Research On Motion Planning For Two Cranes Lifting Base On Inverse-solving

Since that the developing of large-scale projects promotes the lifting industry toward complex and integrated, two cranes lifting(dual-crane lifting system) tends to generalization, while multi-crane lifting(multi-machine lifting system) is gradually common. So guaranteeing lifting security becomes the primary problem. Making lifting scheme is important for lifting safety, and reasonably cranes lifting motion planning plays an important role for guiding the scheme to make. Currently, there exist several problems in the studies of dual-crane lifting system motion planning, such as the low efficiency of motion planning, the non-optimization of sequences, and the larger error of modeling. While it studies less for the multi-crane lifting system motion planning. Therefore, this paper researches on closed-chain constraint and non-holonomic kinematic constraint for dual-crane lifting system, proposes a modeling method of lifted object and crane carriage driving, applies and improves RRT-Connect++motion planning algorithm, validates the feasibility of the idea and the efficiency of motion planning by three cases referring to crane walking, turning, luffing. For multi-crane lifting system, it uses the same modeling way and planning algorithm, and further verifies the applicability of the idea and the efficiency of motion planning by the case of four cranes lifting pipe truss object.Firstly, this paper through analyzing the importance of the dual-crane lifting motion planning, and summarizing current achievement of dual-crane lifting modeling and motion planning, determines that the difficulty of dual-crane lifting motion planning is the closed-chain constraint and non-holonomic kinematic constraint, and then presents the significance of this research.Secondly, for the closed-chain constraint, combining with the current achievement of closed-chain constraint, this paper proposes a modeling method based on lifted object and crane carriage driving, and presents the solving process of inverse equations; for non-holonomic kinematic constraint, according to the similarity of crawler and mobile car wheels it establishes crane carriage model, and then gets the solving equations.Thirdly, based on dual-crane lifting system modeling this paper defines the configuration space, motion inputs, configuration transformation matrix, distance metric and so on. Furthermore, the flow and improvements of RRT-Connect++algorithm are presented. Besides, it verifies the feasibility of solving ideas and the efficiency of motion planning by three cases study, which includes rotating and translating task.Finally, based on the studies of dual-crane lifting system motion planning, it tries to study the multi-crane lifting system motion planning. This paper analyzes the specific modeling process of four cranes cooperating lifting pipe rack object, including the solution of multiple constraints, the definition of pipe rack model configuration, the calculation of lifting points location and so on. After defining the configuration space and motion inputs of the multi-crane lifting system, it carries motion planning on the case of four cranes lifting, moving, and rotating the object. The case result verifies the applicability of the method for solving multi-crane lifting system, the efficiency of motion planning and the optimization of motion sequences.