Recoverability envelope analysis of nonlinear control laws for agile maneuvering aircraft

This paper proposes a novel framework to examine the effectiveness of controllers, which are designed for agile maneuvering aircraft upset recovery. The introduced framework incorporates two main assessment criteria. First, the angular rate envelope extent of the controller is determined, which provides a measure of functionality region of the controller. Second, time histograms are obtained in order to understand how fast does the controller recover the aircraft if the controller can recover the aircraft. In this work, a linear quadratic regulator, a nonlinear dynamic inversion (NDI) based angular rate controller, double loop NDI controller, and another NDI based switching controller are considered for comparison. The latter controller presented in this paper is a new strategy for upset recovery of an agile maneuvering aircraft. Simulations are carried out by employing a nonlinear high fidelity F-16 model. Monte-Carlo simulations show that the switching NDI controller has the superior recovery performance in terms of angular rate envelope extent.