@article {4083, title = {Evaluation of a Simultaneous Myoelectric Control Strategy for a Multi-DoF Transradial Prosthesis}, year = {2020}, author = {C. Piazza and M. Rossi and M. G. Catalano and A. Bicchi and L. Hargrove} } @article {4085, title = {Exploring augmented grasping capabilities in a multi-synergistic soft bionic hand}, journal = {Journal of NeuroEngineering and Rehabilitation}, volume = {17}, year = {2020}, chapter = {116}, doi = {https://doi.org/10.1186/s12984-020-00741-y}, url = {https://jneuroengrehab.biomedcentral.com/articles/10.1186/s12984-020-00741-y$\#$article-info}, author = {C. Piazza and A. M. Simon and K. L. Turner and L. A. Miller and M. G. Catalano and A. Bicchi and L. Hargrove} } @article {4079, title = {Exploring Stiffness Modulation in Prosthetic Hands and Its Perceived Function in Manipulation and Social Interaction.}, journal = {Frontiers in Neurorobotics}, volume = {14}, year = {2020}, month = {06/2020}, abstract = {

To physically interact with a rich variety of environments and to match situation-dependent requirements, humans adapt both the force and stiffness of their limbs. Reflecting this behavior in prostheses may promote a more natural and intuitive control and, consequently, improve prostheses acceptance in everyday life. This pilot study proposes a method to control a prosthetic robot hand and its impedance, and explores the utility of variable stiffness when performing activities of daily living and physical social interactions. The proposed method is capable of a simultaneous and proportional decoding of position and stiffness intentions from two surface electro-myographic sensors placed over a pair of antagonistic muscles. The feasibility of our approach is validated and compared to existing control modalities in a preliminary study involving one prosthesis user. The algorithm is implemented in a soft under-actuated prosthetic hand (SoftHand Pro). Then, we evaluate the usability of the proposed approach while executing a variety of tasks. Among these tasks, the user interacts with other 12 able-bodied subjects, whose experiences were also assessed. Several statistically significant aspects from the System Usability Scale indicate user{\textquoteright}s preference of variable stiffness control over low or high constant stiffness due to its reactivity and adaptability. Feedback reported by able-bodied subjects reveal a general tendency to favor soft interaction, i.e., low stiffness, which is perceived more human-like and comfortable. These combined results suggest the use of variable stiffness as a viable compromise between firm control and safe interaction which is worth investigating further.

}, keywords = {human-robot social interaction, impedance control, prosthetics, Soft robotics, task adaptability}, doi = {10.3389/fnbot.2020.00033}, url = {https://www.frontiersin.org/articles/10.3389/fnbot.2020.00033/full?\&utm_source=Email_to_authors_\&utm_medium=Email\&utm_content=T1_11.5e1_author\&utm_campaign=Email_publication\&field=\&journalName=Frontiers_in_Neurorobotics\&id=503842}, author = {Capsi-Morales, Patricia and C. Piazza and M. G. Catalano and A. Bicchi and G. Grioli} } @article {4081, title = {Exploring the Role of Palm Concavity and Adaptability in Soft Synergistic Robotic Hands}, journal = { IEEE Robotics and Automation Letters }, volume = {5}, year = {2020}, month = {17 June 2020}, pages = {4703 - 4710}, chapter = {4703}, abstract = {

Robotic hand engineers usually focus on finger capabilities, often disregarding the palm contribution. Inspired by human anatomy, this paper explores the advantages of including a flexible concave palm into the design of a robotic hand actuated by soft synergies. We analyse how the inclusion of an articulated palm improves finger workspace and manipulability. We propose a mechanical design of a modular palm with two elastic rolling-contact palmar joints, that can be integrated on the Pisa/IIT SoftHand, without introducing additional motors. With this prototype, we evaluate experimentally the grasping capabilities of a robotic palm. We compare its performance to that of the same robotic hand with the palm fixed, and to that of a human hand. To assess the effective grasp quality achieved by the three systems, we measure the contact area using paint-transfer patterns in different grasping actions. Preliminary grasping experiments show a closer resemblance of the soft-palm robotic hand to the human hand. Results evidence a higher adaptive capability and a larger involvement of all fingers in grasping.

