Recent offshore drilling activities have dramatically bloomed oil and gas production. Due to extreme weather, such as hurricanes and tsunamis, offshore oil platforms may need to be constantly monitored in case of unexpected dangers. Using robots to monitor and prevent these dangerous situations is a cost-effective and safer solution compared to any human involvement. However, one major drawback for robotic intervention is the ability of the robot to operate water tight ship doors designed for marina facilities. Current studies have been focused on robots manipulating normal doors in people's daily life. However their presented methodology may not be suitable for opening heavy watertight ship doors since they have a special locking structure which needs much larger torque to open. This study explores the possibility of opening heavy watertight ship doors with an ordinary mobile robot under remote control. Given the watertight ship door’s unique structure, a door opening tool with a pawl mechanism is designed for a mobile robot, which consists of a robotic arm and a wheeled platform, to complete the task. Experimental results have shown that the mobile robot can operate the tool to open the door and transition through the door.

Three-dimensionally (3D) maneuverable robotic fish are highly desirable due to their abilities to explore and survey the underwater environment. Existing depth control mechanism is focused on using compressed air or piston to generate volume change, which makes the system bulky and impractical in a small size underwater robot. In this paper, a small and compact 3D maneuverable robotic fish is developed. Instead of using a compressed air tank, the robot is equipped with an on-board water electrolyzer to generate the gases for depth change. The fabricated robotic fish shows fast diving and rising performance. A servo motor is used to generate asymmetric flapping motion on the caudal fin, which leads to a two-dimensionally (2D) planar motion. A 3D dynamic model is then derived for the fabricated robotic fish. Several open-loop control experiments have been conducted to validate the model as well as the design. It has been demonstrated in the experimental results that the robot is capable of generating 3D motion. The robot can achieve 0.13 m/s forward velocity, 30.6 degree/s turning rate, and it takes about 5.5 s to dive to 0.55 m and 10 s to rise.