Cooperative dual-crane lifting is an important but challenging process involved in heavy and critical lifting tasks. This paper considers the path planning for the cooperative dual-crane lifting. It aims to automatically generate optimal dual-crane lifting paths under multiple constraints, i.e., collision avoidance, coordination between the two cranes, and balance of the lifting target. Previous works often used oversimplified models for the dual-crane lifting system, the lifting environment, and the motion of the lifting target. They were thus limited to simple lifting cases and might even lead to unsafe paths in some cases. We develop
a novel path planner for dual-crane lifting that can quickly produce optimized paths in complex 3-D environments. The
planner has fully considered the kinematic structure of the lifting system. Therefore, it is able to robustly handle the
nonlinear movement of the suspended target during lifting. The effectiveness and efficiency of the planner are enabled
by three novel aspects: 1) a comprehensive and computationally efficient mathematical modeling of the lifting system;
2) a new multiobjective parallel genetic algorithm designed to solve the path planning problem; and 3) a new efficient
approach to perform continuous collision detection for the dual-crane lifting target. The planner has been tested in
complex industrial environments. The results show that the planner can generate dual-crane lifting paths that are easy
for conductions and optimized in terms of costs for complex environments. Comparisons with two previous methods
demonstrate the advantages of the planner, including safer paths, higher success rates, and the ability to handle
general lifting cases.