Development of dynamic safety envelopes for autonomous remotely operated underwater vehicles

This paper describes the implementation of dynamic safety envelopes for Autonomous Remotely Operated Vehicles (AROVs). A safety envelope is defined as a three-dimensional spatial area around the AROV, which forms a virtual protective barrier against collision with known and unknown obstacles in the subsea environment. The Octree method is used to setup the cuboidal shape of the proposed safety envelope. A Fuzzy Inference System (FIS) is modeled to derive the size of the dynamic safety envelope. The three inputs of the proposed FIS are vehicle velocity, probability of acoustic sensor failure and time to collision risk indicator. A user interface allows for verification and visualization of the resulting dynamic safety envelope during live laboratory tests. The results show that similar to vehicular envelopes in other industries, dynamic safety envelopes can be implemented on AROVs. The proposed dynamic safety envelope may be used to model the behavior of AROVs when confronted with different collision scenarios.