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Journal ArticleDOI

Improved pilot training via bifurcation analysis and robust control for aircraft loss of control problems

08 May 2019-Vol. 233, Iss: 14, pp 5414-5427
TL;DR: A simulator for improved pilot training based on bifurcation and continuation techniques is presented and a robust control-based loss of control handling module is also presented for developing non-intuitive strategies for Loss of control prevention and recovery.
Abstract: Aircraft loss of control is one of the largest contributors to fatal accidents in the aviation environment. The unprecedented change in aircraft dynamics due to loss of control onset and the associ...
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Proceedings ArticleDOI
03 Jan 2022
TL;DR: In this paper , a two-point boundary state problem is formulated for aircraft spiral recovery and a control law based on sliding mode control technique is designed for F-18 High Alpha Research Vehicle (HARV) to demonstrate the proposed work.
Abstract: Aircraft spiral profile is simulated in the present paper. Thereafter, control law based on sliding mode control technique is designed for aircraft spiral recovery. The F-18 High Alpha Research Vehicle (HARV) is considered to demonstrate the proposed work. The present problem is formulated as two-point boundary state problem, wherein, starting point is spiral state and end point is level-trim flight state. Both the reference points are taken from bifurcation analysis of aircraft dynamics. The controller stability for an applied control command is also proved. In the proposed control formulation, aircraft primary controls are derived in a closed-loop form. The chattering free response of control variables is achieved due to implemented power rate reaching law. The contributions of this paper lie in the control formulation, wherein altitude is controlled apart from spiral recovery. Also, the controller is able to achieve the same heading angle and altitude where the recovery attempt was initiated. Moreover, simulation results of the present paper show that the designed control law makes the wing-level flight by controlling the aircraft attitude followed by the altitude control to attain constant-altitude-level flight.
Journal ArticleDOI
25 Mar 2022
TL;DR: In this article , different autonomous landing profiles are formulated and simulated, and the merits and demerits with respect to the practicality of implementation of these profiles are then discussed, and each landing profile has been demonstrated using sliding mode controller (SMC).
Abstract: In the present paper, different autonomous landing profiles are formulated and simulated. Generic landing is modelled first, wherein, approach and acquired runway heading is considered as same. The second-landing profile involves altitude hold when runway is not clear to land the aircraft. Expedited landing is the third profile modelled with a glide slope-maintained descent to reduce the ground distance required pre-touchdown. In either of the landing profiles, flare is kept the same. The merits and demerits with respect to the practicality of implementation of these profiles are then discussed. Each landing profile has been demonstrated using sliding mode controller (SMC). The asymptotic stability and finite-time proofs of the designed controller are shown using Lyapunov function. F-18 HARV aircraft is considered to test the efficacy of the formulated landing profiles. Expedited landing profile proposed here is a novel approach in which altitude descent gradient is maintained with helical descent path. Additionally, results of this approach show significant improvement in terms of possibility of initiating an unconventional and yet safe as well as economical method much nearer to the runway.
Proceedings ArticleDOI
03 Jan 2022
TL;DR: In this paper , a sliding-mode control technique is used to stabilize the aircraft pitch, roll and heading angle and attains the desired attitude in finite time, and the simulation results show that the designed control law succeeds in achieving levelwing flight condition by controlling the aircraft attitude.
Abstract: Aircraft attitude in flat-spin motion is controlled in the present paper using sliding-mode control technique. The designed controller stabilizes the aircraft pitch, roll and heading angle and attains the desired attitude in finite time. In the proposed control formulation, aerodynamic controls namely elevator, aileron and rudder, are derived in a closed-loop form, and chattering free response of control variables is achieved due to the implemented power rate reaching law. This paper contributes to attitude control, even with perturbed inertial property and aerodynamic model of aircraft. Moreover, simulation results of the present paper show that the designed control law succeeds in achieving level-wing flight condition by controlling the aircraft attitude.
References
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Journal ArticleDOI
TL;DR: Design and analysis forVariable structure systems are surveyed in this paper and it is shown that advantageous properties result from changing structures according to this switching logic.
Abstract: Variable structure systems consist of a set of continuous subsystems together with suitable switching logic. Advantageous properties result from changing structures according to this switching logic. Design and analysis for this class of systems are surveyed in this paper.

