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Mine north finder for coal mine drilling rig

1 Overview

The mine north finder is based on a three-axis integrated fiber optic gyro and a three-axis accelerometer, which can complete the initial alignment and attitude maintaining functions, and output the carrier attitude reference value in real time.

The invention is a method for measuring the attitude of a downhole drilling machine. It is fixed on the track of the rig propeller. After starting work, the angular velocity of the sensitive rotational motion and the acceleration of the translational motion are solved in the posture of the processor to obtain the attitude of the rig. Then, the inertial measurement system continuously measures the current rig's current position. Attitude until the end of the measurement. The invention can automatically and quickly and accurately measure and display the posture information of the downhole drilling rig without relying on the external information by means of the external information.

This North Finder is specially developed for coal mines. It reduces the cost of using the North Finder and has stable performance. Many companies have a strong interest in it and express their intention to cooperate with us.

2 Product features and technical indicators

2.1 Main functions

The main functions of the mine north finder include:

1) angular rate and acceleration measurement functions;

2) Self-alignment function;

3) attitude tracking function;

4) RS-422/RS232 serial communication.

The axis definition of the mine north finder is shown in Figure 1. The X axis is positively along the direction of the system connector. When the system is installed through the four mounting flanges on the bottom surface, the Z axis defines the direction of the sky, and X, Y, and Z form a Cartesian orthogonal coordinate system.

The system output heading angle/azimuth angle indicates that the Y-axis is positively angled with the geographic north direction, and the north-north direction is the angle increasing direction.

The system output pitch angle/tilt angle indicates that the Y-axis positive angle is opposite to the horizontal plane, and the upper side is positive.

Figure 1 DBY series north finder coordinate polarity definition (top view)

2.2 Technical indicators

The main technical indicators of DBY series north finder are as follows:

1) North seek time: 3 minutes

2) Continuous working time: no less than 60 minutes

3) Output update rate: 1kHz

4) System alignment accuracy:

l Pitch/roll angle (1σ): ≤0.03°

l Heading angle (1σ): ≤0.5°

5) Maintaining accuracy of posture:

l Pitch/roll angle (20min): ≤0.1°

l Heading angle (20min): ≤0.5°

3 device interface definition

3.1 Data Interface Definition

The SX1 connector leads to a DB9 female connector that is connected to a standard four-wire RS422. The user only needs to connect the above serial port to the acquisition computer to perform measurement. Note that the baud rate is 614.4 kbps, and the corresponding acquisition device is required for data acquisition.

3.2 Hardware Interface Definition

DBY series north finder uses RS422 serial output, the baud rate is 614.4Kbps, each frame of data is 60 bytes, each byte contains 1 start bit (0), 8 data bits, 1 stop bit (1), each word The low bit is transmitted first, and the low byte is transmitted first for each frame of data. There is no parity. The specific data format is shown in the following table:

Table 1 data frame format

Bytes (60 bytes total) Data content Supplementary explanation
1~4 Frame header 0X EB8055AA
5~8 X gyro data First low and then high, dimensionless digital
9~12 Y gyro data First low and then high, dimensionless digital
13~16 Z gyro data First low and then high, dimensionless digital
17~20 X plus table data First low and then high, dimensionless digital
21~24 Y plus table data First low and then high, dimensionless digital
25~28 Z plus table data First low and then high, dimensionless digital
29~32 latitude First low and then high, 0.000001°
33~36 longitude First low and then high, 0.000001°
37~40 height First low and then high, 1m
41~44 counter First low and then high, 2.5ms
45~46 Pitch/tilt First low and then high, 0.01°
47~48 Roll angle First low and then high, 0.01°
49~50 Heading angle/azimuth First low and then high, 0.01°
51~56 Pending byte
57~60 End of frame 0X FF000034

4 related acquisition software description

The simplified version of the mine north finder acquisition software is shown below:

Navigation data module: After the system seeks north, the alignment information is displayed on the left side of the area, and the right part of the system tracks the three-dimensional posture information of the system in real time.

Control command module: “Northward seek command” can re-search north in case of continuous power; input latitude and longitude of current work place in three edit boxes of latitude, longitude and altitude (phone positioning can be used), click “send latitude and longitude after input is completed” "It can be used for latitude and longitude information binding, and it can be written into the internal memory of the system immediately. After the transmission is completed, click "Northward Search Command" to search for the north under the newly input latitude and longitude. The power is not lost. The upper computer is on the upper computer interface - "latitude" When the data at the "longitude, altitude" is updated to the new latitude and longitude, the binding is successful.

Sensor data module: including the raw output data of the gyro and accelerometer; the internal counter is counted when the power is turned on, and is cleared after clicking the “Northern Search Command”; the latitude, longitude and altitude are the binding information.

The data is saved in the current directory of the software, named "0924205117imu_data.txt" (document establishment time), and the data column is three-axis gyro, three-axis plus table, three-axis attitude angle, latitude, longitude, and height.

5 test process and data

5.1 Testing process

The mine north finder should be tested in the correct order of operation. The test procedure is briefly described as follows:

(1) System installation: Fix the DBY series north finder to the test bench base surface through the bottom surface;

(2) Connector connection: connect the power supply and data interface as required, see section 3 for details;

(3) Power-on of the system: After the external linear power supply is confirmed to be debugged, after checking that there is no problem in each part of the connection, turn on the external linear power supply and check whether the power supply current is within the normal power consumption range. If there is excessive current or over-current In small cases, power-off inspection is required, and the current can be continued under the correct current conditions;

(4) System work: After the system is powered on, the data interface connected to SX1 should have data output. For details, see Part 3, and the data can be collected by using the provided DBY series north finder software. After the system is powered on, it needs to be collected. 3 minutes alignment time (seeking north time), try to ensure the system is in a static state within 3 minutes. After the alignment is completed (after 3 minutes), it will enter the navigation phase. At this time, the carrier device can be rotated, and the north finder can track the three in real time. If the attitude angle changes, if you need to realign (seek north), click the “Seeking North Command” button in the third part to search for the north again (third part).