Integrated time-optimal rigid-body and zero-vibration shapers on a two degrees of freedom overhead crane system

This study presents a novel control strategy for an overhead crane system controlled by a predefined acceleration function covering the whole range of the rest-to-rest maneuvers. The proposed TORB-ZV shaper is tailored to eliminate residual oscillations promptly by integrating the inherited speed of the time-optimal rigid-body (TORB) shaper and the oscillation-mitigation capabilities of the zero-vibration (ZV) shaper. During the tri-stage maneuvering process, the system employs the TORB approach during the acceleration stage and the ZV strategy during the deceleration phase. This proposed TORB-ZV scenario provides maximum motor capacity usage and eliminates vibration as the system comes to rest. A double-pendulum model has been used to assess the robustness of the system and to validate the proposed approach numerically and experimentally. The proposed solution extends from the original nonlinear equations of the system by incorporating linear motion equations under minor swing angles for the payload, followed by an exhaustive search optimization to refine the controller, striving for the most efficient performance that combines minimized maneuver time with negligible residual vibrations. The presented technique significantly reduces the maneuvering time by at least 23% compared to the ZV shaper and improves the effectiveness and safety of overhead crane operations.