RECOVERY GUIDANCE SATISFYING INPUT AND STATE CONSTRAINTS - RATE SATURATING ACTUATOR EXAMPLE

When a fixed regulator is used to stabilize a desired state trajectory (guidance law), large initial tracking errors can lead to input satur ation, which can result in performance deterioration. A method to modi fy the guidance law for recovering state-trajectory tracking (without violating input and state constraints) is presented. Although it may b e feasible to find such a satisfactory recovery guidance maneuver for a given initial tracking error, online development of recovery guidanc e maneuvers may not be computationally tractable. A technique Is devel oped to use precomputed recovery guidance maneuvers (precomputed for a finite set of initial tracking errors) to generate recovery guidance maneuvers for other initial errors. The technique is applied to an ill ustrative example with a rate-limited servoactuator, and simulation re sults are presented.