Structural Functions of Underwater Robots
A typical remotely operated vehicle (ROV) consists of surface equipment (including a control console, cable winch, hoisting equipment, power supply system, etc.) and underwater equipment (including a repeater and the ROV itself). The ROV moves underwater using a propulsion system and is equipped with observation equipment (cameras, cameras, lights, etc.) and operational equipment (robotic arms, cutters, cleaners, etc.).
The underwater movement and operations of the submersible are controlled and monitored by an operator on a surface mothership. Power and information exchange are provided to the submersible via cables. Repeaters reduce interference from the cables on the submersible's movement. New submersibles are evolving from simple remote-controlled to monitored systems, with hierarchical control implemented by the mothership's computer and the submersible's own computer. This system processes observational information and builds environmental and internal state models. Operators issue commands using process-oriented abstract symbols or language through a human-machine interface system and receive computer-processed information, monitoring the submersible's operation and troubleshooting. Development of intelligent underwater robot systems has begun. Operators only need to issue the overall task; the robot can automatically plan its actions, avoid obstacles, and autonomously complete the assigned task based on environmental recognition and analysis.
The development trend of unmanned tethered submersibles has the following advantages: First, the water depth is generally around 6000 meters; second, the operation and control systems mostly use large-capacity computers for data processing and digital control; third, the robotic arms on the submersibles adopt multi-functional force feedback monitoring systems; and fourth, the number and power of the thrusters are increased to improve their ability to operate in turbulent waters and their maneuverability. In addition, special attention is paid to the miniaturization of the submersibles and improving their observation capabilities.
Application areas of underwater robots
1. Safety search and rescue field: (1) Can be used to check whether explosives are installed on dams and bridge piers and the condition of the structure; (2) Remote reconnaissance and dangerous goods inspection; (3) Assist in the installation/removal of underwater arrays; (4) Detection of smuggled goods on the side and bottom of ships (public security, customs); (5) Observation of underwater targets, search and rescue of ruins and collapsed mines, etc.; (6) Search for underwater evidence (public security, customs); (7) Maritime rescue and salvage, near-shore search.
2. Pipeline inspection: ( 1) It can be used for the inspection of water tanks, water pipes and reservoirs in municipal drinking water systems; (2) Sewage/drainage pipelines and sewers; (3) Oil pipelines; (4) Pipelines across rivers and streams.
3. Ship, river, and marine oil: (1) Hull repair; underwater anchor, propeller, and hull bottom inspection; (2) Wharf and wharf pile foundation, bridge, and underwater dam inspection; (3) Channel clearance and port operations; (4) Drilling platform underwater structure repair and marine oil engineering.
4. Scientific research and teaching: (1) Observation, research and teaching of aquatic environment and underwater organisms; (2) Marine exploration; (3) Under-ice observation.
5. Underwater entertainment: (1) Underwater television shooting and underwater photography; (2) Diving, boating and yachting; (3) Watching divers and selecting suitable locations before diving.
6. Energy industry: (1) Nuclear power plant reactor inspection, pipeline inspection, foreign object detection and removal; (2) Hydropower station lock maintenance; (3) Hydropower dam and reservoir dam maintenance (sand discharge tunnel, trash rack, and spillway maintenance).
7. Archaeology: Underwater archaeology, underwater shipwreck investigation.
8. Fisheries: Deep-sea cage aquaculture and artificial reef survey.
Unmanned, untethered underwater vehicles (UUVs) are still in the research and trial phase, and several key technical issues need to be resolved. UUVs will develop towards long-range and intelligent capabilities, with an operational range of 250–5000 kilometers. This requires such UUVs to have a power source capable of ensuring long-term operation. The control and information processing systems will employ image recognition, artificial intelligence, large-capacity knowledge base systems, and sensing capabilities to improve information processing and precise navigation and positioning. If these issues can be resolved, then UUVs will become truly intelligent marine robots. The emergence and widespread use of intelligent marine robots will provide the technological guarantee for humans to engage in various marine industrial activities.
