Optimal design of robotic manipulators based on simultaneously considering links and joints flexibility

In this paper, a geometrical optimization and reducers selection method is proposed for robotic manipulators design, which considers the flexibility of links and joints simultaneously. The Lagrangian approach is employed in deriving the dynamic model of a two-DOF manipulator. Timoshenko model is used to discretize the dynamic model. Two criteria, i.e. maximization of fundamental frequency and minimization of self-weight/load ratio, are utilized to optimize the manipulators. The NSGA-II (Fast Elitist Nondominated Sorting Genetic Algorithms) is employed to solve the multi-objective optimization problem. The results indicate that simultaneous consideration of the joints and the links flexibility is very necessary for manipulators optimal design. Finally, several optimal combinations are provided and the effectiveness of the optimization is proved.