Manuel J. Fernandez

Bio: Manuel J. Fernandez is an academic researcher from University of Seville. The author has contributed to research in topics: Wittig reaction & Multirotor. The author has an hindex of 3, co-authored 9 publications receiving 74 citations.

Sensor Installation and Retrieval Operations Using an Unmanned Aerial Manipulator

Abstract: A wide range of applications for which unmanned aerial vehicles (UAVs) are ideally suited rely on the development of manipulators capable of exchanging forces with the environment. One such application is the installation and retrieval of intelligent sensors for monitoring wide-spread areas and locations that are difficult to access by any other means. Within this letter, we report on both indoor and outdoor flights tests of a novel force controlled lightweight compliant manipulator that allows a UAV to carry out this type of task. Installation and retrieval are both demonstrated with different scenarios, indoors and outdoors. Key results include interaction forces up to 22 N exerted by a small-sized multirotor, placement and retrieval operations carried out on flat as well as cylindrical surfaces, and an analysis of the overall system. The results of multiple flight experiments clearly demonstrate the potential of this approach for the deployment of sensors and other force-related tasks.

Lightweight and Compliant Long Reach Aerial Manipulator for Inspection Operations

Abstract: The proximity between the multirotor blades and the environmental obstacles restricts the application of aerial manipulators in inspection tasks due to the risk of impacts, the limitation in the reach of the arm, and the physical interactions. This paper presents a long reach aerial manipulator consisting of a hexarotor platform equipped with a 2-DOF compliant joint arm attached at the tip of a one-meter-length link in passive pendulum configuration. The arm integrates magnetic encoders for force/torque estimation-control based on joint deflection, a range sensor in the forearm link for measuring the distance to the contact point, and a camera for visual inspection. A 2-DOF wearable exoskeleton interface has been developed, allowing the teleoperation of the arm with visual feedback in a more intuitive way. The paper also covers the kinematics and dynamics of the aerial manipulator, including the dynamics of the flexible long reach link. The developed system has been evaluated in test-bench and in outdoor flight tests.

Benchmarks for Aerial Manipulation

Abstract: This letter is devoted to benchmarks for aerial manipulation robots (drones equipped with robotic arms), which are demonstrating their potential to conduct tasks involving physical interactions with objects or the environment in high altitude workspaces, being a cost effective solution for example in inspection and maintenance operations. Thus, the letter deals with different methods and criteria to evaluate and compare the performance of aerial manipulators. This is not an easy task, taking into account the wide variety of designs, morphologies and implementations that can be found in recent works. In order to cope with this problem, this letter analyzes the capabilities and functionalities of several aerial manipulation prototypes (aerial platform + manipulator), identifying a set of relevant metrics and criteria. A number of benchmarks are defined to evaluate the performance of the aerial manipulator in terms of accuracy, execution time, manipulation capability, or impact response. Experimental results carried out with a compliant joint aerial manipulator in test-bench and in indoor-outdoor testbeds illustrate some of the benchmarks.

Experimental Evaluation of a Team of Multiple Unmanned Aerial Vehicles for Cooperative Construction

Abstract: This article presents a team of multiple Unmanned Aerial Vehicles (UAVs) to perform cooperative missions for autonomous construction. In particular, the UAVs have to build a wall made of bricks that need to be picked and transported from different locations. First, we propose a novel architecture for multi-robot systems operating in outdoor and unstructured environments, where robustness and reliability play a key role. Then, we describe the design of our aerial platforms and grasping mechanisms to pick, transport and place bricks. The system was particularly developed for the Mohamed Bin Zayed International Robotics Challenge (MBZIRC), where Challenge 2 consisted of building a wall cooperatively with multiple UAVs. However, our approach is more general and extensible to other multi-UAV applications involving physical interaction, like package delivery. We present not only our results in the final stage of MBZIRC, but also our simulations and field experiments throughout the previous months to the competition, where we tuned our system and assessed its performance.

Securing UAV communications using ROS with custom ECIES-based method

Abstract: This paper is about an application of a method based on the ECIES (Elliptic Curve Integrated Encryption Scheme) to improve the security against malicious attacks of the UAVs (Unmanned Aerial Vehicles) communications system. This system is focused on improving the security conditions in extreme situations and preventing the aircraft for man-made incidents and cyber attacks. The paper briefly describes the different attacks that can affect to the operation of UAVs and the security methods that, nowadays, are used to guarantee the security during the operations. Moreover, it presents a solution to a strong vulnerability detected in the classical scheme used in UAV. This scheme uses ROS (Robot Operating System) as the core of the communication system to interconnect different devices and nodes in this paper, it is demonstrated that if an Intruder is able to enter in the local network of the UAV system, he/she is also able to impersonate the GCS (Ground Control Station) of the UAV and take control of it leading to an undesirable maneuver or even a dangerous crash against a building or a person. The security system proposed to avoid this consists of a simplified method based on ECIES sending packets, between UAV and GCS, which uses ECDSA (Elliptic Curve Digital Signature) and are ciphered in RSA (Rivest–Shamir–Adleman). Thus, it is possible to guarantee that the high level computer of the UAV is able to identify the identity of their GCS and prevent of being commanded by an unauthorized Intruder. Both, the vulnerability and the solution proposed have been experimentally tested and validated through software-in-the-loop simulations and in a outdoor scenario using a small UAV.

