| In this paper,a series and parallel picking manipulator is developed,the picking manipulator includes a series boom and a parallel small arm,when the manipulator performs the picking work,the tandem boom preferentially reaches the initial picking target position,and the parallel small arm is accurately positioned to reach the picking target position,and the series-parallel manipulator works together to achieve tomato fruit picking in the working space.Experimental studies have proved that the robotic arm can realize the function of picking and positioning and smoothly reaching the target spatial position.This paper aims to study the path planning and optimization of picking manipulator,so firstly,the kinematics of the picking manipulator are analyzed,and the kinematic equation is obtained by analyzing the tandem mechanism and parallel mechanism of the picking manipulator,which lays the foundation for the trajectory planning of the manipulator.The schematic diagram of the parallel part of the robotic arm and the overall part of the workspace was simulated by using MATLAB software.After that,the dynamic analysis of the picking robot arm was carried out to obtain the magnitude of the torque it could withstand.According to the results of kinematic analysis,the path planning and trajectory optimization of the manipulator are carried out,and the path is planned and designed by improving the RRT algorithm,and an initial path from the initial point to the target point is obtained,and the path is listed The data of each node,and the kinematic inverse solution of each node data to obtain the rotation angle of each joint motor of the manipulator,lays the foundation for trajectory optimization;in trajectory optimization,by analyzing the characteristics and shortcomings of various polynomial interpolation methods,finally The five-time B-spline curve interpolation method is used to optimize the trajectory,and the smooth motor rotation angle curve is obtained by performing five-time B-spline interpolation on the rotation angle of each joint motor,and the kinematics positive solution is performed on each joint angle curve Finally,the optimal curve of the picking manipulator from the initial point to the target point is obtained.The obtained curve is relatively smooth and has no protrusion,which can meet the stable performance requirements of the picking manipulator.Finally,the overall control system of the manipulator is carried out.For design,three kinds of system control schemes were preselected in this paper.By comparing their control stability,the combination of Googo motion control card and PC was finally selected as the hardware control system to control the movement of the manipulator.The software was written through the simulink module of MATLAB.The designed picking robot arm was made into a prototype,and the point-to-point motion test and path error test were carried out on tomatoes to verify the picking speed and stability to the target point,and 10 groups were tested respectively.The test results of point-to-point movement show that the series mechanism and the parallel mechanism move relatively smoothly when the manipulator moves to a point in space,and the distance between the moving platform and the target fruit deviates from the theoretical value,and the deviation value is less than the design margin.Meet the design requirements.The error test is carried out on the path of the picking manipulator,and the path deviation is tested.10 groups of experiments are carried out respectively,and the average value is taken for analysis.The error test results show that there is a positioning deviation of the robotic arm during the path movement.Since the space enclosed by the gripper will be larger than the space occupied by the fruit,the deviation of the picking path from the starting position to the end position can be determined by the space enclosed by the gripper.Adjustment,the error value is within the controllable range,so the picking robot arm can successfully pick the fruit. |
