UNDERWATER ROBOTIC VEHICLE FOR SHIP HULL INSPECTION: CONTROL SYSTEM ARCHITECTURE

Abstract

The inspection of underwater structure thickness has emerged as an unique and challenging application of robotics. Underwater robots with adherence system are required to precisely determine the position of cracks in these structures. This technological problem has motivated to a group of researchers of the Federal University of ABC for the development of a Hybrid Remotely Operated Vehicle (HROV) having ultrasonic transducers to check the thickness and possible cracks in ship hulls. The HROV consist of a mechanical structure made of polypropylene plates, a pressure vessel for control electronics, a set of sensors, six thrusters, two motorized tracks, an acoustic positioning system and an umbilical cable. This vehicle is classified as a hybrid robot due two operation modes: free-flying and crawler. While in the first mode the vehicle uses thrusters at the second one use the motorized tracks for its locomotion on the surface of the ship hull. The adherence to the ship hull is guaranteed by applying a force normal to the hull surface from vertical thrusters. This work describes the hardware and software architecture developed for controlling the motion of the HROV. The HROV control architecture is based on the VxWorks Real-Time Operating System running on a PC/104 single board computer.