Sensor-based Obstacles Avoidance Using Spiral Controllers for an Aircraft Maintenance Inspection Robot

This paper deals with the problem of obstacle avoidance during an automated preflight inspection. During this mission, safety appears to be a key issue, as numerous obstacles are lying in a close neighborhood of the aircraft. They are very different in terms of size, shape and mobility and are often unforeseen. To cope with this highly evolutive environment, it is necessary to design a method sufficiently generic to deal with the obstacles variety and efficient enough to guarantee non collision and avoid classical problems such as local minima, singularities, etc. In this paper, we have proposed a new sensor-based control strategy fulfilling these two requirements. It consists in defining and following an adaptative spiral around the encountered obstacles while performing preflight inspection. It relies on two main elements: (i) the definition of a spiral whose parameters are continuously updated depending on the robot motion and on the environment; (ii) the coupling of two sensor-based controllers allowing to track the spiral while avoiding singularities. Experimental results conducted on our robot show the relevance and the efficiency of the proposed control strategy.