Simulation And Optimization Of Kinematic Parameters And Structural Parameters Of Ditching Component In Orchard

Orchard ditching is an important process of applying granular fertilizer in orchard,and it is an important means to improve fruit quality and yield.The planting area of fruit trees in hilly and mountainous areas of our country is increasing year by year,but the ditch of fruit trees in hilly and mountainous areas is basically operated by manpower with large labor intensity and low production efficiency and easy to delay the farming season,a need to adapt to hilly and mountainous areas of our country orchard ditching and fertilizing machine.The cutting power consumption is very large in the process of ditching and fertilizing machine,therefore taking the ditching component of the selfdeveloped orchard vertical-single-shaft-ditching-fertilizing machine urgently needed in China’s hilly and mountainous areas as the research object,its structural parameters and motion parameters are optimized to improve the operation efficiency and the quality of ditching and reduce the cutting power consumption.The cutter’s motion parameters are mainly the forward speed(v)and the angular velocity(ω),and structural parameters are the blade bending angle(ε).Therefore,this paper mainly focus on the tool forward speed and angular velocity,and the blade bending angle is optimized to establish the mathematical model of the rotary ditching cutter cutting power consumption and cutter forward speed,angular velocity and blade bending angle to achieve the optimization of rotary ditching cutter while providing the theoretical basis for the optimal design of other tillage equipment.The main contents of the thesis include:According to the specific parameters of the rotary ditching cutter,the 3D solid model of the rotary ditching tool is established by using the 3D modeling software Creo.The process of cutting the soil by rotary ditching cutter is analyzed,and the kinematics and kinetic analysis of the process are analyzed to determine the angle of the blade bending angle from 8 ° to 22 °.In order to meet the normal lifting of the soil during the cutting process,the critical angular velocity of the cutter is 14.94rad/s,and the maximum angular velocity is 31.05rad/s.The numerical simulation method is used to simulate the cutting process of the rotary ditching cutter,in order to avoid the large deformation of the soil during the cutting process,and the soil particle scattering situation can be see so that the model of soil is cut by cutter is more in line with the actual situation.This paper is based on the SPH method to simulate the rotary ditching cutter cutting soil process.In order to meet the requirements of agronomy,the simulation uses cutter forward speed is 0.45m/s,angular velocity is 28rad/s,the blade bending angle is 22°.With the cutter gradually cut into the soil,cutting power consumption gradually increased,when the cutter all enter into the soil cutting power consumption stabilized at 1.919 kW.Through the self-developed,small speed-torque measurement platform to test the rotary ditching cutter cutting soil cutting power consumption,select 20 sets of data to obtain the average value of the average power consumption is 2.07 kW,the error is 7.3%,within the allowable range,indicating that the numerical simulation results and test results are similar to the actual situation.The single-factor virtual test study and quadratic regression orthogonal test are carried out to carry out the research of the rotary ditching cutter.Cutting power consumption and the regression equation between the three are established,after verification of the regression equation is significant,and the equation is fit well,the objective function is provided for the optimization of the rotary ditching cutter.In order to optimize the forward speed,angular velocity and blade bending angle of the rotary ditching cutter,the regression equation is used as the objective function,the productivity,matching power,critical angular velocity,tailored critical speed and blade structure parameters are used as constraint conditions,fmincon function is called in Matlab,with the minimum rotary ditching the cutting power consumption as the goal of carrying out the optimization,the optimal solution are obtained of v、ω、ε,when v=0.222m/s,ω=24rad/s,ε=0.349 rad,namely forward speed is 0.799km/h,speed is 230r/min,blade bending angle is 20°,the soil cutting power consumption for a minimum of 1.758 kW.The simulation results show that the soil power consumption of the ditching cutter is 1.727 kW,and the power consumption is reduced by 10% compared with the previous optimization,so the optimization effect is remarkable.Through the small speed-torque measurement platform to test cutting power consumption of the optimized rotary ditching cutter,select the 20 sets of data to obtain the average cutting power consumption is 1.85 kW,the error is 6.6% compared with the simulation results,within the allowable range of error,so the optimization results are authenticity.