Design And Test Of Taro Harvester

As a vegetable and food crop,taro is not only edible,but also used for medicinal purposes.In China,the traditional form of taro harvesting mainly relies on manual digging using hoes or using semi-mechanized harvesting,semi-mechanized harvesting to remove the stalk before harvesting taro using potato harvesting machines,manual harvesting takes a lot of time and labor,which is not conducive to the industrialization of taro.Taro harvesting includes stalk cutting,excavation,and separation of mother and child taro,for the first two links of taro harvesting,it is proposed to design a harvesting machine that integrates taro stalk cutting and excavation.The design of components such as cutting devices and digging shovels,simulation analysis of key components using EDEM and ANSYS/LS-DYNA,respectively,processing of trial harvesters,and field trials were conducted,and the main research was as follows.(1)Investigation of taro cultivation agronomy and experimental determination of material properties of taro and taro stalks.Investigated the agronomic requirements of taro cultivation and determined the basic parameters of taro cultivation such as row spacing,plant spacing and depth.We conducted material property tests on taro to determine the basic physical parameters of triaxial size,moisture content and elastic modulus of taro,and studied the changes in mechanical properties of taro in compression and shear,and obtained the change curves of loading force-displacement in compression and shear of taro and the factors affecting the rupture force and cut-off force of taro.Water content,the study of the change in mechanical properties of taro stalk bending and shearing,to obtain the change curve of loading force-displacement of taro stalk samples bending and cutting and the factors affecting the cutting force of taro stalk,the results show that: the cutting force of the tool edge angle of 21 ° is smaller than 25 °.(2)The whole machine design of the taro harvester.Based on the agronomic requirements related to taro cultivation,the whole machine structure of the taro harvester was designed,and the key components of the harvester were identified: cutting device,digging device and frame and other related components.The taro harvester can complete multiple processes such as stalk cutting,taro digging,clamping and conveying,and spreading at one time.(3)Design and analysis of the cutting device.The disc type cutter was selected and the kinematic equations of the cutter were established.The basic parameters of the cutter were determined by establishing the equations of no leakage,no collision and no recutting of the cutter;the cutting blade disc was designed with four blades symmetrically installed on the disc,with an effective cutting length of 90 mm,a width of 40 mm and a blade inclination of 0°.And ANSYS/LS-DYNA software was used to simulate the taro stalk cutting process,and the three-way force curve,combined external force curve,energy curve and the stress change of the stalk model in the cutting process were obtained.Using the cutting speed of the cutter,the cutting edge angle and the cutting angle as the influencing factors,an experimental design table with the maximum cutting force and energy loss as indicators was designed using Design-Expert,and 17 sets of experimental factor combinations were derived.And according to the data obtained from ANSYS/LS-DYNA simulation,the best combination of parameters for the stalk cutting tool was derived by substituting into Design Exepert software: cutting speed of 1080 r/min,cutting angle of the tool of 26° and cutting edge angle of 21°.(4)Design and simulation of the digging shovel.According to the frame size of the taro harvester design,the total width of the digging shovel is 680 mm,the single shovel width is 80 mm,and the shovel spacing is 40 mm;by establishing the dynamics model of the digging shovel,the first-order shovel inclination angle is 20°,the first-order shovel length is 180 mm,the second-order shovel inclination angle is 25°,the second-order shovel length is 100 mm,the shovel edge angle is 45°,and the digging depth is 250～300 mm.The resistance of the first-order flat shovel and the second-order clearance shovel is simulated by EDEM software,and the mean resistance reduction rate of the second-order clearance shovel is 10.6% in the X direction and 13.4% in the Y direction.Therefore,the secondorder clearance shovel can save more energy when working,which provides a reference basis for the design of the harvester shovel.(5)Design the frame section of the harvester.The frame part of the taro harvester was designed,and the clamping chain and spreading mechanism were determined.(6)Field performance test.Referring to the potato industry standard NY/T1130-2006,the test index was determined as the rate of bright taro,wounded taro and broken taro.When the tractor output shaft for the speed of 540 r/min,driving speed of 1.0 m / s,taro harvesting operation width of 680 mm,digging depth of 250 mm ～ 300 mm,the results of the field test for the bright taro rate of 97.1%,taro injury rate of 1.84%,broken taro rate of1.88%,in line with relevant agricultural standards,to meet the design requirements.