| Abstract: | The dissipated energy even of a manipulator must be decreased in order to improve the environment of the earth. This paper describes an optimal path which minimizes the dissipated energy in PTP motions of a vertically articulated manipulator. The dynamic equation of the manipulator is nonlinear due to centrifugal, Coriolis, gravity, and Coulomb friction forces. Moreover the driving system of the joints is also nonlinear in that the generating torque is expressed by a third‐degree polynomial with respect to current. Therefore, an optimal path cannot be obtained by solving a two‐point boundary‐value problem analytically. In this paper an optimal path is searched for by a Genetic Algorithm (GA) in cases in which all kinds of nonlinear characteristics of the manipulator, including the driving system, are taken into consideration. The obtained optimal velocity functions are applied to a vertically articulated manipulator with two direct‐drive motors. The dissipated energy is measured by integrating the input power to the motors. Experimental results agree with the simulation values only when all kinds of nonlinearity are taken into consideration. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 26–34, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20437 Copyright © 2006 Wiley Periodicals, Inc. |
