Radial-motion assisted command shapers for nonlinear tower crane rotational slewing

Input shaping is an effective method for reducing motion-induced vibration. The majority of input-shaping theory is based on linear analysis; however, input shaping has proven effective on moderately nonlinear systems. This work investigates the effect of nonlinear crane dynamics on the performance of input shaping. Typical bridge cranes are driven using Cartesian motions and behave nearly linearly. The rotational structure of a tower crane makes nonlinearities more apparent. Nonlinear equations of motion are presented and experimentally verified. Novel command-shaping algorithms are then proposed for reducing vibration during the nonlinear slewing motions of tower cranes.