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Instantaneous transfer entropy for the study of cardiovascular and cardiorespiratory nonstationary dynamics

TitleInstantaneous transfer entropy for the study of cardiovascular and cardiorespiratory nonstationary dynamics
Publication TypeJournal Article
Year of Publication2017
AuthorsValenza, G, Faes, L, Citi, L, Orini, M, Barbieri, R
JournalIEEE Transactions on Biomedical Engineering
Volume65
Pagination1077–1085
Date Published05/2018
URLhttps://ieeexplore.ieee.org/abstract/document/8010795
DOI

Reliability of lagged poincaré plot parameters in ultrashort heart rate variability series: Application on affective sounds

TitleReliability of lagged poincaré plot parameters in ultrashort heart rate variability series: Application on affective sounds
Publication TypeJournal Article
Year of Publication2017
AuthorsNardelli, M, Greco, A, Bolea, J, Valenza, G, Scilingo, EP, Bailon, R
JournalIEEE journal of biomedical and health informatics
Volume22
Pagination741–749
Date Published05/2018
URLhttps://ieeexplore.ieee.org/abstract/document/7903605
DOI10.1109/JBHI.2017.2694999

Integrating wearable haptics and teleimpedance methods for augmented human-robot interaction with synergy-inspired robotic systems

TitleIntegrating wearable haptics and teleimpedance methods for augmented human-robot interaction with synergy-inspired robotic systems
Publication TypeJournal Article
Year of Publication2017
AuthorsFani, S, Ciotti, S, Catalano, MG, Grioli, G, Tognetti, A, Valenza, G, A. Ajoudani, Bianchi, M
JournalRobotic & Automation Magazine, Accepted
URLhttps://scholar.google.com/scholar?cluster=1774931764262806887&hl=en&oi=scholarr

Heart rate variability analysis during muscle fatigue due to prolonged isometric contraction

TitleHeart rate variability analysis during muscle fatigue due to prolonged isometric contraction
Publication TypeConference Paper
Year of Publication2017
Conference NameProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
AuthorsGuidi, A, Greco, A, Felici, F, Leo, A, Ricciardi, E, Bianchi, M, Bicchi, A, Valenza, G, Scilingo, EP
DOI10.1109/EMBC.2017.8037076

Muscle fatigue assessment through electrodermal activity analysis during isometric contraction

TitleMuscle fatigue assessment through electrodermal activity analysis during isometric contraction
Publication TypeConference Paper
Year of Publication2017
Conference NameProceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS
AuthorsGreco, A, Guidi, A, Felici, F, Leo, A, Ricciardi, E, Bianchi, M, Bicchi, A, Citi, L, Valenza, G, Scilingo, EP
DOI10.1109/EMBC.2017.8036846

Synergy-driven performance enhancement of vision-based 3D hand pose reconstruction

TitleSynergy-driven performance enhancement of vision-based 3D hand pose reconstruction
Publication TypeConference Paper
Year of Publication2017
Conference NameWireless mobile communication and healthcare : 6th International conference, MobiHealth 2016, Milan, Italy, November 14-16, 2016, Proceedings
AuthorsCiotti, S, Battaglia, E, Oikonomidis, I, Makris, A, Tsoli, A, Bicchi, A, Agyros, AA, Bianchi, M
DOI10.1007/978-3-319-58877-3_42

Parametric Trajectory Libraries for Online Motion Planning with Application to Soft Robots

TitleParametric Trajectory Libraries for Online Motion Planning with Application to Soft Robots
Publication TypeConference Paper
Year of Publication2017
Conference Name18th International Symposium on Robotics Research
AuthorsMarcucci, T, Garabini, M, Gasparri, GM, Artoni, A, Gabiccini, M, Bicchi, A
Abstract

In this paper we propose a method for online motion planning of constrained nonlinear systems. The method consists of three steps: the offline generation of a library of parametric trajectories via direct trajectory optimization, the online search in the library for the best candidate solution to the optimal control problem we aim to solve, and the online refinement of this trajectory. The last phase of this process takes advantage of a sensitivity-like analysis and guarantees to comply with the first-order approximation of the constraints even in case of active set changes. Efficiency of the trajectory generation process is discussed and a valid strategy to minimize online computations is proposed; together with this, an effective procedure for searching the candidate trajectory is also presented. As a case study, we examine optimal control of a planar soft manipulator performing a pick-and-place task: through simulations and experiments, we show how crucial online computation times are to achieve considerable energy savings in the presence of variability of the task to perform.

