Juan Escareño

Trajectory Control of a Quadrotor Subject to 2D Wind Disturbances

The paper addresses the flight control of a quad-rotor subject to two dimensional unknown static/varying wind disturbances. A model separation is proposed to simplify the control of the six-degrees-of-freedom (6DOF) nonlinear dynamics of the flying robot. Such approach allows to deal with quad-rotor’s 3D-motion via two subsystems: dynamic (altitude and MAV-relative forward velocity) and kinematic (nonholonomic-like navigation) subsystems. In terms of control, a hierarchical control is used as the overall control structure to stabilize the kinematic underactuaded subsystem. A control strategy based on sliding-mode and adaptive control techniques is proposed to deal with slow and fast time-varying wind conditions, respectively. This choice not only provides well tracking control but also improves the estimation of unknown disturbance. The backstepping technique is used to stabilize the inner-loop heading dynamics, such recursive design takes into account a constrained heading rate. Promising simulations results show the validity of the proposed control strategy while tracking a time-parameterized straight-line and sinusoidal trajectory.

Autonomous Hovering of a Noncyclic Tiltrotor UAV: Modeling, Control and Implementation

The aim of this paper is to present a mini tilt-rotor unmanned aerial vehicle which is capable to perform hover flight. Unlike conventional full-scale tiltrotors, in our design we avoid the use of swashplate and we propose a simpler mechanical design which use only the tilting rotors to stabilize the vehicle dynamics. A detailed mathematical model is derived via the Newton-Euler formalism. A nonlinear control scheme, incorporating bounded smooth function, is obtained from the decoupled dynamics and applied to real prototype for controlling hover flight.

Modeling and Global Control of the Longitudinal Dynamics of a Coaxial Convertible Mini-UAV in Hover Mode

The aim of this paper is to present a configuration for a Convertible Unmanned Aerial Vehicle, which incorporates the advantages of the coaxial rotorcraft for hover flight and the efficiencies of a fixed-wing for forward flight. A detailed dynamical model, including the aerodynamics, is obtained via the Newton-Euler formulation. It is proposed a nonlinear control law that achieves global stability for the longitudinal vertical-mode motion. Indeed, we have performed a simulation study to test the proposed controller in presence of external perturbations, obtaining satisfactory results. We have developed an embedded autopilot to validate the proposed prototype and the control law in hover-mode flight.

Vision-based Position Control of a Two-rotor VTOL miniUAV

In this paper we address the stabilization of the attitude and position of a birotor miniUAV to perform autonomous flight. For this purpose, we have implemented a Kalman-based sensor fusion between inertial sensors (gyros-accelerometers) and the optical flow (OF) provided by the vehicle. This fusion algorithm extracts the translational-OF (TOF) component and discriminates the rotational OF (ROF). The aircraft’s position is obtained through an object detection algorithm (centroid tracking). Newton-Euler motion equations were used to deduce the mathematical model of the vehicle. In terms of control we have employed a saturated-based control to stabilize the state of the aircraft around the origin. Experimental autonomous flight was successfully achieved, which validates the sensing strategy as well as the embedded control law.

Real-time altitude robust controller for a Quad-rotor aircraft using Sliding-mode control technique

A real-time robust altitude control scheme is proposed for the efficient performance of a Quadrotor aircraft system. The sensing of altitude measurement sensing is performed by a pressure sensor in order to obtain a robust altitude control of the vehicle in hovering mode both indoor and outdoor. The altitude measurement has the advantage of introducing this state information directly in the closed loop control which should be very useful for achieving robust stabilization of the altitude of the vehicle. To this end, a Sliding Mode Control strategy is implemented for the Quad-rotor aircraft. We have assumed that the actuators are able to respond quickly and accurately and we have not enforced limits on the control signals. Finally, to verify the satisfactory performance of proposed nonlinear control law, simulations and experimental results of the Sliding Mode Control technique for the Quadrotor aircraft in the presence of bounded disturbances are presented.

