Center for Advanced Aerospace Technologies

Sevilla, Spain

Center for Advanced Aerospace Technologies

Sevilla, Spain
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Kondak K.,German Aerospace Center | Huber F.,German Aerospace Center | Schwarzbach M.,German Aerospace Center | Laiacker M.,German Aerospace Center | And 4 more authors.
Proceedings - IEEE International Conference on Robotics and Automation | Year: 2014

This paper is devoted to a system for aerial manipulation, composed of a helicopter and an industrial manipulator. The usage of an industrial manipulator is motivated by practical applications which were identified in different cooperation projects with the industry. We address the coupling between manipulator and helicopter and show that even in case when we have an ideal controller for manipulator and a highperformance controller for helicopter, an unbounded energy flow can be generated by internal forces between helicopter and manipulator if both controllers are used independently. To solve this problem we propose a new kinematical coupling for control by introducing an additional manipulation DoF realized by helicopter rotation around its yaw axis. The new experimental setup and required modifications in the manipulator controller for this purpose are described. Further, we propose dynamical coupling which is implemented by modification of the helicopter controller feeding the interaction force/torque, measured between manipulator base and fuselage, directly to the actuators of the rotor blades. At the end, we present experimental results for aerial manipulation and their analysis. © 2014 IEEE.


Maza I.,University of Seville | Caballero F.,University of Seville | Capitan J.,University of Seville | Martinez-De-Dios J.R.,University of Seville | And 2 more authors.
Journal of Field Robotics | Year: 2011

This paper presents the architecture developed in the framework of the AWARE project for the autonomous distributed cooperation between unmanned aerial vehicles (UAVs), wireless sensor/actuator networks, and ground camera networks. One of the main goals was the demonstration of useful actuation capabilities involving multiple ground and aerial robots in the context of civil applications. A novel characteristic is the demonstration in field experiments of the transportation and deployment of the same load with single/multiple autonomous aerial vehicles. The architecture is endowed with different modules that solve the usual problems that arise during the execution of multipurpose missions, such as task allocation, conflict resolution, task decomposition, and sensor data fusion. The approach had to satisfy two main requirements: robustness for operation in disaster management scenarios and easy integration of different autonomous vehicles. The former specification led to a distributed design, and the latter was tackled by imposing several requirements on the execution capabilities of the vehicles to be integrated in the platform. The full approach was validated in field experiments with different autonomous helicopters equipped with heterogeneous devices onboard, such as visual/infrared cameras and instruments to transport loads and to deploy sensors. Four different missions are presented in this paper: sensor deployment and fire confirmation with UAVs, surveillance with multiple UAVs, tracking of firemen with ground and aerial sensors/cameras, and load transportation with multiple UAVs. Copyright © 2011 Wiley Periodicals, Inc.


Heredia G.,University of Seville | Duran A.,Center for Advanced Aerospace Technologies | Ollero A.,University of Seville | Ollero A.,Center for Advanced Aerospace Technologies
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2012

The "Helicopter ADaptive Aircraft" (HADA) is a reconfigurable UAV that performs both as a helicopter for take-off, landing and hovering flight, but that "morphs" in flight to a conventional fixed wing configuration for cruise flight, unfolding the wings that are beneath the fuselage and transferring power from the main rotor to a pusher propeller. This paper presents the dynamic model of the behaviour of the HADA in the transition phases. The model takes into account the aerodynamic effects and variable mass and inertia characteristics of variable sweeping wings which are present in the HADA design, incorporating wind tunnel data. Simulations of the wing deployment process of the HADA are also presented. © 2011 Springer Science+Business Media B.V.


Conde R.,University of Seville | Alejo D.,University of Seville | Cobano J.A.,University of Seville | Viguria A.,Center for Advanced Aerospace Technologies | And 2 more authors.
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2012

This paper presents a Conflict Detection and Resolution (CDR) method for cooperating Unmanned Aerial Vehicles (UAVs) sharing airspace. The proposed method detects conflicts using an algorithm based on axis-aligned minimum bounding box and solves the detected conflicts cooperatively using a genetic algorithm that modifies the trajectories of the UAVs with an overall minimum cost. The method changes the initial flight plan of each UAV by adding intermediate waypoints that define the solution flight plan while maintaining their velocities. The method has been validated with many simulations and experimental results with multiple aerial vehicles platforms based on quadrotors in a common airspace. The experiments have been carried out in the multi-UAV aerial testbed of the Center for Advanced Aerospace Technologies (CATEC). © 2011 Springer Science+Business Media B.V.