5,076 citations

Journal ArticleDOI
TL;DR: A tutorial account of variable structure control with sliding mode is presented, introducing in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach.
Abstract: A tutorial account of variable structure control with sliding mode is presented. The purpose is to introduce in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach. This approach is particularly attractive for the control of nonlinear systems. Prominent characteristics such as invariance, robustness, order reduction, and control chattering are discussed in detail. Methods for coping with chattering are presented. Both linear and nonlinear systems are considered. Future research areas are suggested and an extensive list of references is included. >

2,884 citations

Journal ArticleDOI
TL;DR: The sparsity of the discretized systems for the computation of limit cycles and their bifurcation points is exploited by using the standard Matlab sparse matrix methods.
Abstract: MATCONT is a graphical MATLAB software package for the interactive numerical study of dynamical systems. It allows one to compute curves of equilibria, limit points, Hopf points, limit cycles, period doubling bifurcation points of limit cycles, and fold bifurcation points of limit cycles. All curves are computed by the same function that implements a prediction-correction continuation algorithm based on the Moore-Penrose matrix pseudo-inverse. The continuation of bifurcation points of equilibria and limit cycles is based on bordering methods and minimally extended systems. Hence no additional unknowns such as singular vectors and eigenvectors are used and no artificial sparsity in the systems is created. The sparsity of the discretized systems for the computation of limit cycles and their bifurcation points is exploited by using the standard Matlab sparse matrix methods. The MATLAB environment makes the standard MATLAB Ordinary Differential Equations (ODE) Suite interactively available and provides computational and visualization tools; it also eliminates the compilation stage and so makes installation straightforward. Compared to other packages such as AUTO and CONTENT, adding a new type of curves is easy in the MATLAB environment. We illustrate this by a detailed description of the limit point curve type.

1,320 citations

Journal ArticleDOI
TL;DR: In this article, a new approach for analyzing nonlinear and high-a dynamic behavior and stability of aircraft is presented, which involves the application of bifurcation analysis and catastrophe theory methodology to specific phenomena such as stall, departure, spin entry, flat and steep spin, nose slice, and wing rock.
Abstract: A new approach is presented for analyzing nonlinear and high-a dynamic behavior and stability of aircraft. This approach involves the application of bifurcation analysis and catastrophe theory methodology to specific phenomena such as stall, departure, spin entry, flat and steep spin, nose slice, and wing rock. Quantitative results of a global nature are presented, using numerical techniques based on parametric continuation. It is shown how our methodology provides a complete representation of the aircraft equilibrium and bifurcation surfaces in the state-control space, using a rigid body model with aerodynamic controls. Also presented is a particularly useful extension of continuation methods to the detection and stability analysis of stable attracting orbits (limit cycles). The use of this methodology for understanding high-a phenomena, especially spin-related behavior, is discussed. RENDS in fighter aircraft design over the past few decades have resulted in configuration s noted for their high speed and performance capability. The cost of achieving this capability has been a drastic, often fatal loss of positive control of the aircraft as the pilot operates at or near the extremes of the flight envelope. This is especially true for aircraft motion at high angles of attack (a), where large deviations both in the state and control variables limits the application of the usual linearized analysis techniques. There is a conspicuous lack of techniques for analyzing global stability and large maneuver response of aircraft. While certain phenomena (e.g., roll coupling) have been analyzed in an isolated manner, there exists a clear need for a unified approach to analyze systematically global aircraft behavior at high a.

205 citations

Journal ArticleDOI
TL;DR: Bifurcation theory has been used to study the nonlinear dynamics of the F-14, and a simple feedback control system was designed to eliminate the wing rock and spiral divergence as mentioned in this paper.
Abstract: Bifurcation theory has been used to study Ihe nonlinear dynamics of the F-14. An 8 degree-of-freedom model that does not include the control system present in operational F-14's has been analyzed. The aerodynamic model, supplied by NASA, includes nonlinearlties as functions of the angles of attack and sideslip, the rotation rate about the velocity vector, and the elevator deflection. A continuation method has been used to calculate the steady states of the F -14 as continuous functions of the elevator deflection. Bifurcations of these steady states have been used to predict the onset of wing rock, spiral divergence, and jump phenomena that cause the aircraft to enter a spin. A simple feedback control system was designed to eliminate the wing rock and spiral divergence instabilities. The predictions were verified with numerical simulations.

147 citations