@conference {AMC08, title = {Physical Human-Robot Interaction: Dependability, Safety, and Performance}, booktitle = {Proc. 10th Intl. Workshop Advanced Motion Control}, year = {2008}, pages = {9-14}, abstract = {

In this paper we discuss the problem of achieving good performance in accuracy and promptness by a robot manipulator under the condition that safety is guaranteed throughout task execution. Intuitively, while a rigid and powerful structure of the arm would favor its performance, lightweight compliant structures are more suitable for safe operation. The quantitative analysis of the resulting design trade-off between safety and performance has a strong impact on how robot mechanisms and controllers should be designed for human-interactive applications. We discuss few different possible concepts for safely actuating joints, and focus on aspects related to the implementation of the mechanics and control of this new class of robots.

}, keywords = {Embedded Control, Physical Human-Robot Interaction (pHRI), Robotics}, author = {A. Bicchi and M. Bavaro and G. Boccadamo and D. De Carli and R. Filippini and G. Grioli and M. Piccigallo and A. Rosi and R. Schiavi and S. Sen and G. Tonietti} } @article {FSB08, title = {Toward Soft Robot you can Depend on}, journal = {IEEE Robotics and Automation Magazine}, volume = {15}, number = {3}, year = {2008}, pages = {31 - 41}, keywords = {Embedded Control, Robotics}, author = {R. Filippini and S. Sen and A. Bicchi} } @conference {schiavi2008icra, title = {VSA-II: A Novel Prototype of Variable Stiffness Actuator for Safe and Performing Robots Interacting with Humans}, booktitle = {Proc. IEEE Int. Conf. on Robotics and Automation}, year = {2008}, pages = {2171 - 2176}, abstract = {

This paper presents design and performance of a novel joint based actuator for a robot run by variable stiffness actuation, meant for systems physically interacting with humans. This new actuator prototype (VSA-II) is developed as an improvement over our previously developed one reported in [9], where an optimal mechanical-control co-design principle established in [7] is followed as well. While the first version was built in a way to demonstrate effectiveness of variable impedance actuation (VIA), it had limitations in torque capacities, life cycle and implementability in a real robot. VSA-II overcomes the problem of implementability with higher capacities and robustness in design for longer life. The paper discusses design and stiffness behaviour of VSA-II in theory and experiments. A comparison of stiffness characteristics between the two actuator is discussed, highlighting the advantages of the new design. A simple, but effective PD scheme is employed to independently control joint-stiffness and joint-position of a 1-link arm. Finally, results from performed impact tests of 1- link arm are reported, showing the effectiveness of stiffness variation in controlling value of a safety metric.

}, keywords = {Robotics}, author = {R. Schiavi and G. Grioli and S. Sen and A. Bicchi} } @conference {filippini2007cda, title = {A Comparative Dependability Analysis of Antagonistic Actuation Arrangements for Enhanced Robotic Safety}, booktitle = {Proc. IEEE Int. Conf. on Robotics and Automation}, year = {2007}, pages = {4349{\textendash}4354}, abstract = {In this paper we introduce an analysis of dependability of an elementary yet critical component of robotic systems designed to operate in environments shared with humans, i.e. the joint-level actuation system. We consider robot joints that implement the Variable Impedance Actuation (VIA) paradigm. The VIA has been demonstrated to be an effective mean to achieve high performance while constantly keeping injury risks to humans by accidental impacts below a given threshold. The paper describe possible implementations of the VIA concept which use the Antagonistic Actuation (AA) in three different arrangements. This study follows a previously reported paper dealing with safety. Here a detailed comparative dependability and performability analysis in front of possible specific failure modes is conducted, whose results provide additional and useful guidelines for design of safe and dependable actuation systems for physical human-robot interaction. }, keywords = {Robotics}, author = {R. Filippini and S. Sen and G. Tonietti and A. Bicchi} } @conference {FSB07, title = {Variable Impedance Actuations for Physical Human Cooperating Robots: a Comparative Analysis of Performance, Safety and Dependability}, booktitle = {Proc. IARP-IEEE/RAS-EURON Workshop on Technical Challenges for Dependable Robots in Human Environments.}, year = {2007}, month = {April}, abstract = {

An antagonistic actuation with variable stiffness is proposed for ensuring safety and performance in human friendly robotic applications. Various arrangements are analysed with respect to performance, safety and dependability. The results are expected to provide useful guidelines for choosing an actuation mechanism and its implementation for human-robot interactive applications.

}, keywords = {Robotics}, author = {R. Filippini and S. Sen and A. Bicchi} } @inbook {BSSTB06, title = {Optimization and Fail-Safety Analysis of Antagonistic Actuation for pHRI}, booktitle = {European Robotics Symposium 2006}, series = {Springer Tracts in Advanced Robotics}, volume = {22}, year = {2006}, pages = {109 - 118}, publisher = {Springer Berlin / Heidelberg}, organization = {Springer Berlin / Heidelberg}, abstract = {

In this paper we consider some questions in the design of actuators for physical Human-Robot Interaction (pHRI) under strict safety requirements in all circumstances, including unexpected impacts and HW/SW failures. We present the design and optimization of agonistic-antagonistic actuation systems realizing the concept of variable impedance actuation (VIA). With respect to previous results in the literature, in this paper we consider a realistic physical model of antagonistic systems, and include the analysis of the effects of cross-coupling between actuators. We show that antagonistic systems compare well with other possible approaches in terms of the achievable performance while guaranteeing limited risks of impacts. Antagonistic actuation systems however are more complex in both hardware and software than other schemes. Issues are therefore raised, as to fault tolerance and fail safety of different actuation schemes. In this paper, we analyze these issues and show that the antagonistic implementation of the VIA concept fares very well under these regards also.

}, keywords = {Physical Human-Robot Interaction (pHRI), Robotics}, author = {G. Boccadamo and R. Schiavi and S. Sen and G. Tonietti and A. Bicchi}, editor = {H. Christensen} } @conference {PHRI06, title = {Safe and Dependable Physical Human-Robot Interaction in Anthropic Domains: State of the Art and Challenges}, booktitle = {Proc. IROS{\textquoteright}06 Workshop on pHRI - Physical Human-Robot Interaction in Anthropic Domains}, year = {2006}, publisher = {IEEE}, organization = {IEEE}, keywords = {Robotics}, author = {R. Alami and A Albu-Schaeffer and A. Bicchi and R. Bischoff and R. Chatila and A. De Luca and De Santis, A and G. Giralt and J. Guiochet and G. Hirzinger and F. Ingrand and V. Lippiello and R. Mattone and D. Powell and S. Sen and B. Siciliano and G. Tonietti and L. Villani}, editor = {A. Bicchi and A. De Luca} }