@conference {2655, title = {Reflex Control of the Pisa/IIT SoftHand during Object Slippage}, booktitle = {IEEE International Conference of Robotics and Automation (ICRA2016)}, year = {2016}, pages = {1972 - 1979}, publisher = {IEEE}, organization = {IEEE}, address = {Stockholm, Sweden}, abstract = {

In this work, to guarantee the Pisa/IIT SoftHand{\textquoteright}s

grasp robustness against slippage, three reflex control modes,

namely Current, Pose and Impedance, are implemented and

experimentally evaluated. Towards this objective, ThimbleSense

fingertip sensors are designed and integrated into the thumb

and middle fingers of the SoftHand for real-time detection and

control of the slippage. Current reflex regulates the restoring

grasp forces of the hand by modulating the motor{\textquoteright}s current

profile according to an update law. Pose and Impedance reflex

modes instead replicate this behaviour by implementing an

impedance control scheme. The difference between the two

latter is that the stiffness gain in Impedance reflex mode is

being varied in addition to the hand pose, as a function of

the slippage on the fingertips. Experimental setup also includes

a seven degrees-of-freedom robotic arm to realize consistent

trajectories (e.g. lifting) among three control modes for the sake

of comparison. Different test objects are considered to evaluate

the efficacy of the proposed reflex modes in our experimental

setup. Results suggest that task-appropriate restoring forces

can be achieved using Impedance reflex due to its capability

in demonstrating instantaneous and rather smooth reflexive

behaviour during slippage. Preliminary experiments on five

healthy human subjects provide evidence on the similarity of the

control concepts exploited by the humans and the one realized

by the Impedance reflex, highlighting its potential in prosthetic

applications.

}, keywords = {Haptics, Robotics}, doi = {10.1109/ICRA.2016.7487344}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7487344}, author = {A. Ajoudani and E. Hocaoglu and Altobelli, A and M. Rossi and E. Battaglia and N G Tsagarakis and A. Bicchi} } @conference {2336, title = {Kinematic Analysis and Design Considerations for Optimal Base Frame Arrangement of Humanoid Shoulders}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2015)}, year = {2015}, pages = {2710 - 2715}, address = {Seattle, USA, 25 - 30 May}, keywords = {Robotics}, doi = {10.1109/ICRA.2015.7139566}, author = {M. Bagheri and A. Ajoudani and J. Lee and D. G. Caldwell and N G Tsagarakis} } @conference {2559, title = {A Reduced-Complexity Description of Arm Endpoint Stiffness with Applications to Teleimpedance Control}, booktitle = {IEEE International Conference of Intelligent Robots and Systems - IROS2015}, year = {2015}, note = {

softhands, wearhap

}, pages = {1017 - 1023}, publisher = {IEEE}, organization = {IEEE}, address = {Hamburg, Germany, 28 Sept - 2 Oct 2015}, abstract = {

Effective and stable execution of a remote task in an uncertain environment requires that the task force and position trajectories of the slave robot be appropriately commanded. To achieve this goal, in teleimpedance control, a reference command which consists of the stiffness and position profiles of the master is computed and realized by the compliant slave robot in real-time. This highlights the need for a suitable and computationally efficient tracking of the human limb stiffness profile in real-time. In this direction, based on the observations in human neuromotor control which give evidence on the predominant use of the arm configuration in directional adjustments of the endpoint stiffness profile, and the role of muscular co-activations which contribute to a coordinated stiffening of the task stiffness in all directions, we propose a novel and computationally efficient model of the arm endpoint stiffness behaviour. With the purpose of real-time tracking of the human arm kinematics, an arm triangle is introduced using three body markers at the shoulder, elbow and wrist joints. In addition, a co-contraction index is defined using muscular activities of a dominant antagonistic muscle pair. Calibration and identification of the model parameters are carried out experimentally, using perturbation-based arm endpoint stiffness measurements in different arm configurations and co-contraction levels of the chosen muscles. Results of this study suggest that the proposed model enables the master to naturally execute a remote task by modulating the direction of the major axes of the endpoint stiffness and its volume using arm configuration and the co-ativation of the involved muscles, respectively.

