Robots

Cost Effective Autonomous Robots for Ballast Water Tank Inspection
Leif Christensen, DFKI GmbH, Bremen/Germany, [e-mail] Niklas Fischer, BALance TC GmbH, Bremen/Germany, [e-mail] Sven Kroffke, DFKI GmbH, Bremen/Germany, [e-mail] Johannes Lemburg, DFKI GmbH, Bremen/Germany, [e-mail] Reinhard Ahlers, BALance TC GmbH, Bremen/Germany, [e-mail] Abstract In this paper we describe the technical concept and first implementation of an autonomous rail guided robot for inspection and maintenance tasks in ballast water tanks (BWTs), especially for double bottom BWTs. We evaluate different locomotion techniques and other robotic principles potentially suited for such application scenarios and propose a modular concept that uses a simple corrosion-free thermoplastic rail which runs 'through' the robot and thus allowing for high payloads and upside-down operation. As a second aspect the paper describes the assessment of life cycle benefits for the developed system with cost parameters like scaffolding costs, tank preparation-, intank inspection- and vessel out-of-service time. 1. Introduction Ballast water is used to stabilize partially loaded or empty ships on the open sea. When needed, ocean or port water is pumped into special ballast water tanks to increase the mass of a ship. Because ocean water is typically contaminated with algae, plankton and other organisms, and due to the aggressive nature of salt water, BWTs are often subject to serious fouling and corrosion. The ballast tanks represent more than 40% of the entire coated area on a vessel. They therefore need frequent inspection, cleaning, and repair. Until now, the maintenance of BWTs cannot be performed under operating conditions. Consequently, ship owners are forced to send their ships to dock inspection every 2.5 or 5 years, causing high costs in labour and ship-downtime. On cruise vessels BWTs are typically built in those spaces of a ship that