A Robot for the Unsupervised Grit-Blasting of Ship Hulls

This paper describes the design and the control architecture of an unsupervised robot developed for grit blasting ship hulls in shipyards. Grit blasting is a very common and environmentally unfriendly operation, required for preparing metallic surfaces for painting operations. It also implies very unhealthy and hazardous working conditions for the operators that must carry it out. The robot presented here has been designed to reduce the environmental impact of these operations and completely eliminate the health associated risks for the operators. It is based on a double frame main body with magnetic legs that are able to avoid the accumulation of ferromagnetic dust during its operation. The control system presents a layered structure with four layers that are physically distributed into two separate components in order to facilitate different operational modes as well as to increase the safety requirements of the system. A low-level control component has been implemented on the robotic unit itself, and a mission planning and control component has been developed on a base station that is also used for interaction with the operator, when the monitoring of the robot's operation is required. This base station component contains three layers of the control system that permit the manual, semiautonomous and autonomous operation of the whole system. A prototype of the robot has been implemented and tested in realistic environments, ascertaining that the design and the control system are perfectly suited to the functions which the robot must carry out.