}, keywords = {Haptics, Robotics}, doi = {10.1109/IROS.2015.7353495}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7353495}, author = {A. Ajoudani and C. Fang and N G Tsagarakis and A. Bicchi} } @conference {2335, title = {On the Role of Robot Configuration in Cartesian Stiffness Control}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2015)}, year = {2015}, pages = {1010 - 1016}, address = {Seattle, USA, 25 - 30 May}, keywords = {Robotics}, doi = {10.1109/ICRA.2015.7139300}, author = {A. Ajoudani and N G Tsagarakis and A. Bicchi} } @article {2158, title = {Tele- Impedance based Assistive Control for a Compliant Knee Exoskeleton: Stiffness Augmentation and Motion Assistance}, journal = {Robotics and Autonomous Systems}, volume = {73 part A}, year = {2015}, note = {

special issue\ "Wearable Robotics"

}, month = {11/2015}, pages = {78-90}, abstract = {

This paper presents a tele-impedance based assistive control scheme for a knee exoskeleton device. The proposed controller captures the user{\textquoteright}s intent to generate task-related assistive torques by means of the exoskeleton in different phases of the subject{\textquoteright}s normal activity. To do so, a detailed musculoskeletal model of the human knee is developed and experimentally calibrated to best match the user{\textquoteright}s kinematic and dynamic behavior. Three dominant antagonistic muscle pairs are used in our model, in which electromyography (EMG) signals are acquired, processed and used for the estimation of the knee joint torque, trajectory and the stiffness trend, in real time. The estimated stiffness trend is then scaled and mapped to a task-related stiffness interval to agree with the desired degree of assistance. The desired stiffness and equilibrium trajectories are then tracked by the exoskeleton{\textquoteright}s impedance controller. As a consequence, while minimum muscular activity corresponds to low stiffness, i.e.\ highly transparent motion, higher co-contractions result in a stiffer joint and a greater level of assistance. To evaluate the robustness of the proposed technique, a study of the dynamics of the human{\textendash}exoskeleton system is conducted, while the stability in the steady state and transient condition is investigated. In addition, experimental results of standing-up and sitting-down tasks are demonstrated to further investigate the capabilities of the controller. The results indicate that the compliant knee exoskeleton, incorporating the proposed tele-impedance controller, can effectively generate assistive actions that are volitionally and intuitively controlled by the user{\textquoteright}s muscle activity.

}, keywords = {Robotics}, doi = {10.1016/j.robot.2014.09.027}, url = {http://www.sciencedirect.com/science/article/pii/S0921889014002127}, author = {N. Karavas and A. Ajoudani and N G Tsagarakis and J. Saglia and A. Bicchi and D. Caldwell} } @article {2080, title = {Variable Stiffness Actuators: the user{\textquoteright}s point of view}, journal = {Int. J. Robotics Research}, volume = {34}, year = {2015}, note = {

Extensions.zip

}, month = {05/2015}, pages = {727-743}, keywords = {Robotics}, doi = {10.1177/0278364914566515}, url = {http://ijr.sagepub.com/cgi/reprint/0278364914566515v1.pdf?ijkey=anmgudvoLz7ZloP\&keytype=finite}, author = {G. Grioli and S. Wolf and M. Garabini and M. G. Catalano and E. Burdet and D. G. Caldwell and R. Carloni and W. Friedl and M. Grebenstein and M. Laffranchi and D. Lefeber and S. Stramigioli and N G Tsagarakis and M. Van Damme and B. Vanderborght and A Albu-Schaeffer and A. Bicchi} } @article {1668, title = {Exploring Teleimpedance and Tactile Feedback for Intuitive Control of the Pisa/IIT SoftHand}, journal = { IEEE Transactions on Haptics}, volume = {7}, year = {2014}, pages = {203 - 215}, keywords = {Haptics, Robotics}, doi = {10.1109/TOH.2014.2309142 }, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6755554}, author = {A. Ajoudani and S. B. Godfrey and M. G. Catalano and M. Bianchi and G. Grioli and N G Tsagarakis and A. Bicchi} } @inbook {1694, title = {HANDS.DVI: A DeVice-Independent programming and control framework for robotic HANDS}, booktitle = {Gearing up and accelerating cross-fertilization between academic and industrial robotics research in Europe - Technology transfer experiments from the ECHORD project}, volume = {94}, number = {Springer Tracts in Advanced Robotics}, year = {2014}, pages = {197-215}, abstract = {