The Transition Phase of a Gun-Launched Micro Air Vehicle

The present paper addresses the transition stage of a Gun-Launched Micro Air Vehicle (GLMAV) whose main goal is to rapidly position a rotorcraft MAV over a high-risk scene (Prison riots, blind zones: e.g. over-the-hill, etc.). The development of this robotic platform is part of an overall ongoing project (GLMAV) headed by the St. Louis French-German Research Institute (ISL). The vehicle is launched at a distance of 500 m and a height of 100 m, where the GLMAV will collect and transmit visual information from the scene. Issues raising from the use of the gun-based launching technique are discussed in detail. A control strategy is proposed to overcome such problems and to stabilize the GLMAV. High-fidelity simulations, covering ballistic and transition phases, validate the control policy adopted to face the MAV gun-launching problem.

Task-based control of a multirotor miniature aerial vehicle having an onboard manipulator

The paper presents the modeling and control of a class of multirotor miniature aerial vehicle (MAV) having an onboard robotic manipulator. These kind of configuration represents the logical evolution in the MAV development race. The main goal is to outstrip the current operational profile, specially in the civilian field, by endowing classical MAV configurations with novel capabilities to interact with the surrounding environment. The equations that describes the dynamic model of this class of aerial robot, for translation and rotational motion, are obtained through the Euler-Lagrange formalism. This energy-based modeling approach allows to obtain the mechanical couplings between both aerial and manipulation systems, the aerial and manipulation. In terms of control, our main goal is to provide a simple-to-implement controller to perform aerial manipulation tasks using multirotor MAVs. A task-based control strategy is then proposed to cancel the couplings in the overall dynamic model (model simplification). The control law for the aerial system relies on a classical two-level scheme to fulfill tracking problem. On the other hand, the motion problem of the manipulation system is addressed via a switching-based controller. The controller corresponding stability proofs are presented and the performance of the control strategy is evaluated at simulation level.

Towards Gun- and Aircraft - launched MAVs: Embedded Flight Control System

The actual paper presents an embedded flight control systems (EFCS) of two micro air vehicles (MAVs) concepts, the gun-launched MAV (GLMAV) and the aircraft-launched MAV (ALMAV), meant to rapidly reach a target zone further away from the launching point. The paper details the embedded architecture used by both vehicles at software and hardware level. The software layer contains the algorithms to process the onboard sensors information as well as to compute the control law. The hardware layer features the bidirectional communication link with the ground workstation and interfaces the control commands with the actuators. The key element of the overall embedded processing architecture is the Gumstix-COM which operates under the Xenomai real-time framework. Concerning the configuration of the airframe, we provide a descriptive study of the transition phase, covering the dynamic model and control scheme. The evaluation of the two concepts implies a comparative, regarding to identify similarities and differences of the configuration, i.e. advantages and drawbacks. Motivating simulations results were obtained in the evaluation of the flight controller within the transition phase. The experimental evaluation of the proposed EFCS during autonomous attitude-stabilized flight has returned promising results.

Quad-tilting thrusters micro submarine: Modeling and control of the attitude

In this paper we present the design, modeling and control of a quad tilting thruster Micro Autonomous Underwater Vehicle (MicroAUV). The detailed dynamic model of the vehicle is deduced via the Euler-Lagrange formulation. We address the stabilization of the attitude of the vehicle to perform manipulation tasks. For this purpose, we have employed a saturated-based control algorithm. Experimental autonomous attitude control was successfully achieved, validating the proposed vehicle as well as the embedded control system.

Estabilización de un mini helicóptero de cuatro rotores basada en flujo óptico y sensores inerciales

This paper addresses the hover flight stabilization problems of a four-rotor rotorcraft using fusion of visual information given by a single camera and inertial information obtained from an Inertial Measurement Unit. We use the optical flow in combination with the integration of gyro measurement to estimate the linear and rotational yaw velocities as well as the position and velocity of a UAV. Experimental results show a satisfactory flight performance of the four-rotor rotorcraft platform.