The Development of Ultrasonic C-Scan for Ferrous Wall Surface using the Climbing Robot

This paper describes the use of a wall-climbing robot for performing the ultrasonic C-Scan of the vertical surface. The robot utilizes permanent magnetic adhesion and can climb the ferrous surface to inspect the ferrous infrastructures like oil tanks. With the wheeled locomotion, encoders in the wheel can be used for locating the robot on the vertical surface. A specially designed housing is fabricated for the robot to hold a 2 MHz probe to perform the ultrasonic testing of the surface that is climbed. The probe holder movement is controlled through a motorized belt drive, enabling the probe to establish contact with the surface and retract. This paper details how the C-Scan is built using the position and A-Scan data thus obtained. Each scan data is processed individually using the MATLAB signal analyzer. It is evident from the results that the defect has a different frequency reflection and is visible from the C-Scan developed. The final C-Scan image was checked by superimposing on with the test surface and the defect was found to agree with the obtained scan image.