The scientific goal of HANDS.DVI consists of developing a common
framework to programming robotic hands independently from their kinematics,
mechanical construction, and sensor equipment complexity. Recent results on the
organization of the human hand in grasping and manipulation are the inspiration
for this experiment. The reduced set of parameters that we effectively use to control
our hands is known in the literature as the set of synergies. The synergistic
organization of the human hand is the theoretical foundation of the innovative approach
to design a unified framework for robotic hands control. Theoretical tools
have been studied to design a suitable mapping function of the control action (decomposed
in its elemental action) from a human hand model domain onto the
articulated robotic hand co-domain. The developed control framework has been
applied on an experimental set up consisting of two robotic hands with dissimilar
kinematics grasping an object instrumented with force sensors.

}, keywords = {Haptics, Robotics}, doi = {10.1007/978-3-319-02934-4_10}, author = {G. Salvietti and G. Gioioso and M. Malvezzi and D Prattichizzo and A. Serio and E. Farnioli and M Gabiccini and A. Bicchi and I. Sarakoglou and N G Tsagarakis and D. G. Caldwell} } @conference {2159, title = {Manipulation Framework for Compliant Humanoid COMAN: Application to a Valve Turning Task}, booktitle = {IEEE-RAS International Conference on Humanoid Robots (HUMANOIDS 2014)}, year = {2014}, pages = {664 - 670}, publisher = {IEEE}, organization = {IEEE}, address = {Madrid, Spain, November 18 - 20}, abstract = {

With the purpose of achieving a desired interaction performance for our compliant humanoid robot (COMAN), in this paper we propose a semi-autonomous control framework and evaluate it experimentally in a valve turning setup. The control structure consists of various modules and interfaces to identify the valve, locate the robot in front of it and perform the manipulation. The manipulation module implements four motion primitives (Reach, Grasp, Rotate and Disengage) and realizes the corresponding desired impedance profile for each phase to accomplish the task. In this direction, to establish a stable and compliant contact between the valve and the robot hands, while being able to generate the sufficient rotational torques depending on the valve{\textquoteright}s friction, Rotate incorporates a novel dual-arm impedance control technique to plan and realize a task-appropriate impedance profile. Results of the implementation of the proposed control framework are firstly evaluated in simulation studies using Gazebo. Subsequent experimental results highlight the efficiency of the proposed impedance planning and control in generation of the required interaction forces to accomplish the task.

}, keywords = {Haptics, Robotics}, doi = {10.1109/HUMANOIDS.2014.7041434}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7041434}, author = {A. Ajoudani and J. Lee and A. Rocchi and M. Ferrati and E. Mingo Hoffman and A Settimi and D. G. Caldwell and A. Bicchi and N G Tsagarakis} } @conference {2127, title = {A modular approach for remote operation of humanoid robots in search and rescue scenarios }, booktitle = {Modelling \& Simulation for Autonomous Systems - MESAS2014}, year = {2014}, address = {Rome, 5-6 May 2014}, keywords = {Robotics}, author = {A Settimi and C. Pavan and V. Varricchio and M. Ferrati and E. Mingo and A. Rocchi and K. Melo and N G Tsagarakis and A. Bicchi} } @conference {1983, title = {Natural Redundancy Resolution in Dual-Arm Manipulation using Configuration Dependent Stiffness (CDS) Control}, booktitle = {2014 IEEE International Conference on Robotics and Automation}, year = {2014}, pages = {1480 - 1486}, publisher = {IEEE}, organization = {IEEE}, address = {Hong Kong, May 31 2014-June 7 2014 }, abstract = {

