Design And Implementation Of Collision-free Path Planning For Mobile Crane

With rapid development of petrochemical industry, oceaneering and electric power construction, more and more super heavy lifts with hundreds or even thousands of tonnage weight are coming out, lift planning'industry will face an important chance. At the same time, the environment of lifting site has become complex increasingly, and the special structure and movement of lifting machinery have some fatal factors, security threats are becoming more and more pronounced. There are more and large and heavy structures which are needed to be carry in construction process, but just one crane usually can not fulfill the task, two cooperative cranes are widely used to implement the task of carrying the heavy structure. The use of cooperative cranes call not only implement the task of carrying the heavy structure, but also take full advantage of the equipments, and reduce the cost. The lifting of two cooperative cranes is more dangerous than that of a single crane. Therefore, it is important to plan a collision-free path for a crane to complete lifting task safely and efficiently.Firstly, according to the general structural characteristics of mobile crane, we analyze its movement and compute the key parameters for mobile crane.Secondly, based on the previous researches on robot path planning, this thesis develops a path planning algorithm for a crane in the complex 3D working environment. We use C-space to describe the planning space, the crane is simplified into three degrees of freedom (DOFs) robot, each of which is represented as an axis of configuration space (C-space).We build a feasible C-space through the restrictions of degrees of freedom under a certain constraint condition. Then the optimal path is searched on the C-space using ant an improved ant colony approach for mobile crane.Thirdly, adopting the method of forward and inverse kinematical calculation, this thesis develops a newly two cooperative cranes path planning. The operators select a crane as main crane from the two cranes, and the other as the following crane. The path of main crane is planned according the heuristic information beforehand, the movement of following crane is planned according the movement of the main crane and the load.Finally, this thesis integrates all the above studies into the 3D Lifting Simulation System. As modules of the system, they can assist the planners to plan the optimal lifting path, obtain the operations sequence, output the simulation results automatically, and improve the efficiency and reliability of lifts planning.