Design of an under-actuated wrist based on adaptive synergies

TitleDesign of an under-actuated wrist based on adaptive synergies
Publication TypeConference Paper
Year of Publication2017
Conference NameRobotics and Automation (ICRA), 2017 IEEE International Conference on
Pagination6679–6686
AuthorsCasini, S, Tincani, V, Averta, G, Poggiani, M, C. Della Santina,, Battaglia, E, Catalano, MG, Bianchi, M, Grioli, G, Bicchi, A
PublisherIEEE
Abstract

An effective robotic wrist represents a key en- abling element in robotic manipulation, especially in prosthetics. In this paper, we propose an under-actuated wrist system, which is also adaptable and allows to implement different under- actuation schemes. Our approach leverages upon the idea of soft synergies - in particular the design method of adaptive synergies - as it derives from the field of robot hand design. First we intro- duce the design principle and its implementation and function in a configurable test bench prototype, which can be used to demonstrate the feasibility of our idea. Furthermore, we report on results from preliminary experiments with humans, aiming to identify the most probable wrist pose during the pre-grasp phase in activities of daily living. Based on these outcomes, we calibrate our wrist prototype accordingly and demonstrate its effectiveness to accomplish grasping and manipulation tasks.

From humans to robots: The role of cutaneous impairment in human environmental constraint exploitation to inform the design of robotic hands

TitleFrom humans to robots: The role of cutaneous impairment in human environmental constraint exploitation to inform the design of robotic hands
Publication TypeConference Paper
Year of Publication2017
Conference NameUltra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2017 9th International Congress on
Pagination179–184
AuthorsAverta, G, C. Della Santina,, Battaglia, E, Ciotti, S, Arapi, V, Fani, S, Bianchi, M
PublisherIEEE
Conference LocationMunich
Abstract

Human hands are capable of a variety of movements, thanks to their extraordinary biomechanical structure and rely- ing on the richness of human tactile information. Recently, soft robotic hands have opened exciting possibilities and, at the same time, new issues related to planning and control. In this work, we propose to study human strategies in environmental constraint exploitation to grasp objects from a table. We have considered both the case where participants’ fingertips were free and with a rigid shell worn on them to understand the role of cutaneous touch. Main kinematic strategies were quantified and classified in an unsupervised manner. The principal strategies appear to be consistent in both experimental conditions, although cluster cardinality differs. Furthermore, as expected, tactile feedback improves both grasp precision and quality performance. Results opens interesting perspective for sensing and control of soft manipulators.

Notes

This work has been awarded with the "Best Student Paper Award" and the "Best Paper in Session - Robotics"

Unvealing the principal modes of human upper limb movements through functional analysis

TitleUnvealing the principal modes of human upper limb movements through functional analysis
Publication TypeJournal Article
Year of Publication2017
AuthorsAverta, G, C. Della Santina,, Battaglia, E, Felici, F, Bianchi, M, Bicchi, A
JournalFrontiers in Robotics and AI
Volume4
Pagination37
Abstract

The rich variety of human upper limb movements requires an extraordinary coordination of different joints according to specific spatio-temporal patterns. However, unvealing these motor schemes is a challenging task. Principal components have been often used for analogous purposes, but such an approach relies on hypothesis of temporal uncorrelation of upper limb poses in time. To overcome these limitations, in this work, we leverage on functional principal component analysis (fPCA). We carried out experiments with 7 subjects performing a set of most significant human actions, selected considering state-of-the-art grasp taxonomies and human kinematic workspace. fPCA results show that human upper limb trajectories can be reconstructed by a linear combination of few principal time-dependent functions, with a first component alone explaining around 60/70% of the observed behaviors. This allows to infer that in daily living activities humans reduce the complexity of movement by modulating their motions through a reduced set of few principal patterns. Finally, we discuss how this approach could be profitably applied in robotics and bioengineering, opening fascinating perspectives to advance the state of the art of artificial systems, as it was the case of hand synergies.

