Working Environments and Controller Design for Unmanned Underwater Vehicles in Offshore Aquaculture – A Review

Abstract

In offshore aquaculture especially fish farming, many manual operations such as inspection on the fish netpen (known as net-cage interchangeably and including the infrastructure to house net-pen) are facing the constraints of labour shortage, safety, productivity and operating costs. To tackle this challenge, unmanned underwater vehicles (UUVs) have been deployed to perform the tasks usually done by humans. Compared to UUVs used in oceanographic research or recreational purpose, UUVs for offshore aquaculture require high maneuverability to operate close to the fish netpen and the infrastructure (e.g., grid system and mooring lines) in a constrained operational environment. Furthermore, most UUVs rely on the limited onboard power supply without tethered power supply due to the constrained operational environment. Optimal utilization of energy is another issue. This paper discusses the applications of UUVs in offshore aquaculture with a focus on their maneuverability and energy optimality.