Incorporation of human motor control principles in the motion control architectures for humanoid robots or assistive and prosthesis devices will permit these systems not only to look anthropomorphic and natural at the body ware level but also to generate natural motion profiles resembling those executed by humans during manipulation and locomotion. In this work, relying on the observations on human bimanual coordination, a novel realtime motion control strategy is proposed to regulate the desired Cartesian stiffness profile during the execution of bimanual tasks. The novelty of the proposed control scheme relies on the use of common mode stiffness (CMS) and configuration dependent stiffness (CDS) to regulate the size and directionality of the task space stiffness ellipsoid. Thanks to the CDS control, the proposed scheme is not only proved to be effective in regulating the desired stiffness ellipsoid but also permits to resolve the manipulator redundancy in a natural manner. The effectiveness of the controller is evaluated in an experimental setup in which two cooperating robotic arms are executing an assembly task. Experimental results demonstrate that the proposed dual-arm CDS-CMS controller is effective in tracking the desired stiffness ellipsoids as well as in producing human-like natural motions for the two robotic arms.

}, keywords = {Haptics, Robotics}, doi = {10.1109/ICRA.2014.6907047}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6945252}, author = {A. Ajoudani and N G Tsagarakis and J. Lee and M Gabiccini and A. Bicchi} } @conference {2120, title = {The Patched Intrinsic Tactile Object: a Tool to Investigate Human Grasps}, booktitle = {Proc. IEEE/RSJ Intl Conf. on Intelligent Robots and Systems (IROS 2014)}, year = {2014}, pages = {1261 - 1268}, address = {Chicago, USA}, abstract = {

In this paper we report on the development of a modular multi-DoF F/T sensor and its use in the implementation of a sensorized object capable of multi-touch detection. The sensor is composed of six 6-axis F/T sensors spatially organized on the faces of a cube. Different calibration methods are presented to directly tackle the coupling phenomena inherent to the spatial organization of the faces and the lightweight construction of the sensor which would have, otherwise, degraded its accuracy. To assess the performances of the calibration methods, a comparison is reported with respect to the measurements obtained with a commercial force/torque sensor considered as ground truth (ATI Delta). Thanks to the modular design and the possibility to cover the sensitive faces with surface patches of different geometry, a variety of sensorized objects with different shapes can be realized. The peculiar feature that all the components of the contact wrench can be measured on each face with high accuracy, renders it a unique tool in the study of grasp force distribution in humans, with envisioned use both in neuroscience investigations and robotic applications.

}, keywords = {Haptics, Robotics}, doi = {10.1109/IROS.2014.6942719}, author = {A. Serio and E. Riccomini and V. Tartaglia and I. Sarakoglou and M Gabiccini and N G Tsagarakis and A. Bicchi} } @conference {2160, title = {Upper-body Impedance Control with an Intuitive Stiffness Emulation for a Door Opening Task}, booktitle = {IEEE-RAS International Conference on Humanoid Robots (HUMANOIDS 2014)}, year = {2014}, pages = {713 - 719}, publisher = {IEEE}, organization = {IEEE}, address = {Madrid, Spain, November 18 - 20}, abstract = {

The advent of humanoids has brought new challenges in the real-world application. As a part of ongoing efforts to foster functionality of the robot accommodating a real environment, this paper introduces a recent progress on a door opening task with our compliant humanoid, CoMan. We presents a task-prioritized impedance control framework for an upper body system that includes a dual-arm, a waist, two soft hands, and 3D camera. Aimed to create desired responses to open the door, a novel stiffness modulation method is proposed, incorporating a realtime optimization. As a preliminary experiment, a full door-opening scenario (approaching to the door and reaching, grasping, rotating and pulling the door handle) is demonstrated under a semi-autonomous operation with a pilot. The experimental result shows the effectiveness and efficacy of the proposed impedance control approach. Despite of uncertainties from sensory data, the door opening task is successfully achieved and safe and robust interaction is established without creating excessive forces.

