Research On Weeding Performance Of Woodland Weeder

Aiming at the problems of the current woodland weeding machine head with complex structure,low flexibility,low weeding rate,high cutting resistance,low operating efficiency,speed mismatch and poor energy utilization during operation,this article is a variable independently developed by the project team.Using DH method,Matlab simulation,LS-DYNA simulation and other means to study the relationship between the motion parameters such as the speed,travel speed,and blade angle of the tool and the weeding rate and cutting force.According to its influence law,the optimal combination of motion parameters is optimized.The specific work is as follows:(1)According to the requirements of the woodland operating environment and based on the principle of dynamic balance,the flailing blades are distributed using a symmetrical double spiral arrangement to design a flaring blade type weeding head;in order to obtain a better weeding effect,a T-shaped flailing blade is used.Through the establishment of the blade cutting weed mechanical model,the corresponding mathematical function is obtained,and the average cutting force is calculated by this function.For further analysis,the flail knife is regarded as a periodic motion around the pin axis,and the corresponding undamped simple harmonic forced The vibration equation is used to obtain the parameters that affect the deflection angle.According to the working principle and kinematic characteristics of the machine tool,based on the D-H method,a kinematic model of the flail is established,and the trajectory function of the flail is solved.Based on the kinematics model,the XY,YZ,XZ surface speed matching mathematical function is established,and the relationship between the missing cut area of the three planes and each parameter is obtained by this,and the core parameters are summarized as the travel speed,the rotation speed,and the tool edge angle.(2)A weed cutting model is established based on LS-dyna simulation software,and the force changes during the cutting process are analyzed based on this.The BBD second-order response surface method was used to carry out the simulation experiment to analyze the compound influence of multiple factors on the cutting force.Then,the cutting force prediction function model was obtained to predict the cutting force of the machine in the field,and the fitting curve was used to prove the accuracy of the prediction function.The results show that the cutting force first increases and then decreases,and is the largest when the contact area between the flail knife and weeds is the largest.The single factor test results show that the cutting force first decreases and then increases with the increase of the speed of the flinger,increases with the increase of the blade angle of the cutter,and decreases with the increase of the luffing speed.Multi-factor analysis shows that the interaction between luffing speed and cutter blade angle has the greatest impact on cutting force.The optimal combination is travel speed 0.2m/s,rotation speed 3000r/min,cutter blade angle 15°,and cutting force 16.7N.(3)Through the field test,the BBD second-order corresponding surface method was also established to carry out the field test,and the prediction function of the weeding rate and the actual cutting force was established.The results showed that the single factor’s influence on the weeding rate was sorted by rotation speed,cutter edge angle,and travel from large to small.Speed,in descending order of the significant degree of weeding rate by the interaction of two factors:travel speed and rotation speed,travel speed and cutter blade angle,rotation speed and cutter blade angle;single factor and multi-factor interaction influence on cutting force The same as the simulation results,the experimental data is basically consistent with the theoretical prediction based on the experimental results,and the error of the optimal combined cutting force is less than 10%.