Design And Experiment Of Variable Distance Seedling Picking Mechanism And Control System

Tomato is a characteristic and advantageous industry in Xinjiang.In order to ensure that the same variety of tomatoes can mature in large batches during the picking period,the promotion of seedling cultivation and transplanting technology has been basically completed in planting.The development of planting industry plays a significant role.However,the transplanting operation in Xinjiang mainly relies on semi-automatic transplanting machines,which require manual delivery of seedlings and the phenomenon of damaged seedlings and missing seedlings,high labor costs,and low work efficiency,which seriously restrict the long-term development of the tomato planting industry in Xinjiang.Therefore,the automatic transplanting machine has become the key to realize the large-scale transplanting and planting in Xinjiang,and the transplanting quality,efficiency and stability of the automatic transplanting machine depend on the performance of the seedling picking mechanism.Therefore,this thesis designs a variable distance seedling picking mechanism and its control system.The main research contents are as follows:(1)Structural design of variable distance seedling picking mechanism and parameter optimization of key components.Firstly,the analysis and summary of the existing hole tray specifications,the mechanical properties of the seedling substrate and different types of seedling collection mechanisms in Xinjiang.According to the working principle,the variable distance seedling picking mechanism is designed,and the kinematic analysis is carried out on the seedling picking manipulator to establish a mathematical model,optimize the objective function and constraint conditions,use the PSO-SA algorithm to solve the optimized parameters,and then use the ADAMS to complete the kinematics simulation analysis.The simulation results show that the manipulator for picking seedlings is optimized to meet the needs of picking and throwing seedlings.(2)Design and simulation of PSO-BP fuzzy PID control strategy.Through the fuzzy PID control algorithm to control the seedling picking and throwing action of the variable distance seedling picking mechanism,the structure and working principle of the control system are determined,and the mathematical model and transfer function of the control system are established through model selection calculation and analysis modeling.Due to the problems of low stability and slow response speed in the traditional PID control strategy,PSO-BP fuzzy PID is used to adjust the parameters of the control strategy online to meet the requirements of the corresponding parameters in the control process.The simulation model is established and the control system simulation analysis is carried out.The control target is the tracking of the step signal.Through the analysis of the step response curve,it can be seen that compared with the traditional PID control strategy,the system stability of the PSO-BP fuzzy PID control strategy is better.The response speed is faster and it has good robustness.The simulation results verify the feasibility of the control system and meet the high-precision,fast and stable control requirements of the variable-distance seedling picking mechanism.(3)Control system design and test platform construction of variable distance seedling picking mechanism.According to the control requirements of the variable-distance seedling picking mechanism,the single-chip microcomputer is selected as the lower computer,and the PC is used as the upper computer to complete the system control and data processing respectively.Complete the selection of each hardware of the control system,and complete the hardware control circuit wiring diagram based on this.Complete the software design of the host computer and the lower computer,including the design of the main program,use Qt to complete the design of the interactive interface and data communication protocol of the control system,and use Keil u Vision5 to complete the design of hardware drive,data collection and exchange functions.Finally,the manufacture of the mechanism prototype and the construction of the test platform were completed.On this basis,the three-factor and three-level orthogonal test was carried out on the128-hole seedling tray.The results of the verification test show that the institution can complete the operation of picking and throwing seedlings well,and the overall performance meets the expected goals and meets the needs of actual transplanting operations.