Path Planning For Two Crawler Cranes’heavy Lifts Based On Rrtconnect

Nowadays, loads, cranes and lifting methods become more and more diversified and complicated, which makes the heavy lifts a high risk activity. Compared with single crane lift, two crawler cranes (dual-crane) lift has a greater risk. To finish the lifting task successfully, it is very important to make a suitable and safe path planning as quickly as possible. So, this paper researches on dual-crane system, abstracts the mathematical model, applies and improves RRTConnect algorithm, proposes general methods which can be used in both translating task and rotating task, and gains an optimized path which fulfills constraints such as collision-free, minimum rope-slope requirement, traveling feature of crawler crane and lifting capacity and so on.Firstly, by analyzing security problem existing in lifting task, and summary current achievement of path planning, we present the purpose and significance of this paper. Moreover, this paper studies on feature of algorithms used in path planning, and chooses RRTConnect (Rapidly-exploring Random Tree with Multi-step Expanding) as basic method to solve path planning of dual-crane.Secondly, based on the previous researches on robot path planning, this paper makes deep study on heavy lifts of dual-crane, and then builds mathematical model for this path planning problem. Moreover, it makes definition and detailed description of the variant relevant to mathematical model.Thirdly, this paper adopts RRTConnect algorithm to search a feasible path. This method can be used in both translating task and rotating task which commonly exist in construction projects. Furthermore, calculation of dual-crane’s initial and target configuration applying inverse kinematical and optimization method are presented. Besides, three cases verify the method is feasible.Finally, it proposes RRTMultiPhrase algorithm which improves RRTConnect algorithm and bases on key configuration to deal with complicated path planning of dual-crane. Whereafter, theory of RRTMultiPhrase algorithm and method of choosing a key configuration are presented. After that, we carry on path planning on two complicated cases with three methods independently. Results indicate the feasibility of proposed methods. This paper analyzes features of dual-crane lift, makes deep exploration of path planning on condition that initial and target configuration is known. This approach takes crane’s traveling, turning, hoisting, slewing and luffing action into consideration, aims to find a path satisfying collision-free, nonholonomic constraint, loop closure constraint and within lifting capacity and so on. Actual cases are described and corresponding results are listed. By analysis of the typical cases, we conclude that the proposed method is practical and efficient.