Motion Control of Underwater Mine Explorer Robot UX-1: Field Trials

In this paper, we present the results of a series of field trials conducted with an underwater vehicle in the increasingly complex underwater environments of the Kaatiala mine in Finland, the Idrija mine in Slovenia, and the Urgeiriça mine in Portugal. These field experiments have been performed to test and validate the motion control systems of the underwater explorer robot (UX-1), which are: a variable ballast system for buoyancy control, a variable pitch system for pitch control, and a propulsion system for depth and heading stabilization. The control method implemented is based on a state feedback linearization algorithm, previously tested and validated in a controlled water tank environment. Several experiments are shown which demonstrate the successful operation of the motion control systems in individual performance tests. Afterward, a full exploration and geo-scientific data collection mission is presented, where all of the motion control systems are active simultaneously during a deep dive to more than 100 m. The results obtained in the field tests demonstrate the effectiveness of the motion control systems and validate the UX-1 Robot platform as capable of performing the complex task of navigation and control in flooded mine environments.