Aircraft Trim Recovery from Highly Nonlinear Upset Conditions

Autor: Elie R. Ballouz, David Hartman, Bor-Chin Chang, Harry G. Kwatny
Rok vydání: 2016
Předmět:
Zdroj: AIAA Guidance, Navigation, and Control Conference.
DOI: 10.2514/6.2016-0880
Popis: Aircraft loss of control (LOC) can result from a large spectrum of causal and contributing factors and is manifested as flight outside of the normal operating envelope and not predictably altered by pilot (or flight system) control inputs. LOC can also be characterized by nonlinear aircraft effects that degrade handling (or flying) qualities, including kinematic and/or inertial coupling, disproportionately large responses to small state variable changes, and oscillatory and/or divergent behavior. Some specific examples of nonlinear upset phenomena include stall / spin, falling leaf, and roll-pitch coupling oscillations. Although LOC need not be unrecoverable, it will become so if proper action is not taken. Recovery depends upon the timely execution of two critical actions: 1.) Determination of a desired feasible trim condition that the aircraft is able to recover to and reside on; and 2.) Determination of a control strategy that is capable of bringing the aircraft back to fly at the desired trim condition. This paper will investigate aircraft recovery from highly nonlinear upset conditions to a desired stable trim point that can be safely maintained. The test bed is a 6 d.o.f 12-state flight dynamics simulation model of an FA-18 like aircraft, which is nonlinear, flight-condition dependent. The proposed LOC prevention and recovery control strategies may also be applied to transport aircraft configurations for which nonlinear upset data is available.
Databáze: OpenAIRE