A reactive control approach for pipeline inspection with an AUV

Recent technological advances and the growing demands for underwater operations suggest that autonomous underwater vehicles will become increasingly present in commercial and research activities, performing tasks such as survey, inspection of sub-sea pipelines and object recovery. This fact calls for the development of guidance and control algorithms for the execution of this kind of mission. This paper proposes a reactive control approach for pipeline following by a torpedo-like autonomous underwater vehicle. The method presented here, called the Deformable Virtual Zones (DVZ) method was originally conceived at the LIRMM for obstacle avoidance by mobile robots and AUVs. It consists of the modelling of a virtual zone around the robot, whose configuration depends on the robots states. The intrusion of proximetric information in this zone inflicts a deformation, and the control signal is computed so that the robot will react in order to minimise this deformation. We extend this sensor-based control method by proposing a new DVZ configuration for pipeline following by an autonomous underwater vehicle. Simulation results allow verifying its robustness as the pipeline changes direction, taking into account AUV dynamics. The proposed method is currently being implemented using the TAIPAN II, a small sized torpedo-like AUV developed at the LIRMM, fitted with a profiling sonar system. Experimental results will soon be available.