Design And Research Of Control System For Picking And Delivering Seedlings Of Vegetable Transplanter

Promoting automatic development of vegetable transplanting machinery can not only effectively increase the output of vegetable industry,but also liberate the labor force and improve the production efficiency.It is of great significance for keeping the supply and demand balance and promoting vigorous development of vegetable industry.The automatic degree of the vegetable transplanting machine mainly manifests in the automation of the feeding seedling system,which mainly consists of the feeder mechanism,the seedling mechanism,the sub-seedling mechanism and the corresponding control system.The key problem in automatic operation of vegetable transplanting machine is to realize the coordination and cooperation between the various institutional units of the seeding delivery system.Therefore,this paper mainly aims at the design and research of the seedling system of vegetable transplanting machine;the specific contents are as follows:(1)Not only referring to the development process of transplanting machine automation at home and abroad,but combined with the structure characteristics and the form of the existing transplanting machine,the mechanical structure and control scheme of the feeding seedling system are designed respectively.The mechanical structure of the system is mainly composed of the stepping shift mechanism,the seedling mechanism and the sub-seedling mechanism.According to the operation mode and control requirement of the proposed three parts,the power distribution of the system and the control loop design of the power actuator are completed,and the mathematical model of the control loop of the system dynamic actuator is established by theoretical deduction.(2)In order to ensure the stable and reliable operation of the feeding system and the coordination between the various agencies,corresponding control algorithm is introduced into the designed control system.The concept of Fuzzy PID is introduced by the traditional PID,and the design process and method of Fuzzy PID control are analyzed,so as to construct a Fuzzy PID controller suitable for the system.Then in the Simulink simulation environment under Matlab Platform,the system modeling and simulation test are completed,and the Fuzzy PID controller can not only realize the fast response of the system,but also obtain the high steady-state precision and the short adjusting time by simulation analysis.It proves the validity and rationality of applying Fuzzy PID control algorithm to the control system of feeding seedling.(3)According to the control requirements of each mechanism unit of the feeding seedling system,the hardware and software circuit of the system are designed by modularization method,and the fabrication and welding of the PCB board are finished.Each unit of the system takes STM32 as the core controller,and the communication mode of the CAN bus is used to realize the data transmission between the mechanism units.The corresponding sensor components and power actuators are selected to complete the data acquisition and power output during the system motion process,and the appropriate power supply equipment and pneumatic equipment are configured as the power source of the system.The software design of the system is based on the hardware circuit,and according to the hardware requirement,the flowchart of each module unit is designed,and the code is written in the Keil ?Vision4 development environment.In addition,the PC and LCD are selected as the human-computer interface when the system is debugged and operated.(4)A test platform for feeding system is set up successfully in this paper,and the performance test of the system is also completed.In our tests,72 points of Pepper are selected as the experimental materials,and the experimental materials are processed in groups.The success rate of taking out seedling,throwing seedling,dividing seedling and total success rate of the system are used as evaluation indexes of system performance.In the test process,the platform is run at the set speed,and then the indoor test of the feeding process of culturing the seedling from the disk with the planting frequency of 50 strains/min,60 strains/min and 70 strains of/min is completed.Based on the analysis of the system's laboratory test results,it is found that under the same working environment and planting rate,the fluctuation range of the system evaluation indexes is smaller and its fluctuation value is within 1.5%,thus the system runs stably.At different planting rates,the value of system evaluation index decreases with the increase of planting rate,but the fluctuation value is in the range of 2.8%,The total success rate of the system can still be maintained above 95%,and the taking out seedling rate and throwing seedling rate can still be maintained above 97%.indicating that the system can achieve rapid and accurate delivery of seedlings while holding good stability and reliability.Then,the test platform is transferred to the outdoor,thus the planting frequency of 60 strains of/min field test is finished.Results of the field test and laboratory test are compared and analyzed,it can be seen that the different operating environment has a certain impact on the system performance under the same planting rate.Although the values of various evaluation indicators of the system have changed,the fluctuation range is still within 1.4% from the overall point of view,which indicates that the feeding system still has a good stability and reliability.Therefore,the system designed in this paper can meet the design requirements and realize the stable and reliable operation in the process of seedling feeding.