# Deep-Sea Underwater Cooperative Operation of
###### Abstract  
In this paper, we propose three cooperative operational modes of manned and unmanned submersibles for a range of different deep-sea application scenarios. For large-scale exploration, a lander or an unmanned surface vehicle (USV) is paired with one or more autonomous underwater vehicles (AUVs), while the liberated research vessel R/V can transport the manned submersible to another area for diving operations. When manned submersibles and AUVs perform small-scale accurate measurements, the research vessel R/V supports both submersible types for diving operations and has a positioning and communication time allocation mechanism for cooperative operations. Through the analysis of the operating efficiency of different modes, we found that the cooperative operational mode based on the pure research vessel R/V is suitable for local small-scale accurate detection, and the cooperative operational mode based on the USV/lander system is suitable for large-scale and long-distance underwater operations. manned submersible; unmanned submersible; cooperative operation; deep sea; AUV; timing allocation 2022109  
An ROV is unmanned and cabled, and it provides energy, transmits data, and executes commands transmitted using armored optoelectronic composite cables. An AUV is suitable for large-scale ocean scanning because it is unmanned, cableless, powered by its own battery, and pre-programmed to complete a specific set of diving tasks [9]. An ARV is a hybrid underwater robot with its own energy and can perform real-time data transmission through optical fiber micro-cables. Not only can it achieve a wide range of detection but it can also carry light tools to complete simple tasks. An AUG is suitable for long-term and large-scale ocean exploration because it uses net buoyancy and attitude angle adjustment to obtain propulsion, and its energy consumption is extremely low. The submersible types discussed above have been widely used in marine scientific research, marine engineering operations, resource and environmental surveys, and military fields [10]. As ocean exploration advances, new tasks demand more stringent requirements for submersibles. However, large-scale and time-sensitive tasks causes relying on a single submersible impractical. Owing to the development and maturity of different submersible technologies, the cooperative operation of multiple submersibles to complete tasks together has become a new form of application [11; 12]. Underwater cooperative operations comprise of multiple homogeneous/heterogeneous submersibles that use underwater acoustic communication, wireless radio communication, and satellite communication as information exchange methods to cooperate with each other and complete the specified tasks [13]. This technique can help to overcome the operating efficiency limitations of a single submersible and realize the operative capabilities of differentiated configuration of several different submersibles, which is an effective way to perform complex underwater tasks [14; 15; 16]. Currently, research pertaining to underwater collaboration mainly focuses on AUV and AUG clusters, which includes formation control, task assignment, path planning, and cooperative navigation. As related technologies improve, they have been widely used in typhoon/hurricane observations, mesoscale eddy observations, hydrothermal plume detection, seabed topography detection, and rapid target search [17; 18; 19]. In recent years, Artificial Intelligence (AI) has developed rapidly and has begun to be applied to object classification in underwater videos [20]. With the development of technology, AI may develop by leaps and bounds in the future, which can replace human perception of unknown environments to achieve deep-sea exploration and cognition. However, at present, the ability of AUVs and AUGs to perceive and autonomously understand the underwater environment cannot replace human thinking and judgment.