The Finite Element Analysis Of High-altitude Working Machine's Boom And Its Leveling System Design

The high-altitude working machine as a large-scale construction machinery equipment is widely used in ships, construction, municipal construction, fire, port cargo and other industries. It is the emerging technical industry, there are broad prospects for development. Despite China has acquired some successes in design and manufacture of the high-altitude working machine, but there is a certain gap between the domestic production of high-altitude working machine and the foreign high-altitude working machine production. This paper proceeds the finite element analysis for the arm support of Hunan Sundawn Technology Development Co., Ltd.25 meters of overhead working truck in two kinds of dangerous working conditions respectively. In addition, an electro-hydraulic means to achieve the leveling of the work platform. It proceeds a great deal of theoretical research and software testing.In chapter 1, it introduced the basic structure of high-altitude working machine, the development and the research status in china and foreign countries of it at first. Then it summarizes the telescopic boom's position in safety of high-altitude working machine. It discusses the working platform leveling mechanism and focus on its key factors of electro-hydraulic control valve. At last, it discusses the primary mission and the significance of the subject study.In chapter 2, it analyses the structure of telescopic boom and determine the load condition and the work condition of high-altitude working machine. Through calculating the stress and deformation of the level condition and the state of maximum working, the strength of the material and structural design meet the design requirements. It uses the ANS YS software once again to analyse the stress of the level condition the deflection and the modality, to analyse the stress of the state of maximum working, the deflection and the flexion. Comparing the results of the analysis with the results of the calculation, confirming the stress and the deformation in dangerous condition meet the design requirement.In chapter 3, it discusses the basic principles of platform leveling for the hydraulic system and the leveling system of working platform of the 25 meters high-altitude working machine. It sets up the mathematic model of the high speed on/off valve controlling the cone-shaped valve, and uses Simulink toolbox in Matlab to adopt S function to conduct the simulation analysis. When inputs a PWM pulse to the mathematic model, gains alteration curves of the spool displacement, pressure and flow rate with time. The experimental results show that the scheme of high-speed switch controlling valve is viable and effective.In Chapter 4, summarizes the research of the whole thesis briefly and brings forward sequential work to be done in the future.