Robust Control Design over Large Flight Envelopes: a Promising Approach for Aerial Robotics

In the coming years, unmanned combat air vehicles will be designed to outperform most pilot-in-the-loop systems. The absence of a pilot onboard allows larger flight envelopes to be considered with, for example, higher load factors. From a control perspective, the above remark induces new needs for improved design methods to obtain robust controllers that will automatically adapt to extremely varying flight conditions. Based on the well-known concept of nonlinear dynamic inversion (NDI), the approach of this paper introduces an original and rather generic “robustification” framework, which leads to a multi-objective H ∞ design problem. The latter is now easily solved by existing and efficient numerical tools based on nonsmooth optimization. The proposed design methodology is illustrated by a combat aircraft control problem.