Ellipsoid Tether Model for Collision Avoidance in a Fleet of ROVs - Summary and Extension

During its navigation, the tether of Remote Operated Vehicle (ROV) is subject to entanglement with obstacles or other ROVs' tethers. This specificity means that the classic literature on multi-robot collision avoidance is not suitable for tethered multi-robot scenarios. Thus, we propose a guarantee ellipsoid model of the ROV's tether and its obstacles to perform a collision avoidance method, adapted for a fleet of ROVs and low in calculation. The model guarantees that if an obstacle is not inside or partially inside the ellipsoid model, then the risk of collision is exclude. The only information required for using this model is the position of the two attachment points and the tether length. A collision avoidance strategy has been developed based on potential field methods, bypass paths and the management of the distance between the two attachment points. Simulations show the effectiveness of the method with several scenarios. The limits of the method are discussed.