Design of an end-effector of a climbing robot for vertical surfaces

This paper proposes a new end-effector for a robot which is able to climb up painted, vertical cylindrical metallic surfaces by means of eight suction cups, able to change its climbing direction and, using an appropriate system carrying an ultrasound probe or other non-destructive testing (NDT) equipment, able to evaluate the thickness and integrity of the metal shells of storage tanks. The paper presents a discussion of the design and construction of the end-effector. Using finite element method, the more stressed components of the system and of the structure as a whole were analyzed to verify that the maximum deflection, due to the elastic deformation of the structure, does not excessively affect the results of ultrasound measurements. Finally, the results of experimental trials in which the robot moved on differently inclined surfaces are reported.