Design and Optimization of a Connecting Joint for Underwater Autonomous Docking and Separation

In this paper, a connecting joint capable of underwater autonomous docking and separation is proposed, which can be used for a reconfigurable articulated underwater robot (RAU robot). The structural design, optimization, and experimental validation of the connecting joint are presented in detail. First, the concept of the RAU robot is introduced, along with its different operational modes and the application scenarios. Second, the specific structural design and basic functions of the connecting joint are described. Third, a dynamic model of the docking process between different vehicles is established and simulated by kinematic simulation software. Through discretely sampling the parameter space, the optimal parameter combination is obtained. Finally, a prototype of the connecting joint is fabricated and functional tests are conducted. The impact forces on the docking rods before and after optimization are compared. The results show that the designed connecting joint can fulfill the functional requirements for autonomous docking of the underwater robot, and the maximum impact force is reduced by 27.08% compared to the one before optimization.