2021
Past, Present, and Future of Aerial Robotic Manipulators
IEEE Transactions on Robotics, Page(s): 1 - 20
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.
@ARTICLE{9462539, author={Ollero, Anibal and Tognon, Marco and Suarez, Alejandro and Lee, Dongjun and Franchi, Antonio}, journal={IEEE Transactions on Robotics}, title={Past, Present, and Future of Aerial Robotic Manipulators}, year={2021}, volume={}, number={}, pages={1-20}, doi={10.1109/TRO.2021.3084395}}
Control Aware of Limitations of Manipulators with Claw for Aerial Robots Imitating Bird’s Skeleton
IEEE Robotics and Automation Letters, Published
Winged animals such as birds, flying mammals or insects have lightweight limbs which allow them to perform different tasks. Although in robotics there are some examples ofwinged robots (called ornithopters), it has not been yet studied how to add them some manipulation-like capabilities, similarly to the anatomy of animals limbs. Adding those capabilities to ornithopters will outperform multirotor platforms giving the possibility to perch in unaccessible places, grasp objects and perform some kind of manipulation while being in proximity to humans. The special manipulator imitates the anatomy of the birds, having a kinematic chain with actuated joints except the first passive one that resembles the claw of a bird with a grasping force. This work analyzes in depth these ornithopterlike manipulators and proposes a nonlinear controller aware of the limitation in the grasping force of the claw, modeled as static friction. The solution is based on a methodology to control constrained-nonlinear systems via diffeomorphisms providing an explicit controller with low torques demand to meet aerial requirements. It is verified on a realistic simulator with 5DOF links—claw, low/upp-er leg, body, neck and beak–, and experimentally validated in a simpler 3DOF prototype.
Event-based human intrusion detection in UAS using Deep Learning
ICUAS 2021, Accepted pp. 91-100
Automatic intrusion detection in unstructured and complex environments using autonomous Unmanned Aerial Systems (UAS) poses perception challenges in which traditional techniques are severely constrained. Event cameras have high temporal resolution and dynamic range, which make them robust against motion blur and lighting conditions. This paper presents an event-by-event processing scheme for detecting human intrusion using UAS. It includes: 1) one method for detecting clusters of events caused by moving objects in static background; and 2) one method based on Convolutional Neural Networks to compute the probability that a cluster corresponds to a person. The proposed scheme has been implemented and validated in challenging scenarios.
@inproceedings{perezcutino2021event, title={Event-based human intrusion detection in UAS using Deep Learning}, author={Pérez-Cutiño, Miguel Angel and Gómez-Eguı́luz, Augusto and Martı́nez-de-Dios, José Ramiro and Ollero, Aníbal}, booktitle={2021 International Conference on Unmanned Aircraft Systems (ICUAS)}, pages={91--100}, year={2021}, organization={IEEE} }
Analysis of Forces Involved in the Perching Maneuver of Flapping-Wing Aerial Systems and Development of an Ultra-Lightweight Perching System
ICUAS 2021, Accepted
Trying to optimize the design of aerial robotics systems, this work presents an optimized low-weight landing system for flapping-wing aerial robots. The design, based on the use of low-sized neodymium magnets, intends to provide that these aerial robots have the capability of landing in restricted areas by using the presented solution. This capacity will increase the application range of these robots. A study of this situation has been done to analyze the perching maneuver forces and evaluate the system. The solution presented is low-weight, low-sized, and also relatively inexpensive. Therefore, this solution may apply to most ornithopter robots. Design, analysis of the implied forces, development and experimental validation of the idea are presented in this work, demonstrating that the developed solution can overcome the ornithopter's payload limitation providing an efficient and reliable solution.
