Abstract
In order to evaluate basic performance of a manipulator quantitatively, the manipulability and the dynamic-manipulability are generally used. These concepts were defined for a ground fixed manipulator firstly, and then, the manipulability was applied to a free flying space robot manipulator by using the generalized Jacobian matrix. However, these study for an unconstrained underwater robot have not be carried out, because all momentum of this system is not consevative.
In this paper, the dynamic manipulability of an unconstrained underwater robot is defined in the frequency range, by linearizing the kinematic equation and the equation of motion and extending the concept of the accelerance of motion. In this definition of the dynamic manipulability, it was shown that the mapping matrix from driving torque to acceleration of a hand, which is equal to accelerance of a robot system, includes ground-fixed and space robot manipulator dynamics. From the results obtained by the numerical calculations, it was made clear that the dynamic manipulability of an unconstrained underwater robot depends on the frequency of the driving torque, and it is not ellipsoid perfectly, and its measures are smaller than that of space robot because of fluid force acting on the robot.
