Design And Research Of A Beatingchestnut Picking Device

At present,the most common way to pick chestnut is to pat it with a bamboo pole.This picking method has high labor cost,many unsafe factors,high labor intensity and low picking efficiency.In this paper,a chestnut picking device with simple structure,safe performance,convenient carrying and easy operation is designed and developed to improve the picking efficiency and solve the problems of high-altitude picking,which is of far-reaching significance to promote the further development of chestnut planting industry.The main research work is as follows:(1)The overall structure and working principle of the picking device are designed,including the selection of driving mode and transmission mode,the effect comparison and scheme determination of telescopic structure,the structural design of key parts and the design of speed regulation system.(2)The kinematics equation of chestnut picking device is established by D-H method.Through kinematics simulation,the position curve and motion trajectory of the end point of the beating rod are obtained,and the working range of chestnut picking device is analyzed.The dynamic equation of chestnut picking device is established by Lagrange equation method,and the dynamic simulation is carried out.The results showed that the parameter design of chestnut picking device was reasonable,and the picking range met the actual needs.At the beginning of the movement,the stress of each part of the mechanism will have a sharp change process of 0.01 s.However,due to its short action time,it will not affect the motion stability of the mechanism.The stress values of each part provide reference value for the optimal design of subsequent key parts.(3)The strength of the main parts and box of the transmission part,expansion part and beating part of the chestnut picking device were analyzed.According to the strength requirements,the related structures are optimized.The modes of telescopic rod and box are analyzed to avoid resonance.Finally,the velocity,acceleration and displacement curves of the clapper before and after optimization are compared by ADAMS simulation.The results show that the motion period of the optimized picking device is reduced,the speed and acceleration curve is smoother,and the picking efficiency is further improved.(4)The three-dimensional flexible body model of chestnut tree is established,and then the harmonic response of the model is analyzed.At the same time,through the rigid-flexible coupling analysis of the beating vibration system of the picking device-chestnut tree,the inertia force of chestnut under different beating speed,beating distance and branch thickness was obtained.The results show that the acceleration at the side branch point is the maximum at the frequency of 7.9 Hz.When the speed is 480 r/min,the beating position is 200 mm,and the branch thickness is 30 mm,the inertia force of chestnut is the largest.As the distance from the root of the branch is closer,the inertia force of chestnut is smaller,which hardly affects chestnut.(5)The tapping experiment is carried out on the picking prototype.Through the dynamic signal acquisition,the strain produced by the tapping rod under the branches of different thicknesses at different speeds is obtained.By comparing the strain obtained by simulation,it is confirmed that the beating force of the beating rod can beat the chestnut down.Finally,the field performance test of the prototype is carried out.Taking the net recovery rate as the index,the beating speed,beating position and branch thickness are selected as the influencing factors for orthogonal test.The results showed that the beating speed had the greatest influence on the picking efficiency,followed by the beating position,and finally the branch thickness.