NONLINEAR CONTROLLERS FOR POSITIVE REAL SYSTEMS WITH ARBITRARY INPUT NONLINEARITIES

Input nonlinearities such as saturation can severely degrade closed-lo op performance due to integrator windup and other effects. For positiv e real plants with positive real controllers, we propose a nonlinear c ontroller modification that effectively counteracts the effects of arb itrary input nonlinearities. For this class of problems, we prove glob al asymptotic stability of the closed-loop system and demonstrate clos ed-loop performance by means of system simulation.