In this paper, the dynamic model of rigid-flexible coupling system for an underwater manipulator based on element coupling deformation is established, in which three reference frames (global frame, floating frame, and element translate frame) are used to describe the configuration of the point in flexible body. A robust sliding mode control is presented for the position control and tracking control of the manipulator. The simulations are performed and the results show that the presented controller has good performance to track some moving underwater object or approach some fixed target point.
There is no doubt that the development and protection of the ocean cannot be separated from research on marine engineering equipment. Underwater manipulators are playing important roles in ocean explore. Study of underwater manipulator is an active field and may have a far-reaching impact on human beings in ocean explore.
Since the sphere of human activity become further and deeper in ocean space, it is essential for technological advances in underwater manipulator systems to enable new and promising marine operations, processes and exploration. Some manipulating modes of large scale of work space are mandated for underwater vehicle to facilitate it to fulfill tasks. As is well known, the load capability of an underwater vehicle is limited and its manipulator of large-scale should be made of lightweight components and parts. For the type of manipulator whose arms are characterized as slender rod, flexibility should be taken into account to set up its dynamic model and to control it (Bauchau and Han, 2014; Carrera, Gaetano and Petrolo,2011).
In the field of aerospace, the manipulators of large scale are used widely in outer space to fulfill some specific tasks such as grasping, repairing, and so on. The astronauts to operate these systems should be trained on some mimic system that is used to be built on the earth, especially in some underwater environment.