DSpace Repository :: Browsing by Author "Giribet, Juan I."

Browsing by Author "Giribet, Juan I."

Now showing 1 - 20 of 29

Aerial multi-camera robotic jib crane
(2021-03) Moreno, Patricio; Presenza, Juan F.; Mas, Ignacio; Giribet, Juan I.
"A formulation based on a team of unmanned aerial vehicles operating as a fully articulated multi-camera jib crane is proposed for the application of aerial cinematography. An optimization-based controller commands the formation to follow an artistic trajectory defined by the director of photography, while actively avoiding collisions and cameras’ mutual visibility. The proposed scheme, based on the cluster-space formulation, presents an intuitive way of maneuvering the virtual camera fixture while automatically adjusting the motions by imposing artistic and safety constraints, facilitating the operator task."
Analysis and design of a tilted rotor hexacopter for fault tolerance
(IEEE, 2016) Giribet, Juan I.; Sanchez-Peña, Ricardo; Ghersin, Alejandro S.
A proof is presented of how a hexagon-shaped hexacopter can be designed to keep the ability to reject disturbance torques in all directions while counteracting the effect of a failure in any of its motors. The method proposed is simpler than previous solutions, because it does not require change of the motor rotation direction or in-flight mechanical reconfiguration of the vehicle. It consists of tilting the rotor a small fixed angle with respect to the vertical axis. Design guidelines are presented to calculate the tilt angle to achieve fault-tolerant attitude control without losing significant vertical thrust. It is also formally proved that the minimum number of unidirectional rotating motors needed to have fault tolerance is 6 and that this can be achieved by tilting their rotors. This proof is essentially a control allocation analysis that recovers in a simple way a result already known: the standard configuration (without tilting the motors) is not fault tolerant. A simulation example illustrates the theory.
Autonomous vehicles for outdoor multidomain mapping
(2018-06) Garberoglio, Leonardo; Moreno, Patricio; Mas, Ignacio; Giribet, Juan I.
"In the last years, progress has been made attempting to replace a unique, complex and expensive vehicle equipped with several sensors such as LIDAR, RGB cameras, thermal sensor, etc. with a group of small vehicles, each of them carrying one sensor. There are several advantages of these segmented architectures, for instance this allows a reduction in the cost of the vehicles (several small vehicles can be less expensive than one big vehicle), the flexibility to choose for a mission only those vehicles with the appropriate sensors, the robustness of the system since it can acquire information even if one vehicle fails, among others. The advantage of segmented architectures is even more noticeable if the vehicles carrying those different sensors, have different characteristics or environments for operations, e.g. aerial, terrestrial or aquatic vehicles. In this work, we present the experimental results obtained with an ASV (Autonomous Surface Vehicle) and a UAV (Unmanned Aerial Vehicle) that cooperate to obtain a topographic survey of the terrain. The ASV is equipped with a LIDAR, meanwhile the UAV is equipped with a monocular RGB camera. The data acquired is post-processed in order to obtain a detailed map of the coastline of a creek and the surrounding area."
Cluster space LPV control of robot formations
(2018-10) Ghersin, Alejandro S.; Giribet, Juan I.; Mas, Ignacio
"Within the Cluster Space robot formation control scheme, a new approach is presented where a cascaded control scheme is proposed. On one hand, a simple secondary (inner) loop is used to control the formation’s velocity in Robot Space, while on the other hand a quasi-LPV (Linear Parameter Varying) approach is employed for the design of the main (outer) control loop where the geometry and kinematics of the problem are captured by the LPV formulation. Certain aspects of the design such as stability are tackled, and the use of parameter-dependent weighting functions is discussed through a design example tested in simulations in order to illustrate the use of the method."
Control robusto H∞ para la velocidad de desplazamiento de un UAV en base a estimación de flujo óptico
(2021-07) Ghersin, Alejandro S.; Giribet, Juan I.; Luiso, Javier E.; Tournour, Andrés
"Se presenta el diseño del control para la velocidad de desplazamiento de un vehículo aéreo de seis rotores. La técnica de diseño utilizada es el control optimo en H-infinito con el objetivo de conseguir rendimiento robusto ante la incertidumbre en el modelo de la dinámica de la velocidad de desplazamiento. Se considera que buena parte de la incertidumbre es atribuible a retardos de tiempo inciertos que introduce el propio algoritmo que se utiliza para estimar la velocidad de desplazamiento. El vehículo realiza a bordo la estimación de esta última a través de un sensor de flujo óptico implementado con una cámara y un procesador de alto nivel en el cual además se implementa la ley de control. Junto con el diseño del control, se muestra el procedimiento de identificación de sistemas utilizado para conseguir una descripción de la dinámica a través de una familia de plantas con incertidumbre dinámica global a través de la toma de datos experimentales. Finalmente se exhiben resultados experimentales con la implementación del sistema de control completo."
