Design Of Missing Seedling Detection And Seedling Replenishment Control System In Transplanting Test-bed

Seedling transplanting is the main tomato planting mode in Xinjiang,most of the existing transplanting machines in China are semi-automatic machines,which need to be manually picked and thrown.Cast-missing is a problem after people work for a long time.Two reasons contribute to the phenomenon of cast-missing.The first one is the failure of the progress in seedling picking,sending and casting.On the other hand,some seedlings could not be raised in plastic trays.So when the manipulator grabs the plug seedlings,there will be an "empty" situation,resulting in the cast-missing.Some negative effects such as low land utilization and yield reduction will appear if this continues.Farmers usually find the missing positions and plant the tomato seedlings one by one,which is time-consuming and labour-intensive work.Aiming at the problem of missing seedlings in the use of transplanters,this thesis designed a control system which can realize seedling leakage detection and supplement.The main research contents and related conclusions are as follows:(1)Given the problem of cast-missing,the requirements of using are analyzed.Sensors are selected which can detect a certain area.We proposed a control plan for the controller,which can collect output signals at intervals.Such a plan can replenish seedlings synchronously after detecting the missing signal.The time of the interval acquisition signal corresponds to the different seedling casting speeds.When the sensor detects the seedling missing,the controller generates a replenishment command to the replenishment module,and the replenishment module reacts to it accordingly.When the sensor detects the seedlings normally,the replenishment module will not act.(2)According to the control planting,the stepper motor,controller,human-computer interaction module,and other parts have been chosen.Completed the I/O port allocation of the PLC according to the number of hardware,and the circuit wiring according to the hardware wiring diagram.(3)The software GX Works2 was used to design the main program of the control system and the part programs.The following steps have been completed:selected the GS2107-WTBD touch screen as the human-computer interaction interface,designed the human-computer interaction interface through the software GT Designer3,completed the software communication settings,carried out co-simulated,and debugged the simulation results.(4)The test bench was assembled and its control system was built.Carried out the test of seedling detecting and seedling casting.Through the detection test,it was found that the sensor can meet the control requirements of the system,and the position of missing seedlings had nothing to do with the detection accuracy.Taking the success rate into account,the test results of the seedling supplement show that:when the casting speed is 40 plants/min,60 plants/min and 80 plants/min respectively,the average success rate is 88.34%,93.33%and 90.00%respectively.When the seedling rate is 60 plants/min,the average success rate of replenishing is 93.33%,which is the highest result,and the success rate has nothing to do with the position of the grid.The test bench can meet the requirements of automatic seedling replenishment,such as leakage detection and seedling replenishment.The work conducted in the thesis verified the feasibility of the system.