Research On Building Method Of Knowledge Based Rapid Design Expert Of Agricultural Machinery Professional Chassis

The research and development of agricultural machinery in China mostly adopts the traditional design patterns which have many shortcomings, such as long design cycle, low efficiency, poor product performance and so on. In order to solve these problems, this paper takes the overall design of agricultural machinery chassis as the research objiect. Based on knowledge engineering, a rapid design system of agricultural machinery universal chassis is constructed using the combine harvestser chassis as an example. At the same time, the key technologies of knowledge acquisition, representation, and storage about agricultural machinery chassis design are researched. Then, the inference mechanism of agricultural machinery chassis rapid design is analyzed. By integrating knowledge engineering and the paramatic CAD models of chassis parts and components, the digital rapid design platform of agricultural machinery chassis is built. The platform can be applied for the rapid design of self-propelled agricultural machinery chassis, shorten the development cycle of new product, and improve product quality, thereby enhance the design level of China’s agricultural machinery chassis design. The main research work of this paper includes the following aspects.Firstly, based on the design needs of agricultural machinery chassis, a knowledge-based process model TFBS is presented. The TFBS model is used to realize the functional structure level of agricultural machinery chassis product and on this basis, the functional model of products is formed by using the modeling method of IDEFO functional description. Then a frame of the rapid design system of agricultural professional chassis is built by using the process model TFBS and the functional model IDEFO.Secondly, based on the study of expert experience and design standards, a large number of design parameters of combine harvesters on existing market are collected. Meanwhile, the integrated application of rough set and regression analysis is used to implement data mining and knowledge discovery, which is to prepare for the construction of knowledge base about the combine harvester chassis’ rapid design.Thirdly, from the analysis of characters of design process knowledge, heuristic knowledge and experiential knowledge, combining with the development of the current knowledge representation technology, the article establishes the framework for cases knowledge representation, the heuristic representation for rules knowledge and the production of empirical knowledge. Then the knowledge of models, experience and design results is packed up by using object-oriented knowledge representation for the general scheme, also the overall design case class and the sub-system case calss are formed. Based on relational database SQL Server2008, the knowleege base and it’s corresponding management system are established, including case base, rule base and data base.Next, the module of reasoning process on rapid design of agricultural machinery chassis is studied. In the process of CBR, the object-oriented case representation method and the nearest neighbor algorithm of case similarity are researched. Also, on the basis of CBR and RBR, the integrated resoning technology of the rapid design of combine harvester chassis is put forward. Finally, based on the above theories and research methods, the key technologies of constructing the rapid design platform of knowledge-based agricultural professional chassis are analyzed. The parametric technology of design models is studied and based on this the parametric model base of agricultural machinery chassis rapid design is established. Then, the managing approaches of the parametric model base are researched. Meanwhile, the working process of the knowledge-based rapid design system of agricultural professional chassis is formed. Based on the development platform of Visual Studio2008, integrated SQL Server knowledge base, reasoning machine and Pro/E secondary development, the rapid design platform of agricultural professional chassis is built and practiced. It’s concluded that the platform can achieve the rapid design of agricultural machinery chassis.