E-030
The range of self-motion of redundant robots
Authors: Jadran Lenarcic
Affiliations: The "Joõef Stefan" Institute, Ljubljana, Slovenia
Abstract
One way to represent and analyze the amount of manipulator kinematic redundancy is
by visualizing and evaluating the mechanism's self-motion ability. The self-motion
of a D-degree-of-redundancy manipulator can be represented as a D-parametric hyper-volume
(area when D = 2, or curve when D = 1) in the n-dimensional configuration space of
joint coordinates whose form and size depend on the mechanism's parameters, mechanism's
configuration, and on the current values of the primary task coordinates.
In this article, we propose a general computational procedure and display the self-motion curves of 1-degree-of-redundancy mechanisms corresponding to various combinations of primary task coordinates that regularly appear in today's robotic practice. We observe that the self-motion curves are periodic functions of joint coordinates (in revolute-joint manipulators, the period in the direction of each joint coordinate is 2pi. We also observe that only in special cases of mechanism's structure and values of primary task coordinates, the self-motion produces connected curves (such as circles, ellipses, fans, etc.) in joint space. This is related to the capacity of the mechanism to circulate through all possible (groups) of configurations.
Jadran Lenarcic
Prof. Dr., Head of Department
Automatics, Biocybernetics and Robotics
The "Joõef Stefan" Institute
Ljubljana, Slovenia
Tel: 386 61 177 33 78
Fax: 386 61 177 35 63
jadran.lenarcic@ijs.si