Disturbance canceling control based on simple input observers with constraint enforcement for aerospace applications

The paper considers input observer based control of uncertain systems. A generalization of a simple input observer, that has been previously used in several automotive applications, is described and merged with a disturbance cancellation controller. The resulting control scheme enjoys semi-global practical closed-loop stability properties, i.e., under suitable assumptions it achieves an arbitrarily large domain of attraction if the observer gain is sufficiently high. In addition, the proposed control scheme facilitates the application of reference governors for non-conservative treatment of constrained systems with large disturbances. The paper illustrates the potential for use of such a control scheme for aircraft and spacecraft control applications.