}, keywords = {Ellipsoids, Grasping, Indexes, Kinematics, Robots, Shape, Thumb}, issn = { 2377-3766}, doi = {10.1109/LRA.2020.3003257}, url = {https://ieeexplore.ieee.org/document/9119822?source=authoralert}, author = {Capsi-Morales, Patricia and G. Grioli and C. Piazza and A. Bicchi and M. G. Catalano} } @proceedings {4106, title = {SIMULTANEOUS AND PROPORTIONAL DECODING OF STIFFNESS AND POSITION INTENTIONS FROM TWO SEMG CHANNELS FOR UL PROSTHETICS}, year = {2020}, month = {07/2020}, abstract = {

To physically interact with a rich variety of environments and situation-oriented requirements, humans continuously adapt both the stiffness and the force of their limbs through antagonistic muscle coactivation. Reflecting this behaviour in prostheses may promote control naturalness and intuitiveness and, consequently, their acceptance in everyday life. We propose a method capable of a simultaneous and proportional decoding of position and stiffness intentions from two surface electro-myographic sensors placed over a pair of antagonistic muscles. First, the algorithm is validated and compared to existing control modalities. Then, the algorithm is implemented in a soft under-actuated prosthetic hand (SoftHand Pro). We investigated the feasibility of our approach in a preliminary study involving one prosthetic user. Our future goal is to evaluate the usability of the proposed approach executing a variety of tasks including physical social interaction with other subjects (see Figure 1). Our hypothesis is that variable stiffness could be a compromise between firm control and safe interaction.

