Abstract
An underactuated manipulator is defined as a manipulator with fewer actuators than degree of freedom of the system, which, for example, corresponds to the situation that some of actuators of a manipulator breaks down. Because it is especially hard to fix the broken actuator in space, control methods of the underactuated manipulator are generally considered to be employed as emergency control methods in space. In this paper, a control method of a two-link underactuated manipulator under zero gravity condition is proposed. By utilizing high-frequency excitation for the underactuated manipulator mounted on a base rotating at a constant angular velocity and experiencing centrifugal force, bifurcation phenomena occurs in the free link. We control the bifurcation phenomena and change stable equilibrium points of the free link where position of the link converges. The control method is theoretically clarified and also experimentally confirmed.
