Development And Experiment Of Orchard Ditcher Based On Computer Simulation Of Soil Cut Process By Cutting Tools

In orchard management,the process of ditching is the most labor-intensive and low work efficiency process.The mechanization level in ditching process is great significance to the development of China’s fruit industry.At present,the power consumption of the ditcher is large,and the ditcher is difficult to meet with the requirements of position,depth and width.In this paper,high density dwarf rootstock apple orchards was taken as the research object,a orchard ditcher was designed considering orchard agronomic requirements.The cutting process was simulated by ANSYS/LS-DYNA,and the microscopic mechanism of cutting process was revealed.And power consumption decreased with optimization of working parameters,field tests were performed.The research contents and main conclusions are obtained as follows:(1)Overall design of a orchard ditcher is determined and developedThe overall design of a orchard ditcher is determined,considering the orchard agronomic requirements.The driving device of the ditcher is an orchard crawler multifunctional operating machine,which is connected to the orchard ditcher through a suspension device.The offset ditcher can ditch close to the fruit trees.The offset stepped orchard ditcher is composed stepped ditching cutter,drive system,frame and diversion cover.The stepped ditching cutter consists of three single discs.The diameter of the single disc near the fruit tree is large,and the diameter of the single disc away from the tree is small to reduce the power consumption.This structure can meet the agronomic requirements of fertilization depth and width.And the ditcher was backward rotation by motion analysis.According to the overall design,an offset stepped cutter orchard ditcher is developed.(2)Simulation analysis of the cutting process of cutterThe cutting process was simulated based on SPH method by ANSYS/LS-DYNA,and the simulation model of cutter-soil is established.The results indicate that during cutting process,the cutting continuity is excellent.The stress and cutting force increased with increase in contact area between cutter and soil,and gradually became stable.The maximum stress occurs at the bending of the cutter.The result of power consumption in simulation under selected soil parameters at speed of 0.27 m/s,rotating speed of 18.85 rad/s and depth of 0.3 m is 2.28 kW,and the error between the theoretical value and the simulation result is 4.1%.Thus,the accuracy of power consumption simulation model is verified by theoretical analysis.(3)Optimization of working parameters of ditcherBased on the simulation model of cutting process,the optimum combination of cutting speed,rotation speed and depth with the minimum power consumption was obtained by orthogonal test.The forward speed is 0.13 m/s,the rotation speed is 20.94 rad/s,and the depth is 0.3 m.And the reasonable working parameters of ditcher can be selected by exploring the influence of working parameters on power consumption.(4)Field testsField tests results show that the ditcher could open a ditch at the depth of 31.72 cm,width of 31.13 cm and depth stability of 97.2% during the speed 1.2 km/h,and which meet the agronomic requirements of depth and width.And the characteristics of ditcher are stable performance and good ditching quality.A speed-torque measurement platform was built,and field experiments verify that the simulation model established is accurate and reliable.