Maneuvering Flight Control with Actuator Constraints

Abstract

Tracking control is addressed. A receding horizon control framework is considered and a novel, optimizationbased, linear tracking control strategy, linear quadratic tracking (LQT), is devised. LQT is used to obtain a closed-form solution to optimization-based tracking of a dynamic reference signal r(t), in the face of both rate and amplitude actuator constraints. Actuator dynamics are considered. Also, there is no inherent requirement for stability of the open-loop plant. At the same time, full state feedback is assumed. The detrimental effects of the actuator constraints are mitigated by giving the control system a nonlinearly modie ed, feasible reference signalr 0 (t), asrequired to preventdownstream actuatorsaturationsfrom occurring. Thus, thecontrollergenerated signal never infringes on the saturation bounds, and saturation caused windup is avoided. The analytic solution to the linear, unconstrained, tracking problem meets the small signal performance specie cations and is stable. The proposed piecewiselinearclosed-form solution to theconstrained tracking problem yieldssatisfactory responses to large inputs and at the sametime requiresmodest on-linecomputation, and hence, it is implementable in real time.