}, url = {https://conferences.lib.unb.ca/index.php/mec/article/view/35}, author = {Capsi-Morales, Patricia and C. Piazza and M. G. Catalano and A. Bicchi and G. Grioli} } @article {3749, title = {Artificial hand}, number = {16/302227}, year = {2019}, month = {09/05}, url = {https://patentimages.storage.googleapis.com/4f/2c/07/915e9723cfe164/US20190269528A1.pdf}, author = {A. Bicchi and M. G. Catalano and C. Piazza and G. Grioli and C. Della Santina and M. Garabini} } @article {3649, title = {A Century of Robotic Hands}, journal = {Annual Review of Control, Robotics, and Autonomous Systems}, volume = {2}, year = {2019}, doi = {https://doi.org/10.1146/annurev-control-060117-105003}, url = {https://www.annualreviews.org/doi/10.1146/annurev-control-060117-105003}, author = {C. Piazza and G. Grioli and M. G. Catalano and A. Bicchi} } @article {3745, title = {Design and Assessment of Control Maps for Multi-Channel sEMG-Driven Prostheses and Supernumerary Limbs}, journal = {Frontiers in neurorobotics}, volume = {13}, year = {2019}, doi = {10.3389/fnbot.2019.00026}, author = {M. Maimeri and C. Della Santina and C. Piazza and M. Rossi and M. G. Catalano and G. Grioli} } @article {3744, title = {Design and Assessment of Control Maps for Multi-Channel sEMG-Driven Prostheses and Supernumerary Limbs}, journal = {Frontiers in neurorobotics}, volume = {13}, year = {2019}, doi = {10.3389/fnbot.2019.00026}, url = {https://www.frontiersin.org/articles/10.3389/fnbot.2019.00026/full}, author = {M. Maimeri and C. Della Santina and C. Piazza and M. Rossi and M. G. Catalano and G. Grioli} } @article {3751, title = {Exploiting Adaptability in Soft Feet for Sensing Contact Forces}, journal = { IEEE Robotics and Automation Letters}, volume = {5}, year = {2019}, month = {11/2019}, chapter = {391}, doi = {https://doi.org/10.1109/LRA.2019.2952292}, url = {https://ieeexplore.ieee.org/document/8894422}, author = {D. Mura and C. Della Santina and C. Piazza and I. Frizza and C. Morandi and M. Garabini and G. Grioli and M. G. Catalano} } @conference {3748, title = {An Objective Functional Evaluation of Myoelectrically-Controlled Hand Prostheses: A Pilot Study Using the Virtual Peg Insertion Test}, booktitle = {IEEE International Conference on Rehabilitation Robotics (ICORR)}, year = {2019}, doi = {10.1109/ICORR.2019.8779550}, author = {C. M. Kanzler and M. G. Catalano and C. Piazza and A. Bicchi and R. Gassert and O. Lambercy} } @conference {3682, title = {Advanced grasping with the Pisa/IIT softHand}, booktitle = {Robotic Grasping and Manipulation Challenge }, year = {2018}, pages = {pp. 19-38}, author = {M. Bonilla and C. Della Santina and A. Rocchi and E. Luberto and G. Santaera and E. Farnioli and C. Piazza and F. Bonomo and A. Brando and A. Raugi and M. G. Catalano and M. Bianchi and M. Garabini and G. Grioli and A. Bicchi} } @conference {3746, title = {Preliminary Results Toward Continuous and Proportional Control of a Multi-synergistic Soft Prosthetic Hand}, booktitle = {International Conference on NeuroRehabilitation}, year = {2018}, doi = {https://doi.org/10.1007/978-3-030-01845-0_15}, author = {C. Piazza and M. G. Catalano and A. Bicchi and L. Hargrove} } @conference {3747, title = {The softpro project: Synergy-based open-source technologies for prosthetics and rehabilitation}, booktitle = {International Symposium on Wearable Robotics}, year = {2018}, doi = {https://doi.org/10.1007/978-3-030-01887-0_71}, author = {C. Piazza and M. G. Catalano and M. Bianchi and E. Ricciardi and D. Pratichizzo and S. Haddadin and Luft, A. R. L. and O. Lambercy and R. Gassert and E. Jakubowitz and H. Van Der Kooij and F. Tonis and F. Bonomo and B. de Jonge and T. Ward and K. Zhao and M. Santello and A. Bicchi} } @article {3366, title = {Towards Dexterous Manipulation with Augmented Adaptive Synergies: the Pisa/IIT SoftHand 2}, journal = {IEEE Transactions on Robotics}, volume = {Early Access}, year = {2018}, month = {06/2018 }, type = {Regular Paper}, abstract = {

In the recent years, a clear trend towards simplification emerged in the development of robotic hands. The use of soft robotic approaches has been a useful tool in this prospective, enabling complexity reduction by embodying part of grasping intelligence in the hand mechanical structure. Several hand prototypes designed according to such principles have accomplished good results in terms of grasping simplicity, robustness, and reliability. Among them, the Pisa/IIT SoftHand demonstrated the feasibility of a large variety of grasping tasks, by means of only one actuator and an opportunely designed tendon driven differential mechanism. However, the use of a single degree of actuation prevents the execution of more complex tasks, like fine pre-shaping of fingers and in-hand manipulation. While possible in theory, simply doubling the Pisa/IIT SoftHand actuation system has several disadvantages, e.g. in terms of space and mechanical complexity. To overcome these limitations we propose a novel design framework for tendon driven mechanisms, where the main idea is to turn transmission friction from a disturbance into a design tool. In this way the degrees of actuation can be doubled with little additional complexity.

By leveraging on this idea we design a novel robotic hand, the Pisa/IIT SoftHand 2. We present here its design, modeling, control, and experimental validation. The hand demonstrates that by opportunely combining only two degrees of actuation with hand softness, a large variety of grasping and manipulation tasks can be performed only relying on the intelligence embodied in the mechanism. Examples include rotating objects with different shapes, opening a jar, pouring coffee from a glass.