Grasp Performance of a Soft Synergy-Based Prosthetic Hand: A Pilot Study

TitleGrasp Performance of a Soft Synergy-Based Prosthetic Hand: A Pilot Study
Publication TypeJournal Article
Year of Publication2017
AuthorsGailey, AS, Godfrey, SB, Breighner, R, Andrews, K, Zhao, K, Bicchi, A, Santello, M
Journal IEEE Transactions on Neural Systems and Rehabilitation Engineering
Volume25
Issue12
Pagination2407 - 2417
Date Published12/2017
ISSN1534-4320
Accession Number17397794
KeywordsHaptics, Robotics
Abstract

Current prosthetic hands are frequently rejected in part due to limited functionality and versatility. We assessed the feasibility of a novel prosthetic hand, the SoftHand Pro (SHP), whose design combines soft robotics and hand postural synergies. Able-bodied subjects (n = 23) tracked cursor motion by opening and closing the SHP and performed a grasp-lift-hold-release (GLHR) task with a sensorized cylindrical object of variable weight. The SHP control was driven by electromyographic (EMG) signals from two antagonistic muscles. Although the time to perform the GLHR task was longer for the SHP than native hand for the first few trials (10.2 ± 1.4 s and 2.13 ± 0.09 s, respectively), performance was much faster on subsequent trials (~5 s). The SHP steady-state grip force was significantly modulated as a function of object weight (p <; 0.001). For the native hand, however, peak and steady-state grip forces were modulated to a greater extent (+68% and +91%, respectively). These changes were mediated by the modulation of EMG amplitude and co-contraction. These data suggest that the SHP has a promise for prosthetic applications and point-to-design modifications that could improve the SHP.

URLhttp://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8094246
DOI10.1109/TNSRE.2017.2737539
Custom 1

Research reported in this publication was supported by the Grainger Foundation, the Eunice Kennedy Shriver National Institute Of Child Health and Human Development of the National Institutes of Health (NIH) under Award Number R21HD081938, and the European Commission within Horizon 2020 2015.ICT.24a Robot- ics RIA, with Grant no. 688857 “SOFTPRO -Synergy-based Open-source Foundations and Technologies for Prosthetics and RehabilitatiOn.” 

Refereed DesignationRefereed

The SoftHand Pro-H: A Hybrid Body-Controlled, Electrically Powered Hand Prosthesis for Daily Living and Working

TitleThe SoftHand Pro-H: A Hybrid Body-Controlled, Electrically Powered Hand Prosthesis for Daily Living and Working
Publication TypeJournal Article
Year of Publication2017
AuthorsPiazza, C, Catalano, MG, Godfrey, SB, Rossi, M, Grioli, G, Bianchi, M, Zhao, K, Bicchi, A
JournalIEEE Robotics and Automation Magazine
Date Published11/2017
ISSN1070-9932
KeywordsHaptics, Robotics
Notes

This work was supported by the European Commission project (Horizon 2020 research program) SOFTPRO 688857, the European Research Council under the Advanced Grant SoftHands “A Theory of Soft Synergies for a New Generation of Artificial Hands,” ERC-291166, and the Proof of Concept Project SoftHand Pro-H, ERC-2016-PoC 727536. 

URLhttp://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8110634
DOI10.1109/MRA.2017.2751662
Refereed DesignationRefereed

Systematic Review of fMRI Compatible Devices: Design and Testing Criteria

TitleSystematic Review of fMRI Compatible Devices: Design and Testing Criteria
Publication TypeJournal Article
Year of Publication2017
AuthorsHartwig, V, Carbonaro, N, Tognetti, A, Vanello, N
JournalANNALS OF BIOMEDICAL ENGINEERING
KeywordsBiomedical Engineering, Compatibility, fMRI, Mechatronic devices, Safety
URLhttp://link.springer.com/journal/volumesAndIssues/10439
DOI10.1007/s10439-017-1853-1
Refereed DesignationRefereed

