Application Cases

Experiment Name: Hardware Implementation of a Pipeline Positioning System

Research Direction: Pipeline Nondestructive Testing

Experimental Content:
A feasibility study of a PCM-based pipeline positioning system was conducted. A function generator was used to produce multi-frequency currents at 4 Hz, 8 Hz, and 72 Hz, which were then output to an Aigtek ATA-308 power amplifier. After adjusting the RMS value of the output current to 1 A, the signal was transmitted through a shielded cable to a pipeline model, simulating a real-world pipeline detection environment. After constructing the experimental platform, the magnetic sensor probe was maintained in a plumb orientation relative to the ground around the pipeline. The horizontal distance, vertical distance, and horizontal angle between the magnetic sensor probe and the pipeline model were adjusted and measured using a tape measure. Subsequently, the relationship between the measurement results at different positions and the actual conditions was recorded.

Testing Equipment: ATA-308 power amplifier, function signal generator, digital multimeter, oscilloscope, etc.

Experimental Procedure:
During the experiment, the probe was kept perpendicular to the ground, while the horizontal distance, vertical distance, and horizontal angle between the probe and the pipeline were varied. The detection probe sensed the magnetic field signals emitted by the pipeline. After filtering and amplification by the signal processing circuit, the signals were transmitted to an STM32F429 embedded processor, which calculated the precise three-dimensional position. The processed pipeline positioning results were displayed on an LCD. The angle, vertical distance, and horizontal distance of the magnetic sensor probe relative to the pipeline model were dynamically adjusted, and the readings on the LCD screen were recorded.

Figure: Testing Environment

Test Results:
After testing, the average error and linearity metrics for horizontal angle, vertical distance, and horizontal distance were satisfactory. The R² values for horizontal distance and vertical distance measurements were both greater than 0.99, and the R² value for horizontal angle measurement also exceeded 0.99. In terms of measurement error, the average error for horizontal angle was 2.51°, for horizontal distance was 2.19 cm, and for vertical height was 2.01 cm. The above experiments experimentally verified the feasibility of the pipeline positioning system, laying a foundation for subsequent testing in real-world environments.

Figure: ATA-308C Power Amplifier Specifications and Parameters