A two axis sensor positioning system to be mounted on the front of an AUV

Abstract

The XAUV is an experimental autonomous underwater vehicle (AUV) intended to be used as a platform to test new cutting edge sensors and mapping algorithms associated with them, as well as control algorithms for the ultimate goal of inspecting naval ship hulls. Current ship hull inspection techniques require divers to inspect by hand. Often the waters are opaque beyond the level that would allow visual inspection to be sufficient, so a tactile inspection is required. This process is slow and dangerous to the inspectors. AUVs with appropriate sensors and algorithms offer the promise of an alternative technique. It is important that the AUV is capable of directing appropriate sensors in the desired directions prescribed by specific mapping algorithms. This could be accomplished by rigidly attaching the sensors to the body of the AUV. However, manipulating the sensors with respect to the AUV may offer substantial benefits. With two degrees of freedom within the positioning system, the rest of the XAUV will be constructed to be capable of both hovering and traveling at a peak speed of about 5 m/s while still scanning the target area. It will also open up possibilities in developing new algorithms that utilize scanning off of the normal of the target surface.

(cont.) This document details the design, construction, and preliminary testing of the multi-axis XAUV positioning system. The design has shown through theory and construction that it will provide a stiff, reliable sensor positioning system that does not affect the dynamic motions of the vehicle regardless of sensor position and acts as a protective housing for the delicate blazed sonar array.