A family of nonlinear H/sup /spl infin//-output feedback controllers

State-space formulas are derived for a family of controllers solving the nonlinear H/sup /spl infin//-output feedback control problem. The formulas given are expressed in terms of the solutions to two Hamilton-Jacobi inequalities in n independent variables. These controllers are obtained by interconnecting the "central controller" with an asymptotically stable, free system having L/sup 2/-gain /spl les//spl gamma/. All proofs given are simple and clear and provide deeper insight in the synthesis of the corresponding linear H/sup /spl infin// controllers.