Design of the High-Payload Flapping Wing Robot E-Flap
IEEE Robotics and Automation Letters, Vol: 6 pp. 3097-3104
Autonomous lightweight flapping-wing robots show potential to become a safe and affordable solution for rapidly deploying robots around humans and in complex environments. The absence of propellers makes such vehicles more resistant to physical contact, permitting flight in cluttered environments, and collaborating with humans. Importantly, the provision of thousands of species of birds that have already mastered the challenging task of flapping flight is a rich source of solutions. However, small wing flapping technology is still in its beginnings, with limited levels of autonomy and physical interaction capability with the environment. One significant limitation to this is the low payload available. Here we show the Eagle-inspired Flapping-wing robot E-Flap, a 510 g novel design capable of a 100% of payload, exceeding the requirement of the computing and sensing package needed to fly with a high degree of autonomy. The concept is extensively characterized, both in a tracked indoor space and in outdoor conditions. We demonstrate flight path angle of up to 50 ∘ and velocities from as low as 2 m/s to over 6 m/s. Overall, the robotic platform has been proven to be reliable, having performed over 100 flights. Through mechanical and electronics advances, the E-Flap is a robust vehicle prototype and paves the way towards flapping-wing robots becoming a practical fully autonomous flying solution
Design and comparison of tails for bird-scale flapping-wing robots
IROS 2021, Accepted
Flapping-wing robots (so-called ornithopters) are a promising type of platform to perform efficient winged flight and interaction with the environment. However, the control of such vehicles is challenging due to their under-actuated morphology to meet lightweight requirements. Consequently, the flight control of flapping-wing robots is predominantly handled by the tail. Most ornithopters feature a tail with two degrees of freedom but the configuration choice is often arbitrary and without indepth study. In this paper, we propose a thorough analysis of the design and in-flight performance for the three tails. Their design and manufacturing methods are presented, with an emphasis on low weight, which is critical in ornithopters. The aerodynamics of the tails is analyzed through CFD simulations and their performance compared experimentally. The advantages and performance metrics of each configuration are discussed based on flight data. Two types of 3D flight tests were carried out: aggressive heading maneuvers and level turns. The results show that an inverted V-tail outperforms the others regarding maneuverability and stability. From the three configurations, only the inverted V-Tail can perform an aggressive stable banked level turn with a radius of 3.7 m at a turning rate of 1.6 rad/s. This research work describes the impact of the tail configuration choice on the performance of bird-scale flapping-wing robots.
Bio-Inspired Morphing Tail for Flapping Wings Aerial Robots using Macro Fiber Composites
Applied Sciences,
The aim of this work is to present the development of a bio-inspired approach for a robotic tail using Macro Fiber Composites (MFC) as actuators. The use of this technology will allow achieving closer to the nature approach of the tail, aiming to mimic a bird tail behavior. The tail will change its shape, performing morphing, providing a new type of actuation methodology in flapping control systems. The work is intended as a first step for demonstrating the potential of these technologies for being applied in other parts of the aerials robotics systems. When compared with traditional actuation approaches, one key advantage that is given by the use of MFC is their ability to adapt to different flight conditions via geometric tailoring, imitating what birds do in nature. Theoretical explanations, design, and experimental validation of the developed concept using different methodologies will be presented in this paper.
@article{perez2021bio, title={Bio-Inspired Morphing Tail for Flapping-Wings Aerial Robots Using Macro Fiber Composites}, author={Perez-Sanchez, Vicente and Gomez-Tamm, Alejandro E and Savastano, Emanuela and Arrue, Bego{\~n}a C and Ollero, Anibal}, journal={Applied Sciences}, volume={11}, number={7}, pages={2930}, year={2021}, publisher={Multidisciplinary Digital Publishing Institute} }
Auto-Tuned Event-Based Perception Schemefor Intrusion Monitoring With UAS
IEEE Access, 9(2021), pp. 44840-44854
This paper presents an asynchronous event-based scheme for automatic intrusion monitoring using Unmanned Aerial Systems (UAS). Event cameras are neuromorphic sensors that capture the illumination changes in the camera pixels with high temporal resolution and dynamic range. In contrast to conventional frame-based cameras, they are naturally robust against motion blur and lighting conditions, which make them ideal for outdoor aerial robot applications. The presented scheme includes two main perception components. First, an asynchronous event-based processing system efficiently detects intrusions by combining several asynchronous event-based algorithms that exploit the advantages of the sequential nature of the event stream. The second is an off-line training mechanism that adjusts the parameters of the event-based algorithms to a particular surveillance scenario and mission. The proposed perception system was implemented in ROS for on-line execution on board UAS, integrated in an autonomous aerial robot architecture, and extensively validated in challenging scenarios with a wide variety of lighting conditions, including day and night experiments in pitch dark conditions.
