Trajectory Planning And Control Implementation For3-DOF Parallel Robot

As a kind of advanced manufacture tool,3-DOF parallel robot is widely applied in electronic, food, medical and other light industries to replace the manual to complete sorting, picking, packing and other tedious repetitive work, which can effectively improve the production efficiency and product quality. Trajectory planning is an important issue in robot control, the pros and cons of trajectory planning will directly affect the course of the robot dynamic performance and efficiency. Therefore, the research on robot trajectory planning is of great significance. In order to get the optimal Pick-and-place trajectory for the3-DOF parallel robot, this paper takes the robot which is designed independently as the study object and discusses its trajectory planning and method of implementation of controlling.Firstly, the structure is analyzed according to the robot. With the aid of vector method, the inverse kinematic, velocity model and acceleration model have been proposed. On this basis, simplifying the quality model of the robot forearm and the rigid body dynamic model of the robot has also been formulated by the means of virtual work principle. This provides necessary theory foundation for the trajectory planning.Secondly, the Door-trajectory based on trapezoidal acceleration-deceleration method is analyzed. According to its discontinuous motion curves, a trajectory method with elliptical interpolation which is based on electronic cam is proposed. In consideration of the kinematics and dynamics constrains, the mathematical model of Time-optimal trajectory planning has been built.Then, to solve the mathematical model of Time-optimal trajectory planning, this paper presents an adaptive genetic algorithm and implements the algorithm programming and solving by using MATLAB. The optimal Pick-and-place time for the robot is obtained. And comparatively analyzing the optimization results between the elliptical trajectory and Door-trajectory. The results show that the elliptical trajectory proposed in this paper is more effective than Door-trajectory on improving the robot dynamic performance and the efficiency of Pick-and-place. On the basis, in order to further verify the validity of the trajectory planning method presented in this paper, the simulation platform is built in ADAMS and the simulation is carried out by leading the optimization results of the elliptical trajectory into ADAMS. Finally, the hardware, the modular design of the trajectory planning and the software of robot control system have been designed based on PC+SC control structure. The hardware design includes:identifying the main hardware configuration, circuit design of PLC model, circuit design of servo system, circuit design of sensor system. The modular design of the trajectory planning includes:module pin design, interpolation process design, module package. The software design includes:communication module design, interactive interface design of PC, trajectory function block design, underlying control program design of PLC. On this basis, building experimental platform and testing the elliptical interpolation trajectory. The results showed that the method proposed can effectively satisfy the conditions of the robot speed applications.