Dynamics Simulation of Grasping Process of Underwater Vehicle-Manipulator System

Underwater vehicle-manipulator system (UVMS) can be applied to fulfill different complex underwater tasks such as grasping, drilling, sampling, etc. It is widely used in the field of oceanographic research, marine exploration, military and commercial applications. In this paper, the dynamic simulation of UVMS is presented in the process of grasping an object. Firstly, the dynamic model of UVMS, which considers the change of the load of manipulator when the end effector of manipulator grasps the object, is developed. To compare different control conditions, the numerical simulation of grasping processes without/with vehicle attitude control are carried out. The results show that the coupling dynamics between the vehicle and the manipulator in the grasping process are clearly illustrated. The tracking position error of end effector without vehicle control is large and UVMS cannot complete the grasping task under this condition. Vehicle control can compensate the motion of vehicle due to the coupling effect caused by the motion of manipulator. This study will contribute to underwater operation mission for UVMS with floating base.