Autopilot for a Nonlinear Non-Minimum Phase Tail-Controlled Missile

Abstract

Acceleration control of highly agile, aerodynamically-controlled missiles is a well-known non-minimum phase control problem. This problem is revisited here for a planar tailcontrolled generic missile, and a globally stable nonlinear autopilot command structure is synthesized to maximize performance. For the first time the non-minimum phase characteristics of the vehicle are addressed by making no modification to the output definition by inducing an inherent time scale separation in the closed-loop dynamics. Unlike, previous time scale control techniques, results presented here are based on theoretical advancements made in control of nonlinear singularly perturbed systems. Conditions under which the induced time scale separation can be employed for a stable autopilot design are also discussed. The state feedback controller proposed is real-time implementable, independent of operating condition and desired output trajectory. Simulation results presented in the paper show that the approach is able to accomplish perfect tracking while keeping all closed-loop signals bounded.