References of "Mejias, Luis"
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See detailCross-Entropy Optimization for Scaling Factors of a Fuzzy Controller: A See-and-Avoid Approach for Unmanned Aerial Systems
Olivares Mendez, Miguel Angel UL; Mejias, Luis; Campoy, Pascual et al

in Journal of Intelligent and Robotic Systems (2013), 69(1-4), 189-205

The Cross-Entropy (CE) is an efficient method for the estimation of rare-event probabilities and combinatorial optimization. This work presents a novel approach of the CE for optimization of a Soft ... [more ▼]

The Cross-Entropy (CE) is an efficient method for the estimation of rare-event probabilities and combinatorial optimization. This work presents a novel approach of the CE for optimization of a Soft-Computing controller. A Fuzzy controller was designed to command an unmanned aerial system (UAS) for avoiding collision task. The only sensor used to accomplish this task was a forward camera. The CE is used to reach a near-optimal controller by modifying the scaling factors of the controller inputs. The optimization was realized using the ROS-Gazebo simulation system. In order to evaluate the optimization a big amount of tests were carried out with a real quadcopter. [less ▲]

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See detailMAVwork: A Framework for Unified Interfacing between Micro Aerial Vehicles and Visual Controllers
Mellado-Bataller, Ignacio; Pestana, Jesús; Olivares Mendez, Miguel Angel UL et al

in Lee, Sukhan; Yoon, Kwang-Joon; Lee, Jangmyung (Eds.) Frontiers of Intelligent Autonomous Systems (2013)

Debugging control software for Micro Aerial Vehicles (MAV) can be risky out of the simulator, especially with professional drones that might harm people around or result in a high bill after a crash. We ... [more ▼]

Debugging control software for Micro Aerial Vehicles (MAV) can be risky out of the simulator, especially with professional drones that might harm people around or result in a high bill after a crash. We have designed a framework that enables a software application to communicate with multiple MAVs from a single unified interface. In this way, visual controllers can be first tested on a low-cost harmless MAV and, after safety is guaranteed, they can be moved to the production MAV at no additional cost. The framework is based on a distributed architecture over a network. This allows multiple configurations, like drone swarms or parallel processing of drones' video streams. Live tests have been performed and the results show comparatively low additional communication delays, while adding new functionalities and flexibility. This implementation is open-source and can be downloaded from github.com/uavster/mavwork [less ▲]

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See detailQuadcopter see and avoid using a fuzzy controller
Olivares Mendez, Miguel Angel UL; Mejias, Luis; Campoy, Pascual et al

in Uncertainty modeling in knowlege engineering and decision making : proceedings of the 10th International FLINS Conference (2012)

Unmanned Aerial Vehicles (UAVs) industry is a fast growing sector. Nowadays, the market offers numerous possibilities for off-the-shelf UAVs such as quadrotors or fixed-wings. Until UAVs demonstrate ... [more ▼]

Unmanned Aerial Vehicles (UAVs) industry is a fast growing sector. Nowadays, the market offers numerous possibilities for off-the-shelf UAVs such as quadrotors or fixed-wings. Until UAVs demonstrate advance capabilities such as autonomous collision avoidance they will be segregated and restricted to flight in controlled environments. This work presents a visual fuzzy servoing system for obstacle avoidance using UAVs. To accomplish this task we used the visual information from the front camera. Images are processed off-board and the result send to the Fuzzy Logic controller which then send commands to modify the orientation of the aircraft. Results from flight test are presented with a commercial off-the-shelf platform. [less ▲]

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See detailRapid Prototyping Framework for Visual Control of Autonomous Micro Aerial Vehicles
Mellado-Bataller, Ignacio; Campoy, Pascual; Olivares Mendez, Miguel Angel UL et al

in Advances in Intelligent Systems and Computing (2012), 193

Rapid prototyping environments can speed up the research of visual control algorithms. We have designed and implemented a software framework for fast prototyping of visual control algorithms for Micro ... [more ▼]

Rapid prototyping environments can speed up the research of visual control algorithms. We have designed and implemented a software framework for fast prototyping of visual control algorithms for Micro Aerial Vehicles (MAV). We have applied a combination of a proxy-based network communication architecture and a custom Application Programming Interface. This allows multiple experimental configurations, like drone swarms or distributed processing of a drones video stream. Currently, the framework supports a low-cost MAV: the Parrot AR.Drone. Real tests have been performed on this platform and the results show comparatively low figures of the extra communication delay introduced by the framework, while adding new functionalities and flexibility to the selected drone. This implementation is open-source and can be downloaded from www.vision4uav.com/?q=VC4MAV-FW [less ▲]

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See detailSee-and-Avoid Quadcopter using Fuzzy Control Optimized by Cross-Entropy
Olivares Mendez, Miguel Angel UL; Campoy, Pascual; Mellado-Bataller, Ignacio et al

in See-and-Avoid Quadcopter using Fuzzy Control Optimized by Cross-Entropy (2012)

In this work we present an optimized fuzzy visual servoing system for obstacle avoidance using an unmanned aerial vehicle. The cross-entropy theory is used to optimise the gains of our controllers. The ... [more ▼]

In this work we present an optimized fuzzy visual servoing system for obstacle avoidance using an unmanned aerial vehicle. The cross-entropy theory is used to optimise the gains of our controllers. The optimization process was made using the ROS-Gazebo 3D simulation with purposeful extensions developed for our experiments. Visual servoing is achieved through an image processing front-end that uses the Camshift algorithm to detect and track objects in the scene. Experimental flight trials using a small quadrotor were performed to validate the parameters estimated from simulation. The integration of cross-entropy methods is a straightforward way to estimate optimal gains achieving excellent results when tested in real flights. [less ▲]