Garcia M.,Center for Advanced Aerospace technologies | Viguria A.,Center for Advanced Aerospace technologies | Ollero A.,Center for Advanced Aerospace technologies | Ollero A.,University of Seville
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2013

This paper discusses several alternatives, based on graph search, to calculate UAV trajectories that avoid regions with dangerous weather effects and with the least deviation from the shortest trajectory. It is also explained how to adapt graph search algorithms to be used for 3D trajectories with UAVs, and which design considerations should be taken into account (for example the discretization of the airspace). Also, an extension of the Lazy Theta * algorithm is presented; a dynamic algorithm that calculates the trajectory while the weather hazards information is updated. The paper includes simulations and experimental results in the CATEC testbed with multiple UAVs. © Springer Science+Business Media Dordrecht 2012.


Sandino L.A.,University of Seville | Bejar M.,Pablo De Olavide University | Kondak K.,German Aerospace Center | Ollero A.,University of Seville | Ollero A.,Center for Advanced Aerospace Technologies
Journal of Intelligent and Robotic Systems: Theory and Applications | Year: 2013

Helicopters are well-known by their hovering capabilities. However, the performance of this valuable feature can be seriously affected by external disturbances such as wind effects. The latter could be even more significant when dealing with small-size helicopters, which are commonly adopted as base platforms for developing unmanned aerial vehicles. Motivated by this context, this work proposes an augmented configuration for performing more stable hovering maneuvers that consists of the unmanned helicopter itself, a tether connecting the helicopter to the ground, and a device on ground adjusting the tether tension. A modeling analysis on the inherent benefits to the proposed configuration as well as the control guidelines to exploit such potentialities are presented in this paper. As a proof a concept, a first basic implementation of the control structure for the entire system is also included. Finally, several demonstrating simulations under artificially generated wind influences are presented to endorse the validity of the proposed approach. © 2012 Springer Science+Business Media B.V.


Ferruz J.,University of Seville | Vega V.M.,University of Seville | Ollero A.,University of Seville | Ollero A.,Center for Advanced Aerospace Technologies | Blanco V.,Airbus
IEEE Transactions on Industrial Electronics | Year: 2011

This paper presents the architecture of an onboard controller developed for the HERO autonomous helicopter, which is a low-cost unmanned aerial vehicle research platform. An embedded digital-signal-processor-based low-level controller is devoted to flight control, while a PC-based high-level controller is used for onboard perception tasks and interaction with other agents in a distributed system. The functional design, software architecture, and implementation of the low-level controller are analyzed in detail, focusing mainly on its runtime environment (JULIET) and its capability for flexible reconfiguration. The connectivity functions of the low-level controller with external possibly distributed agents are also addressed. Finally, the results of real autonomous flight experiments are presented, including the tracking of a smooth 3-D path described by over two hundred waypoints. © 2011 IEEE.


Viguria A.,Center for Advanced Aerospace Technologies | Maza I.,University of Seville | Ollero A.,Center for Advanced Aerospace Technologies | Ollero A.,University of Seville
Advanced Robotics | Year: 2010

This paper presents a system for the coordination of aerial and ground robots for applications such as surveillance and intervention in emergency management. The overall system architecture is described. An important part for the coordination between robots is the task allocation strategy. A distributed market-based algorithm, called S + T, has been developed to solve the multi-robot task allocation problem in applications that require cooperation among the robots to accomplish all the tasks. Using this algorithm, robots can provide transport and communication relay services dynamically to other robots during the missions. Moreover, the paper presents a demonstration with a team of heterogeneous robots (aerial and ground) cooperating in a mission of fire detection and extinguishing. © 2010 VSP.


Alarcon F.,Center for Advanced Aerospace Technologies | Santamaria D.,Center for Advanced Aerospace Technologies | Viguria A.,Center for Advanced Aerospace Technologies
IFAC-PapersOnLine | Year: 2015

The objective of this work is to describe an innovative relative position and velocity state estimation approach for rotatory wing UAV linked with a rope. An autonomous landing of a UAV helicopter in a static and in mobile platform in absence of GPS are presented as application of this technology. The relative estimation is obtained using a device that provides rope orientation, and tension information, an altimeter and an IMU. All this information is combined using a sensor fusion strategy. © 2015, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.


Ruiz J.J.,Center for Advanced Aerospace Technologies | Diaz-Mas L.,Center for Advanced Aerospace Technologies | Perez F.,Center for Advanced Aerospace Technologies | Viguria A.,Center for Advanced Aerospace Technologies
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2013

In this work we evaluated how the use of different positioning systems affects the accuracy of Digital Elevation Models (DEMs) generated from aerial imagery obtained with Unmanned Aerial Vehicles (UAVs). In this domain, state-of-the-art DEM generation algorithms suffer from typical errors obtained by GPS/INS devices in the position measurements associated with each picture obtained. The deviations from these measurements to real world positions are about meters. The experiments have been carried out using a small quadrotor in the indoor testbed at the Center for Advanced Aerospace Technologies (CATEC). This testbed houses a system that is able to track small markers mounted on the UAV and along the scenario with millimeter precision. This provides very precise position measurements, to which we can add random noise to simulate errors in different GPS receivers. The results showed that final DEM accuracy clearly depends on the positioning information.

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