Tham khảo tài liệu 'mobile robots book 2011 part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | The State-of-Art of Underwater Vehicles - Theories and Applications 141 Fig. 6. Autonomous underwater vehicle inspecting and cleaning sea chest of ships. a The diagram of the AUV working on the sea chest of the ship. b A range of foreign invaders hiding in the sea chest. To optimize the knowledge of and reaction to this threat the first task is to inspect the sea chests and collect information about the invaders. Currently divers are sent to do the job which has inherent problems including i high cost ii unavailability of suitably trained personnel for the number of ships needing inspection iii safety concerns iv low throughput and v unsustainable working time underwater to do a thorough job. To reduce the working load of divers and significantly accelerate inspection and or treatment it would be highly desirable and efficient to deploy affordable AUVs to inspect and clean these ship sea chests. Thus this paper presents a low cost AUV prototype emphasizing the unique design issues and solutions developed for this task as well as those attributes that are generalizable to similar systems. Control and navigation are being implemented and are thus not covered here. Hull design Figure 7. shows the AUV prototype weighing 112kg positively buoyant which consists of basic components including main hull two horizontal propellers four vertical thrusters two batteries an external frame and electronics inside the main hull. This section focuses on the hull design. 142 Mobile Robots - State of the Art in Land Sea Air and Collaborative Missions Fig. 7. The hull structure of the vehicle. a - c Design drawings of the vehicle a Top view. b Side view. c Isometric view. d Real picture of the in-house made vehicle The foremost design decision is the shape of the hull. Inspired by torpedoes and submarines a cylindrical hull has been selected. A cylinder has favourable geometry for both pressure no obvious stress concentrations and dynamic reasons minimum drag . To make the hull .