Coordinated ASV-UAV control for marine collision-free navigation
(2019-09) Garberoglio, Leonardo; Mas, Ignacio; Giribet, Juan I.
"There is an increasing interest in replacing a unique, complex, and expensive vehicle equipped with several sensors with a group of small vehicles, each of them carrying fewer sensors. There are several advantages in these segmented architectures, such as cost, flexibility, redundancy, and robustness, among others. The advantage of segmented architectures is even more noticeable if the vehicles carrying those sensors have different characteristics or environments of operation, e.g. aerial, terrestrial or marine vehicles. This work proposes a multi-robot system where an autonomous marine vehicle avoids obstacles relying on aerial images provided by an autonomous flying vehicle. Both robots navigate in a coordinated fashion increasing the detection area and allowing to adjust the obstacle detection horizon. In order to validate the control scheme two simulation scenarios are presented."
Diseño de un autopiloto para pequeños vehículos no tripulados
(2019-06) Garberoglio, Leonardo; Pose, Claudio D.; Mas, Ignacio; Giribet, Juan I.
"En este trabajo se presenta el diseño de un autopiloto para pequeños vehículos autónomos. El trabajo está enfocado principalmente en la arquitectura del sistema, pero se presentan también algunos detalles del firmware desarrollado para el autopiloto. En particular, el firmware incluye el paquete rosserial, que permite una conexión simple con ROS (Robot Operating System), resultando beneficioso para diversas aplicaciones. El desarrollo se valida experimentalmente en un vehículo aéreo no tripulado (UAV1) del tipo multi-rotor y en un vehículo acuático de superficie (ASV2). Estos vehículos han sido desarrollados por nuestro grupo, y en este trabajo puede encontrarse información sobre estos proyectos, lo cual puede ser de utilidad para los interesados en el desarrollo de UAV o ASV."
Diseño, construcción, simulación 3D y control LPV de un cuadricóptero de forma variante
(2019-11) Ghersin, Alejandro S.; Giribet, Juan I.; Pose, Claudio D.; Mas, Ignacio
"En este trabajo se propone el diseño lineal de parámetros variantes (LPV) para el control de un cuadricóptero cuyos brazos pueden moverse respecto del eje vertical del vehículo, cambiando su forma de acuerdo a requerimientos de misión. El trabajo presenta el desarrollo del simulador multicuerpo y del algoritmo de control junto con una introducción al método LPV, mostrando con su utilización. Además, se presenta una explicación detallada del prototipo construido hasta el momento para las pruebas."
Distributed data-driven UAV formation control via evolutionary games: experimental results
(2021-07) Barreiro-Gomez, Julian; Mas, Ignacio; Giribet, Juan I.; Moreno, Patricio; Ocampo-Martínez, Carlos; Sánchez-Peña, Ricardo; Quijano, Nicanor
"This work proposes a novel data-driven distributed formation-control approach based on multi-population evolutionary games, which is structured in a leader-follower scheme. The methodology considers a time-varying communication graph that describes how the multiple agents share information to each other. We present stability guarantees for configurations given by time-varying interaction networks, making the proposed method suitable for real-world problems where communication constraints change along the time. Additionally, the proposed formation controller allows for an agent to leave or enter the group without the need to modify the behaviors of other agents in the group. This game-theoretical approach is evaluated through numerical simulations and real outdoors experimental results using a fleet of aerial autonomous vehicles, showing the control performance."
Experimental validation of a fault-tolerant hexacopter with tilted rotors
(2018) Giribet, Juan I.; Pose, Claudio D.; Ghersin, Alejandro S.; Mas, Ignacio
"Recently, research reporting the advantages of flying with tilted-motor multicopters has surfaced. Particularly, it has been theoretically proven that in the case of a complete failure of one of the motors in a hexagon-shaped hexacopter, complete altitude and attitude control can be maintained. In this work, these theoretical results were experimentally validated."
