Disturbance attenuating output-feedback control of nonlinear systems with local optimality

Recent results on locally optimal and globally inverse optimal full-state feedback designs for strict-feedback systems are being extended for output-feedback systems in output-feedback form. The dynamic output-feedback control law for such systems is constructed under the assumption that the derivative of the measured output is available for feedback, and achieves local optimality and global inverse optimality with a prescribed L/sub 2/-gain. When that assumption is subsequently dropped, the control law achieves semi-global inverse optimality and local near-optimality.