![]() Sanchez Lopez, Jose Luis ![]() in 2015 International Conference on Unmanned Aircraft Systems (ICUAS) (2015, June) The International Aerial Robotics Competition (IARC) aims at pulling forward the state of the art in UAV. The Mission's 7 challenge deals mainly with GPS/Laser denied navigation, Robot-Robot interaction ... [more ▼] The International Aerial Robotics Competition (IARC) aims at pulling forward the state of the art in UAV. The Mission's 7 challenge deals mainly with GPS/Laser denied navigation, Robot-Robot interaction and obstacle avoidance in the setting of a ground robot herding problem. We present in this paper our UAV which took part in the 2014 competition, in the China venue. This year, the mission was not completed by any participant but our team at Technical University of Madrid (UPM) were awarded with two special prizes: Best Target Detection and Best System Control. The platform, hardware and the developed software used in this top leading competition are presented in this paper. This software has three main components: the visual localization and mapping algorithm; the control algorithms; and the mission planner. A statement of the safety measures integrated in the drone and of our efforts to ensure field testing in conditions as close as possible to the challenger's are also included. [less ▲] Detailed reference viewed: 41 (2 UL)![]() ; Sanchez Lopez, Jose Luis ![]() Scientific Conference (2014, August) Detailed reference viewed: 42 (0 UL)![]() Martinez Luna, Carol ![]() in Machine Vision and Applications (2014), 25(5), 1283-1308 The vast majority of approaches make use of features to track objects. In this paper, we address the tracking problem with a tracking-by-registration strategy based on direct methods. We propose a ... [more ▼] The vast majority of approaches make use of features to track objects. In this paper, we address the tracking problem with a tracking-by-registration strategy based on direct methods. We propose a hierarchical strategy in terms of image resolution and number of parameters estimated in each resolution, that allows direct methods to be applied in demanding real-time visual-tracking applications. We have called this strategy the Hierarchical Multi-Parametric and Multi-Resolution strategy (HMPMR). The Inverse Composition Image Alignment Algorithm (ICIA) is used as an image registration technique and is extended to an HMPMR-ICIA. The proposed strategy is tested with different datasets and also with image data from real flight tests using an Unmanned Aerial Vehicle, where the requirements of direct methods are easily unsatisfied (e.g. vehicle vibrations). Results show that using an HMPMR approach, it is possible to cope with the efficiency problem and with the small motion constraint of direct methods, conducting the tracking task at real-time frame rates and obtaining a performance that is comparable to, or even better than, the one obtained with the other algorithms that were analyzed. [less ▲] Detailed reference viewed: 291 (11 UL)![]() ; Sanchez Lopez, Jose Luis ![]() in 2014 American Control Conference (2014, June) The motivation of this research is to show that visual based object tracking and following is reliable using a cheap GPS-denied multirotor platform such as the AR Drone 2.0. Our architecture allows the ... [more ▼] The motivation of this research is to show that visual based object tracking and following is reliable using a cheap GPS-denied multirotor platform such as the AR Drone 2.0. Our architecture allows the user to specify an object in the image that the robot has to follow from an approximate constant distance. At the current stage of our development, in the event of image tracking loss the system starts to hover and waits for the image tracking recovery or second detection, which requires the usage of odometry measurements for self stabilization. During the following task, our software utilizes the forward-facing camera images and part of the IMU data to calculate the references for the four on-board low-level control loops. To obtain a stronger wind disturbance rejection and an improved navigation performance, a yaw heading reference based on the IMU data is internally kept and updated by our control algorithm. We validate the architecture using an AR Drone 2.0 and the OpenTLD tracker in outdoor suburban areas. The experimental tests have shown robustness against wind perturbations, target occlusion and illumination changes, and the system's capability to track a great variety of objects present on suburban areas, for instance: walking or running people, windows, AC machines, static and moving cars and plants. [less ▲] Detailed reference viewed: 45 (0 UL)![]() Sanchez Lopez, Jose Luis ![]() in 2014 International Conference on Unmanned Aircraft Systems (ICUAS) (2014, May) This paper presents a cost-effective framework for the prototyping of vision-based quadrotor multi-robot systems, which core characteristics are: modularity, compatibility with different platforms and ... [more ▼] This paper presents a cost-effective framework for the prototyping of vision-based quadrotor multi-robot systems, which core characteristics are: modularity, compatibility with different platforms and being flight-proven. The framework is fully operative, which is shown in the paper through simulations and real flight tests of up to 5 drones, and was demonstrated with the participation in an international micro-aerial vehicles competition3 where it was awarded with the First Prize in the Indoors Autonomy Challenge. The motivation of this framework is to allow the developers to focus on their own research by decoupling the development of dependent modules, leading to a more cost-effective progress in the project. The basic instance of the framework that we propose, which is flight-proven with the cost-efficient and reliable