Study On The Design Method And Process Planing Of Corn Harvester Frame Based On AD Theory

The frame of the corn harvester is the carrier where working equipment is fixed, such as engines, peeling machines, chopped headers, etc.. It assists the corn harvester successfully completing the basic working process of snapping, peeling, maize ear collecting and straw chopping. Meanwhile, it bears the load induced by road roughness and excitation by vibrating components. Therefore the frame is key to the superior overall performance of corn harvesters. Thus focused on corn harvester frame, the structural characteristics, design methods, strength and vibration stability test methods as well as processing technology were studied, the results of which were of great value for the design, manufacture and test of corn harvester frame. The main researches of this paper are presented as follows:(1) Overall design method of the corn harvester frame based on AD theoryAxiomatic design (AD) is an engineering design theory that provides a framework to decision-making in the designing process. Based on a "what-how" reasoning procedure, the set of FR, and DPS was determined by ’decomposition’ and ’zigzagging’ processes, which must obey independence axiom so as to identify functionally independent design candidates. Thus, the design parameters of the corn harvester frame were extracted, implementing the overall design of the corn harvester frame. Next, process variables named PVs could be acquired by mapping design variables, then the process plan of frame was obtained.(2) Specific design method of corn harvester frame’s structure parameters based on the mechanical modelFirstly, the design method of longitudinal beam section parameters of corn harvester frame was established by building the bending mechanical model. Secondly, the relationship between frame width and torsional stiffness was analyzed by constructing torsional mechanical model. Moreover, the design method of cross beam length was put forward based on the steering geometry model and the quasi-static lateral stability mechanical model. It was also combined with the structure size and layout characteristics of the elevator and engine. Thirdly, the road excitation geometry model is transformed to load model of the frame, so as to calculate the parameters of cross beam section. Finally, the tube beam of rear axle mounting seat was optimum designed on the basis of complex method.(3) Test method of the corn harvester frameAccording to the connection between working components and the corn harvester frame, a FEA loading method was proposed. The method was verified by the strength test of the corn harvester frame under static non-loading condition and static loading condition. Also, the dynamic strength test was carried out under four typical operating conditions in order to analyze the dynamic mechanical properties and vibration stability of frame.(4) Welding process planning of corn harvester frameBased on axiomatic process design, it was necessary to further plan the robot welding process. Above all, a multiple linear regression model was established between the welding process parameters and welding deformation which could be used to optimize welding process parameters. Then, a flexible robot welding platform was designed, such that different types and different series of corn harvester frame could be welded on the platform. Finally, a welding process path was determined for a specific corn harvester frame welding by double welding robots.