Accurate geometric data from a submarine pressure hull is required to define the submarine operational envelope. STACMouseTM is an integrated system for simultaneous submarine pressure hull thickness and circularity measurement. It integrates laser tracker technology for circularity measurement together with ultrasonic testing instrumentation for thickness measurement. Wireless communication between the sensing systems and data acquisition hardware is also provided. This combination of technologies provides an efficient and highly accurate three-dimensional coordinate and thickness survey of the in-service vessel in a simple integrated and portable system. STACMouseTM provides explicit geometric characterization data for analytical models and tracks corrosion wastage and other ultrasonic indications of the pressure-hull condition. The laser tracker consists of a laser source that tracks a mirrored ball and provides 3D coordinates with an accuracy of ±25.4 mm (0.001”) over a 70 m (230 foot) range.
The mouse rolls on the test surface using a triangular array of rolling contacts. The rear of the triangle consists of two ball transfers to permit the back of the unit unrestricted motion on the test surface. The front roller is a ball bearing that provides ergonometric directional control to the scanning process. A rare earth magnet in the center of the triangle of contact points provides a constant attractive force between the test surface and the scanning device. The laser target is mounted directly above the roller probe on a ring-shaped rare earth magnet. The scanner has a handle for convenient operation.
The ultrasonic software provides complete data acquisition, interpretation and display capability. The ultrasonic board is hosted in a portable computer that controls the laser tracker and obtains its position data through a wireless link.