Grasp Quality Evaluation in Underactuated and Compliant Robotic Hands: New Indexes and New Challenges

The new trend in the design of robotic hands is to make them underactuated and compliant, so that they can safely interact with the enviroment, and adapt to the objects they have to grasp.
Evaluating the grasping capabilities of such type of hands is a challenging task because there is the need of an evaluation method that takes into account i) which forces can be actually controlled by the hand, depending on its actuation system, and ii) the parameters that characterize the contact points such as the friction coefficient and the maximum and minimum applicable contact forces.
To this aim, the work presented in [1] revisits some traditional quality measures developed for multi-fingered, fully actuated hands, and applies them to the case of underactuated hands. Measures based on the wrench space computation, namely the largest minimum resisted wrench, and measures of contact and grasp robustness, namely the Potential Grasp Robustness (PGR) and the Potential Contact Robustness (PCR), are compared through simulated examples. Both types of indexes are found to be suitable for evaluating underactuated grasps in a realistic and coherent way, because they can account for friction constraints and physically achievable contact forces.
Underactuated and compliant hands can adapt to the shape of the objects they have to grasp and tend to perform power grasps, rather than precision grasps. This consideration lead to the work described in [2], where authors demonstrate that the PGR can be applied not only to precision grasps, but also to power grasps.
The workshop entitled “Evaluation and benchmarking of underactuated and soft robotic hands” was held at IROS 2016 to discuss on the possibility of having a common benchmarking framework for assessing the quality of compliant and underactuated manipulation systems, and highlighted that in the community there is a clear need of comparability and reproducibility, not only for soft and underactuated hands, but for general robotic grasping systems.
The posters and the slides that were presented at the workshop are available here.

 

References

[1] M. Pozzi, A. M. Sundaram, M. Malvezzi, D. Prattichizzo, and M. A. Roa, “Grasp quality evaluation in underactuated robotic hands,” in Proceedings, IEEE/RSJ International Conference on Intelligent Robots and Systems, 2016. [PDF]

[2] M. Pozzi, M. Malvezzi, and D. Prattichizzo, “On grasp quality measures: Grasp robustness and contact force distribution in underactuated and compliant robotic hands,” IEEE Robotics and Automation Letters, vol. 2, 2017. [Link]

A new perspective paper published on Frontiers on Neurorobotics

A human-robot interaction perspective on assistive and rehabilitation robotics

Philipp Beckerle, Gionata Salvietti, Ramazan Unal, Domenico Prattichizzo, Simone Rossi, Claudio Castellini, Sandra Hirche, Satoshi Endo, Heni Ben Amor, Matei Ciocarlie, Fulvio Mastrogiovanni, Brenna D. Argall and Matteo Bianchi

Abstract Assistive and rehabilitation devices are a promising and challenging field of recent robotics research. Motivated by societal needs such as aging populations, such devices can support motor functionality and subject training. The design, control, sensing and assessment of the devices become more sophisticated due to a human in the loop. This paper gives a human-robot interaction perspective on current issues and opportunities in the field. On the topic of control and machine learning, approaches that support but do not distract subjects are reviewed.  Options to provide sensory user-feedback that are currently missing from robotic devices are outlined. Parallels between device acceptance and affective computing are made. Furthermore, requirements for functional assessment protocols that relate to real-world tasks are discussed. In all topic areas, the design of human-oriented frameworks and methods is dominated by challenges related to the close interaction between the human and robotic device. This paper discusses the aforementioned aspects in order to open up new perspectives for future robotic solutions.
A human-robot interaction perspective on assistive and rehabilitation robotics. Available from: https://www.researchgate.net/publication/316735448_A_human-robot_interaction_perspective_on_assistive_and_rehabilitation_robotics

New Review paper “Haptic Feedback for Microrobotics Applications: A Review” on Frontiers in Robotics and AI

A new article has been published on Frontiers in Robotics and AI.

C. Pacchierotti, S. Scheggi, D. Prattichizzo, S. Misra. “Haptic feedback for microrobotics applications: a review. Frontiers in Robotics and AI, 3(53), 2016.

Screenshot from 2016-09-05 09-15-11

Full article: http://journal.frontiersin.org/article/10.3389/frobt.2016.00053/full

SIRSLab uses MATLAB® and Simulink® for grasp analysis of human and robotic hands

Researchers and students of SIRSLab of Univerisity of Siena use MATLAB® and Simulink® for grasp analysis of human and robotic hands.

Here’s the link to the video of Professor Prattichizzo explaining the job of our team: MathWorks Video.

 

mathworks 5

Paper on “THE” Project published on Physics of Life Reviews

An article summarising the results of the four years EU project “The Hand Embodied – THE “ has been published on the prestigious journal Physics of Life Reviews. Here the link to the article. As University of Siena, we have contributed to the modelling of hand synergies and we have studied a systematic way to transfer human hand skills onto robotic hands. These results can be found here.

