Anti-sway control of a rotary crane via switching feedback control

A stabilization method of a rotary crane via switching control has been proposed in this paper. When boom motion is restricted to the rotation about the vertical axis, dynamics of the crane payload is a kind of non-holonomic system, and it cannot be stabilized by a smooth control law. We consider two linear systems which are linearized about different equilibriums. Each linearized system has an uncontrollable mode, but the union of controllable subspaces of those systems spans all the space. The basic idea of stabilization is that by switching the linearized system, the uncontrollable mode in one system can be settled in the other system using the energy control method. Furthermore, we have introduced an intermediate control step for making a transition of equilibriums to improve the final settling precision. The effectiveness of the method has been shown by simulation.