}, keywords = {Robotics}, doi = {10.1109/HUMANOIDS.2014.7041441}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7041441}, author = {J. Lee and A. Ajoudani and E. Mingo Hoffman and A. Rocchi and A Settimi and M. Ferrati and A. Bicchi and N G Tsagarakis and D. G. Caldwell} } @conference {2077, title = {Yarp Based Plugins for Gazebo Simulator}, booktitle = {2014 Modelling and Simulation for Autonomous Systems Workshop (MESAS)}, year = {2014}, address = {Roma, Italy, 5 -6 May 2014}, keywords = {Robotics}, author = {Mingo, E and Traversaro, S and Rocchi, A and M. Ferrati and A Settimi and Romano, F and Natale, L and A. Bicchi and Nori, F and N G Tsagarakis} } @conference {1434, title = {Human-Like Impedance and Minimum Effort Control for Natural and Efficient Manipulation}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2013)}, year = {2013}, pages = {4499 - 4505}, keywords = {Robotics}, doi = {10.1109/ICRA.2013.6631216 }, author = {A. Ajoudani and M Gabiccini and N G Tsagarakis and A. Bicchi} } @conference {1447, title = {Optimal Control for Maximizing Velocity of the CompActTM Compliant Actuator}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2013)}, year = {2013}, pages = {516 - 522}, keywords = {Robotics}, url = {10.1109/ICRA.2013.6630623}, author = {L. Chen and M. Garabini and M. Laffranchi and N. Kashiri and N G Tsagarakis and A. Bicchi and D. G. Caldwell} } @conference {1435, title = {Tele-Impedance based Stiffness and Motion Augmentation for a Knee Exoskeleton Device}, booktitle = {IEEE International Conference on Robotics and Automation (ICRA2013)}, year = {2013}, pages = {2194 - 2200}, keywords = {Robotics}, url = {10.1109/ICRA.2013.6630872}, author = {N. Karavas and A. Ajoudani and N G Tsagarakis and J. Saglia and A. Bicchi and D. G. Caldwell} } @conference {1666, title = {Teleimpedance Control of a Synergy-Driven Anthropomorphic Hand}, booktitle = {IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 2013}, year = {2013}, month = {November 3-7}, pages = {1985 - 1991}, address = {Tokyo, Japan}, keywords = {Haptics, Robotics}, doi = {10.1109/IROS.2013.6696620 }, author = {A. Ajoudani and S. B. Godfrey and M. G. Catalano and G. Grioli and N G Tsagarakis and A. Bicchi} } @article {1698, title = {Variable Impedance Actuators: a Review}, journal = {Robotics and Autonomous Systems}, volume = {61}, year = {2013}, note = {

Available online 6 August 2013

}, month = {12/2013}, pages = {1601{\textendash}1614}, abstract = {

Variable Impedance Actuators (VIA) have received increasing attention in recent years as many novel applications involving interactions with an unknown and dynamic environment including humans require actuators with dynamics that are not well-achieved by classical stiff actuators. This paper presents an overview of the different VIAs developed and proposes a classification based on the principles through which the variable stiffness and damping are achieved. The main classes are active impedance by control, inherent compliance and damping actuators, inertial actuators, and combinations of them, which are then further divided into subclasses. This classification allows for designers of new devices to orientate and take inspiration and users of VIA{\textquoteright}s to be guided in the design and implementation process for their targeted application.

