Improving lifting motion planning and re-planning of cranes with consideration for safety and efficiency

Safe and efficient operation of cranes requires not only good planning, but also sufficient and appropriate support in real time. Due to the dynamic nature of construction sites, unexpected changes in site layout may create new obstacles for the crane that can result in collisions and accidents. Previous research on construction equipment motion planning focuses on off-line support, which considers static environment or predictable obstacles. These plans may not fit the reality when the environment has any change. In this case on-site safety and efficiency can be affected. In this research, a motion planning algorithm is proposed to efficiently generate safe and smooth paths for crane motions while taking into account engineering constraints and the path quality. Path smoothness is taken into account to provide a realistic path for cranes and to reduce unnecessary movements. A dynamic motion planning algorithm is proposed to ensure safety during the execution stage by quickly re-planning and avoiding collisions. In addition, an anytime algorithm is proposed to search for better solutions during a given time period by improving path smoothness and by reducing path execution time. The proposed algorithms are compared with other available algorithms to evaluate their performance in terms of planning and re-planning time and the cost of the path. Based on the literature review, this is the first time that dual-tree RRT algorithms have been applied to crane motion planning.