ball roll around the rotating shaft. Even if it is slightly disturbed, it can still quickly recover to stability.

[0058] The rotation axis of the detection ball always coincides with a specified sensitive axis of the sensor when the detection ball rotates along the specified sensitive axis. The three-dimensional coordinate transformation of the detection ball can be simplified to a two-dimensional transformation in a plane, which greatly reduces the complexity of the calculation. Meanwhile, the navigation error caused by the zero offset of the sensor perpendicular to the rotation axis direction can be effectively suppressed, so that the average value of the inertial device error in a short time is as close to zero as possible, the cumulative error is reduced, and the positioning accuracy is improved.

[0059] S2, determining the second translational speed of the spherical detector according to the real-time rolling speed of the spherical detector and a pre-established relationship between the rolling speed of the spherical detector (when rotating along the specified sensitive axis) and the second translational speed; wherein the relationship is obtained by fitting analysis of the relationship between the rolling speed of the detection ball and the translational speed of the detector.

[0060] The translational speed is calculated by the rolling speed of the detection ball. For the numerical simulation study of the disturbance flow problem of the moving ball in the water pipeline, a fluid simulation software is needed to establish a suitable geometric model, determine the solver and solving equation, set the boundary conditions and control parameters, perform flow field solving calculation, simulate the surface pressure diagram and velocity diagram of the detection ball in the water pipeline, monitor important parameters such as thrust, torque, and lift of the detection ball, analyze the relationship between the ball motion state and the fluid state parameters in the pipeline, and fully exploit the correlation between the variables. The rolling speed of the detection ball and the translational speed in the forward direction are fitted and analyzed, and it is found that a quadratic function can well fit the relationship between the rolling speed of the detection ball and the translational speed:

[0061] v = k1ω 2 +k2ω+b

[0062] where v represents the second translational speed of the detection ball in the forward direction, ω represents the rolling speed of the detection ball, and coefficients k1, k2, and b are different for different application scenarios.

[0063] As can be seen from the above formula, the second translational speed can be calculated from the known rolling speed of the detection ball, which is used for detection ball speed correction and further improves the positioning accuracy. The rolling speed of the detection ball is calculated from the output of the gyroscope in the direction coinciding with the rotation axis.

[0064] Therefore, the output of the gyroscope in the direction coinciding with the rotation axis is collected, and the second translational speed of the detection ball is calculated by substituting the output into the above formula.

[0065] S3, correcting the first translational speed using the second translational speed, and calculating the pipeline leakage position using the corrected first translational speed.

[0066] Specifically, the first translation velocity calculated by the inertial navigation algorithm is fused with the second translation velocity calculated by the detected ball rolling speed to correct the error and further improve the navigation accuracy.

[0067] With the long-time running of the detection ball in the pipeline, the cumulative error caused by the navigation algorithm in step S1 gradually increases, and finding a suitable correction method is of great significance to improve the long-distance water pipeline leakage positioning accuracy. The embodiment of the application proposes to use the second translation velocity calculated by the detection ball fixed-axis rolling speed to convert the angular velocity of the detection ball rolling in the forward direction collected by the gyroscope in the direction coinciding with the rotation axis into the ball translation velocity, perform extended Kalman filtering on the velocity update value in the navigation algorithm, output the optimal estimation of the velocity, and further use it for position calculation.

[0068] The first translation velocity V k for one-step prediction:

[0069]

[0070] Prior estimation covariance:

[0071]

[0072] wherein

[0073]

[0074] k represents the current time, represents the optimal estimation value of the speed at the last time, represents a part of the predicted value of the speed at the current time, P represents the error estimation covariance matrix, Phi represents the state transition matrix, Gamma represents the error transition matrix, J represents the Jacobi matrix, and Q represents the process noise.

[0075] The second translation velocity Z k as an observation value, together with the predicted speed participate in the current time state update:

[0076]

[0077] Posterior estimation covariance:

[0078] P k =(I-K k H k )P k / k-1

[0079] wherein

[0080]

[0081] Kalman gain:

[0082]

[0083] Z represents the measurement value, H represents the measurement transfer matrix, K represents the Kalman gain, and R represents the measurement noise.

[0084] The Kalman gain K reflects the degree of confidence of the update speed in the predicted and observed values.

[0085] The update speed obtained at this time combines the navigation solution and correction information, and is closer to the true value. Using this speed for position solution will further improve positioning accuracy.

[0086] Specifically, in step S3, the first translational velocity calculated by the inertial navigation algorithm is fused with the second translational velocity inferred from the ball's rolling speed to find the optimal velocity estimate. This is then incorporated into the position update equation to reduce positioning error. Data fusion algorithms that can be used in this step include, but are not limited to, extended Kalman filtering.