Development of a High-Speed Current Injection and Voltage Measurement System for Electrical Impedance Tomography-Based Stretchable Sensors

TitleDevelopment of a High-Speed Current Injection and Voltage Measurement System for Electrical Impedance Tomography-Based Stretchable Sensors
Publication TypeJournal Article
Year of Publication2017
AuthorsRusso, S, Nefti-meziani, S, Carbonaro, N, Tognetti, A
JournalTECHNOLOGIES
Volume5
Keywordsconductive fabric, EIT, pressure sensor, stretchable, wearable
URLhttp://www.mdpi.com/2227-7080/5/3/48
DOI10.3390/technologies5030048
Refereed DesignationRefereed

A Quantitative Evaluation of Drive Pattern Selection for Optimizing EIT-Based Stretchable Sensors

TitleA Quantitative Evaluation of Drive Pattern Selection for Optimizing EIT-Based Stretchable Sensors
Publication TypeJournal Article
Year of Publication2017
AuthorsRusso, S, Nefti-meziani, S, Carbonaro, N, Tognetti, A
JournalSENSORS
Volume17
Keywordsconductive fabric, inverse problem, performance parameters, stretchable sensor
Abstract

Electrical Impedance Tomography (EIT) is a medical imaging technique that has been recently used to realize stretchable pressure sensors. In this method, voltage measurements are taken at electrodes placed at the boundary of the sensor and are used to reconstruct an image of the applied touch pressure points. The drawback with EIT-based sensors, however, is their low spatial resolution due to the ill-posed nature of the EIT reconstruction. In this paper, we show our performance evaluation of different EIT drive patterns, specifically strategies for electrode selection when performing current injection and voltage measurements. We compare voltage data with Signal-to-Noise Ratio (SNR) and Boundary Voltage Changes (BVC), and study image quality with Size Error (SE), Position Error (PE) and Ringing (RNG) parameters, in the case of one-point and two-point simultaneous contact locations. The study shows that, in order to improve the performance of EIT based sensors, the electrode selection strategies should dynamically change correspondingly to the location of the input stimuli. In fact, the selection of one drive pattern over another can improve the target size detection and position accuracy up to 0.04. and 0.18, respectively.

URLhttp://www.mdpi.com/1424-8220/17/9/1999/htm
DOI10.3390/s17091999
Refereed DesignationRefereed

A Multimodal Perception Framework for Users Emotional State Assessment in Social Robotics

TitleA Multimodal Perception Framework for Users Emotional State Assessment in Social Robotics
Publication TypeJournal Article
Year of Publication2017
AuthorsCominelli, L, Carbonaro, N, Mazzei, D, Garofalo, R, Tognetti, A, De Rossi, D
JournalFUTURE INTERNET
Volume9
Keywordshuman-robot interaction, multimodality, perception framework, physiological signal acquisition, social robotics
DOI10.3390/fi9030042
Refereed DesignationRefereed

Characterization of Hand Movements using a Sensing Glove in Hand Assisted Laparoscopic Surgery

TitleCharacterization of Hand Movements using a Sensing Glove in Hand Assisted Laparoscopic Surgery
Publication TypeConference Paper
Year of Publication2017
Conference NameProceedings of the second International Conference on Medical Information and Bioengineering
AuthorsSantos, L, Carbonaro, N, Tognetti, A, Gonzales, R, Fraile, JC, Turiel, JP, De La Fuente, E
Abstract

The past thirty years have seen increasingly rapid advances in the field of laparoscopic surgery, in part because of the use of robots. A well-known example is the da Vinci surgical system. However, far too little attention has been paid to Hand Assisted Laparoscopic Surgery (HALS), a surgery in which the surgeon introduces the non-dominant hand into the abdomen of the patient. The risk of collision between the hand of the surgeon and the tool moved by the robot is the reason why these robots for laparoscopic surgery are not appropriate for HALS. On the other hand, in recent years, there has been an increasing interest in wearables, which have been introduced in our daily life. This interest and the lack of surgery robots for HALS are the reasons to develop a sensing glove which co-works whit a collaborative robot in this kind of surgery. The aim of this paper is to study the use of a sensing glove which will provide information of the movements of the surgeon’s hand to the collaborative robot. This information determinates the actions that the robot will carry on. The first step was to define different movements of the hand which could be identified. An algorithm identifies these movements using the data given by the sensing glove. For the purpose of algorithm accuracy measurement, 4 persons wearing the sensing glove made a sequence with different movements. The evidence from this study suggests that a sensing glove can be used to send information of the movements of the surgeon’s hand to a collaborative robot during a HALS.