platform Parrot AR Drone 2.0 and is open-source, includes several modules that can be reused and modified, such as: a basic sequential mission planner, a basic 2D trajectory planner, an odometry state estimator, localization and mapping modules which obtain absolute position measurements using visual markers, a trajectory controller and a visualization module. [less ▲] Detailed reference viewed: 61 (4 UL)![]() ; Sanchez Lopez, Jose Luis ![]() in 2014 International Conference on Unmanned Aircraft Systems (ICUAS) (2014, May) This paper presents a completely autonomous solution to participate in the 2013 International Micro Air Vehicle Indoor Flight Competition (IMAV2013). Our proposal is a modular multi-robot swarm ... [more ▼] This paper presents a completely autonomous solution to participate in the 2013 International Micro Air Vehicle Indoor Flight Competition (IMAV2013). Our proposal is a modular multi-robot swarm architecture, based on the Robot Operating System (ROS) software framework, where the only information shared among swarm agents is each robot's position. Each swarm agent consists of an AR Drone 2.0 quadrotor connected to a laptop which runs the software architecture. In order to present a completely visual-based solution the localization problem is simplified by the usage of ArUco visual markers. These visual markers are used to sense and map obstacles and to improve the pose estimation based on the IMU and optical data flow by means of an Extended Kalman Filter localization and mapping method. The presented solution and the performance of the CVG UPM team were awarded with the First Prize in the Indoors Autonomy Challenge of the IMAV2013 competition. [less ▲] Detailed reference viewed: 80 (1 UL)![]() Sanchez Lopez, Jose Luis ![]() in Journal of Intelligent and Robotic Systems (2014), 74(1-2), 113--127 Detailed reference viewed: 42 (2 UL)![]() ; ; Sanchez Lopez, Jose Luis ![]() in Journal of Intelligent and Robotic Systems (2014), 73(1-4), 387--400 Detailed reference viewed: 39 (0 UL)![]() ; ; Sanchez Lopez, Jose Luis ![]() in ROBOT2013: First Iberian Robotics Conference (2013, November) Detailed reference viewed: 42 (1 UL)![]() Sanchez Lopez, Jose Luis ![]() in ROBOT2013: First Iberian Robotics Conference (2013, November) Detailed reference viewed: 69 (2 UL)![]() ; Sanchez Lopez, Jose Luis ![]() 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 ▲] Detailed reference viewed: 45 (3 UL)![]() ; ; et al in RIAI - Revista Iberoamericana de Automatica e Informatica Industrial (2013), 10(3), Detailed reference viewed: 69 (1 UL)![]() ![]() Sanchez Lopez, Jose Luis ![]() Scientific Conference (2013, September) Detailed reference viewed: 40 (0 UL)![]() Sanchez Lopez, Jose Luis ![]() in 2013 International Conference on Unmanned Aircraft Systems (ICUAS) (2013, May) In this paper we tackle the problem of landing a helicopter autonomously on a ship deck, using as the main sensor, an on-board colour camera. To create a test-bed, we first adequately simulate the ... [more ▼] In this paper we tackle the problem of landing a helicopter autonomously on a ship deck, using as the main sensor, an on-board colour camera. To create a test-bed, we first adequately simulate the movement of a ship landing platform on the Sea, for different Sea States, for different ships, randomly and realistically enough. We use a commercial parallel robot to get this movement. Once we had this, we developed an accurate and robust computer vision system to measure the pose of the helipad with respect to the on-board camera. To deal with the noise and the possible fails of the computer vision, a state estimator was created. With all of this, we are now able to develop and test a controller that closes the loop and finish the autonomous landing task. [less ▲] Detailed reference viewed: 52 (2 UL)![]() ; ; et al 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 ▲] Detailed reference viewed: 44 (3 UL)![]() Sanchez Lopez, Jose Luis ![]() in 69th American Helicopter Society International Annual Forum 2013 (2013, May) Detailed reference viewed: 26 (0 UL)![]() Olivares Mendez, Miguel Angel ![]() in Sen Gupta, Gourab; Bailey, Donald; Demidenko, Serge (Eds.) et al Recent Advances in Robotics and Automation (2013) The goal of the work described in this paper is to develop a visual line guided system for being used on-board an Autonomous Guided Vehicle (AGV) commercial car, controlling the steering and using just ... [more ▼] The goal of the work described in this paper is to develop a visual line guided system for being used on-board an Autonomous Guided Vehicle (AGV) commercial car, controlling the steering and using just the visual information of a line painted below the car. In order to implement the control of the vehicle, a Fuzzy Logic controller has been implemented, that has to be robust against curvature changes and velocity changes. The only input information for the controller is the visual distance from the image center captured by a camera pointing downwards to the guiding line on the road, at a commercial frequency of 30Hz. The good performance of the controller has successfully been demonstrated in a real environment at urban velocities. The presented results demonstrate the capability of the Fuzzy controller to follow a circuit in urban environments without previous information about the path or any other information from additional sensors. [less ▲] Detailed reference viewed: 374 (7 UL)![]() Martinez Luna, Carol ![]() 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 ▲] Detailed reference viewed: 253 (11 UL)![]() Sanchez Lopez, Jose Luis ![]() Bachelor/master dissertation (2012) Detailed reference viewed: 44 (0 UL)![]() ; Sanchez Lopez, Jose Luis ![]() Scientific Conference (2012, September) Detailed reference viewed: 38 (0 UL) |
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