The Optimization Design Of Structure And Control System Of Small Automatic Wireless Remote Control Vegetable Plug Seedling Transplanter

China is a large agricultural country,and also the largest vegetable production and consumption country in the world.The total planting area of domestic vegetables is second only to grain crops.However,at present,the mechanical products of vegetable transplanting in our country are all semi-automatic transplanters with artificial seeding.The market of full-automatic vegetable transplanters has not yet appeared,and they are mainly in the research stage.The transplanter used for the open field vegetable planting in the facility is the field transplanter,which is too large in size,and the exhaust gas generated by the use of the internal combustion engine is polluted greatly.However,the smallscale vegetable transplanter suitable for the open field planting in the small and medium-sized greenhouse vegetable greenhouse has not yet appeared.Therefore,it is of great significance to develop a fully automatic vegetable transplanter with small size,electric drive and suitable for use in a small greenhouse.Based on the investment of the research group,the structure optimization design and control system improvement design of the existing small automatic vegetable transplanter are carried out in this paper.The main research contents are as follows:(1)The structure optimization design of the seedling taking mechanism of the transplanter was carried out.Due to the unreasonable design of the transplanter’s seedling taking mechanism,there are serious vibration problems,resulting in low transplanting frequency and unreliable seedling taking and throwing.Therefore,this paper mainly carries on the structural optimization design from three aspects: first,to improve the rigidity and strength of the mechanism;second,to increase the vibration absorption device at the end of the cylinder operation;third,to use the flexible variable distance mechanism of the brake line to reduce the weight of the center of the mechanism.After the design of the new seedling taking mechanism,the dynamic simulation analysis is carried out by using A dams software,and the selection of the variable distance cylinder is completed.(2)According to the overall structure and working principle of the small vegetable transplanter,the main control requirements for transplanting parts are put forward.Based on the analysis of the movement of the feeding part,according to the requirements of the seedling feeding accuracy,the hardware selection calculation of the sensor,the stepping motor and the electric cylinder is carried out.There is a certain distance interval between the two trays when manually releasing the tray.Therefore,there are two feeding frequencies for the lon gitudinal feed of the tray: fast feeding and slow feeding,so as to avoid the interval when changing the tray affecting the continuous work of the transplanter.In order to ensure the accuracy of seedling supply,the accumulated error of pulse number in a cycle of stepping motor is analyzed and calculated.The analysis results show that the accumulated error produced by a tray will not affect the accuracy of seedling supply.(3)The coordinated movement of transplanter was studied.This paper mainly studies the coordination between the seedling taking part and the feeding part,and the coordination between the seedling taking part and the seedling separating part.This paper analyzes the process of seedlings taking and throwing,and setting the trigger time of seedlings taking and throwing.In order to improve the efficiency of transplanting and save the cycle time of each part,the falling time of the bowl seedling after the seedling claw is calculated to be 0.1778 s,and the waiting time of the seedling parts is obtained;By calculating and analyzing the falling time of the bowl seedling after the opening of the seedling cup,it is concluded that the bowl seedling can fall off completely only when the bowl seedling is kept for at least 0.237 s after the opening of the seedling cup.(4)The improved control algorithm of the motor is studied.In order to reduce the impact vibration of the seedling separating mechanism caused by the sudden change of the speed of the stepping motor at the start and stop time,an S-curve control algorithm of the stepping motor is proposed.By changing the acceleration change of the motor at the start and stop time,the running speed of the motor is stable,the vibration impact of the seedling separating mechanism is reduced,and the success rate of seedling separating is improved.(5)Prototype test and analysis.After the completion of the structural optimization and control system design of the prototype,the prototype is debugged to verify the reliability of its mechanical structure and the rationality of the control system design.Through the vibration performance test,the vibration damping effect of the new seedling taking mechanism and the vibration damping effect of the speed control method of the stepping motor are verified.The comparison between the test results and the data before the improvement show that the vibration amplitude of the new seedling taking mechanism is up to 4.905,which is 2.001 lower than the original prototype,with obvious vibration damping effect.The running speed of the stepping motor is stable without large impact vibration;The results show that the transplanter could adapt to different varieties of potted seedlings.When the planting frequency was 60 plants / min / row,the success rate of seedling taking and throwing of pepper seedlings was 95.83%,a nd that of cucumber seedlings was 97.22%;The results of simulated field experiment shows that when the planting frequency was 60 plants / min / row,the success rate of pepper seedling was 95.8%,and that of cucumber seedling was 96.5%,which met the requirements of open field planting of vegetables in small and medium-sized greenhouse.