Refereed DesignationRefereed

Estimating Contact Forces from Postural Measures in a class of Under-Actuated Robotic Hands

TitleEstimating Contact Forces from Postural Measures in a class of Under-Actuated Robotic Hands
Publication TypeConference Paper
Year of Publication2017
Conference NameIEEE International Conference of Intelligent Robots and Systems (IROS2017)
AuthorsC. Della Santina,, Piazza, C, Santaera, G, Grioli, G, Catalano, MG, Bicchi, A
PublisherIEEE
Conference LocationVancouver, Canada, September 24–28, 2017
KeywordsRobotics
Refereed DesignationRefereed

Design, control and validation of the variable stiffness exoskeleton FLExo

TitleDesign, control and validation of the variable stiffness exoskeleton FLExo
Publication TypeConference Paper
Year of Publication2017
Conference NameInternational Conference on Rehabilitation Robotics (ICORR)
Pagination539 - 546
AuthorsMghames, S, Laghi, M, C. Della Santina,, Garabini, M, Catalano, MG, Grioli, G, Bicchi, A
PublisherIEEE
Conference LocationLondon, UK, 17-20 July 2017
Accession Number17101547
KeywordsRobotics
Abstract

In this paper we present the design of a one degree of freedom assistive platform to augment the strength of upper limbs. The core element is a variable stiffness actuator, closely reproducing the behavior of a pair of antagonistic muscles. The novelty introduced by this device is the analogy of its control parameters with those of the human muscle system, the threshold lengths. The analogy can be obtained from a proper tuning of the mechanical system parameters. Based on this, the idea is to control inputs by directly mapping the estimation of the muscle activations, e.g. via ElectroMyoGraphic(EMG) sensors, on the exoskeleton. The control policy resulting from this mapping acts in feedforward in a way to exploit the muscle-like dynamics of the mechanical device. Thanks to the particular structure of the actuator, the exoskeleton joint stiffness naturally results from that mapping. The platform as well as the novel control idea have been experimentally validated and the results show a substantial reduction of the subject muscle effort.

URLhttp://ieeexplore.ieee.org/document/8009304/
DOI10.1109/ICORR.2017.8009304
Refereed DesignationRefereed

Design and characterization of a novel high-compliance spring for robots with soft joints

TitleDesign and characterization of a novel high-compliance spring for robots with soft joints
Publication TypeConference Paper
Year of Publication2017
Conference NameIEEE International Conference on Advanced Intelligent Mechatronics (AIM)
AuthorsNegrello, F, Catalano, MG, Garabini, M, Poggiani, M, Caldwell, DG, Tsagarakis, NG, Bicchi, A
PublisherIEEE
Conference LocationMunich, Germany, 3-7 July 2017
Accession Number17136847
KeywordsRobotics
Abstract

Low stiffness elements have a number of applications in Soft Robotics, from Series Elastic Actuators (SEA) to torque sensors for compliant systems. In its general formulation, the design problem of elastic components is complex and depends on several variables: material properties, load range, shape factor and size constraints. Consequently, most of the spring designs presented in literature are based on heuristics or are optimized for specific working conditions. This work presents the design study and characterization of a scalable spoked elastic element with hinge tip constraints. We compared the proposed design with three existing spring principles, showing that the spoked solution is the convenient option for low-stiffness and low shape factor elastic elements. Therefore, a design analysis on the main scaling parameters of the spoked spring, namely number of spokes and type of constraints, is presented. Finally, an experimental characterization has been conducted on physical prototypes. The agreement among simulations and experimental results demonstrates the effectiveness of the proposed concept.