Fault tolerance analysis for a class of reconfigurable aerial hexarotor vehicles
(2020-08) Pose, Claudio D.; Giribet, Juan I.; Mas, Ignacio
"Several works have addressed the issue of fault tolerance in multirotors in case of a rotor total failure, particularly their ability to keep full independent control of attitude and altitude. It has been proven that to achieve this, a minimum of six rotors is needed. In this work, the performance of several standard and nonstandard hexarotor structures is analyzed, both for a nominal case (without failure) and in the case where one of the actuators is under failure (incapability to exert thrust). The performance is shown in terms of maximum rotational torque and vertical force that the vehicle can exert. The main contribution of this work is the proposal and analysis of converting these vehicles into reconfigurable ones through the addition of a minimum number of servomotors, to deal with failures and to greatly improve the maneuverability under these conditions, in order to identify the reconfigurable structure with the best performance. An experimental demonstration in an outdoor environment is shown for the proposed reconfigurable structure with best performance in case of a full rotor failure."
Fault tolerance analysis of a hexarotor with reconfigurable tilted rotors
(2020) Pose, Claudio D.; Giribet, Juan I.; Mas, Ignacio
"Tilted rotors in multirotor vehicles have shown to be useful for different practical reasons. For instance, increasing yaw maneuverability or enabling full position and attitude control of hexarotor vehicles. It has also been proven that a hexagon-shaped multirotor is capable of complete attitude and altitude control under failures of one of its rotors. However, when a rotor fails, the torque that can be reached in the worstcase direction decreases considerably. This work proposes to actively change the tilt angle of the rotors when a failure occurs. This rotor reconfiguration increases the maximum torque that can be achieved in the most stressful direction, reducing maneuverability limitations. Experimental validations are shown, where the proposed reconfigurable tilted rotor is used in order to control a hexarotor vehicle when a failure appears mid-flight. The impact of the delay in the reconfiguration when a failure occurs is also addressed."
Fault tolerance analysis of a multirotor with 6DOF
(2019-09) Giribet, Juan I.; Pose, Claudio D.; Mas, Ignacio
"Several works have addressed the issue of obtaining a six degree of freedom (6DOF) capable multirotor. However, the capability of keeping full control in the case of a total failure in one of the rotors has not yet been analyzed. In this work, it is proven that eight is the minimum number of rotors necessary to achive 6DOF control of a multirotor, in the case of a total failure in one of them. Also, an octorotor configuration with 6DOF control capabilities in a failure situation is proposed and analyzed through numerical simulations, comparing its flight performance in a nominal and a failure case. "
Fault tolerant control of an hexacopter with a tilted-rotor configuration
(2020) Giribet, Juan I.; Pose, Claudio D.; Mas, Ignacio
"Recientemente, han surgido algunos trabajos reportando las ventajas de volar con multicópteros con rotores inclinados, es decir, rotores que no apunten en la dirección de la vertical del vehículo. En particular, se demostró que para lograr un vehículo hexa-rotor capaz de tolerar fallas en uno de sus rotores es necesario que éstos estén inclinados. Hasta el momento, las validaciones experimentales de estos resultados han considerado fallas parciales en los rotores. Más precisamente, se han analizado casos en los cuales uno de los rotores pierde capacidad de empuje. Sin embargo, los resultados teóricos admiten una falla total de los rotores, es decir, que uno de los rotores se detenga completamente. En este trabajo validamos experimentalmente la falla total de un rotor y mostramos cómo un vehículo hexa-rotor es capaz de mantener su capacidad de maniobra ante la pérdida total de uno de sus rotores."
Fault tolerant control of an hexacopter with a tilted-rotor configuration
(2017) Giribet, Juan I.; Pose, Claudio D.; Mas, Ignacio
"Recently, it was shown that an hexagon-shaped hexa-rotor micro aerial vehicle with unidirectionally spinning tilted rotors is capable of fault tolerant attitude and altitude control. This result has been theoretically proven and validated by simulations. However, experimental results have never been reported yet. In this work experimental results are presented, and a comparison between a tilted-rotor hexacopter with one in a standard rotor configuration is carried out."
