A small low-cost low-weight inspection robot with passive-type locomotion

In this paper a control methodology applied to the SCID (Sliding Climbing Inspection Device) robot is described. In order to reduce its dimensions, weight and cost, this robot does not adopt any actuator for locomotion and uses very simple sensors. The robot has been designed to slide down over a flat ferromagnetic vertical surface, using two electromagnets and the force of gravity. The on-board electronics and control algorithms used allow the system to control its velocity and trajectory. The design of the SCID robot was mainly aimed at reducing the weight of the system and power consumption, maximizing payload. Its purpose can be to carry sensors for NDI (Non Destructive Inspection), for example a CCD camera, for rapid inspection of the target surface (visual inspection). The system has been experimentally tested and a simplified mathematical model, in which friction influence is included, has been computed.