| The research and development of the oil peony fruit harvesting machine has important significance for the development of the mechanization and the comprehensive development of the fruit picking operation. As the carrier of picking and transporting device, chassis is the main structure of the harvester, which stability is directly related to the performance and effect of the harvester. The stability and vibration characteristics of the high clearance chassis, which ground clearance is large, the center of mass is highly, and the working condition is complex, are the key problems in this paper. The main research and conclusions of this paper are as follows:1. Compared with the characteristics of domestic and international harvester chassis and according to the planting environment of oil peony and requirements of picking operation, it determines the whole scheme of oil peony fruit harvester, including the design of the chassis frame structure and function.2. According to the overall scheme, it designs the hydraulic drive system, including the determination of the main parameters of hydraulic components and hydraulic drive program. And it established a hydraulic drive system model of high clearance chassis by the AMESim software. Through the simulation analysis of the model, the parameters of the key components such as the pressure of the system, the hydraulic pump and the hydraulic motor are obtained which are in agreement with the theoretical calculation.3. The stability analysis of high clearance chassis was studied. According to the center position of mass, it calculates the ultimate tilting angle. The uphill and downhill ultimate tilting angle are 40.75°and 52.06°, lateral limit tilting angle is 39.43°,which could meet the requirements of working on flat and sloping field. And it proves the rationality of the overall layout of the chassis. According to the static analysis by using ANSYS finite element model, getting the maximum stress is 31.86MPa, maximum deformation is 0.97mm, which could meet the requirements of strength and stiffness. And proving the structure design of the frame is reasonable. Through the modal analysis, the first ten order natural frequencies and vibration modes of the chassis frame are obtained, which provide an important basis for avoiding the resonance of the frame and optimizing the structure.4. Due to the high clearance of the chassis frame vibration, it will influence of harvester work performance and reduce the stability. Therefore, vibration test on chassis was carried out. Based on the test results, it gets the large vibration frequency and vibration source. And it was studied that the diesel engine is the main vibration source. According to the results of the modal analysis, it determines the frequency range of the resonance, and provides basic data for further optimization design of chassis frame.5. In order to improve the low order natural frequency and reduce the frame quality, the structure of the high clearance chassis frame is optimized, based on the Workbench ANSYS simulation platform. After optimization, the fourth order frequency of the high ground clearance chassis frame is increased to 75.54Hz, which is higher than the engine excitation frequency, and avoiding the occurrence of resonance. At the same time, the quality of the frame is reduced by 12.4%. Through the optimization, the stability of the high clearance chassis is further improved. |
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