@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 {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} }