@article{, author={Rodríguez-Gómez, Juan Pablo and Eguíluz, Augusto Gómez and Martínez-De Dios, José Ramiro and Ollero, Anibal}, title={Auto-Tuned Event-Based Perception Scheme for Intrusion Monitoring With UAS}, year={2021}, volume={9}, number={}, pages={44840-44854}, doi={10.1109/ACCESS.2021.3066529}}
Why fly blind? Event-based visual guidance for ornithopter robot fligh
IROS 2021, Accepted
The development of perception and control meth-ods that allow bird-scale flapping-wing robots (a.k.a. ornithopters) to perform autonomously is an under-researched area. This paper presents a fully onboard event-based method for ornithopter robot visual guidance. The method uses event cameras to exploit their fast response and robustness against motion blur in order to feed the ornithopter control loop at high rates (100 Hz). The proposed scheme visually guides the robot using line features extracted in the event image plane and controls the flight by actuating over the horizontal and vertical tail deflections. It has been validated on board a real ornithopter robot with real-time computation in low-cost hardware. The experimental evaluation includes sets of experiments with different maneuvers indoors and outdoors.
The GRIFFIN Perception Dataset: Bridging the Gap Between Flapping-Wing Flight and Robotic Perception
IEEE Robotics and Automation Letters (RA-L), 6(2021), pp. 1066-1073
The development of automatic perception systems and techniques for bio-inspired flapping-wing robots is severely hampered by the high technical complexity of these platforms and the installation of onboard sensors and electronics. Besides, flapping-wing robot perception suffers from high vibration levels and abrupt movements during flight, which cause motion blur and strong changes in lighting conditions. This letter presents a perception dataset for bird-scale flapping-wing robots as a tool to help alleviate the aforementioned problems. The presented data include measurements from onboard sensors widely used in aerial robotics and suitable to deal with the perception challenges of flapping-wing robots, such as an event camera, a conventional camera, and two Inertial Measurement Units (IMUs), as well as ground truth measurements from a laser tracker or a motion capture system. A total of 21 datasets of different types of flights were collected in three different scenarios (one indoor and two outdoor). To the best of the authors' knowledge this is the first dataset for flapping-wing robot perception.
@article{, author={Rodríguez-Gómez, Juan Pablo and Tapia, Raul and Paneque, Julio L. and Grau, Pedro and Gómez Eguíluz, Augusto and Martínez-de Dios, Jose Ramiro and Ollero, Anibal}, journal={IEEvolume={6},E Robotics and Automation Letters}, title={The GRIFFIN Perception Dataset: Bridging the Gap Between Flapping-Wing Flight and Robotic Perception}, year={2021}, volume={6}, number={2}, pages={1066-1073}, doi={10.1109/LRA.2021.3056348}}
2020
Towards UAS Surveillance using Event Cameras
SSRR, pp.71-76
Aerial robot perception for surveillance and search and rescue in unstructured and complex environments poses challenging problems in which traditional sensors are severely constrained. This paper analyzes the use of event cameras onboard aerial robots for surveillance applications. Event cameras have high temporal resolution and dynamic range, which make them very robust against motion blur and lighting conditions. The paper analyzes the pros and cons of event cameras and presents an event-based processing scheme for target detection and tracking. The scheme is experimentally validated in challenging environments and different lighting conditions.
@INPROCEEDINGS{9292606, author={Martínez-de Dios, J.R. and Gómez Eguíluz, A. and Rodríguez-Gómez, J.P. and Tapia, R. and Ollero, A.}, booktitle={2020 IEEE International Symposium on Safety, Security, and Rescue Robotics (SSRR)}, title={Towards UAS Surveillance using Event Cameras}, year={2020}, volume={}, number={}, pages={71-76}, doi={10.1109/SSRR50563.2020.9292606}}
SMA Actuated Low-Weight Bio-Inspired Claws for Grasping and Perching Using Flapping Wing Aerial Systems
IROS 2020, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
Taking inspiration from nature, the work presented in this paper aims to develop bio-inspired claws to be used for grasping and perching in flapping-wing aerial systems. These claws can be 3D printed out of two different materials and will be capable of adapt to any shape. Also, they will be soft for avoiding undesired damages on the objects when performing manipulation. These claws will be actuated by shape memory alloys (SMA) springs to get rid of the weight of traditional servos. The design of all the components will be explained in this work. Also, the challenges of being able to control SMA using only a LiPo battery on an aerial vehicle will be exposed. The solutions applied and electronics used will be also described. Lastly, experiments made both in test bench as on flight will be summarized.
