Application of non-linear H∞ control to the Tetrabot robot manipulator

Abstract

Abstract In this paper, an application of a non-linear H ∞ control law for an industrial robot manipulator is presented. Control of the manipulator motion is formulated into a non-linear H ∞ optimization problem, namely optimal tracking performance in the presence of modelling uncertainties and external disturbances. Analytical solutions for this problem are implemented on a real robot. The robot under consideration is the six-degrees-of-freedom GEC Tetrabot. Investigations are made into the selection of weights for the H ∞ controller and it is shown how different selections of weights affect the Tetrabot performance. The authors believe this to be the first robotic application of nonlinear H ∞ control. Comparisons of the proposed control strategy with conventional proportional-derivative and proportional-integral-derivative controllers show favourable performance of the Tetrabot under the new non-linear H ∞ control scheme.