Felix Antonio Claudio Mora-Camino

Adaptive sliding mode control for quadrotor attitude stabilization and altitude tracking

Adaptive control algorithms are of interest in flight control systems design not only for their capability to improve performance and reliability but also for handling aerodynamic parameter uncertainties, external disturbances and modeling inaccuracies. In this paper, a direct adaptive sliding mode control is developed for the quadrotor attitude stabilization and altitude trajectory tracking. First, developed controller is applied without considering disturbances and parameter uncertainties. After, a centered white gaussian noise with some parameter uncertainties are added to the considered output vector, mass and inertia matrix, respectively. The synthesis of the adaptation laws is based on the positivity and Lyapunov design principle. Numerical simulations are performed showing the robustness of the proposed control technique.

Flight-Path Tracking Control of a Transportation Aircraft: Comparison of Two Nonlinear Design Approaches

For transport aircraft, the primary control objective for an autopilot system engaged during approach and landing is relative to the flight-path tracking on the basis of highly simplified linear models of flight dynamics. The dynamics governing the flight-path of an aircraft are in general highly nonlinear and involve complex physics for which no accurate models are available. In the past decades, some new nonlinear control design techniques appeared of interest for the development of improved control schemes for the flight-path tracking mode. In this communication, two nonlinear control techniques are used for the design of flight-path tracking control laws for a transport aircraft. A first control technique adopts a classical nonlinear dynamic inversion control scheme where enhanced robustness is introduced, and a second control scheme based on the backstepping technique is developed. These two approaches are compared in terms of applicability, complexity and robustness with respect to modeling inaccuracies and external perturbations. Finally, simulation results are displayed and discussed

A heuristic approach based on shortest path problems for integrated flight, aircraft, and passenger rescheduling under disruptions

In this paper, we present a heuristic method to solve an airline disruption management problem arising from the ROADEF 2009 challenge. Disruptions perturb an initial flight plan such that some passengers cannot start or conclude their planned trip. The developed algorithm considers passengers and aircraft with the same priority by reassigning passengers and by creating a limited number of flights. The aim is to minimize the cost induced for the airline by the recovery from the disruptions. The algorithm is tested on real-life-based data, as well as on large-scale instances and ranks among the best methods proposed to the challenge in terms of quality, while being efficient in terms of computation time.

A fuzzy logic approach for car-following modelling

In this communication, the classical car-following theory, which is based on intuitiveness and behavioural representation, is revisited from the point of view of cybernetics theory. Then, a new approach, based on fuzzy modelling, is proposed to estimate the main parameters of the basic car following model. This approach, contrarily to earlier fuzzy logic approaches, maintains the structure of the classical car-following model, limits its complexity and provides means to take into account the main parameters influencing the behaviour of the driver and allows a formal verification of local and global stability of the simulated traffic flow. So, after introducing a new approach based on cybernetics concepts for the modelling of car-following, which provides a theoretical basis for the basic model, the main concepts of fuzzy logic theory and of fuzzy modelling are briefly presented. Then a fuzzy estimation approach is proposed for the main parameters of the basic car-following model. Finally, simulation results making use of the proposed modelling approach are presented.

Dynamic programming for trajectory optimization of engine-out transportation aircraft

The purpose of this communication is to contribute to the development of a new trajectory management capability for an engine-out transportation aircraft. Engine-out is a dramatic situation for flight safety and this study focuses on the design of a management system for emergency trajectories at this special situation. First the gliding characteristics and flying qualities of a transport aircraft with total engine failure are analyzed while gliding range estimation is considered. Then a new representation of the flight dynamics of an engine-out aircraft is proposed where the space variable is chosen as independent parameter instead of the time variable. This allows to propose a new formulation of the corresponding trajectory optimization problem and to develop a reverse dynamic programming solution technique. Simulation results are displayed and new development perspectives are discussed.

Space-Based Nonlinear Dynamic Inversion Control for Aircraft Continuous Descent Approach

With the growth of civil aviation traffic, enhanced accuracy performances are required from guidance systems to maintain efficiency and safety in flight operations. This communication proposes a new representation of aircraft flight dynamics at approach for landing and a space-based nonlinear dynamic inversion control for a transportation aircraft. The main novelty is that the adopted independent variable is the distance to land. This new representation of flight dynamics should support the development of improved aircraft guidance systems.

Non-Linear Control Structures for Rotorcraft Positioning

The purpose of this communication is to apply and compare three different non-linear control approaches to the design of control structures with control laws allowing autonomous positioning and orientation for a four-rotor aircraft. Realistic rotorcraft flight dynamics are established and analyzed so that a reference three-layers control structure is defined. Then are introduced different non-linear control approaches: non-linear inverse control, backstepping control and differential flat control. The compatibility of these control approaches with the three-layer control structure is assessed and adaptations are .proposed so that they can cope with the guidance of the rotorcraft. The corresponding control laws are detailed and their expected performances are discussed. The simplification of these control laws around equilibrium conditions produces close quasi-linear proportional derivative controllers. A careful tuning of one of them provides a reference to evaluate the improvements resulting from the use of full non-linear control laws, when applied to the positioning and orientation problem. This evaluation is performed by simulation and numerical results are displayed for analysis.

Inverse control and stabilization of free-flying flexible robots

SUMMARY The question of control and stabilization of flexible space robots is considered. Although, this approach is applicable to space robots of other configurations, for simplicity, a flexible planar two-link robot, mounted on a rigid floating platform, is considered. The robotic arm has two revolute joints and its links undergo elastic deformation in the plane of rotation. Based on nonlinear inversion technique, a control law is derived for controlling output variables describing the position and orientation of the platform and the joint angles of the robot. Although, the inverse controller accomplishes reference trajectory tracking, it excites the elastic modes of the arm. For the vibration suppression, three different stabilizer are designed. Using linear quadratic optimal control theory, a composite stabilizer for stabilization of the rigid and flexible modes and a decoupled flexible mode stabilizer are designed for regulating the end point of the robot to the target point and vibration suppression. Stabilization using only elastic mode velocity feedback is also considered. For large maneuvers, first the inverse controller is active, and the stabilizer is switched for regulation when the motion of the robot lies in the neighborhood of the terminal equilibrium state. Simulation results are presented to show that in the closed-loop system including the inverse controller and each of the stabilizers, trajectory tracking and stabilization of elastic modes are accomplished.

Aircraft fault tolerant control based on active set method

This communication considers the case in which an aerodynamic actuator failure occurs to an aircraft while it has to perform a guidance manoeuver. The problem considered deals with the reassignment of the remaining actuators to continue to perform the manoeuver while maintaining the structural integrity of the aircraft. A nonlinear inverse control technique is used to generate online nominal moments along the three main axes of the aircraft. Then, taking into account all material and structural constraints as well as the redundant effects from other actuators, a Mathematical Programming problem to be solved online is introduced. The proposed on line solution method is based on an active set method which appears to provide acceptable response times according to the simulation results. Then new development perspectives are discussed.

Differential flatness applied to vehicle trajectory tracking

Differential flatness, a property of some dynamic systems which has been recognized only recently, has made possible the development of new tools to control complex nonlinear dynamic systems. Guidance dynamics of many different systems have been recognized as being explicitly or implicitly differentially flat as it is the case for flight guidance dynamics of conventional aircraft. In this paper, a new control structure is proposed to achieve trajectory tracking for vehicles: a neural network deals with the inversion of nominal guidance dynamics while a linear corrector cope with modelling errors and perturbations so that control directives to conventional autopilot systems can be generated in real time. The proposed approach is illustrated in the case of conventional aircraft flight dynamics.