Abstract:Delta parallel robot has the advantages of fast speed, simple structure and strong bearing capacity, and is widely used in pot seedling transplanting, product sorting and packaging. Aiming at the problems of the analysis of the influence of structural parameters on the kinematics performance of Delta parallel robot and the complete theoretical system for the optimization design of systematic structural parameters, the distribution of condition numbers and the distortion constraint conditions were obtained by analyzing the distribution law of the Jacobian matrix condition in accessible workspace, the constraint relation of structural parameters, and the change law and correlation of kinematic performance with structural parameters. On this basis, it was concluded that the increase of the radius difference of dynamic and static platform, the increase of the length of the driving arm and the decrease of the length of the driven rod can make the mechanism performance better. Then, given the design workspace, the parameters of the original structure were optimized. The optimization model was established combining the condition number distribution characteristics and distortion constraints, the envelope penalty function and the kinematic performance evaluation function that was obtained by using multivariate nonlinear fitting and linear weighted grouping method, and the genetic algorithm was used to optimize the structure. Compared with before optimization, while the volume of the accessible workspace was reduced by 14.26%, the mean value and standard deviation of the global condition number in the design workspace were reduced by 31.20% and 11.78% respectively after optimization. Moreover, the distribution law of the condition number in each section of the design workspace verified the reliability of the condition number distribution characteristics. It provided a reference for the structure optimization and performance analysis of Delta parallel robot.
