OPTIMAL NONLINEAR, BUT CONTINUOUS, FEEDBACK-CONTROL OF SYSTEMS WITH SATURATING ACTUATORS

This paper presents a modification of the optimal saturating feedback control laws given by Frankena and Sivan (1979) and Ryan (1982 a) for asymptotically stable systems. Unlike their results, which involve ban g-bang action and singular extremals, the modified control law is cont inuous. Specifically, the new control law is linear inside a cylinder set and saturated elsewhere. Using steady-state Hamilton-Jacobi-Bellma n theory, this control law is shown to be optimal for a modified perfo rmance functional with a discontinuous integrand.