Research On Computer Aided Design System Of The Telescopic Boom Of Building Maintenance Unit

With the acceleration of urbanization, the high-rise buildings on behalf of the urbanization level are increasing rapidly. The equipment used for maintaining and cleaning the external wall of those buildings are known as Building Maintenance Unit(BMU), and now the demand of BMU is growing. As non-standard products, BMU doesn’t have a specific product serial. The design of BMU is inefficient because it requires complicated calculation and a lot of time in drawing. In order to meet the efficient design philosophy, a computer aided design system for BMU is developed in this thesis.According to the structural characteristics of the BMU, several types of software such as Visual Basic, AutoCAD, VBA etc are used to develop a computer aided design system. This system can estimate the parameters of main structure, examine the stability of the whole machine, establish the gallery of detail diagrams, and draw the assembly diagram of the BMU.First of all, make full use of the visual character of the programming language Visual Basic(VB), create a interactive interface for inputting original data. As the user input the design condition from the interface, the program coded by VB would run in the background,calculate the parameters and pick out the functional unit of the telescopic boom. Then AutoCAD would draw the assembly diagram according the parameter calculated by VB.Secondly, according the National Standard of BMU and traditional design experience, the design rules of then telescopic boom is presented. As the basic design parameters are known,the length and sectional dimension of telescopic boom can be calculated rapidly and can be checked in the rules of strength and stiffness. The design parameters can be adjusted according to the strength and stability. Finally, using the secondary development tool VBA embedded in AutoCAD the parts library is programmed and established. Then the system can draw the assembly diagram using the library according to the real structure.The works that research and develop the computer aided design system of BMU improve the way of traditional pattern and shorten the cycle of product development. In addition, the new design ideal is presented by using the gallery of detail diagrams to manual assemble the whole machine manually.