State-feedback H-infinity control of nonlinear singularly perturbed systems

We study the H-infinity control problem for an affine singularly perturbed system, which is nonlinear in the state variables. Under suitable assumptio ns on the linearized problem, we construct epsilon -independent composite a nd linear controllers that solve the local H-infinity control problem for t he full-order system for all small enough epsilon. These controllers solve also the corresponding problem for the descriptor system. The 'central' non linear controller can be approximated in the form of expansions in the powe rs of epsilon. An illustrative example shows that the higher-order approxim ate controller achieves the better performance, while the composite (zero-o rder approximate) controller leads to the better performance than the linea r one. Copyright (c) 2001 John Wiley & Sons, Ltd.