Towards autonomous detection and tracking of electric towers for aerial power line inspection

in 2014 International Conference on Unmanned Aircraft Systems (ICUAS) (2014)

Floor Optical Flow Based Navigation Controller for Multirotor Aerial Vehicles

in ROBOT2013: First Iberian Robotics Conference (2013, November)

Vision based GPS-denied Object Tracking and following for unmanned aerial vehicles

in 2013 IEEE International Symposium on Safety, Security, and Rescue Robotics (SSRR) (2013, October)

We present a vision based control strategy for tracking and following objects using an Unmanned Aerial Vehicle. We have developed an image based visual servoing method that uses only a forward looking ... [more ▼]

We present a vision based control strategy for tracking and following objects using an Unmanned Aerial Vehicle. We have developed an image based visual servoing method that uses only a forward looking camera for tracking and following objects from a multi-rotor UAV, without any dependence on GPS systems. Our proposed method tracks a user specified object continuously while maintaining a fixed distance from the object and also simultaneously keeping it in the center of the image plane. The algorithm is validated using a Parrot AR Drone 2.0 in outdoor conditions while tracking and following people, occlusions and also fast moving objects; showing the robustness of the proposed systems against perturbations and illumination changes. Our experiments show that the system is able to track a great variety of objects present in suburban areas, among others: people, windows, AC machines, cars and plants. [less ▲]

Identificación y control en cascada mediante inversión de no linealidades del cuatrirrotor para el Concurso de Ingeniería de Control CEA IFAC 2012

in RIAI - Revista Iberoamericana de Automatica e Informatica Industrial (2013), 10(3),

A general purpose configurable navigation controller for micro aerial multirotor vehicles

in 2013 International Conference on Unmanned Aircraft Systems (ICUAS) (2013, May)

In this paper, we consider the problem of autonomous navigation of multirotor platforms in GPS-denied environments. The focus of this work is on safe navigation based on unperfect odometry measurements ... [more ▼]

In this paper, we consider the problem of autonomous navigation of multirotor platforms in GPS-denied environments. The focus of this work is on safe navigation based on unperfect odometry measurements, such as on-board optical flow measurements. The multirotor platform is modeled as a flying object with specific kinematic constraints that must be taken into account in order to obtain successful results. A navigation controller is proposed featuring a set of configurable parameters that allow, for instance, to have a configuration setup for fast trajectory following, and another to soften the control laws and make the vehicle navigation more precise and slow whenever necessary. The proposed controller has been successfully implemented in two different multirotor platforms with similar sensoring capabilities showing the openness and tolerance of the approach. This research is focused around the Computer Vision Group's objective of applying multirotor vehicles to civilian service applications. The presented work was implemented to compete in the International Micro Air Vehicle Conference and Flight Competition IMAV 2012, gaining two awards: the Special Award on “Best Automatic Performance - IMAV 2012” and the second overall prize in the participating category “Indoor Flight Dynamics - Rotary Wing MAV”. Most of the code related to the present work is available as two open-source projects hosted in GitHub. [less ▲]

Cross-Entropy Optimization for Scaling Factors of a Fuzzy Controller: A See-and-Avoid Approach for Unmanned Aerial Systems

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 ▲]

Autonomous Landing of an Unmanned Aerial Vehicle using Image-Based Fuzzy Control

in Second Workshop on Research, Development and Education on Unmanned Aerial Systems (RED-UAS 2013) (2013)

This paper presents a vision based autonomous landing control approach for unmanned aerial vehicles (UAV). The 3D position of an unmanned helicopter is estimated based on the homographies estimated of a ... [more ▼]

This paper presents a vision based autonomous landing control approach for unmanned aerial vehicles (UAV). The 3D position of an unmanned helicopter is estimated based on the homographies estimated of a known landmark. The translation and altitude estimation of the helicopter against the helipad position are the only information that is used to control the longitudinal, lateral and descend speeds of the vehicle. The control system approach consists in three Fuzzy controllers to manage the speeds of each 3D axis of the aircraft’s coordinate system. The 3D position estimation was proven first, comparing it with the GPS + IMU data with very good results. The robust of the vision algorithm against occlusions was also tested. The excellent behavior of the Fuzzy control approach using the 3D position estimation based in homographies was proved in an outdoors test using a real unmanned helicopter. [less ▲]

Towards autonomous air-to-air refuelling for UAVs using visual information

in 2013 IEEE International Conference on Robotics and Automation (2013)

A Hierarchical Tracking Strategy for Vision-Based Applications On-Board UAVs

in Journal of Intelligent & Robotic Systems (2013), 72(3-4), 517-539

In this paper, we apply a hierarchical tracking strategy of planar objects (or that can be assumed to be planar) that is based on direct methods for vision-based applications on-board UAVs. The use of ... [more ▼]

In this paper, we apply a hierarchical tracking strategy of planar objects (or that can be assumed to be planar) that is based on direct methods for vision-based applications on-board UAVs. The use of this tracking strategy allows to achieve the tasks at real-time frame rates and to overcome problems posed by the challenging conditions of the tasks: e.g. constant vibrations, fast 3D changes, or limited capacity on-board. The vast majority of approaches make use of featurebased methods to track objects. Nonetheless, in this paper we show that although some of these feature-based solutions are faster, direct methods can be more robust under fast 3D motions (fast changes in position), some changes in appearance, constant vibrations (without requiring any specific hardware or software for video stabilization), and situations in which part of the object to track is outside of the field of view of the camera. The performance of the proposed tracking strategy onboard UAVs is evaluated with images from realflight tests using manually-generated ground truthinformation, accurate position estimation using a Vicon system, and also with simulated data from a simulation environment. Results show that the hierarchical tracking strategy performs better than well-known feature-based algorithms and wellknown configurations of direct methods, and that its performance is robust enough for vision-in-theloop tasks, e.g. for vision-based landing tasks. [less ▲]

AR Drone identification and navigation control at CVG-UPM

Scientific Conference (2012, September)