Design And Experimental Study Of Potato Pickup Device Based On Discrete Element Method

Aiming at the problems of high intensity of manual picking and low rate of mechanized harvest in the process of potato segmented harvest in our country,a potato picking device was designed to replace manual picking.Through the analysis of its working principle,combined with the picking process,the key components of the spring tooth picking device are optimized.Measuring potato and soil related physical parameters;The simulation test model was established.Through Adams-EDEM coupling method,the potato picking process simulation experiment was carried out,and the simulation experiment results were carried out in the field.The main research contents are as follows:(1)Optimization design of pickup mechanism.Taking Xuechuan red potato as an example,the three-axis size,ridge width,single ridge and double ridge potato excavator working width were measured and counted.The picking process of potato picking device,lifting and transporting,and arranging potato were analyzed.The cam curve is designed according to the ideal working trajectory of picking up elastic teeth,the kinematic model is established,the dynamic simulation of elastic teeth is carried out,and the reasonable working parameter range of picking up device is obtained.(2)Measurement and calibration of physical parameters of potato-soil-picking mechanism.The calibration test of soil particle accumulation Angle was carried out by discrete element method,and the actual measured simulation Angle of repose(35.5°)was taken as the response value.The significant factors affecting the soil model were JKR surface energy(0.356),soil particle restitution coefficient(0.45)and soil particle rolling friction coefficient(0.15).The static friction coefficient(rubber plate 0.56,ordinary carbon steel plate 0.45),dynamic friction coefficient(0.27),collision recovery coefficient(0.45)and density(1184 kg/m~3)of potato were determined to provide data reference for the establishment of simulation test model based on discrete element method.(3)Simulation experiment of potato picking process based on discrete element method.The simulation models of soil,potato and picking device were constructed.The simulation environment of multi-body dynamics and discrete element coupling was established,and the simulation experiment of potato picking process was carried out,and the maximum force of potato in the process of picking was 71.5N.The response surface method was used to carry out multi-factor tests to optimize the operation parameters of the pickup device,and the loss rate was 1.55%under the optimal pickup parameters when the forward speed was 0.6 m/s,the spring tooth speed was 20 r/min,and the soil depth was 80 mm.(4)Field experiments.The experimental results show that the loss rate of the picking device is 3.36%.The experimental results are consistent with the simulation results,and the picking effect is good,which meets the agronomic requirements of potato harvest.