CN211450057U - Mileage locator for detection in pipeline - Google Patents

Abstract

The utility model provides an in-pipe detection mileage locator, comprising an FPGA chip module, wherein the FPGA chip module is respectively connected with a three-axis acceleration sensor, an ADC conversion module, a level conversion module, two SPI Flash chip modules, and two RS485 Interface chip module, crystal oscillator, temperature compensated crystal oscillator and power management module. The utility model installs the three Hall angle sensors in the three mileage wheels respectively, and transmits the incremental pulse signals whose phase difference is 90° electronic angle to the FPGA in a differential manner, and uses the pulse signals of the three mileage wheels to adopt The mileage wheel pulse equalization algorithm is used to calculate the speed of the detector, and at the same time collect the three-axis acceleration signal to compensate the mileage data, which improves the anti-interference ability and measurement accuracy of the mileage positioning system. It communicates with the internal detector through RS485, and transmits the data to the internal detector for storage quickly and in real time, so as to realize the precise positioning of the defect or geometric deformation position.

Description

An in-pipe detection mileage locator

technical field

The utility model relates to an in-pipe detection mileage locator, which belongs to the field of in-pipe detection.

Background technique

Long-distance pipelines are prone to cracks, corrosion, and thinning of pipe walls due to exposure to various complex and harsh environmental conditions, which bring major safety hazards to the normal operation of pipelines. Therefore, it is necessary to carry out internal inspection and defect location of long-distance pipelines to minimize the probability of pipeline leakage accidents and provide technical guarantees for the safe operation of long-distance pipelines.

In-pipeline inspection utilizes a magnetic flux leakage detector or an internal deformation detector to detect metal corrosion defects and geometric deformations on the inner and outer walls of the pipeline, and uses a mileage wheel to locate the defect or geometric deformation in the pipeline. When the inner detector passes through the elbow, the mileage wheel will not be able to contact the pipe wall well, resulting in slippage, resulting in inaccurate mileage positioning. Therefore, designing a mileage positioning system with strong anti-interference ability, real-time detection and high precision can provide important technical guarantee for corrosion detection, precise positioning and safe operation of long-distance pipelines.

SUMMARY OF THE INVENTION

The purpose of the utility model is to provide an in-pipe detection mileage locator in order to overcome the above-mentioned defects of the prior art, so as to realize precise positioning of the defect or geometric deformation position in the pipe.

In order to achieve the above purpose, the technical solution of the present utility model provides an in-pipe detection mileage locator, the mileage locator is placed in the pipeline in-pipe detector, and communicates with the in-pipe detector through RS485, which is characterized in that it includes an FPGA chip module , the FPGA chip module is respectively connected with a three-axis acceleration sensor for collecting the acceleration signal of the detector in the pipeline to compensate the mileage data;

The Hall angle sensor is used to convert the magnetic field change generated by the rotation of the mileage wheel into an incremental pulse signal and send it to the FPGA chip module to record the mileage of the inner detector;

Two SPI Flash chip modules, the first SPI Flash chip module is used to store the measured mileage data and the three-axis acceleration sensor data; the second SPI Flash chip module is used for FPGA chip module program storage;

Two RS485 interface chip modules, the first RS485 interface chip module is used to transmit the driving distance and GPS time to the external internal detector to synchronize pipeline defects or geometric deformation, driving distance and GPS time; the RS485 interface chip module two is used to receive external GPS The timing signal of the timer is used to synchronize the system clock.

Crystal oscillator, used to provide clock signal for FPGA chip module;

Temperature-compensated crystal oscillator, used to provide a stable GPS clock with temperature compensation based on GPS timing signals;

The power management module is used to provide the power required by the FPGA chip module.

Preferably, the three-axis acceleration sensor is connected in communication with the FPGA chip module through an ADC conversion module.

Preferably, the Hall angle sensors are respectively installed in three mileage wheels.

Preferably, the Hall angle sensor is connected to the FPGA chip module through a level conversion module.

