Design And Experiment Of Obstacle Avoidance Mower For Trunk Orchards

With the increasing planting area of forest and fruit industry in China,mechanized management of orchard has become a mainstream management mode.The removal of weeds in orchards is an important part of orchard management.At present,orchard mowing can not meet the needs of simultaneous removal of weeds between rows and plants.Weed growers between plants need to carry out manual secondary cutting or use chemical agents to remove,which not only increases labor costs and reduces work efficiency,but also pollutes the orchard environment and fruits.In order to achieve scientific and effective removal of inter-plant weeds and achieve the purpose of healthy growth of fruit trees and high quality and high yield of fruits,an inter-plant obstacle avoidance mower suitable for trunk orchards was developed,and the performance test of inter-plant obstacle avoidance mower was carried out.The main research contents are as follows:（1）Through on-the-spot investigation to understand the orchard planting mode,consult the relevant literature to summarize the existing orchard obstacle avoidance mower in China.At present,the main orchard planting characteristics in China are that the orchard row spacing is3～5m and the plant spacing is 1.5～2.5m.According to this characteristic and the relevant national standards,the overall structure design scheme of the inter-row obstacle avoidance mower is determined,and the transmission system and the specific technical parameters of the machine are designed.（2）Design and finite element simulation of the key components of the machine,such as cutter,frame,obstacle avoidance rod and suspension frame.Through the selection of cutter arrangement and cutter type,it is determined that the prototype（inter-row mowing）adopts spiral arrangement,bending angle of 135°,cutting width of 35 mm,blade thickness of 10 mm,bending radius of 45mm,total length of 130 mm Y-type flail cutter.The statics and kinematics of the cutter are analyzed,and the rationality of the cutter design is verified and the conditions for not missing cutting are determined.Through the modal analysis of the frame,it is determined that the excitation source will not resonate with the frame;ANSYS19.2 Workbench was used to analyze the obstacle avoidance rod and suspension frame.The maximum equivalent stress,equivalent elastic deformation and maximum displacement deformation of the obstacle avoidance rod were179.72 MPa,9.25×10^-4and 34.418 mm,respectively.The maximum equivalent stress,equivalent elastic deformation and maximum displacement deformation of the suspension frame are 22.11MPa,1.117×10^-4mm and 0.208 mm,which verifies the rationality of the design of the obstacle avoidance rod and suspension frame.（3）The kinematics simulation analysis of the obstacle avoidance device between plants was carried out by using ADAMS software,and the main influencing factors of the working efficiency of the mower were determined.The forward speed of the mower,the compression speed of the hydraulic cylinder and the elastic coefficient of the reset spring were orthogonally tested.The results showed that the forward speed of the machine had a significant effect on the inter-plant leakage rate（P<0.01）.The compression speed of the hydraulic cylinder and the elastic coefficient of the reset spring had significant effects on the inter-plant leakage rate（P<0.05）.The regression model was analyzed by the Design-Expert 11 software optimization module,and the optimal solutions of the three test factors were obtained.When the tractor forward speed was 1.5 km/h,the hydraulic cylinder compression speed was 225 mm/s,and the elastic coefficient of the reset spring was 29 N/mm,the inter-plant leakage rate was 7.65%.（4）In order to verify the practicability and versatility of the lawn mower,the field verification test was carried out by using the optimal parameters obtained by the solution.The test results showed that when the best operating parameters were used,the tractor forward speed was 1.5km/h,the hydraulic cylinder compression speed was 225 mm/s,and the elastic coefficient of the reset spring was 29 N/mm,the average value of the orchard inter-plant leakage rate was 7.64%,and the obstacle avoidance pass rate was 100%.The lawn mower has high working efficiency and good working performance.