Development of Recovery System for Underwater Glider

Abstract

This study proposes a novel autonomous system that is able to retrieve an underwater glider safely and quickly. After a long-period mission, the glider is out of its energy, floats up in the middle of the sea, and needs retrieval. However, most of the recovery processes are conducted manually, which is not effective and even damages the glider or injures the worker. In this study, we propose the use of a remotely operated vehicle (ROV) in a recovery process that consists of three stages: (i) driving the ROV into the near area of the glider, (ii) automatically catching the glider using the ROV’s onboard sensors and capturing mechanisms, and (iii) retrieving the glider to the mother ship or station. Mathematical models were formulated to realize the feasibility of the system. A cascade adaptive sliding mode control-proportional integral controller is designed to cope with the thruster’s characteristics, the dynamics of the ROV and the glider, and oceanic disturbances. Finally, simulation studies were conducted in the system operation scenarios and their results validate the efficiency of the proposed process.