| With the rapid development of microelectronics technology,integrated circuits are gradually developing towards high performance and micro volume.As the key technology of packaging integrated circuits,surface mount technology determines the packaging quality of electronic products.In order to improve the intelligence of surface mount production line,realize continuous automatic production.Aiming at the problems of surface mount technology,raw material pickup and release,and workpiece assembly in surface mount production line,a method of visual pickup and release and visual guide assembly based on multi-d OF collaborative robot is proposed in this paper.The main research work of this paper is as follows:(1)To solve the sticking deviation problem of SMT machine,a PCB carrier scheme based on magnet adsorption and fixation was proposed.According to the equivalent magnetic charge and magnetostatic theory,a magnetic calculation model was established.The magnetic force simulation analysis was carried out based on the finite element model of magnetic strip adsorption carrier,and the variation law of magnetic force of magnetic strip with the cross-section size of magnetic strip was studied.In order to check the magnetic force of magnetic stripe to meet the constraint requirement of fixed PCB,the reliability of magnetic force constraint was verified by collision dynamics experiment.(2)Aiming at the problem that the robot cannot adapt to the change of target position and correct the grasping position in real time,intelligent cooperative robot with vision system is adopted to complete the assembly task,and a vision positioning algorithm based on the minimum external rectangle and Hough transform is proposed.The graham method and the convex hull boundary rotation method are used to solve the minimum enclosing rectangle of the target contour,and the central coordinates are obtained.Hough method and principal axis method were used to calculate the rotation angle.The results show that the angle error of Hough method do not exceed 0.2°,and the angle error of principal axis method do not exceed 0.5°,the calculation time is about 35%shorter than principal axis method.(3)The time-optimal trajectory planning problem of a six-degree-of-freedom manipulator is studied.The D-H parameter method is used to establish the forward and inverse kinematics solving models of the manipulator.According to the 3-5-3 interpolation method,an improved particle swarm optimization algorithm for the shortest of joint movement time,in view of the inertia weight for a linear gradient change of the particle swarm into the local convergence problem,dynamically changing inertia weight is presented based on the similarity of particle swarm optimization algorithm,the overall motion time of the 3-5-3 interpolation curve after time optimization is shortened by about 26%.(4)Build a robot vision assembly system and mount system,complete the development of visual function and motion control function.the theoretical results proposed above are applied to practice,and real machine experiments are carried out for the three functions of workpiece positioning,time optimization and magnetic fixation,and the effectiveness of the method is verified.The magnetic vehicle and robot visual positioning assembly method studied in this paper can solve the problems of raw material supply and workpiece assembly automation in the surface mount production line,and can cope with the complex and changeable working environment,so it has certain application value. |
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