Unmanned Aerial Vehicles in Agriculture: A Review of Perspective of Platform, Control, and Applications

Abstract: For agricultural applications, regularized smart-farming solutions are being considered, including the use of unmanned aerial vehicles (UAVs). The UAVs combine information and communication technologies, robots, artificial intelligence, big data, and the Internet of Things. The agricultural UAVs are highly capable, and their use has expanded across all areas of agriculture, including pesticide and fertilizer spraying, seed sowing, and growth assessment and mapping. Accordingly, the market for agricultural UAVs is expected to continue growing with the related technologies. In this study, we consider the latest trends and applications of leading technologies related to agricultural UAVs, control technologies, equipment, and development. We discuss the use of UAVs in real agricultural environments. Furthermore, the future development of the agricultural UAVs and their challenges are presented.

A Unified Passivity Based Control Framework for Position, Torque and Impedance Control of Flexible Joint Robots.

Abstract: This paper describes a general passivity-based framework for the control of flexible joint robots. Recent results on torque, position, as well as impedance control of flexible joint robots are summarized, and the relations between the individual contributions are highlighted. It is shown that an inner torque feedback loop can be incorporated into a passivity-based analysis by interpreting torque feedback in terms of shaping of the motor inertia. This result, which implicitly was already included in earlier work on torque and position control, can also be used for the design of impedance controllers. For impedance control, furthermore, potential energy shaping is of special interest. It is shown how, based only on the motor angles, a potential function can be designed which simultaneously incorporates gravity compensation and a desired Cartesian stiffness relation for the link angles. All the presented controllers were experimentally evaluated on DLR lightweight robots and their performance and robustness shown with respect to uncertain model parameters. Experimental results with position controllers as well as an impact experiment are presented briefly, and an overview of several applications is given in which the controllers have been applied.

Οδηγός για το Raspberry Pi 3 Model B

Abstract: It is an accepted fact that, as the years go by, technology rapidly evolves. For this reason, it is absolutely necessary to constantly watch its evolution, to search for new ways for its progression, adjusting to the new conditions and demands. This effort can be mainly fulfilled by computers. Computers allow us to comprehend the development of technology, assisted by the growing development of the tool-programs that can be used. Another fundamental stepping stone for the technological evolution is the electrical machines which replace manual labor, since they are faster, more precise, and dependable. On a long term, using the electrical machines decreases the cost, whereas manual labor loses its prestige as the years go by. The present project extensively discusses the Raspberry Pi, one of the most sophisticated pocket computer models, which is able to conduct more complex implementations than the rest of the available models, using more program languages. More specifically, in the 1st chapter, we will make a small introduction about the Raspberry Pi, mentioning its definition and its history, referring to the date of the release of each model and some details about each one of them. We will, also, discuss the differentiations of each model and, this very chapter will make us understand what we can do with each one of the models. In the 2nd chapter, we will refer to the raspberry hardware. First of all, the pins of the Raspberry Pi will be introduced and analyzed. The attachments needed for the activation of the Raspberry Pi will be mentioned and the right steps for the installation of the NOOBS operating system to the SD Card will be studied. Moreover, the RASPBIAN operating system will be installed to the Raspberry Pi 3. Finally, the first steps that we need to make once the Raspberry Pi turns on will be mentioned. In the 3rd chapter we will talk about the SSH. We will closely take a look at the steps needed in order to install the RASPBIAN operating system to the SD Card. We will see what the SSH is, as well. In the 4th chapter, we will study the examples where the micro-controller is used, the attachments needed for each project, and we will analyze the circuits for each of the examples. We will be citing the circuit through the FRITZING and we will be discussing the code of each example so that the application can function. The examples will be of a gradual difficulty. The present dissertation aims to inform the students about an innovative micro-controller; the Raspberry Pi 3 Model B. The truth is that only few people are aware of this micro-controller. For this reason, our goal is to make the micro-controller more comprehensive to you.

Past, Present, and Future of Aerial Robotic Manipulators

Abstract: This article analyzes the evolution and current trends in aerial robotic manipulation, comprising helicopters, conventional underactuated multirotors, and multidirectional thrust platforms equipped with a wide variety of robotic manipulators capable of physically interacting with the environment. It also covers cooperative aerial manipulation and interconnected actuated multibody designs. The review is completed with developments in teleoperation, perception, and planning. Finally, a new generation of aerial robotic manipulators is presented with our vision of the future.