01812nas a2200157   4500008004100000245011600041210006900157300001600226520122400242653001301466100001501479700001501494700001101509700001501520856011901535       2008                        eng d00aVSA-II: A Novel Prototype of Variable Stiffness Actuator for Safe and Performing Robots Interacting with Humans0 aVSAII A Novel Prototype of Variable Stiffness Actuator for Safe   a2171 - 21763 a<p>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.</p>
10aRobotics1 aSchiavi, R1 aGrioli, G.1 aSen, S1 aBicchi, A.  uhttp://615830.rige.asia/publications/vsa-ii-novel-prototype-variable-stiffness-actuator-safe-and-performing-robots