Development of Flight Control Law for Improvement of Uncommanded Lateral Motion of the Fighter Aircraft

The Abrupt Wing Stall (AWS) at moderate Angle-of-Attacks (AoA) and transonic flight conditions can result in uncommanded lateral motions such as heavy wing, wing drop and wing rock that degrade handling qualities, mission performance and safety of flight for the aircraft. This phenomenon caused by asymmetric wing flows makes it difficult to perform precision tracking or maneuvering in the transonic flight envelope. According to the previous research results, this substantial phenomenon has occurred in a large number of the fighter aircraft programs, typically at the early flight test development stage, and a lot of budgets and efforts are required through the development period of the aircraft. To compensate for this drawback, Free-To-Roll (FTR) wind tunnel test is adopted as a method to identify the uncommanded lateral motions of the aircraft and improve the flight characteristics at the configuration design stage. However, using only the existing control methods such as the feed-forward control methods as well as the configuration design can reduce limitedly the uncommanded lateral motion. Besides, the feedback control methods using optimal control, adaptive and neural network control which do not provide a deterministic solution are limited to obtain the airworthiness certification. This paper presents a new design approach in which uncommanded lateral motions of the aircraft can be reduced even more than the existing methods. That is the additional augmentation control method, using angular acceleration measurement, that improves the flight characteristics using a feedback control technique based on the Incremental Nonlinear Dynamic Inversion (INDI). To evaluate the performances of the proposed control method, we perform the frequency-domain linear analysis and time-domain numerical simulations based on the mathematical model of advanced trainer aircraft. The evaluation result reveals that the proposed control method reduces effectively uncommanded lateral motions and improves the handling qualities of the aircraft.

[1]  Kevin A. Wise,et al.  Flight Testing of Reconfigurable Control Law on the X-36 Tailless Aircraft , 2001 .

[2]  Jay M. Brandon,et al.  Transonic Free-To-Roll Analysis of the F/A-18E and F-35 Configurations , 2004 .

[3]  J. J. Harris,et al.  F-35 Flight Control Law Design, Development and Verification , 2018, 2018 Aviation Technology, Integration, and Operations Conference.

[4]  Miroslav Krstic,et al.  Control of Wing Rock Motion Using Adaptive Feedback Linearization , 1996 .

[5]  L. Hsu,et al.  Analysis and design of I/O based variable structure adaptive control , 1994, IEEE Trans. Autom. Control..

[6]  W. S. Pi,et al.  Investigation of steady and fluctuating pressures associated with the transonic buffeting and wing rock of a one-seventh scale model of the F-5A aircraft , 1978 .

[7]  Robert Hanley.  Development of an airframe modification to improve the mission effectiveness of the EA-6B airplane , 1987 .

[8]  Sahjendra N. Singh,et al.  Variable Structure Adaptive Control of Wing-Rock Motion of Slender Delta Wings , 1997 .

[9]  Rudolph D Van Dyke,et al.  Flight measurements of the wing-dropping tendency of a straight-wing jet airplane at high subsonic Mach numbers , 1951 .

[10]  Scott Stevenson,et al.  Parameter identification of AV-8B wingborne aerodynamics for flight simulator model updates , 1992 .

[11]  J. R. Chambers,et al.  Analysis of lateral directional stability characteristics of a twin jet fighter airplane at high angles of attack , 1969 .

[12]  Mark B. Tischler,et al.  Lateral/Directional Control Law Design and Handling Qualities Optimization for a Business Jet Flight Control System , 2013 .

[13]  Jia Luo,et al.  Control of Wing-Rock Motion of Slender Delta Wings , 1993 .

[14]  W. J. Sefic,et al.  Flight measurements of buffet characteristics of the F-104 airplane for selected wing-flap deflections , 1972 .

[15]  W. S. Pi,et al.  Investigation of Northrop F-5A wing buffet intensity in transonic flight , 1974 .

[16]  John Carter,et al.  Multi-application controls: Robust nonlinear multivariable aerospace controls applications , 1994 .

[17]  John Valasek,et al.  Reentry Vehicle Flight Controls Design Guidelines: Dynamic Inversion , 2002 .

[18]  J. R. Chambers,et al.  Historical Review of Uncommanded Lateral-Directional Motions at Transonic Conditions , 2003 .

[19]  Christopher J. Miller,et al.  Nonlinear Dynamic Inversion Baseline Control Law: Flight-Test Results for the Full-scale Advanced Systems Testbed F/A-18 Airplane , 2011 .

[20]  R. C. Monaghan,et al.  Effects of flaps on buffet characteristics and wind-rock onset of an F-8C airplane at subsonic and transonic speeds , 1973 .

[21]  Liu Hsu,et al.  Variable structure model-reference adaptive control (VS-MRAC) using only input and output measurements: the general case , 1990 .

[22]  Kamran Rokhsaz,et al.  Optimal feedback control of a nonlinear system - Wing rock example , 1996 .

[23]  Ke Lu,et al.  A L1 Adaptive Control Scheme for UAV Carrier Landing Using Nonlinear Dynamic Inversion , 2019, International Journal of Aerospace Engineering.

[24]  Richard S. Bray,et al.  The Effectiveness of Wing Vortex Generators in Improving the Maneuvering Characteristics of a Swept-wing Airplane at Transonic Speeds , 1955 .

[25]  E. J. Ray,et al.  Subsonic characteristics of a twin-jet swept-wing fighter model with maneuvering devices , 1973 .

[26]  T. R. Sisk,et al.  Precision controllability of the YF-17 airplane , 1979 .

[27]  E. L. Friend,et al.  Flight comparison of the transonic agility of the F-111A airplane and the F-111 supercritical wing airplane , 1978 .

[28]  Sahjendra N. Singh,et al.  Direct Adaptive and Neural Control of Wing-Rock Motion of Slender Delta Wings , 1995 .

[29]  Anuradha M. Annaswamy,et al.  Stable Adaptive Systems , 1989 .

[30]  Chong-Sup Kim,et al.  Development of the Model-/Sensor-Based Nonlinear Dynamic Inversion Control Technique for Highly Maneuverability Fighter , 2018 .

[31]  Andrew Berry,et al.  Flight test Experience of a Non-linear Dynamic Inversion Control Law on the VAAC Harrier , 2000 .