@inproceedings{gomez2020sma, title={SMA Actuated Low-Weight Bio-Inspired Claws for Grasping and Perching Using Flapping Wing Aerial Systems}, author={Gomez-Tamm, AE and Perez-Sanchez, V and Arrue, BC and Ollero, A}, booktitle={Proceedings of the 2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Las Vegas, NV, USA}, pages={25--29}, year={2020} }
ASAP: Adaptive Scheme for Asynchronous Processing of event-based vision algorithms
IROS 2020, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
Event cameras can capture pixel-level illumination changes with very high temporal resolution and dynamic range. They have received increasing research interest due to their robustness to lighting conditions and motion blur. Two main approaches exist in the literature to feed the event-based processing algorithms: packaging the triggered events in event packages and sending them one-by-one as single events. These approaches suffer limitations from either processing overflow or lack of responsivity. Processing overflow is caused by high event generation rates when the algorithm cannot process all the events in real-time. Conversely, lack of responsivity happens in cases of low event generation rates when the event packages are sent at too low frequencies. This paper presents ASAP, an adaptive scheme to manage the event stream through variable- size packages that accommodate to the event package processing times. The experimental results show that ASAP is capable of feeding an asynchronous event-by-event clustering algorithm in a responsive and efficient manner and at the same time prevent overflow.
@inproceedings{tapia2020asap, title={ASAP: Adaptive scheme for asynchronous processing of event-based vision algorithms}, author={Tapia, R and Egu{\i}luz, A G{\'o}mez and Mart{\i}nez-de Dios, J and Ollero, A}, booktitle={2020 IEEE ICRA Workshop on Unconventional Sensors in Robotics. IEEE}, year={2020} }
Asynchronous Event-based Line Tracking for Time-to-Contact Maneuvers in UAS
IROS 2020, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
This paper presents an bio-inspired event-based perception scheme for agile aerial robot maneuvering. It tries to mimic birds, which perform purposeful maneuvers by closing the separation in the retinal image (w.r.t. the goal) to follow time-to-contact trajectories. The proposed approach is based on event cameras, also called artificial retinas, which provide fast response and robustness against motion blur and lighting conditions. Our scheme guides the robot by only adjusting the position of features extracted in the event image plane to their goal positions at a predefined time using smooth timeto-contact trajectories. The proposed scheme is robust, efficient and can be added on top of commonly-used aerial robot velocity controllers. It has been validated on-board a UAV with real-time computation in low-cost hardware during sets of experiments with different descent maneuvers and lighting conditions.
@article{eguiluzasynchronous, title={Asynchronous Event-based Line Tracking for Time-to-Contact Maneuvers in UAS}, author={Egu{\i}luz, A G{\'o}mez and Rodr{\i}guez-G{\'o}mez, JP and Mart{\i}nez-de Dios, JR and Ollero, A} }
Adaptive Nonlinear Control For Perching of a Bioinspired Ornithopter
IROS 2020, IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)
This work presents a model-free nonlinear controller for an ornithopter prototype with bioinspired wings and tail. The size and power requirements have been thought to allocate a customized autopilot on board. To assess the functionality and performance of the full mechatronic design, a controller has been designed and implemented to execute a prescribed perching 2D trajectory. Although functional, its 'handmade' nature forces many imperfections that cause uncertainty that hinder its control. Therefore, the controller is based on adaptive backstepping and does not require any knowledge of the aerodynamics. The controller is able to follow a given reference in flight path angle by actuating only on the tail deflection. A novel space-dependent nonlinear guidance law is also provided to prescribe the perching trajectory. Mechatronics, guidance and control system performance is validated by conducting indoor flight tests.