Preferably, the acceleration signal collected by the three-axis acceleration sensor is converted by the ADC conversion module and stored in the SPI Flash chip module 1 through the FPGA chip module.

Preferably, the incremental pulse signal of the Hall angle sensor is transmitted in a differential manner as a series of square wave pulses with a phase difference of 90° electronic angle, and is stored in the SPI Flash chip module 1 through the FPGA chip module.

Compared with the prior art, the beneficial effects of the present utility model are:

The utility model installs the three Hall angle sensors in the three mileage wheels respectively, and transmits the incremental pulse signals whose phase difference is 90° electronic angle to the FPGA in a differential manner, and uses the pulse signals of the three mileage wheels to adopt The mileage wheel pulse equalization algorithm is used to calculate the speed of the detector, and at the same time collect the three-axis acceleration signal to compensate the mileage data, which improves the anti-interference ability and measurement accuracy of the mileage positioning system. It communicates with the internal detector through RS485, and transmits the data to the internal detector for storage quickly and in real time, so as to realize the precise positioning of the defect or geometric deformation position.

Description of drawings

1 is a schematic diagram of a locator module for detecting mileage in a pipeline of the present invention;

Figure 2 is the incremental pulse output protocol diagram of the Hall angle sensor, in which the horizontal axis represents the position and the vertical axis represents the pulse signal;

Figure 3 is a circuit diagram of the Hall angle sensor interface;

Figure 4 is a circuit diagram of a three-axis acceleration sensor interface;

Fig. 5 is the interface circuit diagram of ADC conversion module;

Fig. 6 is the connection diagram of the mileage locator and the inner detector in the pipeline.

Detailed ways

In order to make the present utility model more obvious and easy to understand, preferred embodiments are described below in detail with the accompanying drawings.

The utility model is an in-pipe detection mileage locator which is placed in the in-pipe detector, communicates with the in-pipe detector through RS485, and comprises an FPGA chip module, a three-axis acceleration sensor, three Hall angle sensors, and two SPI Flash chip module, two RS485 interface chip modules, a crystal oscillator, a temperature compensated crystal oscillator, an ADC conversion module, a level conversion module and a power management module. The frequency of the crystal oscillator is 100MHz, and the frequency of the temperature-compensated crystal oscillator is 10MHz. The FPGA chip module is respectively connected to a three-axis acceleration sensor, an ADC conversion module, a level conversion module, two SPIFlash chip modules, two RS485 interface chip modules, a crystal oscillator module, a temperature compensated crystal oscillator module and a power management module. The three-axis acceleration sensor is connected to the FPGA chip module through the ADC conversion module, and the Hall angle sensor is connected to the FPGA chip module through the level conversion module, as shown in Figure 1.

The FPGA chip module adopts Spartan-6XC6SLX45 FGPA, which is used to realize mileage positioning data acquisition. SPIFlash chip module 1 is used to store the measured mileage data and three-axis acceleration sensor data. The SPI Flash chip module 2 is used for program storage of the FPGA chip module. RS485 interface chip module - used to transmit mileage and GPS time to an external internal detector to synchronize pipeline defects or geometric deformation, mileage and GPS time. RS485 interface chip module 2 is used to receive GPS timing signal to synchronize the clock. The frequency of the crystal oscillator is 100MHz, which is used to provide the clock signal for the FPGA chip. The temperature compensated crystal oscillator is used to provide a stable GPS clock with temperature compensation based on the GPS timing signal. The power management module is used to provide +1.8V, +1.2V, +3.3V and +5V power for the FPGA chip module.