Fault-tolerant systems for unmanned multirotor aerial vehicles
(2020) Giribet, Juan I.; Pose, Claudio D.; Mas, Ignacio
"This chapter presents some recent results on fault-tolerant control systems for unmanned aerial systems, in particular for multirotor-type vehicles, commonly known as drones. Over the last years, these vehicles have become widely popular. Simplicity and cost-effectiveness have turned out to be very appealing and, as a consequence, an increasing number of applications have risen in many fields such as agriculture, surveillance, and photography, among others. As mission requirements become more demanding, the matter of fault tolerance emerges as a key challenge, especially if system certification is sought. Here, the focus is placed particularly on rotor failures in multirotor vehicles, and a specific definition for fault tolerance is considered based on the maneuverability capabilities in case of a failure. A geometric analysis is presented to evaluate the fault tolerant capabilities of a given vehicle, together with an experimental validation. Then, the limitations of this concept are analyzed. Finally, a novel reconfigurable structure is proposed for a fault-tolerant hexarotor, that presents good flight performance in failure cases, together with experimental results."
Formation control for multi-domain autonomous vehicles based on dual quaternions
(2017-06) Mas, Ignacio; Moreno, Patricio; Giribet, Juan I.; Valentino Barzi, Diego
"Unmanned networked multirobot systems have the potential to accomplish complex field tasks with minimum human intervention. Motion coordination of vehicles that operate in different domains (land, sea, air) is one of the problems that need to be addressed to achieve such a goal. This article presents a representation method based on dual quaternions for leaderfollower formation control architectures. This representation offers the most compact and computationally efficient screw transformation formalism and can be used to describe rigid body motions because they simultaneously describe positions and orientations with only eight parameters. A controller in dual quaternion formation space is proposed and analyzed. Computer simulation results and experimental tests applied to the task of escorting an UGV with UAVs are shown to verify the functionality of the proposed system."
Hexacopter fault tolerant actuator allocation analysis for optimal thrust
(2017) Pose, Claudio D.; Giribet, Juan I.; Ghersin, Alejandro S.
"Recently, it was shown that an hexagon shaped hexarotor vehicle with tilted rotors, is capable of fault tolerant attitude and altitude control. In this work, we propose a strategy to select the signals commanded to each rotor in order to achieve a desired torque and vertical force. The proposed strategy is optimal in the sense that minimizes the maximum force exerted by the rotors. A comparison with the commonly used strategy based upon the Moore-Penrose pseudoinverse is carried out. It is shown that, with the optimal strategy proposed here, maneuverability is improved, because the new method takes into account the actuators constraints. Although the optimal strategy is computationally more demanding than the classical method, the additional computational burden is not significant when both strategies are compared in a real application. To show this, both algorithms were programmed in an autopilot based on an ARM Cortex M3 microcontroller, and the experimental results are presented."
Multi-UAV specification and control with a single pilot-in-the-loop
(2019-09) Moreno, Patricio; Esteva, Santiago; Mas, Ignacio; Giribet, Juan I.
"This work presents a multi-unmanned aerial vehicle formation implementing a trajectory following controller based on the cluster-space robot coordination method. The controller is augmented with a feed-forward input from a control station operator. This teleoperation input is generated by means of a remote control, as a simple way of modifying the trajectory or taking over control of the formation during flight. The cluster-space formulation presents a simple specification of the system’s motion and, in this work, the operator benefits from this capability to easily evade obstacles by means of controlling the cluster parameters in real time. The proposed augmented controller is tested in a simulated environment first, and then deployed for outdoor field experiments. Results are shown in different scenarios using a cluster of three autonomous unmanned aerial vehicles."
Multi-UAV specification and control with a single pilot-in-the-loop
(2020-10) Moreno, Patricio; Esteva, Santiago; Mas, Ignacio; Giribet, Juan I.
"This work presents a multi-unmanned aerial vehicle formation implementing a trajectory-following controller based on the clusterspace robot coordination method. The controller is augmented with a feed-forward input from a control station operator. This teleoperation input is generated by means of a remote control, as a simple way of modifying the trajectory or taking over control of the formation during flight. The cluster-space formulation presents a simple specification of the system’s motion and, in this work, the operator benefits from this capability to easily evade obstacles by means of controlling the cluster parameters in real time. The proposed augmented controller is tested in a simulated environment first, and then deployed for outdoor field experiments. Results are shown in different scenarios using a cluster of three autonomous unmanned aerial vehicles."

Browsing by Author "Giribet, Juan I."

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