@inproceedings{maldonado2020adaptive, title={Adaptive nonlinear control for perching of a bioinspired ornithopter}, author={Maldonado, FJ and Acosta, JA and Tormo-Barbero, J and Grau, P and Guzman, MM and Ollero, A}, booktitle={2020 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages={1385--1390}, year={2020}, organization={IEEE} }
A bio-inspired manipulator with claw prototype for winged aerial robots: Benchmark for design and control
Applied Sciences, vol. 10, no. 18, pp. 6516
Nature exhibits many examples of birds, insects and flying mammals with flapping wings and limbs offering some functionalities. Although in robotics, there are some examples of flying robots with wings, it has not been yet a goal to add to them some manipulation-like capabilities, similar to ones that are exhibited on birds. The flying robot (ornithopter) that we propose improves the existent aerial manipulators based on multirotor platforms in terms of longer flight duration of missions and safety in proximity to humans. Moreover, the manipulation capabilities allows them to perch in inaccessible places and perform some tasks with the body perched. This work presents a first prototype of lightweight manipulator to be mounted to an ornithopter and a new control methodology to balance them while they are perched and following a desired path with the end effector imitating their beaks. This allows for several possible applications, such as contact inspection following a path with an ultrasonic sensor mounted in the end effector. The manipulator prototype imitates birds with two-link legs and a body link with an actuated limb, where the links are all active except for the first passive one with a grabbing mechanism in its base, imitating a claw. Unlike standard manipulators, the lightweight requirement limits the frame size and makes it necessary to use micro motors. Successful experimental results with this prototype are reporte
@article{feliu2020bio, title={A Bio-Inspired Manipulator with Claw Prototype for Winged Aerial Robots: Benchmark for Design and Control}, author={Feliu-Talegon, Daniel and Acosta, Jos{\'e} {\'A}ngel and Suarez, Alejandro and Ollero, Anibal}, journal={Applied Sciences}, volume={10}, number={18}, pages={6516}, year={2020}, publisher={Multidisciplinary Digital Publishing Institute} }
Asynchronous event-based clustering and tracking for intrusion monitoring in UAS
ICRA2020, pp. 8518-8524
Automatic surveillance and monitoring using Unmanned Aerial Systems (UAS) require the development of perception systems that robustly work under different illumination conditions. Event cameras are neuromorphic sensors that capture the illumination changes in the scene with very low latency and high dynamic range. Although recent advances in eventbased vision have explored the use of event cameras onboard UAS, most techniques group events in frames and, therefore, do not fully exploit the sequential and asynchronous nature of the event stream. This paper proposes a fully asynchronous scheme for intruder monitoring using UAS. It employs efficient event clustering and feature tracking modules and includes a sampling mechanism to cope with the computational cost of event-by-event processing adapting to on-board hardware computational constraints. The proposed scheme was tested on a real multirotor in challenging scenarios showing significant accuracy and robustness to lighting conditions.
@INPROCEEDINGS{, author={Rodríguez-Gomez, J.P. and Eguíluz, A. Gómez and Martínez-de Dios, J.R. and Ollero, A.}, booktitle={2020 IEEE International Conference on Robotics and Automation (ICRA)}, title={Asynchronous event-based clustering and tracking for intrusion monitoring in UAS}, year={2020}, volume={}, number={}, pages={8518-8524}, doi={10.1109/ICRA40945.2020.9197341}}
Effects of Unsteady Aerodynamics on Gliding Stability of a Bio-Inspired UAV
ICUAS, Proceedings of the ICUAS 2020, pp. 1596-1604, September 2020
This paper presents a longitudinal dynamic model to be used in the control of new animal flight bio-inspired UAVs designed to achieve better performance in terms of energy consumption, flight endurance, and safety when comparing with conventional multi-rotors. In order to control these UAVs, simple models are needed to predict its dynamics in real time by the on-board autopilots, which are very limited in term of computational resources. To that end, the model presented considers transitional aerodynamic unsteady effects, which change significantly the evolution of the system. The physical relevance of these aerodynamic unsteady terms in gliding flight is validated by comparing with results when these new terms are neglected. Finally, an analysis of dynamic stability is proposed in order to characterize the transitional phases of gliding flight.
@INPROCEEDINGS{9213965, author={Sanchez-Laulhe, Ernesto and Fernandez-Feria, Ramon and Acosta, José Ángel and Ollero, Anibal}, booktitle={2020 International Conference on Unmanned Aircraft Systems (ICUAS)}, title={Effects of Unsteady Aerodynamics on Gliding Stability of a Bio-Inspired UAV}, year={2020}, volume={}, number={}, pages={1596-1604}, doi={10.1109/ICUAS48674.2020.9213965}}
POSITRON: Lightweight Active Positioning Compilant Joints Robotic Arm in Power Lines Inspection
ICUAS, Proceedings of ICUAS 2020, PP 729-736
This paper presents the design and implementation of a compliant lightweight manipulator with an special end-effector to attach to power-lines. The manipulator can be mounted in aerial robots allowing to compute its relative position from the contact point. The purpose of this device is to obtain an estimate of the UAV's position to close the control loop. Controlling the position of the UAV close to the power-line enables a new wide range of inspection and maintenance tasks in this infrastructure. The article describes the model of the positioning tool and the sensors it uses to provide the necessary information for the UAV controller. It can be built using additive manufacturing techniques and its components are low-cost and available in common robotic stores so anyone can reproduce and use it. Validation experiments have been carried out in an Optitrack system as ground-truth.