URLhttp://ieeexplore.ieee.org/document/8014029/
DOI10.1109/AIM.2017.8014029
Refereed DesignationRefereed

Postural Hand Synergies during Environmental Constraint Exploitation

TitlePostural Hand Synergies during Environmental Constraint Exploitation
Publication TypeJournal Article
Year of Publication2017
AuthorsC. Della Santina,, Bianchi, M, Averta, G, Ciotti, S, Arapi, V, Fani, S, Battaglia, E, Catalano, MG, Santello, M, Bicchi, A
JournalFronters in Neurorobotics
Date Published08/2017
KeywordsHaptics, Robotics
Abstract

Humans are able to intuitively exploit the shape of an object and environmental constraints to achieve stable grasps and perform dexterous manipulations. In doing that, a vast range of kinematic strategies can be observed. However, in this work we formulate the hypothesis that such ability can be described in terms of a synergistic behavior in the generation of hand postures, i.e., using a reduced set of commonly used kinematic patterns. This is in analogy with previous studies showing the presence of such behavior in different tasks, such as grasping. We investigated this hypothesis in experiments performed by six subjects, who were asked to grasp objects from a flat surface. We quantitatively characterized hand posture behavior from a kinematic perspective, i.e., the hand joint angles, in both pre-shaping and during the interaction with the environment. To determine the role of tactile feedback, we repeated the same experiments but with subjects wearing a rigid shell on the fingertips to reduce cutaneous afferent inputs. Results show the persistence of at least two postural synergies in all the considered experimental conditions and phases. Tactile impairment does not alter significantly the first two synergies, and contact with the environment generates a change only for higher order Principal Components. A good match also arises between the first synergy found in our analysis and the first synergy of grasping as quantified by previous work. The present study is motivated by the interest of learning from the human example, extracting lessons that can be applied in robot design and control. Thus, we conclude with a discussion on implications for robotics of our findings.

URLhttps://www.frontiersin.org/articles/10.3389/fnbot.2017.00041/full
DOI10.3389/fnbot.2017.00041
Refereed DesignationRefereed

Preliminary results toward a naturally controlled multi-synergistic prosthetic hand

TitlePreliminary results toward a naturally controlled multi-synergistic prosthetic hand
Publication TypeConference Paper
Year of Publication2017
Conference NameInternational Conference on Rehabilitation Robotics (ICORR)
AuthorsRossi, M, C. Della Santina,, Piazza, C, Grioli, G, Catalano, MG, Bicchi, A
ISBN Number978-1-5386-2296-4
KeywordsRobotics
Abstract

Robotic hands embedding human motor control principles in their mechanical design are getting increasing interest thanks to their simplicity and robustness, combined with good performance. Another key aspect of these hands is that humans can use them very effectively thanks to the similarity of their behavior with real hands. Nevertheless, controlling more than one degree of actuation remains a challenging task. In this paper, we take advantage of these characteristics in a multi-synergistic prosthesis. We propose an integrated setup composed of Pisa/IIT SoftHand 2 and a control strategy which simultaneously and proportionally maps the human hand movements to the robotic hand. The control technique is based on a combination of non-negative matrix factorization and linear regression algorithms. It also features a real-time continuous posture compensation of the electromyographic signals based on an IMU. The algorithm is tested on five healthy subjects through an experiment in a virtual environment. In a separate experiment, the efficacy of the posture compensation strategy is evaluated on five healthy subjects and, finally, the whole setup is successfully tested in performing realistic daily life activities.

