| The main mode of growing tomato seedlings in Xinjiang is the use of transplanters.The fully automatic transplanter has a higher transplanting efficiency and quality than the semi-automatic transplanter with the addition of automatic seedling picking and feeding device.In this thesis,we designed a flip-type automatic seedling picking and feeding device,including a seedling picking and feeding robot,a mechanical arm flip mechanism and a mechanical arm pitch mechanism,to address the problems of low success rate of seedling picking and feeding and injury of seedlings.The structure of the seedling picking and feeding robot and the flipping robot arm are optimized through mechanism simulation analysis;the trajectory of the seedling picking and feeding robot is optimized through kinematic simulation;the pitch change of the seedling picking and feeding robot is analyzed to design the robot arm pitch mechanism.Design the seedling picking and feeding control system to control the robot to complete the seedling picking and feeding action.Build the prototype of automatic seedling picking and delivery device and carry out seedling picking and delivery performance test.The main research contents of this thesis are as follows:1.Transplanting cavity tray seedling parameters measurement and seedling picking and delivery scheme design: measuring tomato seedling plant morphology,substrate three-dimensional size,seedling tray parameters and other data,and determine the robot seedling needle,seedling claw size parameters accordingly.Based on the demand of seedling picking and seedling delivery,the design of seedling picking and delivery robot,flipping robot arm and robot arm variable distance mechanism are determined,and the coordination of each mechanism of the automatic seedling picking and delivery device is determined.2.Key mechanism design: The key mechanisms of automatic seedling picking and delivery device include seedling picking and delivery robot,mechanical arm flipping mechanism and mechanical arm pitching mechanism.The design of the seedling feeding robot includes seedling needle,shovel-shaped seedling claw and seedling needle retracting mechanism;the design of the mechanical arm turning mechanism includes turning slide and turning mechanical arm;the design of the mechanical arm pitch mechanism includes seedling dividing plate,positioning slots and pitch slider.After the seedling pick-up and delivery robot picks up the seedling of the cavity tray,it is transported by the robot arm flip mechanism,meanwhile,the robot arm pitch mechanism realizes the whole row of seedling of the cavity tray to change the pitch,and each mechanism cooperates with each other to complete the seedling pick-up and delivery process.3.Mechanism simulation analysis: Static analysis of the state of the seedling needle and shovel-shaped seedling claw when clamping the substrate,according to the stress and deformation,optimize the structural parameters of the robotic seedling needle and shovel-shaped seedling claw.The kinematic simulation was carried out in Adams to obtain the theoretical trajectory of the robot by setting different lengths of the arm.According to the requirements of the seedling picking and feeding position,analyze the motion trajectory and determine the optimal flip robot arm length parameters.4.Control system design: According to the process of seedling pick-up and delivery,the sequence of movement of each mechanism in the device is determined,and the control scheme is determined.PLC is used as the main control element to build the control system,the actuator hardware is selected according to the drive mode of each mechanism,the sensor is selected to obtain the robot position information,and the seedling picking and feeding control program is written on the GXworks2 software according to the control flow chart,and the PLC is written for the control system operation test.5.Bench test: The test prototype is processed according to the optimized 3D model of the mechanism,and the actual trajectory of the seedling picking and feeding robot is obtained by means of high-speed photography tracing,and the rationality of the theoretical trajectory is verified by comparing the theoretical and actual trajectories.The optimal parameters of seedling picking and delivery performance were selected by orthogonal test,seedling claw angle and seedling needle speed,and the seedling needle length of 130 mm,seedling needle angle of 30°,and seedling needle speed of 30mm/s were determined through the optimization search.The seedling picking and feeding performance of the device was verified. |
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