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See detailUAS See-and-Avoid using two different approaches of Fuzzy Control
Olivares Mendez, Miguel Angel UL; Mejias, Luis; Campoy, Pascual et al

in 2012 International Conference on Unmanned Aircraft Systems (ICUAS'12) (2012)

This work presents two UAS See and Avoid approaches using Fuzzy Control. We compare the performance of each controller when a Cross-Entropy method is applied to optimase the parameters for one of the ... [more ▼]

This work presents two UAS See and Avoid approaches using Fuzzy Control. We compare the performance of each controller when a Cross-Entropy method is applied to optimase the parameters for one of the controllers. Each controller receive information from an image processing frontend that detect and track targets in the environment. Visual information is then used under a visual servoing approach to perform autonomous avoidance. Experimental flight trials using a small quadrotor were performed to validate and compare the behaviour of both controllers. [less ▲]

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See detailA multi-resolution image alignment technique based on direct methods for pose estimation of aerial vehicles
Martinez Luna, Carol UL; Mejias, Luis; Campoy, Pascual

in 2011 International Conference on Digital Image Computing: Techniques and Applications (2011)

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See detailAerial object following using visual fuzzy servoing
Olivares Mendez, Miguel Angel UL; Mondragon, Ivan; Campoy, Pascual et al

in First Workshop on Research, Development and Education on Unmanned Aerial Systems (RED-UAS 2011) (2011)

This article presents a visual servoing system to follow a 3D moving object by a Micro Unmanned Aerial Vehicle (MUAV). The presented control strategy is based only on the visual information given by an ... [more ▼]

This article presents a visual servoing system to follow a 3D moving object by a Micro Unmanned Aerial Vehicle (MUAV). The presented control strategy is based only on the visual information given by an adaptive tracking method based on the color information. A visual fuzzy system has been developed for servoing the camera situated on a rotary wing MAUV, that also considers its own dynamics. This system is focused on continuously following of an aerial moving target object, maintaining it with a fixed safe distance and centered on the image plane. The algorithm is validated on real flights on outdoors scenarios, showing the robustness of the proposed systems against winds perturbations, illumination and weather changes among others. The obtained results indicate that the proposed algorithms is suitable for complex controls task, such object following and pursuit, flying in formation, as well as their use for indoor navigation [less ▲]

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See detailUnmanned aerial vehicles UAVs attitude, height, motion estimation and control using visual systems
Mondragon, Ivan F.; Olivares Mendez, Miguel Angel UL; Campoy, Pascual et al

in AUTONOMOUS ROBOTS (2010), 29(1), 17-34

This paper presents an implementation of an aircraft pose and motion estimator using visual systems as the principal sensor for controlling an Unmanned Aerial Vehicle (UAV) or as a redundant system for an ... [more ▼]

This paper presents an implementation of an aircraft pose and motion estimator using visual systems as the principal sensor for controlling an Unmanned Aerial Vehicle (UAV) or as a redundant system for an Inertial Measure Unit (IMU) and gyros sensors. First, we explore the applications of the unified theory for central catadioptric cameras for attitude and heading estimation, explaining how the skyline is projected on the catadioptric image and how it is segmented and used to calculate the UAV's attitude. Then we use appearance images to obtain a visual compass, and we calculate the relative rotation and heading of the aerial vehicle. Additionally, we show the use of a stereo system to calculate the aircraft height and to measure the UAV's motion. Finally, we present a visual tracking system based on Fuzzy controllers working in both a UAV and a camera pan and tilt platform. Every part is tested using the UAV COLIBRI platform to validate the different approaches, which include comparison of the estimated data with the inertial values measured onboard the helicopter platform and the validation of the tracking schemes on real flights. [less ▲]

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See detailComputer Vision Onboard UAVs for Civilian Tasks
Campoy, Pascual; Correa, Juan F.; Mondragon, Ivan et al

in Journal of Intelligent and Robotic Systems (2009), 54(1-3), 105-135

Computer vision is much more than a technique to sense and recover environmental information from an UAV. It should play a main role regarding UAVs' functionality because of the big amount of information ... [more ▼]

Computer vision is much more than a technique to sense and recover environmental information from an UAV. It should play a main role regarding UAVs' functionality because of the big amount of information that can be extracted, its possible uses and applications, and its natural connection to human driven tasks, taking into account that vision is our main interface to world understanding. Our current research's focus lays on the development of techniques that allow UAVs to maneuver in spaces using visual information as their main input source. This task involves the creation of techniques that allow an UAV to maneuver towards features of interest whenever a GPS signal is not reliable or sufficient, e. g. when signal dropouts occur (which usually happens in urban areas, when flying through terrestrial urban canyons or when operating on remote planetary bodies), or when tracking or inspecting visual targets-including moving ones-without knowing their exact UMT coordinates. This paper also investigates visual servoing control techniques that use velocity and position of suitable image features to compute the references for flight control. This paper aims to give a global view of the main aspects related to the research field of computer vision for UAVs, clustered in four main active research lines: visual servoing and control, stereo-based visual navigation, image processing algorithms for detection and tracking, and visual SLAM. Finally, the results of applying these techniques in several applications are presented and discussed: this study will encompass power line inspection, mobile target tracking, stereo distance estimation, mapping and positioning. [less ▲]

Detailed reference viewed: 148 (3 UL)