| The large-scale planting of peppers and tomatoes in Xinjiang was inseparable from the seedling transplanting technology.Both manual transplanting and semi-automatic transplanting restrict the development of the industry,and the development of fully automatic transplanting equipment needs to be solved urgently.When the semi-automatic transplanting machine is mature,the automatic seedling removal device has become the core of the research.The automatic seedling removal device will directly determine the efficiency of the seedling transplanting operation and is the key to upgrading from semi-automatic to automatic.After analyzed the research status of automatic seedling removal devices at home and abroad,combined with Xinjiang pepper and tomato planting modes,this paper designs and studies a picking seedling robot arm for plug seedling transplanter.The research contents mainly include:(1)The structural design and joint size parameter optimization of the picking seedling robot arm.First,the seedling tray specifications and seedling morphological parameters were analyzed,and the seedling taking and feeding system was designed.According to the requirements of the entire row of seedling picking operations,the picking seedling robot arm and the picking whole row of seedlings end-effector were designed,its working principle was analyzed.From the inclusive relationship between the working space of the picking seedling robot arm and the target working space,the constraint conditions for the optimization of the joint size parameters of the picking seedling robot arm are obtained.At the same time,the parameter optimization target is established,the genetic algorithm is used to solve the multi-objective parameter optimization function to complete the structure design of the picking seedling robot arm.(2)Kinematics research and simulation of the picking seedling robot arm.The DH parameter method is used to establish the linkage coordinate system of the picking seedling robot arm,the transformation matrix between the kinematic joints and the kinematic equation of the picking seedling robot arm are obtained,and the algebraic method is used to obtain the inverse kinematics solution of the picking seedling robot arm.After the seedling removal operation process of the picking seedling robot arm,the quintic polynomial interpolation method is used to plan the movement trajectory of the picking seedling robot arm to obtain the trajectory function.Use Solid Works to establish a three-dimensional model of the picking seedling robot arm,analyze the properties of the model,and provide a reference for prototype construction.Use Adams to establish a virtual prototype model of the picking seedling robot arm for kinematics simulation.The simulation results show that the picking seedling robot arm has good motion characteristics,which verifies the correctness of kinematics analysis and the rationality of trajectory planning.(3)The design of the control system of the picking seedling robot arm and the performance test of the prototype taking the seedlings.Through the analysis of the control requirements of the picking seedling robot arm,the single-chip microcomputer is selected as the core controller of the control system.The hardware and circuit of the system are selected and designed,and the motion control process of the picking seedling robot arm is analyzed.On the basis of completing the structural design and control system design of the picking seedling robot arm,a test prototype of the picking seedling robot arm was built,and the seedling clamping angle and versatility of the picking seedling robot arm were tested.The test results showed that the seedling clamping angle was equal to the inclination angle of the inner wall of the hole.The effect is best when the seedlings are picked at the time.The effective seedling rate for 72-hole and128-hole plugs reaches 61 plants/min and 79 plants/min,which meets the design requirements of high-speed seedling collection for the whole row and a certain generality. |
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