Anti-sway control system of a rotational crane using the nonlinear controller

We report a control method for a rotational crane system using a nonlinear controller. Until now, the control problem of such a system has been treated as a problem using a linear model. However, the control system designed by this method does not show good performance. In general, the rotational crane can be expressed as a nonlinear dynamical system with infinitely many modes at high frequencies. So, we consider an approximate nonlinear model having similar performance to the actual crane, and make the nonlinear terms of this model the control input, in order to convert the nonlinear control problem to the linear one. In the simulation system, the controller was achieved by taking out again the nonlinear factor from the control input, so as to be useful in the actual crane. The simulation results show us that this approach is effective for the control of the rotational crane.