Event-triggered attitude control for flying robots using an event approach based on the control

International audienceThis paper presents the development of a quaternion-based nonlinear event-triggered control for the attitude stabilization of Flying robots. Firstly, it is proved the existence of a Control Lyapunov Function. Unlike some previously proposed schemes, the aim of this paper is to propose a new and simpler event function. The control law ensures the asymptotic stability of the closed-loop system to the desired attitude. The approach is validated in real-time using a quadrotor mini-helicopter. The experiments show that the event driven controller reduces the control update without deteriorating the closed-loop system performance

Event-triggered attitude control for flying robots using an event approach based on the control

International audienceThis paper presents the development of a quaternion-based nonlinear event-triggered control for the attitude stabilization of Flying robots. Firstly, it is proved the existence of a Control Lyapunov Function. Unlike some previously proposed schemes, the aim of this paper is to propose a new and simpler event function. The control law ensures the asymptotic stability of the closed-loop system to the desired attitude. The approach is validated in real-time using a quadrotor mini-helicopter. The experiments show that the event driven controller reduces the control update without deteriorating the closed-loop system performance

Integral backstepping control for trajectory tracking of a hybrid vehicle

International audienceThis article is focused on the trajectory tracking using a hybrid terrestrial aerial vehicle. An integral back-stepping control is proposed for the UAV vehicle mode. In addition, a nested saturation control is developed and applied to regulate the position of the cart vehicle. These control laws are validated by simulations and some experimental results on position control was performed by applying the techniques aforementioned. I. SYSTEM DESCRIPTION In this work control laws are developed for trajectory tracking of a hybrid terrestrial aerial vehicle. These kinds of vehicles have the advantage to be used as a flying vehicle or as a cart depending on the situation. Some situations may be when the vehicle find an obstacle and it has to take the more convenient mode of operation to overcome or to avoid the obstacle. Controlling these hybrid vehicles becomes a challenge. It is necessary to design and implement control laws for the trajectory following in the air and over the floor. The control strategy has to generate a smooth transition when the drone is passing from air to floor or vice versa. There are several works dedicated to path following with hexarotors and also for carts, see for example [1]–[3]. This work considers a particular hybrid vehicle : a mini-UAV that is converted in a cart by attaching to it two wheels without any additional motors as in Fig. 1. The orientation and position of the cart will be controlled by the yaw and pitch angles and by the thrust generated by its helices. Among its characteristics, the thrust direction can be inversed as a result of the pitch angle variation. Therefore, the cart-drone can move forward or backward depending on the sign of pitch angle. This hybrid vehicle in terrestrial mode can turn around z axis. It is also a nonholonomic system because it is not capable to move on the wheels axis direction in terrestrial mode. For more references in cart control refer to [4]–[6]

Velocity control of mini-UAV using a helmet system

International audienceThe usage of a helmet to command a mini-unmanned aerial vehicle (mini-UAV), is a telepresence system that connects the operator to the vehicle. This paper proposes a system which remotely allows the connection of a pilot's head motion and the 3D movements of a mini-UAVs. Two velocity control algorithms have been tested in order to manipulate the system. Results demonstrate that these movements can be used as reference inputs of the controller of the mini-UAV

Attitude Stabilization of a Quadrotor by Means of Event-Triggered Nonlinear Control

International audienceEvent-triggered control is a resource-aware sampling strategy that updates the control value only when a certain condition is satis ed, which denotes event instants. Such a technique allows to reduce the control computational cost and communications. In this paper, a quaternion-based feedback is developed for event-triggered attitude stabilization of a quadrotor mini-helicopter. The feedback is derived from the universal formula for eventtriggered stabilization of general nonlinear systems a ne in the control. The proposed feedback ensures the asymptotic stability to the desired attitude. Real-time experiments are carried out in order to show the convergence of the quadrotor states to the desired attitude as well as the robustness with respect to external disturbances. Results show that the proposed control can reduce by 80 % the communications of the embedded system without sacri cing performance of the whole system. To the best of the authors' knowledge, this is the rst time that a nonlinear event-triggered controller is experimentally applied to the attitude stabilization of an unmanned aircraft system

