Pipeline internal detection azimuth sensor and azimuth angle calculation method

Abstract

The invention discloses a pipeline internal detection azimuth sensor and an azimuth angle calculation method, and relates to the technical field of pipeline internal detection. Comprising a three-axis acceleration sensor and an MCU, the three-axis acceleration sensor is connected with the MCU through an SPI interface, and the MCU is connected with a pipeline inner detector data acquisition and storage system through a UART or DAC conversion transmission interface; the three-axis acceleration sensor is used for acquiring accelerations in three space coordinate directions of x, y and z; the MCU performs initial configuration, calibration and data reading on the three-axis acceleration sensor through an SPI (Serial Peripheral Interface); the three-axis acceleration sensor and the MCU are both connected with the power supply module. The device is low in cost, small in occupied space and easy to assemble, mechanical faults of an existing sensor cannot occur, and the device can be highly matched with current inner detector signal acquisition systems of various types.

Description

Technical Field

[0001] The present invention relates to the technical field of in-pipeline detection, and in particular to an in-pipeline detection azimuth sensor and an azimuth angle calculation method. Background Art

[0002] The position collection of most existing pipeline internal detectors relies on a code disk and a weight to locate the 6 o'clock position. Then, the specific hourly position of the internal defect of the pipeline is determined by arranging special probes on the inner detector in a circle. However, this mechanical positioning solution is costly, occupies a large space, and is complex to assemble. The vibration of the inner detector during operation can easily cause the weight to get stuck or fall off, causing damage to the equipment. The sensor used in the above-mentioned inner detector occupies a large space and will increase the axial length of the inner detector cabin, which is very unfavorable for the passability of the inner detector itself. In addition, the installation of the position sensor is complicated, and the weight may get stuck or even fall off during the operation of the inner detector, which may damage the equipment in severe cases.

[0003] In summary, the present invention designs an azimuth sensor and an azimuth angle calculation method that are independent of mechanical structures. Summary of the invention

[0004] In view of the shortcomings of the existing in-pipeline azimuth detection sensors in the art, such as high cost, large space occupation, complex assembly, and prone to mechanical failure, the purpose of the present invention is to provide an in-pipeline azimuth detection sensor and an azimuth angle calculation method.

[0005] In order to achieve the above-mentioned purpose, the present invention is implemented through the following technical scheme: a pipeline detection azimuth sensor, including a three-axis acceleration sensor and an MCU, the three-axis acceleration sensor is connected to the MCU through an SPI interface, and the MCU is connected to a data acquisition and storage system of the pipeline detector through a UART or DAC conversion transmission interface; the three-axis acceleration sensor collects accelerations in the three spatial coordinate directions of x, y, and z; the MCU initializes, configures, calibrates, and reads data of the three-axis acceleration sensor through the SPI interface; the three-axis acceleration sensor and the MCU are both connected to a power supply module.

[0006] Preferably, the three-axis acceleration sensor utilizes the gravity-sensitive characteristic to obtain the direction of gravity acceleration in the current state through mechanical decomposition, that is, the 6 o'clock position of the detector in the pipeline.

[0007] Preferably, the MCU converts the sensor data read into azimuth angles, and then transmits the converted data to the data acquisition and storage system of the detector in the pipeline through UART or DAC.

[0008] A method for calculating the detection azimuth angle in a pipeline comprises the following steps:

[0009] 1. Install the in-pipe detection position sensor perpendicular to the axial direction of the internal detector;

[0010] 2. The internal detector always moves along the z-axis direction of the sensor inside the pipeline, so the acceleration component generated by the medium pressure in the xy plane is 0. The acceleration components of the three-axis acceleration sensor in the x-axis and y-axis directions are ax and ay respectively; the following relationship can be obtained:

[0011]

[0012] in

[0013] φ is the angle between the gravitational acceleration g and the z-axis;

[0014] θ is the angle between the projection of gravitational acceleration on the xy plane and the x-axis;

[0015] 3. Obtain the clock azimuth angle of the inner detector by the following calculation method:

[0016]

[0017] in

[0018] θ is the angle between the projection of the gravitational acceleration on the xy plane and the x-axis.

