Optimization and Analysis of a Pilot-Activated Automatic Recovery System

Abstract

Pilot-activated automatic recovery systems (PARS) are a common feature of combat aircraft and are used to recover an aircraft to straight and level flight in the event of the pilot experiencing disorientation. The recovery consists of an orchestrated sequence of pitch and roll maneuvers and has been studied extensively in the past using numerical optimization methods. The primary objective of this paper is to design a recovery maneuver that minimizes a physics-based proxy function for the energy loss experienced during recovery from initial conditions corresponding to climbing flight. This study also considers the case where the altitude loss needs to be minimized when the aircraft is initially in a descent. The specific proxy function used in the paper is a novel feature of our analysis and enables us to derive explicit, closed-form formulae for the high-level control inputs required for the recovery. The theoretical approach of this paper complements and explains the results of numerical optimization, and provides a computationally inexpensive alternative to numerical optimization for designing PARS. It also provides a rigorous method for refining the existing recovery maneuvers.