Design Of Seedling Separation By Reciprocating Movement Of Seedling Cups With Full-automatic Plug Seedling Transplanters

According to statistics,more than half varieties of vegetables are planted by the way of transplanting seedlings in China.The research on semi-automatic and fully automatic transplanter in China is mainly focused on the transplanting mechanism and the planting device,rotary cup(seedling cup)is widely used in the seeding-dividing machine,the mechanical structure,the power transmission system and the transmission torque are large.The seedling separating device is a connecting link between the preceding and the following transplanting machines,the structure of seeding-dividing machine directly determines the speed of seedling and the speed of planting.Therefore,it is significant to study a kind of seeding-dividing machine of reciprocating seedling cup(cup)which has the advantages of simple structure,quick response and easydriving.The kind of seeding-dividing machine has broad market prospects.The main work of this paper is divided into the following sections:Firstly,according to the operating parameters and agronomic requirements of vegetable transplanting and the present situation of the research on the seedling transplanter in China,we need to design a kind of linear reciprocating device.The design requirements of the whole plant are analyzed,and the specific path of the seedling is planned;According to the requirements of the control system,the software and hardware of the control part is designed according to the seeding path.Secondly,based on the rack-pinion drive,the design concept of the seedling movement is designed which has reciprocating motions on linear guide rail.According to this idea,the mechanical structure of the main parts is designed.The transplanting device,seedling dropping device and seedling cups are desgined in detail,the stepping motor in the transplanting device and cylinders in seedling dropping device are calculated.Then,design and performance simulation of three dimensional virtual prototype for seedling separating device is completed.Using the Solid Works 3D software,the three-dimensional design of the seedling device was carried out from top to bottom,and the components of the device are designed in detail and the dimensions are optimized.After simplifying the 3D model,we import it into the ADAMS simulation software.The software is used to carry out the virtual modeling and kinematics simulation of the linear transmission,and analyze the dynamic characteristics of the gear.Then,the control system of mobile seedling cup type seedling separating device is designed.The hardware part of the system is composed of the programmable controller、the PLC、position sensors、cylinders and the step motor.It also needs to realize the function of fixed point seedling,fixed point seedling-dropping and quick seedling-cutting;The software part uses XCPPro software which belongs to the company called XinJie;The touch screen is designed,which can be used to change the parameters in the man-machine interface;The flow chart of the control is designed,and the control steps are optimized to reduce the instructionFinally,the positioning accuracy test of the linear transmission device and the success rate test of the seedling device were carried out on the developed seedling device.Through the experiment,it is found that the positioning accuracy of the linear transmission device decreases gradually with the increase of the speed of the seedling,especially when the motor pulse frequency is more than 20000 Hz,the motor will be out of step,and the accuracy will decline rapidly.When the pulse frequency is more than 20000 Hz,the positioning accuracy decreases rapidly.After setting the different pulse frequency of the motor,the numerical range of the error is kept between 0.2mm~0.8mm,which meets the requirements of the seedling positioning.The success rate of split seedling was tested,and the success rate of seedling decreased gradually with the increase of seedling rate,and the success rate of 180 working cycle /min seedlings is 91.11%.This shows that the structure of the mechanical parts meet the requirements of seedling movement,the optimization of the control system can make the positioning accuracy meet the requirements,and finally achieve the purpose of automatic seedling separation.