Adaptive Techniques for Multiple Actuator Blending

Advanced missiles employ multiple actuators to enhance maneuverability and to improve the intercept probability against highly maneuverable targets. Actuators employed in such missiles include aerodynamic control surfaces and reaction jets. While the usage of aerodynamic surfaces are not generally constrained, reaction jet usage has to be minimized due to the limited amount of fuel available on-board. A blending logic is employed to optimally allocate the actuators in response to commands from the autopilot. This paper discusses the development of a fuel conservative actuator blending logic that provides relatively invariant actuator performance over widely varying flight conditions. The invariant performance is obtained using the model reference adaptive control technique. Multiple adaptation strategies are employed to ensure rapid convergence and stable behavior. The performance of the model reference adaptive actuator blending strategy is illustrated using a realistic missile model.