Global stabilisation of the PVTOL aircraft with lateral force coupling and bounded inputs

"This work is devoted to prove that the nonlinear control scheme previously proposed by Zavala-Río, Fantoni and Lozano for the global stabilisation of the planar vertical take-off and landing (PVTOL) aircraft with bounded inputs neglecting the lateral force coupling is robust with respect to the parameter characterising such a lateral force coupling, ϵ, as long as such a parameter takes small enough values. In other words, global stabilisation is achieved even if ϵ > 0, provided that such a parameter be sufficiently small. As far as the authors are aware, such a property has not been proved in other existing control schemes when the value of ϵ is not known. The presented methodology is based on the use of embedded saturation functions. Furthermore, experimental results of the control algorithm implemented on a real prototype are presented.

Flat systems, equivalence and trajectory generation

Flat systems, an important subclass of nonlinear control systems introduced via differential-algebraic methods, are defined in a differential geometric framework. We utilize the infinite dimensional geometry developed by Vinogradov and coworkers: a control system is a diffiety, or more precisely, an ordinary diffiety, i.e. a smooth infinite-dimensional manifold equipped with a privileged vector field. After recalling the definition of a Lie-Backlund mapping, we say that two systems are equivalent if they are related by a Lie-Backlund isomorphism. Flat systems are those systems which are equivalent to a controllable linear one. The interest of such an abstract setting relies mainly on the fact that the above system equivalence is interpreted in terms of endogenous dynamic feedback. The presentation is as elementary as possible and illustrated by the VTOL aircraft

Robust structural feedback linearization based on the nonlinearities rejection

International audienceIn this paper, we consider a class of affine control systems and propose a new structural feedback linearization technique. This relatively simple approach involves a generic linear-type control scheme and follows the classic failure detection methodology. The robust linearization idea proposed in this contribution makes it possible an effective rejection of nonlinearities that belong to a specific class of functions. The nonlinearities under consideration are interpreted here as specific signals that affect the initially given systems dynamics. The implementability and efficiency of the proposed robust control methodology is illustrated via the attitude control of a PVTOL

Vers une simplification de la commande non linéaire : l'exemple d'un avion à décollage vertical

International audience``Model-Free Control'' and ``Control with a Restricted Model'', which were recently introduced, yield an elementary and easy to tune control strategy for a ``Planar Vertical Take-off and Landing'' (PVTOL) aircraft, which has been largely studied in the academic literature via various advanced nonlinear control techniques. The efficiency of our approach is demonstrated by several convincing computer simulations

Some tracking problems for aerospace models with input constraints

We study tracking controller design problems for key models of planar vertical takeoff and landing (PVTOL) aircraft and unmanned air vehicles (UAVs). The novelty of our PVTOL work is the global boundedness of our controllers in the decoupled coordinates, the positive uniform lower bound on the thrust controller, the applicability of our work to cases where the velocity measurements may not be available, the uniform global asymptotic stability and uniform local exponential stability of our closed loop tracking dynamics, the generality of our class of trackable reference trajectories, and the input-to-state stability of the controller performance under actuator errors of arbitrarily large amplitude. The significance of our UAV results is the generality of the trackable trajectories, the input-to-state stability properties of the tracking dynamics with respect to additive uncertainty on the controllers, and our ability to satisfy command amplitude and command rate constraints as well as state dependent command constraints and a state constraint on the velocity. Our work is based on a Matrosov approach for converting a nonstrict Lyapunov function for the UAV tracking dynamics into a strict one, in conjunction with asymptotic strict Lyapunov function methods and bounded backstepping

Research on reconfigurable control for a hovering PVTOL aircraft

This paper presents a novel reconfigurable control method for the planar vertical take-off and landing (PVTOL) aircraft when actuator faults occur. According to the position subsystem within the multivariable coupling, and the series between subsystems of position and attitude, an active disturbance rejection controller (ADRC) is used to counteract the adverse effects when actuator faults occur. The controller is cascade and ensures the input value of the controlled system can be tracked accurately. The coordinate transformation method is used for model decoupling due to the severe coupling. In addition, the Taylor differentiator is designed to improve the control precision based on the detailed research for tracking differentiator. The stability and safety of the aircraft is much improved in the event of actuator faults. Finally, the simulation results are given to show the effectiveness and performance of the developed method

Rechazo activo de perturbaciones en vehículos aéreos multirotor.

Objetivos y metodo de estudio: ´ The general objective of this thesis is to create and test a control for multirotor aircraft that is resistant to disturbances. Contribuciones y conlusiones: The proposed controller has the ability to be implemented into any type of multirotor vehicle

Effect of rotor tilt on the gust rejection properties of multirotor aircraft

In order to operate safely in windy and gusty conditions, multirotor VTOL aircraft require gust resilience. This paper shows that their gust rejection properties can be improved by applying a small amount of fixed outward rotor tilt. Standard aerodynamic models of the rotors are incorporated into two dynamic models to assess the gust rejection properties. The first case is a conceptual birotor planar VTOL aircraft. The dependence of the trim and stability on the tilt angle are analyzed. The aircraft is stabilized using a pole-placement approach in order to obtain consistent closed-loop station-keeping performance in still air. The effect of gusts on the resulting response is determined by simulation. The second case study is for a quadrotor with a 10∘" role="presentation" style="max-height: none; display: inline; line-height: normal; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; min-width: 0px; min-height: 0px; border-width: 0px; border-style: initial; position: relative;">10∘ outward rotor tilt. The aerodynamic coefficients are analyzed for trimmed station-keeping over a range of steady wind speeds. An LQR controller is used to apply station-keeping that includes integral action, and the gust responses are again obtained using simulation. The results show that the outward rotor tilt causes the aircraft to pitch down into a lateral gust, providing lateral force that opposes the gust and so significantly improving the gust rejection properties

Modeling and Control of mini UAV

International audienc