Slow and safe motion trajectory generation for final positioning support of a load considering load-sway and obstacle avoidance in large rotary crane operation

Rotary crane systems are essential for transporting heavy loads and hazardous materials. Manual operation can be challenging for new or unskilled operators. This study addresses the challenge of precise final load positioning in construction sites by proposing a trajectory generation system that integrates obstacle avoidance and load-sway suppression. A load monitor camera (LMC) captures the load environment, and the result is displayed on a user-friendly interface designed with error prevention, simplicity, and ergonomic considerations. A usability evaluation has confirmed that the interface reduces task completion time and is well accepted by novice users. The operator selects the final load position from the LMC image, after which a slow-motion trajectory is automatically generated using a cycloidal velocity profile to suppress load-sway. The A* algorithm is used for obstacle avoidance, and its efficiency has been validated through comparison with the Dijkstra algorithm. A benchmark comparison with an S-curve trajectory using trapezoidal trajectory profile has demonstrated the proposed method’s superiority in minimizing sway. Additionally, a disturbance sensitivity analysis under wind conditions has evaluated system robustness and highlights potential improvements. Simulations and lab-scale experiments have confirmed that the proposed method enables safe, smooth, and precise final positioning while avoiding obstacles.