[0019] The present invention has the following beneficial effects:

[0020] 1. The pipeline internal detection position sensor of the present invention utilizes the characteristic that the three-axis acceleration sensor is sensitive to gravity, and determines the specific clock position of the internal detector through mechanical decomposition. The sensor does not rely on mechanical structure, so it takes up little space and will not have mechanical failures of existing sensors. In addition, the programmable characteristics of MCU make the output mode of the position sensor proposed in the present invention customizable, which can be highly adapted to the current various types of internal detector signal acquisition systems, thereby smoothly replacing existing sensors.

[0021] 2. The method for calculating the azimuth angle of the in-pipe detection of the present invention limits the tangent value to the range of [0, 1) according to the characteristics of the inverse tangent function, thus avoiding the phenomenon of data overflow during the calculation process. It is also easy to make an inverse tangent vector table according to the accuracy requirements, and quickly calculate the angle between the 6 o'clock position of the internal detector and the x-axis direction of the sensor by looking up the table. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments;

[0023] Figure 1 It is the overall block diagram of the in-pipeline detection position sensor of the present invention;

[0024] Figure 2 It is a schematic diagram of acceleration analysis of the triaxial acceleration sensor of the present invention when the detector is running in a pipeline;

[0025] Figure 3 is a circuit schematic diagram of a three-axis acceleration sensor of the present invention;

[0026] Figure 4 This is a circuit diagram of a power supply module of the present invention;

[0027] Figure 5 It is the MCU circuit principle diagram of the present invention;

[0028] Figure 6 This is a flow chart of the algorithm for detecting azimuth angles in a pipeline according to the present invention. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0030] Reference Figure 1-6 The present specific implementation adopts the following technical scheme: a pipeline detection orientation sensor, including a three-axis acceleration sensor 1 and an MCU2, the three-axis acceleration sensor 1 is connected to the MCU2 through an SPI interface, and the MCU2 is connected to a pipeline detector data acquisition storage system 3 through a UART or DAC conversion transmission interface; the three-axis acceleration sensor 1 collects accelerations in the three spatial coordinate directions of x, y, and z; the MCU2 initializes, configures, calibrates, and reads data of the three-axis acceleration sensor through the SPI interface; the three-axis acceleration sensor 1 and the MCU2 are both connected to a power supply module.

[0031] It is worth noting that the three-axis acceleration sensor 1 utilizes the gravity-sensitive characteristics to obtain the direction of gravity acceleration in the current state through mechanical decomposition, that is, the 6 o'clock position of the detector in the pipeline.

[0032] In addition, the MCU2 converts the sensor data read into azimuth angles, and then transmits them to the data acquisition and storage system of the detector in the pipeline through UART or DAC conversion.

[0033] A method for calculating the detection azimuth angle in a pipeline comprises the following steps:

[0034] 1. Install the in-pipe detection position sensor perpendicular to the axial direction of the internal detector;

[0035] 2. If Figure 2As shown, the internal detector always moves along the z-axis direction of the sensor inside the pipeline, so the acceleration component generated by the medium pressure in the xy plane is 0. The acceleration components of the three-axis acceleration sensor in the x-axis and y-axis directions are ax and ay respectively; the following relationship can be obtained:

[0036]

[0037] in

[0038] φ is the angle between the gravitational acceleration g and the z-axis;

[0039] θ is the angle between the projection of gravitational acceleration on the xy plane and the x-axis;

[0040] 3. Ideally, the clock azimuth angle of the internal detector can be obtained by the formula θ=arctan(ay / ax). However, the range of ay / ax is (-∞, +∞), which can easily lead to data overflow and errors when calculating in an embedded system. To solve this problem, the present invention proposes the following calculation method:

[0041]

[0042] in

[0043] θ is the angle between the projection of the gravitational acceleration on the xy plane and the x-axis.

[0044] The software implementation process of the method for calculating the azimuth angle of detection in the pipeline includes a main program and an interrupt program. The main program includes the following steps:

[0045] 1. Initialize MCU interfaces, including SPI, DAC, and UART;

[0046] 2. Initialize the configuration of the three-axis acceleration sensor, including initial reset, measurement range setting, sampling frequency setting, detection action threshold setting, and detection mode start setting;

[0047] 3. Initialize the internal clock of the MCU, including the frequency division coefficient configuration, count value configuration, and clock interrupt priority configuration;

[0048] 4. Enable clock interrupt;

[0049] 5. Wait for interrupt. If an interrupt event occurs, call the interrupt function.

