Development And Experiment Of Auto-follow Row Weeding Machine For Paddy Fields

Rice is the staple food for more than 70%of the population in China.Weed damage is an important reason for the decrease of grain crop yield.To prevent and control weeds,effective weeding during the time of intertillage period is a crucial part of rice production.Eco-friendly mechanical weeding machines have begun to be promoted and promoted.Paddy field weeding machine is a typical mechanical weeding equipment,but the operation efficiency and effect of weeding are affected by the accuracy of intra-row weeding-end and follow row accuracy of equipment,and its performance needs to be improved urgently.In view of the complex environment of paddy fields and inspired by the existing research,this paper designs an auto-follow row weeding machine for paddy fields,including inter-row weeding roller,intra-row multi-finger weeding end,profiling mechanism,and transverse auto-follow row system.The main research contents are as follows:（1）Optimized and design of inter-row weeding roller and intra-row multi-finger weeding-end suitable for paddy field environment and expounded the working principle of the two weed ends.The motion characteristics of the multi-finger weeding-end are analyzed,and its motion characteristic equation is established.Using MATLAB software to draw its trajectory,analyze the factors affecting the trajectory and the number of fingers of the multi-finger weeding-end is determined to be 8.The constitutive model of paddy soil was constructed by EDEM discrete element simulation software,and the paddy field-multi-finger weeding-end interaction simulation was carried out.Four parameters of forward speed,in-soil depth,tilt angle and finger bending angle of steel finger were selected for orthogonal test analysis.The optimal parameter combination of finger weeding end is forward speed 1 m?s^-1,in-soil depth 40 mm,tilt angle 30°,and finger bending angle 60°.（2）The hydraulic drive transverse auto-follow row system is designed,and the working principle of the transverse auto-follow row system is expounded.The transverse auto-follow row mechanism including stator and mover driven by double acting hydraulic cylinder is designed and its static analysis is carried out to verify the correctness of the mechanism design.The hydraulic system with accumulator auxiliary energy supply is designed,and the hydraulic circuit is simulated by AMEsim software to verify its correctness.The simulation model of hydraulic-PID control system is established,and the PID parameters are adjusted.When K_p=2.508,K_i=0.08,K_d=0.0255,the best hydraulic cylinder action response curve is obtained.The hydraulic-PID control system is simulated by simulating the actual working conditions.The actual working conditions are simulated and the PID parameters are further fine-tuned.Finally,the tracking test of transverse auto-follow row system is carried out.The test results show that the average tracking response deviation is 2.32 mm,and the maximum tracking response deviation is 5.22 mm.It verifies the feasibility of the transverse auto-follow row system designed in this paper.（3）The model of the weeding machine was established,and the prototype was trial-produced,including the transverse auto-follow row mechanism and the weeding monomer composed of the profiling mechanism,weeding roller and multi-finger weeding-end.The performance test of the assembled weeding monomer was carried out in the soil trough test bench.The experimental results show that when the operating forward speed is about 0.5 m?s^-1,the average weeding rate of the inter and intra row is86.67%and 75.47%respectively.The average seedling injury rate was 4.3%,which verified the feasibility of the weeding roller and multi-finger weeding-end.