Publication

New bracket polynomials associated with the general Gough-Stewart parallel robot singularities

Conference Article

Conference

IEEE International Conference on Robotics and Automation (ICRA)

Edition

2023

Pages

9728-9734

Doc link

https://doi.org/10.1109/ICRA48891.2023.10161484

File

Download the digital copy of the doc pdf document

Abstract

It is well known that the singularities of a Gough-Stewart platform arise when the determinant of the Plücker coordinates of the robot leg lines vanish. The direct expansion of this determinant in terms of the configuration of the moving platform leads to an intimidating algebraic expression which is difficult to organize in a manner that facilitates extracting geometric conditions for singularities to occur. The use of Grassmann-Cayley algebra has permitted expressing this determinant as a bracket polynomial which is easier to manipulate symbolically. Each monomial in this polynomial is the product of three brackets, 4×4 determinants involving the homogeneous coordinates of four leg attachments. In this paper, we show how to derive, using elementary linear algebra arguments, bracket polynomials where all brackets can be interpreted as reciprocal products between lines. Contrarily to what one might expect, these new bracket polynomials are simpler in general than those previously obtained using Grassmann-Cayley algebra.

Categories

automation.

Author keywords

Gough-Stewart parallel robot, line geometry, singularities

Scientific reference

F. Thomas. New bracket polynomials associated with the general Gough-Stewart parallel robot singularities, 2023 IEEE International Conference on Robotics and Automation, 2023, London (UK), pp. 9728-9734.