The Hall angle sensor uses the Vert-X 31E angle sensor of CONTELEC Company, which is used for the acquisition of the pulse signal of the mileage wheel. Three Hall angle sensors are used and are installed inside three different mileage wheels. The Vert-X31E sensor features mechanical wear-free magnetic field inductive measurement, incremental pulse output, 360° range, IP67 degree of protection, 14-bit resolution and independent linearity <±0.5%. The sensor consists of a magnetic block and a sensor. The magnetic block is installed on the rotating shaft of the mileage wheel. The rotation of the mileage wheel causes the direction of the magnetic field to change. The position information is obtained by calculating each incremental value (number of steps) from a certain origin. A real-time digital angle signal is output, and every 128 pulses is a circle. Figure 2 shows the incremental pulse output protocol of Vert-X 31E, where u is the reference pulse. Incremental signals are transmitted as a series of square wave pulse signals _UA and UB with _a phase difference of 90° electronic angle. _The distance between two adjacent edges of the incremental signals _UA and UB is one measurement step. In order to ensure that the signal can be output in a differential manner and improve the anti-interference ability of the sensor, the sensor also outputs the inverted signals U _A - and U _B - of the incremental signal. Figure 3 shows the VERT-X31E interface circuit, U9 is the VERT-X31E sensor, the sensor output is 5V level, and the FPGA I/O interface level is 3.3V, in the figure U6 uses TI's LSF0108 to achieve 3.3V to 5V level conversion. The LSF0108 is a bidirectional voltage translation that does not require the use of the DIR pin and supports level translation speeds up to 100MHz.

The three-axis acceleration sensor samples Freescale's high-precision analog three-axis acceleration sensor MMA7361. Since the inner detector will tilt forward, backward, left and right when it is running in the pipeline, it will affect the mileage positioning. Therefore, the MMA7361 is used to detect the acceleration value in real time to calibrate the mileage information. MMA7361 has two ranges of 1.5g and 6g, which can change the voltage value of the output signal according to the movement direction of the internal detector. Its core algorithm is to establish a functional mapping relationship between the output voltage and acceleration. Figure 4 shows the MMA7361 interface circuit, and U4 in the figure is the MMA7361 sensor. According to the actual operation of the detector in the pipeline, set the g-SELECT pin to a high level, that is, select the 6g mode, and its corresponding sensitivity is 206mv/g. In normal operation, the ACC_SLEEP signal is high. At the same time, the SELF Test mode is started, and the chip completes the internal self-test before working. When the signal of each axis is not moving (0g), its output is 1.65V. If it moves in a certain direction, the output voltage will change its output voltage according to the direction of its movement and the set sensor sensitivity.

Taking the X-axis as an example, the corresponding relationship between the acceleration and the output voltage is as follows:

Among them, ADC_ACCX is the binary number sampled by the ADC, 14 is the resolution of the ADC, V _REF is the ADC reference voltage, V _ZERO is the ADC sampling value when the detector does not move (0g), and gRange is 6g. Using the ADC conversion module to read this output signal, its motion and direction can be detected.

The ADC conversion module sampling adopts the 14-bit SAR type ADCAD7949 of ADI Company, which is used to collect the three-axis acceleration signal. Its typical offset error is ±0.5LSB, the integral nonlinearity is ±0.5LSB, and the signal-to-noise ratio of the output signal is 85.5dB. The voltage base VREF of the ADC is selected as 2.5V, and the ADC uses the SPI bus to communicate with the FPGA. Figure 5 is the interface circuit of AD7949, U1 is AD7949 chip.

FIG. 6 is a connection diagram of a mileage locator and an inner detector provided by the utility model. Among them, the inner detection mileage locator is connected to the inner detector through the RS485 interface module, and the other RS485 interface of the inner detector is connected to the laser gyroscope. Connect the PC through the serial port.

