Loop Shaping Design for Missile Autopilots: Controller Configurations and Weighting Filter Selection

The design of a homing, tail-controlled missile autopilot using a loop shaping approach is considered. The designer input in this control methodology consists of a set of shaping filters that in turn lead to an ℋ_∞ optimal controller that guarantees stability. Several configurations are contrasted. These differ as to the location in the loop of the shaping filters and optimal controller. It is shown that the choice of configuration has implications as to the form of the shaping filters. It is also demonstrated how intuition from classical three-loop controllers can be used to select these filters. Finally, for one configuration, analytic formulas for a set of generic shaping filters are derived that lead to good tracking performance and robustness margins.