URLhttp://ieeexplore.ieee.org/abstract/document/8009437/
DOI10.1109/ICORR.2017.8009437
Refereed DesignationRefereed

Enhancing Adaptive Grasping Through a Simple Sensor-Based Reflex Mechanism

Title Enhancing Adaptive Grasping Through a Simple Sensor-Based Reflex Mechanism
Publication TypeJournal Article
Year of Publication2017
AuthorsLuberto, E, Wu, Y, Santaera, G, Gabiccini, M, Bicchi, A
JournalIEEE Robotics and Automation Letters
Volume2
Issue3
Pagination1664 - 1671
Date Published07/2017
KeywordsHaptics, Robotics
Abstract

This paper presents an approach to achieve adaptive grasp of unknown objects whose position is only approximately known via point-cloud data. We exploit the adaptability of a soft robotic hand which can autonomously conform to the shape of a grasped object if properly approached. Once a grasp approach has been preliminarily planned based only on rough estimates of the object position, the hand is shaped to a pregrasp configuration. Before closing the hand, a sensor-based algorithm is applied that corrects the relative hand-object posture so as to enhance the probability that the object is uniformly approached by all fingers, thus avoiding undesired premature contacts. The algorithm minimizes the distance between the hand's fingerpads and the object by continuously controlling both the wrist pose and orientation and the hand closure. Experimental studies with a Kuka-LWR arm and a Pisa/IIT Softhand illustrate the benefit of the developed technique and the improvement in grasping performance with respect to open-loop execution of grasps planned on the basis of prior RGB-D cues only.

URLhttp://ieeexplore.ieee.org/document/7875417/
DOI10.1109/LRA.2017.2681122
Refereed DesignationRefereed

Modular One-to-many Clutchable Actuator for a Soft Elbow Exosuit

TitleModular One-to-many Clutchable Actuator for a Soft Elbow Exosuit
Publication TypeConference Paper
Year of Publication2017
Conference Name International Conference on Rehabilitation Robotics (ICORR 2017)
Pagination1679-1685
Date Published07/2017
AuthorsCanesi, M, Xiloyannis, M, A. Ajoudani, Bicchi, A, Masia, L
Conference LocationLondon, UK, July 17 - 20, 2017
KeywordsRobotics
DOI10.1109/ICORR.2017.8009489
Refereed DesignationRefereed

Choosing Poses for Force and Stiffness Control

TitleChoosing Poses for Force and Stiffness Control
Publication TypeJournal Article
Year of Publication2017
AuthorsA. Ajoudani, Tsagarakis, NG, Bicchi, A
JournalIEEE Transactions on Robotics
Date Published06/2017
KeywordsRobotics
Abstract

In humanoids and other redundant robots interacting with the environment, one can often choose between different configurations and control parameters to achieve a given task. A classic tool to describe specifications of the desired force/displacement behavior in such problems is the stiffness ellipsoid, whose geometry is affected by the choice of parameters in both joint control and redundancy resolution—namely, gains and angles. As is well known, impedance control techniques can regulate gains to realize any desired shape of the Cartesian stiffness ellipsoid at the end-effector, so that robot geometry selection could appear secondary. However, humans do not use this possibility: To control the stiffness of our arms, we predominantly use arm configurations. Why is that, and does it makes sense to do the same in robots? To understand this discrepancy, we provide a more complete analysis of the task-space force/deformation behavior of compliant redundant arms to illustrate why the arm geometry plays a dominant role in interaction capabilities of robots. We introduce the notion of allowable Cartesian force/displacement (“stiffness feasibility”) regions (SFR) for compliant robots with given torque boundaries. We show that different robot configurations modify such regions and explore the role of robot geometry in achieving an appropriate SFR for the task at hand. The novel concepts and definitions are first illustrated in simulations. Experimental results are then provided to verify the effectiveness of the proposed Cartesian force and stiffness control.

URLhttp://ieeexplore.ieee.org/document/7951027/
DOI10.1109/TRO.2017.2708087
Refereed DesignationRefereed

Reduced-Complexity Representation of the Human Arm Active Endpoint Stiffness for Supervisory Control of Remote Manipulation

TitleReduced-Complexity Representation of the Human Arm Active Endpoint Stiffness for Supervisory Control of Remote Manipulation
Publication TypeJournal Article
Year of Publication2017
AuthorsA. Ajoudani, Fang, C, Tsagarakis, NG, Bicchi, A
JournalInternational Journal of Robotics Research
Volume37
Start Page155
Issue1
Date Published11/2017
URLhttps://journals.sagepub.com/doi/full/10.1177/0278364917744035
DOI10.1177%2F0278364917744035

