Key Technology Of Mulberry Sapling Harvester And Whole Machine Development

Tender mulberry,a new functional feed,has great application prospective in animal husbandry.The way is turned to harvesting whole mulberries from picking epicormic branch as demand expands gradually and mulberries are not harvested one time a year.Focusing on key problems like high labor intensity in harvesting process and growth disorder influencing next harvesting caused by varying height,rough cut and damaged cut of stubble.the main works are summarized as follow:(1)A design plan of tender mulberry harvesting machine has been carried out aiming at main problems in harvesting process.concerned with functional requirements,the machine is divided into four modules which are crawler chassis?harvesting platform,conveying mechanism and bundling mechanism.(2)A design plan of crawler chassis is proposed to satisfy the requirements of gradeability and passing ability taking both complex terrain of planting mulberries and travel requirements into account.The chassis structure is designed and 3-D model has been established.(3)Cutting disc with high-speed revolution is applied to cut tender mulberry as required to solve the problems of rough cut and damaged cut after making comparison of several cut ways.The project of harvesting platform which is able to adjust the height has been proposed concerning movement characteristic of cutting disc and stubble requirements.The harvesting platform is designed and 3-D model has been established.(4)A mechanical structure to collect cut mulberries to work out high labor intensity in the collection process is designed,in which structures of putting together,clamping,conveying and bundling are included.(5)A hydraulic system for the harvester is designed in view of power need of each functional unit.AMESim is applied to simulate the proposed hydraulic system after calculating and determining specific components andparts.rationality of the proposed hydraulic system has been analyzed.Impact value of hydraulic motor at Startup instant is reduced to 23 N.m from 29 N.m after hydraulic system optimization analysis and hydraulic impact resulted from transition of working conditions of hydraulic cylinders has been eliminated.(6)Modal analysis of frame has been done based on established finite element model of frame.topological optimization is used to achieve structure optimization of frame.The optimization results have demonstrated that first order natural frequency of harvester frame is raised to 51.45 Hz from 33.9Hz and second order natural frequency is up to 66.71 Hz from 42.43 Hz.The corresponding amplification is 51% and 57% respectively.It works well to avoid resonances.