The working process of the locator for detecting mileage in the pipeline of the utility model is as follows:

(1) Set a marker box on the ground to segment the pipeline for geographic coordinate positioning. When the inner detector passes under the ground marker box, it will send a signal to the ground marker box, and the marker box will record the GPS time and position of the inner detector passing through. information;

(2) Before the detection in the pipeline, use the external GPS timer to grant the GPS clock to the internal detector and the mileage locator respectively to synchronize the system clock. The mileage locator calculates its position in the pipeline according to the internal 10MHz temperature compensated crystal oscillator time;

(3) The mileage locator adopts the mileage wheel pulse averaging algorithm, and selects the average value of 3 mileage wheel pulses to calculate the speed of the inner detector;

(4) The mileage locator collects the three-axis acceleration signal to judge the acceleration of the inner detector;

(5) The mileage locator uses the following method to calculate the mileage of the inner detector within a certain period of time:

When the pressure difference between the two sides of the inner detector pipeline remains unchanged, the traveling speed of the inner detector remains unchanged, which is the initial speed v ₀ , and the mileage of the inner detector at time t is:

Since the velocity of the medium in the pipeline is affected by factors such as pipeline deformation, elbow and pressure difference changes, the velocity of the inner _detector in the pipeline often changes. The acceleration of the inner detector is a(t), then the velocity at time t is:

Then the mileage of the inner detector is:

(6) The mileage locator transmits the mileage and corresponding time to the inner detector through the RS485 interface;

(7) The pipeline defect or geometric deformation value, mileage and GPS time detected by the inner detector using GPS time synchronization;

(8) The inner detector reads the data of the laser gyroscope in real time and stores it;

(9) After the inspection in the pipeline is completed, the defect or geometric deformation information of the inner detector, the mileage and time collected by the mileage locator, and the data of the laser gyroscope are imported into the PC;

(10) Import the GPS time and position information recorded by each ground marker box to the internal detector into the PC;

(11) The PC uses the defect or geometric deformation information of the inner detector, the mileage and time collected by the mileage locator, the GPS time and position information passed by the inner detector recorded by the ground marker box, the laser gyroscope data, and the offline calculation pipeline. The precise location of defects or geometric deformations in the pipeline.

Claims (6)

1. The utility model provides a detect mileage locator in pipeline, mileage locator places in the pipeline in the detector, through RS485 and the communication of pipeline in the detector, its characterized in that: the device comprises an FPGA chip module, wherein the FPGA chip module is respectively connected with a three-axis acceleration sensor and is used for collecting acceleration signals of a detector in a pipeline to compensate mileage data;

the Hall angle sensor is used for converting the magnetic field change generated by the rotation of the mileage wheel into an incremental pulse signal and sending the incremental pulse signal to the FPGA chip module for recording the mileage of the internal detector;

the SPI Flash chip module is used for storing measured mileage data and triaxial acceleration sensor data; the SPI Flash chip module II is used for storing programs of the FPGA chip module;

the RS485 interface chip module I is used for transmitting the driving mileage and the GPS time to an external internal detector so as to synchronize the pipeline defect, the driving mileage and the GPS time; the RS485 interface chip module II is used for receiving a time service signal of an external GPS time service device so as to synchronize a system clock;

the crystal oscillator is used for providing a clock signal for the FPGA chip module;

the temperature compensation crystal oscillator is used for providing a stable GPS clock with temperature compensation based on the GPS time service signal;

and the power supply management module is used for providing power supply required by the FPGA chip module.

2. The in-duct mileage detecting locator as claimed in claim 1, wherein: and the three-axis acceleration sensor is in communication connection with the FPGA chip module through the ADC conversion module.

3. The in-duct mileage detecting locator as claimed in claim 1, wherein: the Hall angle sensors are respectively installed in the three mileage wheels.

4. The in-duct mileage detecting locator as claimed in claim 1, wherein: the Hall angle sensor is connected with the FPGA chip module through the level conversion module.

5. The in-duct mileage detecting locator as claimed in claim 1, wherein: the triaxial acceleration sensor converts the acquired acceleration signal through the ADC conversion module and then stores the converted acceleration signal into the SPI Flash chip module I through the FPGA chip module.

6. The in-duct mileage detecting locator as claimed in claim 1, wherein: the increment pulse signal of the Hall angle sensor is transmitted in a differential mode by using a series of square wave pulses with the phase difference of 90-degree electronic angle, and is stored into the SPI Flash chip module I through the FPGA chip module.

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