}, issn = {Print 1552-3098; Onlline 1941-0468}, author = {C. Della Santina and C. Piazza and G. Grioli and M. G. Catalano and A. Bicchi} } @article {3750, title = {Underactuated robotic hand}, number = {15/772368}, year = {2018}, month = {11/01}, url = {https://patentimages.storage.googleapis.com/c3/76/f4/3f31e20b15ad53/US20180311827A1.pdf}, author = {A. Bicchi and C. Della Santina and M. G. Catalano and C. Piazza and G. Grioli and A. Brando} } @conference {3220, title = {Estimating Contact Forces from Postural Measures in a class of Under-Actuated Robotic Hands}, booktitle = {IEEE International Conference of Intelligent Robots and Systems (IROS2017)}, year = {2017}, publisher = {IEEE}, organization = {IEEE}, address = {Vancouver, Canada, September 24{\textendash}28, 2017}, keywords = {Robotics}, author = {C. Della Santina and C. Piazza and G. Santaera and G. Grioli and M. G. Catalano and A. Bicchi} } @conference {3215, title = {Preliminary results toward a naturally controlled multi-synergistic prosthetic hand}, booktitle = {International Conference on Rehabilitation Robotics (ICORR)}, year = {2017}, 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.

}, keywords = {Robotics}, isbn = {978-1-5386-2296-4}, doi = {10.1109/ICORR.2017.8009437}, url = {http://ieeexplore.ieee.org/abstract/document/8009437/}, author = {M. Rossi and C. Della Santina and C. Piazza and G. Grioli and M. G. Catalano and A. Bicchi} } @article {2875, title = {The Quest for Natural Machine Motion: An Open Platform to Fast-Prototyping Articulated Soft Robots}, journal = {IEEE Robotics and Automation Magazine }, volume = {24}, year = {2017}, note = {

Open access

e wish to thank Samuele Batazzi, Fabio Bonomo, Alberto
Brando, Andrea Di Basco, Tommaso Pardi, Riccardo Persichi-
ni, and Alessandro Raugi for their valuable support in the
development of the hardware prototype. This work was sup-
ported by SOFTPRO (grant 688857) and SOMA (grant
645599){\textemdash}projects of the European Commission{\textquoteright}s Horizon
2020 research program{\textemdash}and by Walk-Man grant 611832.
Support also came from the European Research Council
under an Advanced Grant for {\textquotedblleft}SoftHands: A Theory of Soft
Synergies for a New Generation of Artificial Hands{\textquotedblright} (grant
ERC-291166).
}, pages = {48 - 56}, abstract = {
Soft robots are one of the most significant recent evolutions in robotics. They rely on compliant physical structures purposefully designed to embody desired characteristics. Since their introduction, they have shown remarkable applicability in overcoming their rigid counterparts in such areas as interaction with humans, adaptability, energy efficiency, and maximization of peak performance. Nonetheless, we believe
that research on novel soft robot applications is still slowed by the difficulty in obtaining or developing a working soft robot structure to explore novel applications.
In this article, we present the Natural Machine Motion Initiative (NMMI), a modular open platform that aims to provide the scientific community with tools for fast and easy prototyping of articulated soft robots. Such a platform is composed of three main open hardware modules: the Qbmoves variable-stiffness actuators (VSAs) to build the main robotic structure, soft end effectors (EEs) to interact with the world, and a pool of application-specific add-ons. We also discuss many novel uses of the platform to rapidly prototype (RP) and test new robotic structures with original soft capabilities, and we propose NMMI- based experiments.
}, keywords = {Robotics}, issn = {1070-9932 }, doi = {10.1109/MRA.2016.2636366}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=7857692}, author = {C. Della Santina and C. Piazza and Gasparri, G. M. and M. Bonilla and M. G. Catalano and G. Grioli and M. Garabini and A. Bicchi} } @article {3725, title = {SoftHand at the CYBATHLON: A user{\textquoteright}s experience}, journal = {JOURNAL OF NEUROENGINEERING AND REHABILITATION}, year = {2017}, doi = {10.1186/s12984-017-0334-y}, author = {S. B. Godfrey and M. Rossi and C. Piazza and M. G. Catalano and M. Bianchi and G. Grioli and K. Zhao and A. Bicchi} } @article {3258, title = {The SoftHand Pro-H: A Hybrid Body-Controlled, Electrically Powered Hand Prosthesis for Daily Living and Working }, journal = {IEEE Robotics and Automation Magazine}, year = {2017}, note = {

