Time-Optimal Motion Generation and Load-Sway Suppression for Rotary Cranes with a Two-Stage S-Curve Trajectory Based on Skilled Operation Analysis

This paper presents an angular velocity trajectory generation method for a rotary crane boom based on the analysis of skilled operation, which is able to suppress the two-dimensional load-sway consisting of radial and tangential components in a short time by only boom horizontal rotational motion. The proposed trajectory consists of two-stage S-curve profiles for both acceleration and deceleration periods so that the natural period of the load-sway can be changed effectively to achieve the short motion time with load-sway suppression. The proposed trajectory is generated by solving the problem to find minimal motion time considering crane dynamics and constraints on load-sway and machine limitation. The motion performance by the proposed trajectory is compared with the conventional trajectory in simulation considering rope length change and boom-twist typical in a large crane. The proposed trajectory successfully suppresses the load-sway while satisfying the crane constraints in a short time.