@inproceedings{perez2020positron, title={POSITRON: Lightweight active positioning compliant joints robotic arm in power lines inspection}, author={Perez-Jimenez, M and Montes-Grova, MA and Ramon-Soria, P and Arrue, BC and Ollero, A}, booktitle={2020 International Conference on Unmanned Aircraft Systems (ICUAS)}, pages={729--736}, year={2020}, organization={IEEE} }
Winged Aerial Manipulation Robot with Dual Arm and Tail
APPLIED SCIENCES, PP: 20
This paper presents the design and development of a winged aerial robot with bimanual manipulation capabilities, motivated by the current limitations of aerial manipulators based on multirotor platforms in terms of safety and range/endurance. Since the combination of gliding and flapping wings is more energy efficient in forward flight, we propose a new morphology that exploits this feature and allows the realization of dexterous manipulation tasks once the aerial robot has landed or perched. The paper describes the design, development, and aerodynamic analysis of this winged aerial manipulation robot (WAMR), consisting of a small-scale dual arm used for manipulating and as a morphing wing. The arms, fuselage, and tail are covered by a nylon cloth that acts as a cap, similar to a kite. The three joints of the arms (shoulder yaw and pitch, elbow pitch) can be used to control the surface area and orientation and thus the aerodynamic wrenches induced over the cloth. The proposed concept design is extended to a flapping-wing aerial robot built with smart servo actuators and a similar frame structure, allowing the generation of different flapping patterns exploiting the embedded servo controller. Experimental and simulation results carried out with these two prototypes evaluate the manipulation capability and the possibility of gliding and flying
@article{suarez2020winged, title={Winged aerial manipulation robot with dual arm and tail}, author={Suarez, Alejandro and Grau, Pedro and Heredia, Guillermo and Ollero, Anibal}, journal={Applied Sciences}, volume={10}, number={14}, pages={4783}, year={2020}, publisher={Multidisciplinary Digital Publishing Institute} }
A Linearized Model for an Ornithopter in Gliding Flight: Experiments and Simulations
ICRA 2020,
This work studies the accuracy of a simple but effective analytical model for a flapping-wings UAV in longitudinal gliding flight configuration comparing it with experimental results of a real ornithopter. The aerodynamic forces are modeled following the linearized potential theory for a flat plate in gliding configuration, extended to flapping-wing episodes modeled also by the (now unsteady) linear potential theory, which are studied numerically. In the gliding configuration, the model reaches a steady-state descent at given terminal velocity and pitching and gliding angles, governed by the wings and tail position. In the flapping-wing configuration, it is noticed that the vehicle can increase its flight velocity and perform climbing episodes. A realistic simulation tool based on Unreal Engine 4 was developed to visualize the effect of the tail position and flapping frequencies and amplitudes on the ornithopter flight in real time. The paper also includes the experimental validation of the gliding flight and the data has been released for the community.
@inproceedings{lopez2020linearized, title={A Linearized Model for an Ornithopter in Gliding Flight: Experiments and Simulations}, author={Lopez-Lopez, R and Perez-Sanchez, V and Ramon-Soria, P and Martin-Alcantara, A and Fernandez-Feria, R and Arrue, Bego{\~n}a C and Ollero, An{\'\i}bal}, booktitle={2020 IEEE International Conference on Robotics and Automation (ICRA)}, pages={7008--7014}, year={2020}, organization={IEEE} }
Benchmarks for Aerial Manipulation
Letters, vol. 5, no. 2, pp. 2650-2657
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.
@article{suarez2020benchmarks, title={Benchmarks for aerial manipulation}, author={Suarez, Alejandro and Vega, Victor M and Fernandez, Manuel and Heredia, Guillermo and Ollero, Anibal}, journal={IEEE Robotics and Automation Letters}, volume={5}, number={2}, pages={2650--2657}, year={2020}, publisher={IEEE} }
Towards flapping wing robot visual perception: Opportunities and challenges
RED-UAS, pp: 335-343.
The development of perception systems for bio-inspired flapping wing robots, or ornithopters, is very challenging due to their fast flying maneuvers and the high amount of vibrations and motion blur originated by the wing flapping. Visual sensors have been widely used in aerial robot perception due to their size, weight, and energy consumption capabilities. This paper analyzes the issues and challenges for vision sensors onboard ornithopter robots. Two visual sensors are evaluated: a monocular camera and an event-based camera. First, the pros and cons of integrating different sensors on flapping wing robots are studied. Second, the paper experimentally evaluates the impact of wing flapping frequency on both sensors using experiments with the ornithopter developed in the EU-funded GRIFFIN ERC project.
