During the last decade, the first autonomous under-In this paper, details of the development of ODIN-Ill are water robot Of the Autonomous system Laboratory Of the UNversity of Hawaii, ODIN (0"-Directional Intelligent Navigator) built in 1991 has produced a lot of valuable results in development control methods 11-51. Recently, ODIN was bo,.,, again in the 3rd eeneration with unioue features under recent techuoloeies described,-as well as the basic algorithm for the framework, and experimental results for a fine motion control scheme using a null motion solution considering practical issues such as energy consumption and thruster saturation. such-as abundant system resources owing to a PC104+, iew vehicle system software architectures with an object-oriented concept and its implementation, a graphical user interface and an independent algorithm module using a dynamic linking library (DLL) based on the Windows operating system. These give us an ideal enrimnment for developing various algorithms which are needed for developing an advanced underwater mbotic vehicle. This paper describes details of the development of ODIN-111 and presents Initial experimental results for fine motion control.

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This paper describes the development of a laserbased ranging device, as part of a sensor work package that is to be integrated into an autonomous underwater vehicle. The objective of the laser ranging component includes robust operation in turbid ocean environments from 1 to 10 meters with a balance of accuracy and speed. A calibration technique that utilizes a spline interpolation is employed as an accurate, yet simple alternative to conventional triangulation methods. The resulting configuration is capable of range detection witbin 2% absolute error, at a 10 Hz refresh rate, out to 4 meters in turbid ocean conditions, and to greater than 10 meters in air. The maximum underwater range of the system is currently limited by the existing hardware, whereas the software is ready for any future system upgrades.

This paper describes a model-based thruster fault detection scheme for an autonomous underwater vehicle. For a vehicle equipped with servo motor based marine thrusters, the velocity and current feedback from the motor controllers can be used to derive two independent thrust approximations. The difference between the two models reveals the presence of fault conditions, and quantifies the error of the output thrust relative to the desired reference. The method is proven effective through experimental validation.