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

}, month = {11/2017}, keywords = {Haptics, Robotics}, issn = {1070-9932}, doi = {10.1109/MRA.2017.2751662}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8110634}, author = {C. Piazza and M. G. Catalano and S. B. Godfrey and M. Rossi and G. Grioli and M. Bianchi and K. Zhao and A. Bicchi} } @inbook {2886, title = {From Soft to Adaptive Synergies: The Pisa/IIT SoftHand}, booktitle = {Human and Robot Hands}, volume = {Springer Series on Touch and Haptic Systems}, year = {2016}, publisher = {Springer}, organization = {Springer}, chapter = {101 - 125}, abstract = {

Taking inspiration from the neuroscientific findings on hand synergies discussed in the first part of the book, in this chapter we present the Pisa/IIT SoftHand, a novel robot hand prototype. The design moves under the guidelines of making an hardware robust and easy to control, preserving an high level of grasping capabilities and an aspect as similar as possible to the human counterpart. First, the main theoretical tools used to enable such simplification are presented, as for example the notion of soft synergies. A discussion of some possible actuation schemes shows that a straightforward implementation of the soft synergy idea in an effective design is not trivial. The proposed approach, called adaptive synergy, rests on ideas coming from underactuated hand design, offering a design method to implement the desired set of soft synergies as demonstrated both with simulations and experiments. As a particular instance of application of the synthesis method of adaptive synergies, the Pisa/IIT SoftHand is described in detail. The hand has 19 joints, but only uses one actuator to activate its adaptive synergy. Of particular relevance in its design is the very soft and safe, yet powerful and extremely robust structure, obtained through the use of innovative articulations and ligaments replacing conventional joint design. Moreover, in this work, summarizing results presented in previous papers, a discussion is presented about how a new set of possibilities is open from paradigm shift in manipulation approaches, moving from manipulation with rigid to soft hands.

}, issn = {978-3-319-26705-0}, doi = {10.1007/978-3-319-26706-7_8}, author = {M. G. Catalano and G. Grioli and E. Farnioli and A. Serio and M. Bonilla and M. Garabini and C. Piazza and M Gabiccini and A. Bicchi} } @conference {2892, title = {Natural encoding of user intentions in a soft prosthesis using Dynamic Synergies}, booktitle = {International Workshop on Human-Friendly Robotics}, year = {2016}, author = {C. Piazza and C. Della Santina and M. G. Catalano and G. Grioli and M. Garabini and A. Bicchi} } @conference {2725, title = {SoftHand Pro-D: Matching Dynamic Content of Natural User Commands with Hand Embodiment for Enhanced Prosthesis Control}, booktitle = {IEEE International Conference of Robotics and Automation (ICRA2016)}, year = {2016}, note = {

softpro soma softhands

}, pages = {3516 - 3523}, publisher = {IEEE}, organization = {IEEE}, address = {Stockholm, Sweden, May 16-21}, abstract = {

State of the art of hand prosthetics is divided between simple and reliable gripper-like systems and sophisticate hi-tech poly-articular hands which tend to be complex both in their design and for the patient to operate. In this paper, we introduce the idea of decoding different movement intentions of the patient using the dynamic frequency content of the control signals in a natural way. We move a step further showing how this idea can be embedded in the mechanics of an underactuated soft hand by using only passive damping components.