Abstract of the paper
phyLif

The term ‘synergy’ – from the Greek synergia – means ‘working together’. The concept of multiple elements working together towards a common goal has been extensively used in neuroscience to develop theoretical frameworks, experimental approaches, and analytical techniques to understand neural control of movement, and for applications for neuro- rehabilitation. In the past decade, roboticists have successfully applied the framework of synergies to create novel design and control concepts for artificial hands, i.e., robotic hands and prostheses. At the same time, robotic research on the sensorimotor integration underlying the control and sensing of artificial hands has inspired new research approaches in neuroscience, and has provided useful instruments for novel experiments.

The ambitious goal of integrating expertise and research approaches in robotics and neuroscience to study the properties and applications of the concept of synergies is generating a number of multidisciplinary cooperative projects, among which the recently finished 4-year European project “The Hand Embodied” (THE). This paper reviews the main insights provided by this framework. Specifically, we provide an overview of neuroscientific bases of hand synergies and introduce how robotics has leveraged the insights from neuroscience for innovative design in hardware and controllers for biomedical engineering applications, including myoelectric hand prostheses, devices for haptics research, and wearable sensing of human hand kinematics. The review also emphasizes how this multidisciplinary collaboration has generated new ways to conceptualize a synergy-based approach for robotics, and provides guidelines and principles for analyzing human behavior and synthesizing artificial robotic systems based on a theory of synergies.

Creating an artificial sense of touch through electrical stimuli

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A study led by neuroscientists from UChicago shows that artificial touch is highly dependent on several features of electrical stimuli, such as the strength and frequency of signals, and describes the specific characteristics of these signals.

Source: Creating an artificial sense of touch through electrical stimuli 

New paper published on The International Journal of Robotics Research: “Cutaneous haptic feedback to ensure the stability of robotic teleoperation systems”

Cutaneous haptic feedback can be used to enhance the performance of robotic teleoperation systems while guaranteeing their safety. Delivering ungrounded cutaneous cues to the human operator conveys in fact information about the forces exerted at the slave side and does not affect the stability of the control loop.

In this work we analyze the feasibility, effectiveness, and implications of providing solely cutaneous feedback in robotic teleoperation.

Screenshot from 2015-10-20 09:57:36

We carried out two peg-in-hole experiments, both in a virtual environment and in a real (teleoperated) environment. Two novel 3-degree-of-freedom fingertip cutaneous displays deliver a suitable amount of cutaneous feedback at the thumb and index fingers. Results assessed the feasibility and effectiveness of the proposed approach.

Pacchierotti2015-IJRR

Cutaneous feedback was outperformed by full haptic feedback provided by grounded haptic interfaces, but it outperformed conditions providing no force feedback at all. Moreover, cutaneous feedback always kept the system stable, even in the presence of destabilizing factors such as communication delays and hard contacts.

Video: https://youtu.be/mQ8AYmNUBFo
PDF: http://sirslab.dii.unisi.it/papers/2015/Pacchierotti.IJRR.2015.Subtraction.pdf

C. Pacchierotti, L. Meli, F. Chinello, M. Malvezzi, D. Prattichizzo. Cutaneous haptic feedback to ensure the stability of robotic teleoperation systems. International Journal of Robotics Research, 2015. doi: 10.1177/0278364915603135.pdf

4th Wearhap Consortium Meeting

The WEARHAP Consortium met in the Madrid, Spain for it 4th Consortium Review Meeting. It was held in Madrid, Spain on 17th and 18th of November 2014. The meeting was reviewed by Prof. Karen Maclean of University of British Columbia and Dr. Patrick Helmer, CEO of Force Dimension. All the partners involved in the consortium were represented in the meeting.

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The venue was Universidad Rey Juan Carlos, hosted by Prof. Miguel Otaduy. This gathering of the consortium reviewed the progress and forged ideas to moved towards the ultimate objectives of the project. The meeting ended on a high note as the progress of the project is as planned. All the outstanding and future issues came under rigorous discussions and presentations, lasting two days.

UNISI participated in the meeting with a lot of enthusiasm and managed to appreciate the beauty of Madrid and the generosity of our hosts after the work-sessions. It was a joy able work and personal experience for everyone who took part in this Review Meeting from Siena.

Here are some of the pictures from the event.
Pictures of 4th WEARHAP Consortium Meeting

Videoconference of Prof. Roudolf Kalman-June 9-11, 2014 @UNIBO

The School of Engineering and Architecture, in collaboration with the research group “Studies on epistemology and philosophy of science” at the Department of Philosophy and Communication, presented the conference:

“The lesson of the last 100 years.
Accomplishments of control theory and related fields since the beginning of World War One”
9th June 2014, Bologna, Italy – UniBo

“The recent history of System theory and new research directions in the 21st century”
Prof. Rudolf Kalman
11th June 2014, Bologna, Italy – UniBo