Crawler inspection vehicle with precise mapping capability

摘要

A crawler vehicle for inspection of the floor of a tank partially filled with a liquid includes telemetry carried by a tether between the vehicle and the remote station for communication of data and control signals between the vehicle and personnel within the station. The vehicle carries a Hall-effect sensor to sense anomalies in a magnetic flux outside the plate resulting from pitting within the plate. An array of ultrasonic transducer probes provides a detailed picture of the defect. A proximity sensor determines the presence of a step abutment between contiguous plates to command for a retraction of the magnet to prevent collision with the step abutment. A pressure sensor measures the depth between the vehicle and a planar surface of the liquid, used as a reference plane, to determine a degree of flatness of the floor and the presence of any settling of the floor. Shaft-angle encoders on a drive wheel and steering mechanism provide for accurate dead reckoning for the position of the vehicle, particularly during repetitive backing up movements of the vehicle. The data gathered by the various sensors is integrated to generate an accurate map of the tank floor for assessing need for further inspection and/or repair.