In this paper, bifurcation analysis-based methodology is used in conjunction with a sliding-mode-based control algorithm to construct and simulate maneuvers for a nonlinear, 6 degree-of-freedom, F-18 high-alpha research vehicle aircraft model. Three different types of maneuvers, namely, a minimum-radius level turn, velocity vector roll, and spin recovery to a level flight condition, are attempted to demonstrate the usefulness of the proposed approach. The procedure involves constructing the desired maneuvers using constrained bifurcation analysis-based methodology. The results obtained from bifurcation analysis provide the reference inputs for the sliding mode controller to switch the aircraft between desired flight conditions. Robustness of the sliding mode controller is also examined by introducing uncertainties in aerodynamic parameters. Closed-loop simulation results are later presented to show the effectiveness of the proposed technique. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc.

Nandan Kumar Sinha

Department of Aerospace Engineering

Aerodynamic parameters

AIRCRAFT MANEUVERS

Bifurcation analysis

Closed-loop simulations

Flight conditions

REFERENCE INPUTS

RESEARCH VEHICLES

Sliding mode controller

Sliding modes

Spin recovery

Velocity vectors

Algorithms

Bifurcation (mathematics)

Sliding mode control

aircraft

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Aircraft Maneuver Design Using Bifurcation Analysis and Sliding Mode Control Techniques

Journal of Guidance, Control, and Dynamics

Physical systems such as air vehicles are inherently nonlinear and complex. A complete treatment of air vehicle from design, modeling, analysis, and simulation until control design for vehicle autonomy demands, therefore, application of tools from nonlinear dynamics and control theories. Blending dynamical systems theory and nonlinear control techniques provides a unique and physically intuitive methodology for developing control algorithms for various complex tasks. Our recent works on highly nonlinear aircraft models have led to the development of a generic simulation platform for guidance, control, and navigation of six degree-of-freedom (dof) air vehicles in a completely nonlinear framework. An overview of the nonlinear framework involved in the development of the unique platform and its applications to maneuvering and waypoint navigation of two vehicle models are presented in the paper. © 2019 IEEE.

2019 5th Indian Control Conference, ICC 2019 - Proceedings

Integrated Nonlinear System Framework for Air Vehicle Autonomy Design and Validation

Aircraft loss of control is an acute phenomenon that has far reaching consequences irrespective of the class and type of aircraft. In order to ensure safe aircraft operation, loss of control problem has to be addressed efficaciously. This paper investigates various factors that trigger the onset of loss of control events and recovery solutions for the same. Rather than relying on statistics alone, this paper concentrates on simulation-based investigation towards various loss of control scenarios and subsequent recovery schemes. Through bifurcation analysis, distinct abnormal dynamics have been identified and their contributions in driving the aircraft towards loss of control have been examined. The effect of steady wind on aircraft dynamics and the evolution of chaotic dynamics as a precursor to loss of control are presented. Aircraft loss of control under actuator impairment conditions are also probed into. Various loss of control recovery schemes have been investigated and a robust loss of control recovery solution based on sliding mode control is also presented. © IMechE 2019.

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering

An investigation into aircraft loss of control and recovery solutions

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 associated structural constraints make loss of control prevention and/or recovery a challenging task. State-of-the-art autopilots are generally designed for nominal aircraft operations and disengage under off-nominal conditions, hence cannot be viewed as a safety solution during loss of control onsets. Herein lies the importance of providing training to pilots so as to equip themselves to rescue aircraft from loss of control events. Current pilot training methodologies have significant limitations when it comes to loss of control prevention and recovery strategies. In this context, a simulator for improved pilot training based on bifurcation and continuation techniques is presented in the paper. Augmenting these techniques with the current pilot training procedure can significantly improve the quality of training. This methodology can help pilots to distinguish various loss of control scenarios and aid them in taking appropriate recovery decisions intuitively. Meanwhile, a robust control-based loss of control handling module is also presented for developing non-intuitive strategies for loss of control prevention and recovery. This module can simulate adequate control profiles that the pilot can follow to get in and out of various loss of control scenarios. Moreover, it can be used as pilot activated recovery system in case of pilot disorientation and as a fully autonomous recovery system for much complex scenarios. The simulator is developed in MATLAB/SIMULINK platform and is shown to realize diverse loss of control events like spiral, spin, etc., and subsequent recovery from the same. © IMechE 2019.

