Research And Optimization For Lifting System Of Super Large Crawler Cranes

With the development and improvement of our society and technologies, integral lifting has been playing an important and indispensable role in the jobs of engineering constructions. Because super large crawler cranes have some advantages that other lifting machines can’t offer, the importance and necessity of super large crawler cranes stand out from others. Further, super crawler cranes attract people’s attention and favor. As a lifting machine, the security and stability of the lifting system are extremely important. In the lifting system, one of the problems that threaten the security and stability of crawler cranes is the problem of second lifting, i. e. how to prevent the unexpected drops. The problem affects the performance and the life of the whole machine. Moreover, super large crawler cranes are manufactured with a closed hydraulic system, the problem of second lifting will be much more serious than the middle and small cranes and those manufactured with an open hydraulic system. At present, the study of super large crawler cranes domestic has falls behind other countries. There are little appropriate paper and information that could be checked. This paper offers a solution to this problem of second lifting in super crawler cranes. Research and optimization are achieved through theoretical analysis and simulation. And some support and reference can be presented for the research and development in reality to improve the dynamic performance of super large crawler cranes.In the first chapter, on the basis of checking and reading lots of paper and documents on the problem of second lifting of super large crawler cranes, things included that are presented as followed the status of manufacturing and application at home and abroad, the universality of second lifting problem and status of research and solutions on the problem nowadays. Furthermore, the similarities and differences in the problem of second lifting between the super large crawler cranes in this paper and the ones mentioned in the paper and documents. Through all of this, the meaning and contents of this subject are presented.In the second chapter, the principle of the electro-hydraulic controlling system in the lifting system of super large crawler cranes is designed. Also, the principle of every part of the lifting system and solution of controlling are introduced.In the third chapter, according to the real situation, the key parameters of the lifting system are determined, and key components are selected. Mathematical modeling and theoretical analysis are used to analyze the influences on the lifting system of the key parameters in the electro-hydraulic controlling system. And the results of analysis through the theoretical are optimized.In the fourth chapter, based on the AMESim software, the lifting system of super crawler cranes is modeled and simulated. Based on the theoretical results of last chapter, the simulations are accomplished and analyzed, and the results are optimized.In the fifth chapter, the achievements in this paper and inadequacies to improve are summarized. And expectations of further research on the lifting system of super large crawler cranes are put forward.