Navigation autonome d'un drone en intérieur basée sur les images

This thesis presents the design and practical implementation of aquadrotor indoor navigation system using a vision system whose inputdata are obtained from environment information acquired by an embedded camera placed on quadrotor system. Actually, some used techniquesare mono vision, stereo vision, SLAM among others. For our researchwe propose to work with mono vision system, due the limited payload ofa quadrotor system. Properties in image perspective are used to designthe embedded vision system which aim is to extract visual information,to fly placed always in the center of a corridor. Camera rotation matrix is obtained by means of orthogonal directions extracted by vanishingpoints, which directions define a common structured environment. Then,to control and to stabilize our quadrotor system, a quaternion boundedcontrol scheme is presented, which stabilize quadrotor’s orientation, andalso is used to control its heading direction merging visual information.Quadrotor estimation positions with respect to world reference in y andz-axes are used as input for the bounded position control to pose it atdesired position. It should be mentioned that vision strategy is not ableto estimate x-axis, thus this axis is controlled manually.In order to corroborate ours results, mathematical model, control lawand vision system are simulated to corroborate the closed-loop system’sstability and for test our result in real world some platforms have beendeveloped, proposing a new quasi-virtual system that merge virtual worldwith real platform.Cette thèse présente la conception et la mise en œuvre pratique d’unsystème de navigation intérieure d’un Drone en utilisant un système de vision dont les données sont obtenues à partir des informations sur l'environnement acquises par une caméra embarquée sur un Drone. Les techniques récemment utilisent les systèmes mono vision, vision stéréo et SLAM. Dans cette thèse nous développons de techniques pour la mono vision, en raison de la charge utile limitée dans un Drone. Les propriétés de perspective dans le traitement d’images sont utilisées pour concevoir le système de vision embarquée qui vise à extraire des informations visuelles. Afin de réaliser la navigation au milieu d’un couloir, la matrice de rotation de la caméra est obtenue à partir de directions orthogonales extraites par des points de fuite, dont les directions définissent un environnement structuré commun. Pour commander et stabiliser notre système de type Drone, un schéma de commande à base de quaternion borné est présenté, celui stabilise l'orientation du Drone, et il est également utilisé pour commander sa direction, en fusionnant les informations visuelles et celles provenant de la centrale inertielle.Pour corroborer nos résultats, le modèle mathématique du drone, les lois de commande et le système de vision, sont simulés afin de tester la stabilité du système complet. Une fois les simulations validées, la navigation autonome d’un drone dans le monde réel a été réalisée. Finalement, nous avons fait évoluer une plateforme réelle dans un environnement virtuel, intitulé quais-virtuel

Event-triggered nonlinear control for attitude stabilization of a quadrotor

International audienceEvent-triggered control is a ressource-aware sampling strategy that updates the control value only when a certain condition is satisfied, which denotes event instants. Such a technique allows to reduce the control computational cost and communications. In this paper, a quaternion-based feedback is developed for event-triggered attitude stabilization of a quadrotor mini-helicopter. The feedback is derived from the universal formula for event-triggered stabilization of general nonlinear systems affine in the control. The proposed feedback ensures the asymptotic stability and it is smooth everywhere except at the origin. Real-time experiments are carried out in order to show the convergence of the quadrotor states to the desired attitude as well as the robustness with respect to external disturbances. Results show that the proposed control can reduce by 80 $\%$ the communications of the embedded system without sacrificing performance of the whole system. To the best of the authors' knowledge, this is the first time that a nonlinear event-triggered controller is experimentally applied to the attitude stabilization of an unmanned aircraft system

Event-Based LQR Control for Attitude Stabilization of a Quadrotor

International audienc

Rotorcraft with a 3DOF Rigid Manipulator: Quaternion-Based Modeling and Real-time Control Tolerant to Multi-Body Couplings

International audienceThis paper proposes a simple solution for the stabilization of a mini-quadcopter carrying a 3DoF (degrees of freedom) ma-nipulator robot in order to enhance its achievable workspace and application profile. Since the motion of the arm induces torques which degrade the stability of the system, in the present work, we consider the stabilization of both subsystems: the quadcopter and the robot- ic arm. The mathematical model of the system is based on quaternions. Likewise, an attitude control law consisting of a bounded qua- ternion-based feedback stabilizes the quadcopter to a desired attitude while the arm is evolving. The next stage is the translational dy-namics which is simplified for control (nonlinear) design purposes. The aforementioned controllers are based on saturation functions whose stability is explicitly proved in the Lyapunov sense. Finally, experimental results and a statistical study validate the proposed control strategy