@INPROCEEDINGS{, author={Eguíluz, A. Gómez and Rodríguez-Gómez, J.P. and Paneque, J.L. and Grau, P. and de Dios, J.R. Martínez and Ollero, A.}, booktitle={2019 Workshop on Research, Education and Development of Unmanned Aerial Systems (RED UAS)}, title={Towards flapping wing robot visual perception: Opportunities and challenges}, year={2019}, volume={}, number={}, pages={335-343}, doi={10.1109/REDUAS47371.2019.8999674}}
2019
ROSS-LAN: RObotic Sensing Simulation Scheme for Bioinspired Robotic Bird LANding
ROBOT-2019, pp: 49-59
Aerial robotics is evolving towards the design of bioinspired platforms capable of resembling the behavior of birds and insects during flight. The development of perception algorithms for navigation of ornithopters requires sensor data information to evaluate and solve the limitations presented during the flight of these platforms. However, the payload constraints and hardware complexity of ornithopters hamper the sensor data acquisition. This paper focuses on the development of a multi-sensor simulator to retrieve the sensor information captured during the landing maneuvers of ornithopters. The landing trajectory is computed by using a bioinspired trajectory generator relying on tau theory. Further, a dataset of the sensor information records obtained during the simulation of several landing trajectories is publicly available online.
@InProceedings{,author={Rodr{\'i}guez-G{\'o}mez, Juan Pablo and G{\'o}mez Egu{\'i}luz, Augusto and Mart{\'i}nez-de Dios, Jos{\'e} Ramiro and Ollero, An{\'i}bal}, editor={Silva, Manuel F. and Lu{\'i}s Lima, Jos{\'e} and Reis, Lu{\'i}s Paulo and Sanfeliu, Alberto and Tardioli, Danilo}, title={ROSS-LAN: RObotic Sensing Simulation Scheme for Bioinspired Robotic Bird LANding}, booktitle={Robot 2019: Fourth Iberian Robotics Conference}, year={2020}, publisher={Springer International Publishing}, address={Cham}, pages={48--59}, }
Online Detection and Tracking of Pipes During UAV Flight in Industrial Environments
ROBOT-2019, pp: 28-39
3D LiDaR-based perception has been used in robotics for obtaining accurate representations of the robot surroundings. As pipes are one of the most common objects in industrial environments, cylinder detection systems provide valuable information for robot navigation in industrial scenarios. However, most cylinder detection approaches using 3D LiDaRs suffer from high computational requirements and, therefore, their on-line implementation on real robots is limited for certain applications. This work proposes a computationally-light probabilistic approach to pipe detection and tracking suitable for aerial robot mapping and navigation. The proposed method was tested in both simulation and real scenarios. Through a combination of previous estimates and the localisation of the robot, the proposed approach is capable of reducing the computational cost of the RANSAC algorithm while keeping high detection accuracy.
@InProceedings{, author={G{\'o}mez Egu{\'i}luz, Augusto and Paneque, Julio Lopez and Mart{\'i}nez-de Dios, Jos{\'e} Ramiro and Ollero, An{\'i}bal}, editor={Silva, Manuel F. and Lu{\'i}s Lima, Jos{\'e} and Reis, Lu{\'i}s Paulo and Sanfeliu, Alberto and Tardioli, Danilo}, title={Online Detection and Tracking of Pipes During UAV Flight in Industrial Environments}, booktitle={Robot 2019: Fourth Iberian Robotics Conference}, year={2020}, publisher={Springer International Publishing}, address=Cham}, pages={28--39},}
Current State and Trends on Bioinspired Actuators for Aerial Manipulation
International Workshop on Research, Education and Development on Unmanned Aerial Systems (RED-UAS), Cranfield, UK. pp. 352-361.
Recently, several research has been developed to embed manipulators and actuators in Unmanned Aerial Vehicles (UAVs) to allow them to interact with the environment. However, there are strong limitations with these actuators which are mainly related with the weight and efficiency. This article reviews the state of art of bio-inspired solutions for aerial manipulators and presents cutting edge bio-inspired technologies that are potentially profitable in the field of aerial robotics.