[0050] The interrupt procedure comprises the following steps:

[0051] 1. Read the acceleration values ​​ax and ay of the three-axis accelerometer in the x-axis and y-axis directions;

[0052] 2. Calculate the value of |ax| / |ay| or |ay| / |ax|, and calculate the azimuth angle by looking up the inverse tangent vector table;

[0053] 3. Convert the calculated angle and output it through the DAC and UART interface of the MCU

[0054] 4. The interrupt ends and returns to the main program.

[0055] This specific implementation method utilizes a three-axis acceleration sensor, does not rely on a mechanical structure, greatly reduces the occupied space, and improves the passability of the internal detector. There is no risk of mechanical failure, and the weight can be prevented from getting stuck or falling off, thereby improving the stability and safety of the equipment. The installation process is simplified, and maintenance costs and time are reduced. The programmable nature of the MCU makes the sensor output method customizable and adaptable to various types of internal detector signal acquisition systems. By limiting the tangent value range and using the inverse tangent vector table, data overflow is avoided, and the azimuth angle is calculated quickly and accurately. These advantages enable the sensor to smoothly replace existing sensors and improve the efficiency and reliability of in-pipeline detection.

[0056] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A pipeline detection position sensor, characterized in that: The invention comprises a three-axis acceleration sensor (1) and an MCU (2); the three-axis acceleration sensor (1) is connected to the MCU (2) via an SPI interface; the MCU (2) is connected to a data acquisition storage system (3) of a detector in a pipeline via a UART or DAC conversion transmission interface; the three-axis acceleration sensor (1) acquires accelerations in three spatial coordinate directions of x, y and z; the MCU (2) performs initialization configuration, calibration and data reading on the three-axis acceleration sensor via the SPI interface; the three-axis acceleration sensor (1) and the MCU (2) are both connected to a power supply module.

2. The in-pipeline detection position sensor according to claim 1, characterized in that: The three-axis acceleration sensor (1) utilizes the gravity-sensitive characteristic and obtains the direction of gravity acceleration in the current state through mechanical decomposition.

3. The in-pipeline detection position sensor according to claim 1, characterized in that: The MCU (2) converts the sensor data read into an azimuth angle, and then transmits the converted data to the data acquisition and storage system of the detector in the pipeline through UART or DAC.

4. A method for calculating the azimuth angle of detection in a pipeline, characterized in that: The following steps are involved: (1) Install the in-pipe detection position sensor perpendicular to the axial direction of the internal detector; (2) The internal detector always moves along the z-axis direction of the sensor inside the pipeline, so the acceleration component generated by the medium pressure in the xy plane is 0; the acceleration components of the three-axis acceleration sensor in the x-axis and y-axis directions are ax and ay respectively; the following relationship can be obtained: in φ is the angle between the gravitational acceleration g and the z-axis; θ is the angle between the projection of gravitational acceleration on the xy plane and the x-axis; (3) Obtain the clock azimuth angle of the inner detector by the following calculation method: in θ is the angle between the projection of the gravitational acceleration on the xy plane and the x-axis.

5. The method for calculating the azimuth angle of in-pipe detection according to claim 1, characterized in that: The software implementation process includes a main program and an interrupt program, and the main program includes the following steps: (1) Initialize MCU interfaces, including SPI, DAC, and UART; (2) Initialize the configuration of the three-axis acceleration sensor, including initial reset, measurement range setting, sampling frequency setting, detection action threshold setting, and detection mode start setting; (3) Initialize the MCU internal clock, including frequency division coefficient configuration, count value configuration, and clock interrupt priority configuration; (4) Enable clock interrupt; (5) Wait for interrupt. If an interrupt event occurs, call the interrupt function.

6. A method for calculating the azimuth angle of in-pipe detection according to claim 5, characterized in that: The interrupt procedure comprises the following steps: (1) Read the acceleration values ​​ax and ay of the three-axis acceleration sensor in the x-axis and y-axis directions; (2) Calculate the value of |ax| / |ay| or |ay| / |ax|, and calculate the azimuth angle by looking up the inverse tangent vector table; (3) Convert the calculated angle and output it through the DAC and UART interface of the MCU; (4) The interrupt ends and returns to the main program.

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