Applications of plant inversion via state feedback to missile autopilot design

A linearizing transformation technique developed for the control of nonlinear systems is applied to the autopilot design of air-to-air missile systems. The plant inversion characteristic of this methodology is clearly displayed, and stability problems associated with nonminimum-phase plants are identified. To avoid the difficulty associated with the non-minimum-phase dynamics of missile acceleration, the plant inversion is first applied to the control of angle-of-attack and sideslip. Owing to simplifications made by the plant inversion, a point design is enough to provide the desired closed-loop responses for all fight conditions. Normal and lateral accelerations are then controlled by the classical integral feedback. The gain-scheduling required is minimal and transparent. The procedure is applied to the autopilot design of skid-to-turn and bank-to-turn missiles to obtain satisfactory performance of both missile designs