@inproceedings{gomez2019current, title={Current state and trends on bioinspired actuators for aerial manipulation}, author={Gomez-Tamm, AE and Ramon-Soria, P and Arrue, BC and Ollero, A}, booktitle={2019 Workshop on Research, Education and Development of Unmanned Aerial Systems (RED UAS)}, pages={352--361}, year={2019}, organization={IEEE} }
TCP muscle tensors: Theoretical analysis and potential applications in aerial robotic systems
Fourth Iberian Robotics Conference (ROBOT 2019), Porto, Portugal. Pp 40-51
The use of aerial systems in a variety of real applications is increasing nowadays. These offer solutions to existing problems in ways that have never seen before thanks to their capability to perform perching, grasping or manipulating in inaccessible or dangerous places. Many of these applications require small-sized robots that can maneuver in narrow environments. However, these are required to have also strength enough to perform the desired tasks. This balance is sometimes unreachable due to the fact that traditional servomotors are too heavyweight for being carried by such small unmanned aerial systems (UAS). This paper, offers a innovative solution based on twisted and coiled polymers (TCP) muscles. These tensors have a high weight/strength ratio (up to 200 times) compared with traditional servos. In this work, the practical and modeling work done by the authors is presented. Then, a preliminary design of a bio-inspired claw for an unmanned aerial system (UAS) is shown. This claw has been developed using additive manufacturing techniques with different materials. Actuated with TCP, it is intrinsically compliant and offers a great force/weight ratio.
@inproceedings{gomez2019tcp, title={Tcp muscle tensors: Theoretical analysis and potential applications in aerial robotic systems}, author={Gomez-Tamm, Alejandro Ernesto and Ramon-Soria, Pablo and Arrue, Bego{\~n}a C and Ollero, An{\'\i}bal}, booktitle={Iberian Robotics conference}, pages={40--51}, year={2019}, organization={Springer} }
Small-Scale Compliant Dual Arm With Tail for Winged Aerial Robots
IEE/RSJ International Conference on Intelligent Robots and Systems (IROS 2019), Macau, China. Pp 208-214.
Winged aerial robots represent an evolution of aerial manipulation robots, replacing the multirotor vehicles by fixed or flapping wing platforms. The development of this morphology is motivated in terms of efficiency, endurance and safety in some inspection operations where multirotor platforms may not be suitable. This paper presents a first prototype of compliant dual arm as preliminary step towards the realization of a winged aerial robot capable of perching and manipulating with the wings folded. The dual arm provides 6 DOF (degrees of freedom) for end effector positioning in a human-like kinematic configuration, with a reach of 25 cm (half-scale w.r.t. the human arm), and 0.2 kg weight. The prototype is built with micro metal gear motors, measuring the joint angles and the deflection with small potentiometers. The paper covers the design, electronics, modeling and control of the arms. Experimental results in test-bench validate the developed prototype and its functionalities, including joint position and torque control, bimanual grasping, the dynamic equilibrium with the tail, and the generation of 3D maps with laser sensors attached at the arms.
@inproceedings{suarez2019small, title={Small-Scale Compliant Dual Arm with Tail for Winged Aerial Robots}, author={Suarez, Alejandro and Perez, Manuel and Heredia, Guillermo and Ollero, Anibal}, booktitle={2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)}, pages={208--214}, year={2019}, organization={IEEE} }
A Simple Model for Gliding and Low-Amplitude Flapping Flight of a Bio-Inspired UAV
International Conference on Unmanned Aircraft Systems (ICUAS), Atlanta, Georgia (USA). Pp 729-737.
Inspired by the efficiency of soaring birds in crossing very large distances with barely flap their wings, this work presents a simple model of UAV that, adopting the capabilities of these animals, could improve the existent multi-rotor devices, not only in efficiency but also in safety and accessibility. Thus, simple analytical approximations to reproduce the behavior of flapping wings UAVs are explored, expecting their integration in on-board CPUs to be solved in real-time flight episodes. A comparison between gliding and wing flapping with these models indicates that the thrust generated by wingstrokes should be controlled in further studies in order to mitigate the oscillations along the path of the vehicle. The geometric parameters of the ornithopter are found to be decisive in this sense, so special attention should be paid during the design stage.
@inproceedings{martin2019simple, title={A simple model for gliding and low-amplitude flapping flight of a bio-inspired UAV}, author={Mart{\'\i}n-Alc{\'a}ntara, A and Grau, P and Fernandez-Feria, R and Ollero, A}, booktitle={2019 International Conference on Unmanned Aircraft Systems (ICUAS)}, pages={729--737}, year={2019}, organization={IEEE} }
