Optimization Design And Experiment Research On Two-degree-of Freedom Five-bar Flower Transplanting Mechanism

In recent years,the flower industry has developed rapidly.In 2018,the national flower planting area reached 1.63 million hectares,with an output value of 261.4 billion yuan.At present,the flower industry is still dominated by artificial planting,with high labor intensity and poor economic returns.With the continuous development of the flower industry,the demand for flower transplanting equipment is growing.However,at present,the research on automatic flower transplanting equipment in China is still not perfect.When working,it is necessary to take the planting mechanism,the basin sending mechanism and the feeding mechanism to complete the flower transplanting.And the intermittent movement of the feeding mechanism causes difficulty in the movement coordination between the various mechanisms of the transplanting equipment.The equipment is less automated and less efficient.And foreign flower transplanting mechanism can achieve automatic flower transplanting,and the production efficiency is high,but the mechanism is large,expensive,and difficult to maintain,so it’s not suitable for the flower transplanting industry in China.Therefore,aiming at the characteristics of low,small and scattered flower transplanting industry in China,it is of great significance to design a flower transplanting mechanism with a simple movement,a high degree of automation,simple structure and strong versatility.The mechanism of less freedom has the advantages of simple structure,easy control,low cost,and can achieve any trajectory in the working space.At present,less-degree-of-freedom mechanism is widely used in stamping machinery,parallel robots,etc.The mechanism proposed in the paper chooses five-bar mechanism as the carrier,combines the two-degree-of-freedom five-bar mechanism with flower transplanting,and this paper completes the analysis of flower transplanting operation,optimization of mechanism parameters,structural design of transplanting mechanism,design of kinematics and control system design,etc.A two-degree-of-freedom five-bar flower transplanting mechanism capable of "seedling collecting in different points and planting in fixed point" was proposed and applied to flower transplanting.The main research contents of the thesis are listed as follows:(1)The motion characteristics of the five-bar mechanism are analyzed,and the constraints were provided for the optimization design of the mechanism.According to the requirements of the flower agronomy,the two trajectories of picking seedling were compared,and a trajectory with a buckle was selected as the seedling trajectory.Based on this,a transplanting trajectory of "seedling collecting in different points and planting in fixed point" was designed.Points control the trajectory shape were selected in AutoCAD and the initial trajectory was obtained by the spline curve.(2)Based on the selected trajectory shape control points and the reverse principle of the 2-R rod group,the mathematical model of the optimization design of the five-bar mechanism was established,and the optimization software of the mechanism was developed.The configuration parameters of the five-bar mechanism and the motion parameters of the connecting 2-R rods were obtained based on the genetic algorithm optimization;(3)The structural design and parts assembly of the two-degree-of-freedom five-bar flower transplanting mechanism were completed by SolidWorks.The three-dimensional model was imported into ADAMS to complete the motion simulation of the virtual prototype of the mechanism,and the simulation trajectory was obtained and compared with the theoretical design trajectory.The feasibility of the structural design of the mechanism and the correctness of the assembly were verified,and the prototype processing was carried out.(4)The design of the control system was completed by using the obtained angular displacement function of two linkages.Then the DDA linear interpolation algorithm is used to fit the motion functions of the two linkages,and the synchronous linkage control of the two servo motors was achieved.The electromagnet was controlled by the single-chip pulse signal and the optocoupler relay.(5)The test rig was set up and the mechanism was debugged.The trajectory of the execution point of the transplanting arm was obtained by the high-speed photographic analysis software.The actual trajectory was compared with the simulated trajectory to verify the correctness of the control system design.Finally,the transplant experiment was completed.The transplanting trajectory of"seedling collecting in different points and planting in fixed point" was realized.