Practical stabilization of exponentially unstable linear systems subject to actuator saturation nonlinearity and disturbance

Abstract—We study the problem of stabilizing exponentially unstable linear systems with saturating actuators. The study begins with planar sys-tems with both poles exponentially unstable. For such a system, we show that the boundary of the domain of attraction under a saturated stabi-lizing linear state feedback is the unique stable limit cycle of its time-re-versed system. A saturated linear state feedback is designed that results in a closed-loop system having a domain of attraction that is arbitrarily close to the null controllable region. This design is then utilized to construct state feedback laws for higher order systems with two exponentially unstable poles. Index Terms—Actuator saturation, domain of attraction, null control-lable region, semiglobal stabilization. I