Dynamic Modeling And Motion Control Of Underwater Vehicle-Manipulator System

The exploitation of ocean resources is more and more important because of the depletion of natural resources on the land as the development of human societies and the advancement of material civilization. During tasks of expedition and exploration about the environment and resources of ocean, the underwater vehicle equiped with manipulators can accomplish not only monitoring observation, but also more complex task. Thus it's important to study the dynamic modeling, motion control and stability of Underwater Vehicle-Manipulator System (UVMS).In this paper the product exponentials formula is applied to analyze the kinematics of UVMS, and the velocity and acceleration of each part of UVMS are gotten. Then based on the kinematic analysis and the analysis of inertial forces and active forces dynamic model of UVMS is given out.Because of dynamic coupling between the manipulator and the underwater vehicle during the movement of UVMS, the movement of manipulator will cause the motion of underwater vehicle. In order to minimize the influence of manipulator movement on the underwater vehicle, the trajectory of manipulator movement is planned. On the basis of dynamic balance theory shaking force and shaking moment applied on the underwater vehicle are studied. Then Genetic Algorithm method is used to optimize the parameters of manipulator movement. The validity of this method is proved by the numerical simulation using the dynamic modeling of UVMS.In order to study the stability of the UVMS, linear motion equations of UVMS are presented from non-linear equations. Then the first method of Lyapunov is used to study the stability of the UVMS with the eigenvalues of the linear motion equation.UVMS is a kinematic redundant system, it's necessary to deal with this problem before the motion controller being designed. The task priority method based on fuzzy rule is taken as the resolution to the redundancy, and at the same time, the situation of singular configuration and joint mechanical limit are also considered. Finally, the validity of this redundancy resolution is proved by numerical simulation.