Robust Vibration Control of an Overhead Crane by Elimination of the Natural Frequency Component

This study aims at developing a systematic approach for designing the control input for an overhead crane. In a previous report, numerical simulations showed that residual vibrations can be suppressed in nonlinear damped systems by eliminating the natural frequency component from the apparent external force, which includes the influence of the system nonlinearity and damping. One problem is that the proposed method requires knowledge of the natural frequency of the system, which is generally difficult to estimate on-site with high accuracy. This paper employs two methods to improve the robustness to the estimation error for the natural frequency. One is to increase the number of eliminated frequency components, and the other is to make the frequency derivatives of the frequency component zero at the estimated natural frequency. Numerical simulations demonstrated the effectiveness of these approaches for reducing residual vibration in overhead crane operation, showing that they exhibit similar robustness. However, the latter is easier to use because it does not need additional parameters to be determined.