Structural Deign Optimization for A Two-link Robot to Suppress Undesirable Vibration

Abstract

In this study, we address the case of a horizontal two-link robot with flexible timing belts and present a structural design guideline to reduce its undesirable vibration. First, an equation of motion was constructed using Lagrange's equation, and its validity was examined by comparing the experimental and simulation results using an index to estimate the undesirable vibration. As a result, it was determined that the mathematical model could be used as a simulation tool for design optimization. Then, by a simple structural modification, a design guideline was proposed to reduce the undesirable vibration in the extension motion: namely, a robot arm was designed such that the location of its center of gravity is near the rotation center and its moment of inertia is small. Other optimum structural design may be obtained for the other motion of robot. The points of this study are to propose the design method that includes the definition of objective function for the optimum design and to show a design guideline to reduce the undesirable vibration for a certain motion of robot.