Comparison of command shaping controllers for suppressing payload sway in a rotary boom crane

This paper presents the simulation results for two variations on a basic command shaping filter designed to reduce operator induced pendulation in a rotary boom crane. The crane model and the basic command shaper design are based on the authors´ previous work (1998), which consists of a fixed vertical support, a boom capable of rotating about the vertical and elevating with respect to the horizontal, and a lift-line of variable length which sways about the boom tip in a spherical pendulum. The command shaper adapts to changes in the crane configuration and notches out the pendulation frequency, reducing pendulation. The two alternate designs contain additional time-varying elements to improve anti-sway performance. Command shaper stability is studied via conditions for slowly time-varying systems developed by Desoer (1968). Stability is evaluated for the analytic models and verified with numerical simulation results