Robust regulation of a class of nonlinear systems using singular perturbation approach

In this paper, we consider robust regulation of a class of nonlinear systems, via H∞ controller using singular perturbation approach. First, using normal form equations, we eliminate the nonlinear part of the system matrix of equations of system and transform it to a linear diagonal form. Separating new equations to slow and fast subsystems, due to the singular perturbation approach and with the assumption of norm-boundedness of the fast dynamics, we can treat them as disturbance and design H∞ controller for a system with a lower order than the original one that stabilizes the overall closed loop system. The proposed method is applied to a single link, flexible joint robot manipulator.