Research On The Grabing-feeding System Of Automatic Transplanter

The automatic transplanter not only has low production cost,but also can prolong the growth cycle of crops and improve the yield of crops.It has a broad application prospect.However,the development of automatic transplanter is limited due to the disadvantages of low working efficiency,low success rate and high Seedling injury rate of the grabing-feeding system.In view of the shortcomings of the system,this paper proposes a symmetrical single pendulum system,and studies the efficiency and stability of the system.The specific research content includes the following aspects:?1?Based on the analysis of the working principle of the system,the paper puts forward the symmetrical single pendulum feeding track and the whole system.Based on the mechanical analysis,the mechanism of the system is selected,and the whole three-dimensional model of the system is established by using UG.?2?Through the analysis of pneumatic principle,the mathematical model of cylinder motion is established,and the model is built and simulated with Simulink.The influence of cylinder diameter,working air pressure and initial volume of intake cavity on the motion law of cylinder is analyzed.The results show that the response speed of cylinder increases with the increase of cylinder diameter and working pressure,and decreases with the increase of initial volume.According to the motion law of the cylinder,the cylinder diameter is 25 mm and the working pressure is 0.4-0.6 MPa.The measures to reduce the connection length of the gas pipe and increase the response speed of the cylinder are put forward.?3?In order to meet the requirements of the control system,the key hardware is selected.The electrical principle design is completed by analyzing the executive components of the system and determining the input and output address assignment of PLC.According to the movement law of the cylinder,the working efficiency of the system is determined to be 90 plants/min,and the control strategy of the cylinder is designed.The simulation experiments of symmetrical pendulum system and asymmetric system are carried out by using UG.The effects of the two systems on the injury rate,system stability and cylinder life are analyzed when the working efficiency is 90 plants/min.The results show that compared with the asymmetric system,the symmetrical single pendulum system has smaller injury rate,better system stability and longer cylinder life.The maximum angular displacement deviation of the manipulator in symmetric system is only 0.003 rad,which is less than 0.008 rad in asymmetric system.When the angular displacement of the frame is large,the force of the manipulator in symmetric system is more stable than that in asymmetric system.In the symmetrical system,all parameters of the cylinder are within the reasonable value,and the service life is longer.The speed and the maximum mutation force of the symmetrical manipulator were 0.29 m/s and 1.2 N,respectively,which were significantly lower than those of the asymmetrical manipulator,0.6 m/s and 2.2 N.?4?According to the size of virtual prototype,the test platform was manufactured and assembled on the semi-automatic transplanter.According to the relevant data,the multi factor orthogonal test and system reliability test were carried out with the seedling species z,matrix moisture content w,seedling depth h and working pressure p as the test parameters,and the success rate S₁ and plant integrity rate S₂ as the evaluation indexes.The results showed that the highest success rate and integrity rate of seedling were 98.61%and 97.22%respectively under different levels of factors.At this time,pepper was the type of seedling,the moisture content was 35%,the depth of taking seedling was 40 mm,and the working pressure was 0.6 MPa.Under the worst operating parameters,the success rate is 86.11%,which shows that the system can adapt to different working conditions and has good universality.In the reliability test,the average success rate was 95.46%,and the standard deviation was 2.06.Compared with the success rate of the same parameter combination in the orthogonal test,the deviation was 3.30%,indicating that the system has high reliability.To sum up,the system can meet the design requirements under the efficiency of 90 plants/min.