| Pennisetum.sp grown is the largest labour intensity and the most cumbersome process links in Pennisetum.sp production.The labor cost can be reduced and the working efficiency can be improved effectively by the mechanized Pennisetum.sp cultivation.Roller distributor is the key component to realize the automation of planting equipment,which is the key factor affects the quality,performance and germination rate of the planting.There are some problems such as low degree of automation,poor planting uniformity and continuity,and damage of plant stem,etc.,which is not conducive to the promotion and sustainable development of Pennisetum.sp planting technology.Based on virtual prototype technology to the design of the Pennisetum.sp seed metering device,on the one hand,to replace the t°itional physical prototype design needed for the agricultural machinery design,manufacturing,assembly and test,able to effectively plan design,model assembly,simulation experiment was carried out,on the other hand,to speed up the development cycle and the quality of research.This paper combined with the natural science foundation of Fujian province(2016J01209)project,based on the existing relevant research results at home and abroad,using the theory and methods of the agricultural machinery design methods,virtual prototype simulation technology,3D model reconstruction,response surface analysis,to conductas the throretical analyses,structure design and experimental research of the Pennisetum.sp pre-cut kind of roller type metering device.The main research contents and conclusions are as follows:(1)Study on the Physical Parameters and Mechanical Properties of the stem of the Pennisetum.spSystematically testing and analyzing the mechanical parameters and mechanical properties of semi-annual Pennisetum.sp,parameters such as geometric characteristics,density,friction coefficient,and stiffness coefficient of the whole straw were obtained.Finally,the main application objects was determined to selected the stems of 15-22 mm and 270-290 mm in length are used as for realizing mechanized seeding of seed metering devices.They provide theoretical basis and basic parameters for structural design and dynamics simulation analysis of Pennisetum.sp seedlings.(2)Establishment of the overall design and dynamics model of the Pennisetum.sp roller distributorThe main structure and working principle of the Pennisetum.sp roller distributor were studied and analyzed.The structural optimization model related to the seed feeding link was established.The factors that affected the stress value of the seedling stem were analyzed,and the relevant virtual prototype three-dimensional model was established.Reverse engineering technology was used to reconstruct three-dimensional model of stem body.ANSYS was used to realize the flexibility of the stem model,and a dynamic simulation model was established by ADAMS/View software.(3)Simulation Optimization and Experimental Analysis of Key Parameters in Seed Feeding ProcessIn order to optimize seed feeding performance of roller distributor,ADAMS/View software was used to perform single-factor and multi-factor simulation analysis on various factors affecting seed stem stress during seed meter feeding,and passed the bench test to the test.The results were comprehensively analyzed to study the effects of various factors and their interactions on the stems,and finally determine the structure parameters and operating parameters of the feeding roller.The test results show that the designed seed-feeding roller has a high fluency and the seed stem stress value is less than its compressive strength,which meets the requirements for the planting of the Pennisetum.sp.Final determination of the structure parameters of the feeding roller and its operating parameters:feeding slot height range:19-20 mm,pre-draining slot length:136 mm,feeding slot roller speed:30 r/min,pre-slotting slot angle:60-75°,sending slot angle°ius range:0-4 mm,stems to the main stem-based,and the stem diameter value of the difference is appropriate within 2 mm. |
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