Design And Optimization Technique Research For Rice Transplanter High-speed Transplanting Mechanism With Special Shape Planetary Gear Train

Transplanting mechanism is a corn part for rice transplanter,it has a direct influence on planting quality,reliability,and working performance,etc.In this paper,aim at the core technology and difficult problems in the mechanism design and the parameter optimization technology of the high-speed transplanting mechanism with planetary gear train,a design theory and parameter optimization technology for transplanting mechanism with special shape planetary gear train was researched.The topology structure of the high-speed transplanting mechanism was analyzed based on the Yan's mechanism creative design methods,the design requirements and constraint conditions were proposed by using this creative strategy.Aim at the problem that the damaged seedling ratio was increased with increasing the speed of the transplanting mechanism,a three planting bars of high-speed transplanting mechanism with a variable speed rotation was proposed by using the generalization and number synthesis method,it's kinematic model was also built,reduced the taking seedling velocity of the transplanting mechanism by 33.3%under the conditions of similar operating condition.The variable speed rotation of transplanting mechanism and the planting bar quantity impacted on the transplanting parameters and performance index such as the static and dynamic trajectory of planting hoe,the row spacing of plants,the taking planting velocity,the transplanting hole length,and the pushing planting angle,etc.was studied.The two type of the design and kinematic analysis model for the high-speed transplanting mechanism with elliptic planetary gear train were built according to the planting hoe whether or not passed a given constraint coordinate point.A motion interference checking analytical method which used two adjacent planting hoes and the mostly possible interference point for planting hoe was proposed,and building a human-computer interactive platform of kinematic analysis and motion interference for high-speed transplanting mechanism.A parameter optimization method by combining genetic algorithm and virtual response surface regression for high-speed transplanting mechanism was proposed,an optimal parameter combination which meet the requirement in solving precision was direct acquired by solving the regression mathematical model between the optimization objectives with the parameters of the high-speed transplanting mechanism.Contrasted the value between optimization solution with theoretical calculation,the error of the trajectory height of the planting hoe and the pushing seedling angle was less than 0.3%,the error of the transplanting hole length was less than 4.5%.In the design method which reverse design the transplanting mechanism based on a given planting hoe static trajectory,using the cubic non-uniform B-spline curve to describe the static trajectory of the planting hoe,a uniqueness solution problem in solving the corner relationship between the planet gear with the sun gear by using a modified Newton-Simpson iteration calculation method.A transmission ratio relation model which only contains the radius vector of the sun gear was built;the transmission ratio distribution problem of special shaped gear planetary gear train was solved by using an iteration translation solving arithmetic.The tooth profile design method of special shape gear was introduced,and a 3D digitalization model of the three planting bars was built.The reverse design method correctness was verified by using virtual prototype technology and high-speed photography to contrastive analysis the motion trail and kinematic parameter of a three planting bars of high-speed transplanting mechanism with special shaped gear planetary gear train.Realizing parameterization for the virtual prototype simulation model of the transplanting mechanism with special shape gear by using spline function to dive the planting bar and the rotation box instead of the special shape gear transmission relationship,it solved the problem that the model reusing ratio was low and the modeling process was complex by using the contract analysis method in the special shape gear transmission model.Contact stress of the special shape gear was analyzed by using transient dynamics finite element simulation method,the comparison result between the theoretical calculations with the simulation result showed that the finite element method was validity.A transplanting mechanism test platform was used to verify these parameters which solved based on the virtual regression model such as the trajectory height of the planting hoe,the transplanting hole length and the pushing seedling angle,etc.the test result show that the parameter optimization method was very correct.A planting quality contrast test was done among the variable speed three planting bars transplanting mechanism with the contrast common transplanting mechanism,and also an influence relation test between the transplanting mechanism working parameters of the three planting bars of variable speed and special shape gears with the field transplanting quality was tested by using orthogonal experimental design method.The test result show that the revolving speed of the transplanting mechanism has a maximum effect on the damaged seedling ratio,reducing the revolving speed of the transplanting mechanism could significant lower the damaged seedling ration and also promoting seedling tillering and increasing the yield of riceo?The predicted yield result indicated that the average yield and the number of productive ear of the three planting bars of high-speed transplanting mechanism respectively increased by 4.63%and 10.37%over the two planting bars of high-speed transplanting mechanism.