Study On The Harvesting Mechanism And Equipment Of Pinellia Ternata In Clay Soi

Pinellia ternata plantation in Hezhang County,Bijie City,Guizhou Province is the largest production place in China.Pinellia ternata is also one of the most common Chinese medicinal materials in Guizhou Province.It has the effects of stopping vomiting and resolving phlegm.At present,because there is no harvesting machine for Pinellia ternata in Hezhang County,it mainly relies on manual excavation and picking for harvesting.The problems of high labor intensity and high harvesting cost restrict the development of Pinellia ternata industry.The introduction of small and medium-sized machinery to harvest Pinellia ternata limited the use of the machinery because it was not suitable for Guizhou terrain.In order to fill the gap of Pinellia ternata harvesting machine in Hezhang County and reduce the labor intensity,aiming at the problems of soil viscosity and scattered terrain in Hilly and mountainous areas of Guizhou Province,this paper carried out the research work on the determination of physical properties of Pinellia ternata and soil in Hezhang County,Bijie City,Guizhou Province,the comparative analysis of different harvesting and separation methods,and the design and optimization of excavation device based on simulation software.The main research results are as follows:(1)A field survey was conducted on Pinellia ternata plantation in Hezhang County,Bijie City,Guizhou Province.It is mainly to measure and sample the ridge of Pinellia ternata plantation.Firstly,the ridge height,ridge distance,ridge top width and ridge bottom width of Pinellia ternata were measured.Secondly,the five point sampling method was used to sample Pinellia ternata and soil with every 50mm soil depth as a sample layer.Finally,physical tests were carried out on Pinellia ternata and soil samples.The results showed that the ridge height,ridge spacing,ridge top width and ridge bottom width of Pinellia ternata were 150～180mm,1050～1010mm,730～780mm and 760～800mm respectively.The average moisture content,density,elastic modulus and Poisson’s ratio of Pinellia ternata were 76.62%,0.808g/cm~3,5.73MPa and 0.47 respectively.The average density,maximum moisture content and maximum firmness of soil were 1.87g/cm~3,33.84%and 883KPa respectively.The above parameters are obtained from the changes of Pinellia ternata ridge and soil during the growth period.These parameters provide a basis for the width design of the Pinellia ternata harvester and the simulation parameters of the excavation device.(2)Aiming at the problems of soil viscosity and complex topography in Pinellia ternata plantation in Hezhang County,different harvesting methods and different separation methods were studied.Firstly,three harvesting methods are designed according to the planting mode of Pinellia ternata and the results of physical properties of Pinellia ternata and soil.Through edem simulation analysis,the resistance of plane shovel,mining and throwing shovel and combined digging device are 3643.91N,3044.87N and 2826.67N respectively.Secondly,through the edem simulation analysis of the three commonly used separation methods based on the planting mode of Pinellia ternata and the results of Pinellia ternata and soil particle size,the separation efficiencies of lifting chain,vibrating screen and rolling screen are 70.18%,48.84%and 59.97%respectively.According to the experimental results of the harvesting and separation methods,the overall structure of the harvester is designed by selecting the composite shovel with less resistance and the lifting chain with better separation effect.The power consumption and structural parameters of the key components were determined to solve the problems of large digging resistance and missing digging of Pinellia ternata.The calculation results show that the matching power of Pinellia ternata harvesting machine is 12k W,and the harvesting width is 800mm,which can meet the harvesting demand of Pinellia ternata.(3)The reliability of key components of Pinellia ternata harvester was analyzed statically.Firstly,the 3D modeling of the rack,digging shovel and mining and throwing wheel is carried out through the UG NX 8.5 modeling module,and Q235 is selected as the key component material.The static analysis of the frame shows that the maximum strain and maximum stress are 3.357×10-4mm and 0.391MPa respectively.By analyzing the excavation device,it is concluded that the maximum stress and maximum deformation of the excavation shovel are 28.51MPa and 0.265mm respectively.Through the static analysis of the frame and digging shovel,it shows that Q235 material is suitable and can be used as a complete machine.The natural vibration frequency of the first mode of the mining and throwing wheel is 86.0522Hz,which is much higher than the excitation frequency(0～30Hz)during operation.Therefore,the mining and throwing wheel will not have resonance.The static analysis of key components lays a foundation for the discrete element analysis and structural design of the excavation device.(4)The discrete element analysis of the excavating device of Pinellia ternate harvester was carried out.Firstly,the single factor tests are carried out on the four factors of the digging shovel’s inclination,the unit’s forward speed,the number of blades of the mining and throwing wheel and the speed of the mining and throwing wheel.The results show that the maximum resistance of the digging device is 2477.29N when the inclination of the digging surface is 25°;When the forward speed of the unit is 0.3m/s,the maximum resistance of the excavation device is 2580.11N;When the number of blades of the mining and throwing wheel is 2,the maximum resistance of the excavation device is 2287.94N;When the speed of the mining and throwing wheel is 100r/min,the maximum resistance of the excavation device is 2338.37N.Through the orthogonal test of four factors and three levels designed for single factor results,the influence of interactive factors on excavation resistance and mining and throwing volume can be obtained.The results show that the mining and throwing wheel speed,the unit forward speed and the shovel face angle have great influence on the excavation resistance;The forward speed of the unit,the speed of the mining and throwing wheel,the inclination of the shovel surface and the number of blades of the mining and throwing wheel have a great impact on the mining and throwing volume.Through the above conclusions,the four factors are optimized,and the optimal working parameter combination is obtained,so that the harvester can achieve the best working state during operation.