Design Of Push-clip-pull Picking Seedling Mechanism On Automatic Transplanting Machine

The picking seedling mechanism is the core part of automatic transplanting machine and a sign to distinguish between automatic and semi-automatic transplanters.Automatic picking seedling mechanism with whole row actuator developed by the project group in the earlier period,which has high requirements for the quality of seedlings.When the seedlings are picked up at high speed,the seedlings with poor quality are often damaged under the adhesion force of the seedling and the plug.Only rely on actuator is it impossible to ensure a high success rate of taking seedlings and integrity rate of plug seedling.The technical study of push-clip-pull picking seedling was based on automatic picking seedling mechanism developed by the project group in the earlier period and picking seedling method of pushing seedlings out of the plug made by foreign automatic transplanter,in order to solve the problem.In view of above,main contents of this paper are as follows:(1)The shaft diameter and the spacing of shaft of the pushing seedling mechanism were preliminarily determined through measurement of the diameter of the scupper and the spacing of the scupper.The influence of pushing seedling speeds and shaft diameters on the compressive resistance of the plug seedling was studied through the experiment of compressive experiment of plug seedling,The effect of pushing seedling speed on adhesion force and shedding displacement and the relationship between adhesion force and shedding displacement were analysised through the experiment of the adhesion of vegetable plug seedling.Comprehensive consideration of all factors,the shaft diameter is 6mm,the pushing displacement is 8mm.(2)The picking seedling mechanism and pushing seedling mechanism were designed,the picking seedling mechanism include turnover mechanism and insert-draw mechanism.The pushing seedling mechanism is the key to ensure the success rate of taking seedlings and integrity rate of plug seedling,and the method of pushing plug seedling is similar to interval picking seedling.Based on the previous experimental results,the picking seedling mechanism and pushing seedling mechanism was optimized.(3)A mathematical model of the cylinder was established based on MATLAB/SIMULINK and a virtual prototype model was established based on ADAMS,and a mechanical-aerodynamic co-simulation model of the picking seedling mechanism was established to achieve a more realistic simulation of the mechanical system.The influence of the cylinder diameter D and working pressure on the displacement,speed and thrust of the cylinder piston rod,the rotating angle and angular velocity of picking seedling mechanism,contact force of the block and picking seeding frame,working chamber air pressure and exhaust chamber air pressure was discussed to select the proper working parameters of cylinder.in short,working pressure is between 0.5MPa~0.6MPa,the cylinder diameter is 32 mm.(4)The test equipment of the picking seedling mechanism and pushing seedling mechanism was manufactured to study the influence of the impact rebound of the cylinder on the precise positioning of the picking seedling actuator through experiment on the motion accuracy of picking seedling mechanism,and select the best picking seedling mode through the mode experiment of push-clip-pull picking seedling,and the best working parameters are as follows: the pushing displacement is 15 mm,the insertion depth is 35 mm,and the insertion speed is 225mm/s through the multi-factor experiment of the test device.