Research On Motion Path Planning Of Picking Manipulator

The mechanization and automation of fruit and vegetable harvesting has become an urgent problem in China.In order to achieve the efficiency and real-time of fruit and vegetable harvesting,intelligent harvesting robot has gradually become a research hotspot.Different from the industrial manipulator,the working environment of the picking manipulator becomes relatively complex because of the irregular distribution of picking targets and obstacles.Based on the high requirements of picking accuracy and efficiency,the control of the manipulator is particularly important.For this reason,this paper carries out the research on the modeling and kinematics analysis of the picking manipulator,the trajectory planning of joint space,and the path planning algorithm of obstacle avoidance of the manipulator.Firstly,according to the complexity of the picking environment,the open-chain six-degree-of-freedom manipulator is selected as the research object.The kinematics model of picking manipulator was constructed by D-H method,and the forward and inverse kinematics were calculated and the results were verified.On this basis,the method of selecting the optimal inverse solution with the objective of "lowest energy consumption" and "highest efficiency" is put forward,and the solution of the optimal inverse solution is achieved through practical examples.Secondly,under the condition of obstacle-free working space,the trajectory planning of the joint space of the picking manipulator is studied.By analyzing and comparing the trajectory planning curves obtained by the four methods of cubic polynomial,quintic polynomial,trapezoidal curve and five-section S curve,it is found that the trajectory curve obtained by the five-section S curve is continuous and the change is gentle;the speed changes smoothly and the speed is controllable in the start-stop stage;there is no sudden change in acceleration,the peak value is small,and the manipulator has less inertia force and no impact.The trajectory planning of the joint can meet the requirements of the picking manipulator.Finally,the correctness of the trajectory planning results is verified by forward kinematics calculation.Finally,the collision-free path planning method of the manipulator is studied.Taking the shortest path and the fastest planning speed as evaluation indexes,the application effects of ant colony algorithm and artificial potential field method in path planning of robot arm without collision are compared.The results show that ant colony algorithm is more suitable for path planning of picking robot arm.