Design And Obstacle Avoidance Research Of Grape Bagging Manipulator

Fruits need to be bagging when they grow to a certain period, because fruits bagging can effectively prevent pests and diseases, reduce pesticide residues, and improve the appearance and the quality of the fruits. However, fruits bagging mainly bases on manual operation at present,it takes a lot of time and labor. Therefore, it is an important practical significance to develop intelligent bagging robot for reducing labor intensity and improve the bagging efficiency, and important strategic significance to promote in-depth study and application of relevant technologies of agricultural robot.This paper trys to design a four-DOF manipulator and its end effector, and develops the method to avoid the obstacles in the grape bagging processing. Research contents are listed as follows:1. Based on the characteristics of the grape growing environment and bagging operations, a four-DOF manipulator program is put forward. The manipulator’s operating range is simulated by CAD drawing technology. The optimal solution of the manipulator structural parameters is got by setting up the optimization model and constraints, which is programmed on MATLAB. Contrary to the traditional complex bagging way, a relatively simple way to automate suitable bagging operation is designed.2. D-H coordinate system is established as the manipulator’s kinematics model, the forward kinematics and inverse kinematic are solved separately by homogeneous transformation, and the solutions are simulated and verified. Based on forward kinematics solutions and Monte Carlo principle, manipulator’s workspace is draught to analyse. Based on the jacobian matrix of the manipulator,which is solved by vector product method, velocity and acceleration are solved. Based on Robotics Toolbox, trajectory is planned in configuration space.3. Dynamics model is established firstly, then, Lagrangian equation is used to solve each joint’s dynamics equation. ADAMS, which is a simulate software, is used to build the3D simulation model. The manipulator’s kinematics property and dynamics property are simulated and verified by ADAMS and MATLAB.4. According to the characteristics of the grape growing environment, obstacle model is established. Base on the property of C-space obstacle and the conversion ideology of3D C-space obstacle, the method to avoid obstacle is put forward for the manipulator. W-space of obstacle is transformed into C-space by solving the forbidden region, in which joint and linkage will collid with obstacles. C-space information is described by grids. A-star algorithm is applied to achieve the obstacle avoidance path planning, and then, its3D path curve will be further smoothed.Finally, based on MATLAB platform and ADAMS software, avoidance simulation is done to the situation of cylindrical obstacle. The results show that this avoidance algorithm achieves the effect to avoid obstacles safely and efficiently.5. Finally, experiments are done to test the property of the bagging manipulator, including its positioning accuracy and carrying capacity. In the experiment environment, the bagging experiments are done to measure the bagging velocity and success rate. The experiment results show that grapes bagging robot can take and bag quickly and accurately.