抄録
The dynamics of a manipulator with free joints is described by nonlinear ordinary differential equations with nonintegrable differential constraints. Such a dynamical system cannot be converted to a linear system using an exact linearization method such as the computed torque method. Control methods using nonlinear properties of such a system are studied in many fields of robotics. In this paper, we consider behavior of the free link on a two-link planer manipulator under commanding repetitive tasks to the actuated link. As previous reported, we numerically observed some periodic motions and chaotic states as a steady state on the manipulator. Computing bifurcation diagrams and basins of attraction for typical periodic motions, we investigate a relation between the viscous friction of the free joint and bifurcation phenomena on the manipulator. We also observe some periodic motions on an experimental manipulator system.