[0087] Taking the detection ball equipped with a nine-axis strapdown inertial navigation module as an example, the coordinate state of the fixed-axis rolling detection ball during operation is as follows: Figure 5 As shown, the quadrilateral represents the strapdown inertial navigation module (integrated into a chip), consisting of a 3-axis accelerometer, a 3-axis gyroscope, and a 3-axis magnetometer. It is mounted at the center of mass of the detection sphere and fixed to the sphere. The x1, y1, and z1 axes always point forward, to the right, and below the assembly plane. The x2, y2, and z2 axes represent the navigation coordinate system, which always points north, east, and to the ground relative to the current geographic coordinates. They do not rotate with the spherical detector, and the origins of the two coordinate systems coincide to minimize the complexity of navigation solutions and error correction. When operating, the detection sphere can stably roll around the y1 and y2 axes. The gyroscope measurement on the y1 axis reflects the rotational speed of the detection sphere during rolling. This rotational speed can be used to deduce the second translational velocity. Using this velocity relationship as a correction, the positioning accuracy of the detection sphere can be further improved.

[0088] The embodiment of the present invention adopts a detection ball equipped with a strapdown inertial navigation module and capable of fixed-axis rolling in a pipeline, and uses extended Kalman filtering technology to fuse nine-axis raw data; a global satellite navigation system is used to locate ground markers, and the position is calibrated every 2 kilometers; the navigation information is further corrected to address the non-integrity constraints of the pipeline environment, that is, the detection ball will not slip laterally or jump vertically in straight pipe sections; and an innovative positioning correction method for a pipeline leakage detection device based on its own motion state is proposed to further improve positioning accuracy.

[0089] An embodiment of the present invention provides a positioning and correction system for a gravity-flow water pipeline leakage detection device, comprising: a computer-readable storage medium and a processor;

[0090] The computer readable storage medium is used for storing executable instructions.

[0091] The processor is used for reading the executable instructions stored in the computer readable storage medium, and performing the method as described in any of the above embodiments.

[0092] The embodiment of the present application provides a computer readable storage medium, which stores computer instructions, and the computer instructions are used for making a processor execute the method as described in any of the above embodiments.

[0093] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A positioning correction method for a gravity water pipeline leakage detection device, characterized in that: The detection device is a spherical detector equipped with a strapdown inertial navigation module and rotating along a fixed axis with the water flow in a water pipeline. The method includes: S1, determining a first translational velocity of the spherical detector in the water pipeline using an inertial navigation algorithm; S2, determining the second translational speed of the spherical detector based on the real-time rolling speed of the spherical detector and a pre-established relationship between the rolling speed of the spherical detector and the second translational speed; wherein the relationship is obtained by fitting the relationship between the rolling speed of the spherical detector and the second translational speed; S3, using the second translational velocity to correct the first translational velocity, and calculating the pipeline leakage position according to the corrected first translational velocity; wherein the first translational velocity obtained by the navigation solution algorithm is For one-step forecast: A priori estimate of the covariance: in Indicates the current moment, represents the optimal estimate of the velocity at the previous moment, represents the one-step prediction value of the current speed, P represents the error estimation covariance matrix, represents the state transition matrix, represents the error transfer matrix, J represents the Jacobian matrix, represents process noise; The second translational velocity calculated by detecting the relationship between ball rolling and translation As an observed quantity, and the predicted speed Join us for the current status update: Posterior estimated covariance: in Kalman gain: Indicates the measured value, represents the measurement transfer matrix, represents the Kalman gain, and R represents the measurement noise.

2. The method according to claim 1, wherein The relationship between the rolling speed and the second translation speed of the spherical detector is: in, is the rotational speed of the spherical detector with fixed axis rolling, 、 and b are fitting coefficients.

3. The method according to claim 1, wherein The outer shell surface of the spherical detector is evenly provided with additional parts for increasing the thrust difference between the side of the spherical detector close to the pipeline center axis and the side close to the pipeline wall, so that the spherical detector can rotate around the fixed axis in the water pipeline.

4. The method according to claim 3, wherein The additional parts are protrusions or depressions evenly distributed along the outer surface of the spherical detector.

5. The method according to claim 4, wherein The protrusion or depression is in an arc shape and is surrounded by two arcs with different curvatures.

6. A positioning and correction system for a gravity water pipeline leakage detection device, characterized in that: include: Computer-readable storage medium and processor; The computer-readable storage medium is used to store executable instructions; The processor is configured to read the executable instructions stored in the computer-readable storage medium and execute the method according to any one of claims 1 to 5.

7. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to execute the method according to any one of claims 1 to 5.

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