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

Airship is lighter than air vehicle filled with lifting gas such as helium or hydrogen and can be operated at a desired altitude with long endurance. Airship can remain airborne for extended period of time1 without spending a lot of energy. Airships have also been proven to be effective in diffcult fiight conditions1 and perform better than conventional aerial vehicles in these diffcult fight conditions like planetary ight forexploration of planets. There has been an increasing interest in recent times in this field due to major applications ranging from defence, scientific exploration2, advertising to even remote monitoring. Above mentioned applications are also the driving factor in research and development of various airship designs and their control systems. These applications require advanced control systems. The uncertain environment in which airships operate makes the task of designing control system very challenging. Linear control methodology such as gain scheduling is simply insuffcient under different operating conditions. Several nonlinear control methodologies dealing with system uncertainties, such as, variable structure control,3,4 robust control,5 feedback linearization control,6,78 and adaptive control9 have been proposed in literature. Most of these control schemes have been implemented on airship models with conventional control surfaces. These control algorithms are very well suited to systems that can be defifined in control affne form and assuming that system’s parameters are known. Considering that airship’s parameters are not exactly known, practical implementation of above control schemes based on conventional formulation may not be directly applicable. Further complexities related to control afinity are encountered while formulating control laws for nonlinear airship models including thrust vectoring capabilities. A MIMO nonlinear adaptive sliding mode control is designed for thrust vectoring airship in this paper. Closed loop simulation results are provided at the end to show the effectiveness of proposed control technique on thrust vectoring airship. © 2018, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

AIAA Guidance, Navigation, and Control Conference, 2018

Design of adaptive sliding mode control for uncertain thrust vectored airship

A systematic methodology for conceptual aircraft design using constrained bifurcation and continuation technique is studied. The methodology uses a full six-degrees-of-freedom nonlinear mathematical model for flight dynamic stability analysis; stability and control derivatives required for analysis are estimated through standard empirical relations available in design books. To illustrate the design approach using the constrained bifurcation and continuation method, a vertical tail sizing problem of a generic six-seater airplane is investigated. Stability analysis of the aircraft lateral-directional modes with variation in vertical tail size is carried out, and a comparison of computed stability parameters is made with flying quality specifications to optimally size the vertical tail.

Journal of Aircraft

Aircraft design using constrained bifurcation and continuation method

A sliding-mode (SM) controller designed for recovery of an aircraft from flat oscillatory spin is discussed. Aircraft controls aileron δa, rudder δr, and elevator δe were used as active controls within the limits. A sliding surface was designed depending upon available control authority and acceptable error dynamics. SM controller based on variable-structure control technique for nonlinear systems is suitable for all nonlinear controllers. Limits on the control surfaces, both in position and in rate, are maintained during the computation of control commands. The low-angle-of-attack segment is the stable level-trim state. The SM controller recovers the aircraft to the level flight trim state within the limits specified on the rudder saturation rates, which could be achieved using the nonlinear dynamic inversion (NDI) controller.

Aircraft spin recovery using a sliding-mode controller

Analysis of Flexible Aircraft Dynamics Using Bifurcation Methods

Journal of Computer and Systems Sciences International

Computing short-time aircraft maneuvers using direct methods

Control and Robustness Analysis for a High-Infinity Maneuverable Thrust-Vectoring Aircraft

Automatica

Fault tolerant control using sliding modes with on-line control allocation

Aircraft maneuver design using bifurcation analysis and sliding mode control techniques

Journal	Journal of Guidance, Control, and Dynamics
ISSN	07315090
Open Access	No