Biomimetic Surfaces Of Snapping Rolls With Lower Damage Action And Simulation Of No-row Feed-in Mechanism Of Corn Harvesters

Research & Development in corn (maize) no-row harvesting technology and its equipment is an urgent project at present in China. The FDP (Functional Digital Prototyping) is an advanced product development technology in 21st century. FDP is a quickly and effectively means for the mechanical products. But it isn't reported that the FDP was used in R&D of the corn (maize) harvest machinery, at present, with the exclusion of the research works about this dissertation.This work was supported by National Science Fund for Distinguished Young Scholars of China, and Hi-tech Research and Development Program (863 Program) of China. The work puts forward to Research & Develop the no-row corn (maize) harvesting technology based on FDP, and centering on to analyze some key problems in corn (maize) harvesting technology, especially in the technology of lower damage with snapping rolls to pick down the corn (maize) ears based on bionical technology.Firstly, it was discussed that the key problems in corn (maize) harvesting, and the research thought and the technical route of the work was introduced. The design norm for snapping rolls design was bring forward after the detailed expounding on the working principle of pick off the ear from cornstalk. And some ignored questions in snapping corn cob was put forward. A series field tests for corn harvesting were done with the cooperative supports famed national corn harvester company. And series multi-factor tests were done in snapping rolls tester which was been trial-manufactured by this work. The degree of influencing factor on the performance of corn picking was demonstrated. The new type roll with bionic surface structures was been designed. By minishing the rolls diameter markedly based on the bionical engineering, the damage of snapping rolls was reduced evidently.Based on the CAD/CAE technology, the simulation model for the feed-in mechanism with guide rod of a national no-row corn harvester was set up. The kinematic simulation of holding and supporting the corn stalks was carried out for the diverse working parameters based on software MSC.ADAMS. The results demonstrated that the driving feed-in mechanism was able to avoid the forward collapse and the guide-rod played an important role of avoiding the lateral leaning in no-row corn harvesting. Some ameliorative suggestions were given for the designing of the feed-in mechanism.The feed-in mechanism model of a harvester with finger rotor has been researched based on CAD software. The mechanical dynamics software MSC.ADMAS was used to establish the 3-D kinematic simulation model of corn stalks feed-in mechanism for no-row corn harvesting. The process of making kinematics model and its simulating were been statement in detail. The simulation based on software MSC.ADAMS was successfully got along. The results demonstrated that the harvesting speed and the rotating speed of finger rotor were main influencing parameters on the performance of the feed-in mechanism. The shape of finger rotator, especially the shape of the fingers' end, had a notable influence on the motion of corn stalks. Some ameliorative suggestions were provided to the corresponding physical mechanism.The no-row harvesting technology,the bottleneck in the development of maize (corn) harvest machinery, was lucubrated. The influencing principle of key components, the feed-in mechanical components with varying parameter, was been analyzed using the techniques of virtual simulation.The main contents and innovative works in the dissertation are as follows:a) The working principle of snapping corn ears was lucubrated on the base of present research in corn harvest machinery. The working process of snapping rolls with an obliquity was analyzed. It was put forward that the design norm for snapping rolls design aimed to lower damage of corn ears by rolls.b) The mechanics performance of cornstalk in harvesting period was been studied. Its influences of water content of cornstalks to corn harvesting mechanization were discussed. The results demonstrated that the water content is the main factor which influencing the harvesting performance and the height of corn ears isn't observably related to the height of corn plant.c) A series field tests for corn harvesting were done with the main national corn harvester to discover the main factor which influencing the corn harvesting performance. The results were demonstrated that the rolls' type play an important role in picking corn ears, and the working speed had an unobservable influence to picking corn ears but feed-in mechanism.d) A device for testing the performance of snapping rolls of corn harvester was researched and developed. The influencing factors on picking maize-cob were discussed. In the designing of the tester, the regulating and controlling factors influencing the roller-type picking mechanism were considered. The working factors can be adjusted and controlled in monofactorial tests & multifactorial tests. The snapping-rolls of main corn harvester made in China can be installed easily.e) According to the engineering bionics principle, several structures of snapping rolls with bionical geometry structures, protruding surface & concave hole on the roll's surface, were been worked out to keep up the seizing ability by enlarging equivalent coefficient friction to between the cornstalk and the rolls which the diameter was observably minished. The field tests about it were conducted, and the results showed that the expectant purpose were come true. The sizes and mass was minished observably.f) The feed-in process of cornstalks was studied based on the theoretical, simulation analysis, and verifying testing. It is discovered which the basis to analyze the key mechanism for no-row corn harvesting. In the dissertation, the next research is suggested that the mechanics basis of corn plants and the innovation of corn-pick mechanism. The studies should go on in the cooperation with multi-system and multi-domain, and the R&D of corn (maize) harvesting technology should lucubrate between the whole work tache.