}, keywords = {Robotics, Soft robotics, Variable Impedance Actuators}, url = {http://www.sciencedirect.com/science/article/pii/S0921889013001188}, author = {B. Vanderborght and A Albu-Schaeffer and A. Bicchi and E. Burdet and D. G. Caldwell and R. Carloni and M. G. Catalano and O. Eiberger and W. Friedl and G. Ganesh and M. Garabini and M. Grebenstein and G. Grioli and S. Haddadin and H. Hoppner and A. Jafari and M. Laffranchi and D. Lefeber and F. Petit and S. Stramigioli and N G Tsagarakis and M. Van Damme and R. Van Ham and L. C. Visser and S. Wolf} } @conference {1238, title = {Tele-Impedance: Exploring the Role of Common-Mode and Configuration-Dependant Stiffness}, booktitle = {IEEE-RAS International Conference on Humanoid Robots}, year = {2012}, pages = {363-369}, address = {Osaka, Japan}, keywords = {Robotics}, author = {A. Ajoudani and M Gabiccini and N G Tsagarakis and A Albu-Schaeffer and A. Bicchi} } @article {ATB12, title = {Tele-impedance: Teleoperation with Impedance Regulation Using a Body-Machine Interface}, journal = {International Journal of Robotics Research}, volume = { 31 }, year = {2012}, month = {11/2012}, pages = {1643 - 1656}, chapter = {1643}, keywords = {Robotics}, author = {A. Ajoudani and N G Tsagarakis and A. Bicchi} } @conference {ATB12, title = {Tele-Impedance: Towards Transferring Human Impedance Regulation Skills to Robots}, booktitle = {International Conference of Robotics and Automation - ICRA 2012}, year = {2012}, month = {May 14 - 18}, pages = {382 - 388 }, address = {Saint Paul, MN, USA}, keywords = {Robotics}, author = {A. Ajoudani and N G Tsagarakis and A. Bicchi} } @conference {CGGBDBTB12, title = {A Variable Damping module for Variable Impedance Actuation}, booktitle = {International Conference of Robotics and Automation - ICRA 2012}, year = {2012}, month = {May 14 - 18}, pages = {2666 - 2672}, address = {Saint Paul, MN, USA}, keywords = {Robotics}, author = {M. G. Catalano and G. Grioli and M. Garabini and F. A. W. Belo and A. Di Basco and N G Tsagarakis and A. Bicchi} } @article {1245, title = {Variable Impedance Actuators: Moving the Robots of Tomorrow}, year = {2012}, keywords = {Robotics}, author = {B. Vanderborght and A Albu-Schaeffer and A. Bicchi and E. Burdet and D. G. Caldwell and R. Carloni and M. G. Catalano and G. Ganesh and M. Garabini and G. Grioli and S. Haddadin and A. Jafari and M. Laffranchi and D. Lefeber and F. Petit and S. Stramigioli and N G Tsagarakis and M. Van Damme and R. Van Ham and L. C. Visser and S. Wolf} } @conference {SGSTB11, title = {A decoupled Impedance observer for a Variable Stiffness Robot}, booktitle = {2011 IEEE International Conference on Robotics and Automation}, year = {2011}, month = {May 9 - 13}, pages = {5548 - 5553}, address = {Shangai, China}, keywords = {Robotics}, author = {A. Serio and G. Grioli and I. Sardellitti and N G Tsagarakis and A. Bicchi} } @conference {ATB11, title = {Tele-Impedance: Preliminary Results on Measuring and Replicating Human Arm Impedance in Tele Operated Robots}, booktitle = {IEEE International Conference on Robotics and Biomimetics - ROBIO 2011}, year = {2011}, note = {

Accepted, youtube: http://www.youtube.com/watch?v=KPO6IO7Tr-Q

}, month = {December 7 - 11}, pages = {216 - 223}, address = {Phuket, Thailand}, keywords = {Robotics}, author = {A. Ajoudani and N G Tsagarakis and A. Bicchi} } @conference {CGGBB11, title = {VSA - CubeBot. A modular variable stiffness platform for multi degrees of freedom systems}, booktitle = {2011 IEEE International Conference on Robotics and Automation}, year = {2011}, month = {May 9 - 13}, pages = {5090 - 5095}, address = {Shangai, China}, keywords = {Robotics}, author = {M. G. Catalano and G. Grioli and M. Garabini and F. Bonomo and M. Mancini and N G Tsagarakis and A. Bicchi} }