Enhanced controllability through vortex manipulation on fighter aircraft at high angles of attack

1986 ◽  
Author(s):  
G. MALCOLM ◽  
A. SKOW
Keyword(s):  
Fighter Aircraft ◽  
High Angles Of Attack

On Nonlinear Dynamics and Flight Control at High Angles of Attack With Uncertain Aerodynamics

2016 ◽  
Author(s):  
Mateus de Freitas Virgílio Pereira ◽  
Igor Afonso Acampora Prado ◽  
Davi Ferreira de Castro ◽  
José Manoel Balthazar ◽  
Roberto Gil Annes da Silva ◽  
...  
Keyword(s):  
Flight Control ◽  
Parametric Uncertainty ◽  
Linear Feedback ◽  
Fighter Aircraft ◽  
Generalized Polynomial ◽  
Hamilton Jacobi Bellman Equation ◽  
Optimal Linear ◽  
Hamilton Jacobi Bellman ◽  
High Angles Of Attack ◽  
Lyapunov Sense

In this paper we consider the flight dynamics of fighter aircraft at high angles of attack with uncertain aerodynamic coefficients. Stochastic parametric uncertainty is dealt with by employing spectral decomposition of the random variables by means of the generalized polynomial chaos expansion. We propose an optimal linear feedback strategy for the automatic pilot system to recover the aircraft from stall and provide acceptable dynamic response. Optimality of the proposed control law is proved by solving the Hamilton-Jacobi-Bellman equation and asymptotically stability of the controlled nonlinear aircraft model is guaranteed in the Lyapunov sense. Numerical results are verified with Monte-Carlo simulations.

Nonlinear dynamics and linear control applied to an fighter aircraft in longitudinal flight at high angles of attack

2018 ◽  
Author(s):  
Guilherme Pacheco dos Santos ◽  
Angelo Marcelo Tusset ◽  
Frederic Conrad Janzen ◽  
Rodrigo Tumolin Rocha ◽  
Airton Nabarrete ◽  
...  
Keyword(s):  
Nonlinear Dynamics ◽  
Linear Control ◽  
Fighter Aircraft ◽  
High Angles Of Attack

Trimmed deep stall on the F-16 Fighting Falcon

2001 ◽  
Vol 105 (1054) ◽  
pp. 679-683 ◽  
Author(s):  
L. D. Evangelou ◽  
A. W. Self ◽  
J. E. Allen ◽  
S. Lo
Keyword(s):  
High Performance ◽  
Reliable Method ◽  
Control Problems ◽  
Fighter Aircraft ◽  
Handling Qualities ◽  
Handling Characteristics ◽  
Combat Effectiveness ◽  
Flight Envelope ◽  
High Angles Of Attack

Abstract High performance fighter aircraft have problems with handling qualities, at high angles of incidence. Pilots are limiting combat effectiveness by cautiously avoiding hazardous regions of the flight envelope. This paper presents and extends existing work on the F-16 aircraft's handling characteristics during the deep stall condition. Inflight experience shows that there are two types of control problems when flying at high angles-of-attack, the ‘pitch departures’ and the ‘deep stall trim’. This paper investigates the critical deep stall condition, assesses the effectiveness of the proposed method of recovery and suggests an augmented and reliable method of returning to normal flight.

scholarly journals Aircraft pitch control tracking with sliding mode control

2018 ◽  
Vol 7 (4.13) ◽  
pp. 62
Author(s):  
Nurhana M. Rouyan ◽  
Renuganth Varatharajoo ◽  
Samira Eshghi ◽  
Ermira Junita Abdullah ◽  
Shinji Suzuki
Keyword(s):  
Sliding Mode Control ◽  
Flight Control ◽  
Sliding Mode ◽  
Aerodynamic Characteristics ◽  
Control Methods ◽  
Fighter Aircraft ◽  
Pitch Control ◽  
Mode Control ◽  
Numerical Treatments ◽  
High Angles Of Attack

Sliding mode control (SMC) is one of the robust and nonlinear control methods. An aircraft flying at high angles of attack is considered nonlinear due to flow separations, which cause aerodynamic characteristics in the region to be nonlinear. This paper presents the comparative assessment for the flight control based on linear SMC and integral SMC implemented on the nonlinear longitudinal model of a fighter aircraft. The controller objective is to track the pitch angle and the pitch rate throughout the high angles of attack envelope. Numerical treatments are carried out on selected conditions and the controller performances are studied based on their transient responses. Obtained results show that both SMCs are applicable for high angles of attack.  

A Multidisciplinary Analysis of Tail Buffeting Alleviation Using Streamwise Fences

2003 ◽  
Vol 9 (5) ◽  
pp. 583-604 ◽  
Author(s):  
Essam F. Sheta
Keyword(s):  
Data Transfer ◽  
Vortex Breakdown ◽  
Delta Wing ◽  
Vortical Flow ◽  
Geometrical Shape ◽  
Fighter Aircraft ◽  
Grid Deformation ◽  
Multidisciplinary Analysis ◽  
Wide Range ◽  
High Angles Of Attack

A multidisciplinary analysis of vertical tail buffeting and buffeting alleviation of generic fighter aircraft is conducted. This complex multidisciplinary problem is solved for the fluid dynamics, structure dynamics, fluid-structure coupling, and grid deformation using a computing environment that controls the temporal synchronization of the data transfer between the analysis modules. The generic fighter aircraft consists of a sharp-edged delta wing with an aspect ratio of one and a swept-back, flexible, vertical twin tail with a taper ratio of 0.23. Twin streamwise fences are located at the 30% chord-station of the delta wing. The fences are used to alter the vortical flow and to delay the onset of vortex breakdown above the delta wing, in order to alleviate the twin-tail buffeting. The effect of the geometrical shape of the fences on the buffeting responses is investigated. The performance of the fences over a wide range of high angles of attack is also investigated. The trapezoidal configuration of the fences at a taper ratio of 0.7 produced the most favorable results. The results indicated that the fences are effective in reducing the aeroelastic loads and responses, especially at angles of attack less than 30°.

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