Distributed Task-priority Based Control in Area Coverage & Adaptive Sampling

TitleDistributed Task-priority Based Control in Area Coverage & Adaptive Sampling
Publication TypeConference Paper
Year of Publication2017
Conference NameMTS/IEEE Oceans 2017
AuthorsFabbri, T, Simetti, E, Casalino, G, Pallottino, L, Caiti, A
PublisherIEEE
Conference LocationAberdeen, Scotland, June 2017
KeywordsRobotics
Abstract

The paper presents the first simulative results and algorithmic developments of the task-priority based control applied to a distributed sampling network in an area coverage or adaptive sampling mission scenario. The proposed approach allowing the fulfilment of a chain of tasks with decreasing priority each of which directly related to both operability and safety aspects of the entire mission. The task-priority control is presented both in the centralized and decentralized implementations showing a comparison of performance. Finally simulations of the area coverage mission scenario are provided showing the effectiveness of the proposed approach.

Refereed DesignationRefereed

Cerebellar-Inspired Learning Rule for Gain Adaptation of Feedback Controllers

TitleCerebellar-Inspired Learning Rule for Gain Adaptation of Feedback Controllers
Publication TypeConference Paper
Year of Publication2017
Conference NameIEEE Mediterranean Conference on Control and Automation
AuthorsHerreros, I, Arsiwalla, XD, C. Della Santina,, Puigbo, J-Y, Bicchi, A, Verschure, PFMJ
PublisherIEEE
Conference Location3-6 July 2017 in Valletta, Malta
Abstract

The cerebellum is a crucial brain structure in enabling precise motor control in animals. Recent advances suggest that the timing of the plasticity rule of Purkinje cells, the main cells of the cerebellum, is matched to behavioral function.Simultaneously, counter-factual predictive control (CFPC), a cerebellar-based control scheme, has shown that the optimal rule for learning feed-forward action in an adaptive filter playing the role of the cerebellum must include a forward model of the system controlled. Here we show how the same learning rule obtained in CFPC, which we term as Model-enhanced least mean squares (ME-LMS), emerges in the problem of learning the gains of a feedback controller. To that end, we frame a model-reference adaptive control (MRAC) problem and derive an adaptive control scheme treating the gains of a feedback controller as if they were the weights of an adaptive linear unit. Our results demonstrate that the approach of controlling plasticity with a forward model of the subsystem controlled can provide a solution to a wide set of adaptive control problems

Refereed DesignationRefereed

Online Model Based Estimation of Complete Joint Stiffness of Human Arm

TitleOnline Model Based Estimation of Complete Joint Stiffness of Human Arm
Publication TypeJournal Article
Year of Publication2017
AuthorsFang, C, A. Ajoudani, Bicchi, A, Tsagarakis, NG
JournalIEEE Robotics and Automation Letters
Volume3
Issue1
Pagination84 - 91
Date Published01/2018
KeywordsHaptics, Robotics
Abstract

The endpoint stiffness of the human arm has been long recognized as a key component ensuring the quasi-static stability of the arm physical interactions with the external world. Similarly, the understanding of the joint stiffness behavior can provide complementary insights, e.g., on the underlying stiffness regulation principles across different joints including the nullspace stiffness profiles. Traditionally, the experimental modeling and estimation of the human arm joint stiffness is achieved by the transformation of the identified arm endpoint stiffness to the joint coordinates. Due to the underlying kinematic redundancy, the obtained joint stiffness matrix is rank-deficient which implies that the information in the joint stiffness matrix is incomplete. While in robotics applications this issue can be addressed by designing a desired nullspace stiffness behavior through appropriate projections, the use of a similar technique in the identification of human joint stiffness profile is meaningless. Hence, the first objective of this work is to address this issue by developing a novel technique to identify the complete and physiologically meaningful joint stiffness of human arm. Second, we present a model-based online estimation technique to estimate the seven-dimensional complete joint stiffness in various arm poses and activation levels of the two dominant arm muscles that correspond to the geometric and volume modifications of the joint stiffness profile, respectively.

URLhttp://ieeexplore.ieee.org/document/7990237/
DOI10.1109/LRA.2017.2731524
Refereed DesignationRefereed