In particular we devise a method to design the hand hardware to obtain a given desired motion. This method, that we call of the dynamic synergies, builds on the theory of linear descriptor systems, and is based on the division of the hand movement in a slow and a fast components. We use this method to evolve the design of the Pisa/IIT SoftHand in a prototype prosthesis which, while still having 19 degrees of freedom and just one motor, can move along two different synergistic directions of motion (and combinations of the two), to perform either a pinch or a power grasp. Preliminary experimental results are presented, demonstrating the effectiveness of the proposed design

}, keywords = {Haptics, Robotics}, doi = {10.1109/ICRA.2016.7487532}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7487532}, author = {C. Piazza and C. Della Santina and M. G. Catalano and G. Grioli and M. Garabini and A. Bicchi} } @conference {2881, title = {Toward an Adaptive Foot for Natural Walking}, booktitle = {International Conference on Humanoid Robots (HUMANOIDS2016)}, year = {2016}, address = {Cancun, Mexico, November 15-17, 2016}, abstract = {

Many walking robot presented in literature stand
on rigid flat feet, with a few notable exceptions that embed
flexibility in their feet to optimize the energetic cost of walking.
This paper proposes a novel adaptive robot foot design, whose
main goal is to ease the task of standing and walking on uneven
terrains. After explaining the rationale behind our design
approach, we present the design of the SoftFoot, a foot able
to comply with uneven terrains and to absorb shocks thanks to
its intrinsic adaptivity, while still being able to rigidly support
the stance, maintaining a rather extended contact surface,
and effectively enlarging the equivalent support polygon. The
paper introduces the robot design and prototype and presents
preliminary validation and comparison versus a rigid flat foot
with comparable footprint and sole.

}, keywords = {Robotics}, doi = {10.1109/HUMANOIDS.2016.7803423}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=7803423}, author = {C. Piazza and C. Della Santina and Gasparri, G. M. and M. G. Catalano and G. Grioli and M. Garabini and A. Bicchi} } @article {1665, title = {Adaptive Synergies for the Design and Control of the Pisa/IIT SoftHand}, journal = {International Journal of Robotics Research}, volume = {33}, year = {2014}, pages = {768{\textendash}782}, keywords = {Haptics, Robotics}, doi = {10.1177/0278364913518998}, author = {M. G. Catalano and G. Grioli and E. Farnioli and A. Serio and C. Piazza and A. Bicchi} } @conference {2232, title = {Grasping with Soft Hands}, booktitle = {IEEE-RAS International Conference on Humanoid Robots (HUMANOIDS 2014)}, year = {2014}, pages = {581 - 587}, address = {Madrid, Spain, November 18 - 20}, abstract = {

Despite some prematurely optimistic claims, the ability of robots to grasp general objects in unstructured environments still remains far behind that of humans. This is not solely caused by differences in the mechanics of hands: indeed, we show that human use of a simple robot hand (the Pisa/IIT SoftHand) can afford capabilities that are comparable to natural grasping. It is through the observation of such human-directed robot hand operations that we realized how fundamental in everyday grasping and manipulation is the role of hand compliance, which is used to adapt to the shape of surrounding objects. Objects and environmental constraints are in turn used to functionally shape the hand, going beyond its nominal kinematic limits by exploiting structural softness. In this paper, we set out to study grasp planning for hands that are simple {\textemdash} in the sense of low number of actuated degrees of freedom (one for the Pisa/IIT SoftHand) {\textemdash} but are soft, i.e. continuously deformable in an infinity of possible shapes through interaction with objects. After general considerations on the change of paradigm in grasp planning that this setting brings about with respect to classical rigid multi-dof grasp planning, we present a procedure to extract grasp affordances for the Pisa/IIT SoftHand through physically accurate numerical simulations. The selected grasps are then successfully tested in an experimental scenario.

}, keywords = {Haptics, Robotics}, doi = {10.1109/HUMANOIDS.2014.7041421}, url = {http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=\&arnumber=7041421\&queryText\%3DGrasping+with+Soft+Hands}, author = {M. Bonilla and E. Farnioli and C. Piazza and M. G. Catalano and G. Grioli and M. Garabini and M Gabiccini and A. Bicchi} } @conference {1188, title = {Adaptive Synergies for a Humanoid Robot Hand}, booktitle = {IEEE-RAS International Conference on Humanoid Robots}, year = {2012}, note = {

Best Paper Award

}, pages = {7-14}, address = {Osaka, Japan}, keywords = {Robotics}, author = {M. G. Catalano and G. Grioli and A. Serio and E. Farnioli and C. Piazza and A. Bicchi} }