@article {1798,
	title = {Effects of assist-as-needed upper extremity robotic therapy after incomplete spinal cord injury: a parallel-group controlled trial},
	journal = {Frontiers in Neurobotics},
	volume = {11},
	number = {26},
	year = {2017},
	attachments = {https://mahilab.rice.edu/sites/default/files/publications/fnbot-11-00026.pdf},
	author = {John M. Frullo and Jared Elinger and Ali Utku Pehlivan and Kyle Fitle and Kathryn Nedley and Gerard Francisco and Fabrizio Sergi and Marcia K. O{\textquoteright}Malley}
}
@proceedings {1821,
	title = {Effects of Discretization on the K-Width of Series Elastic Actuators},
	year = {2017},
	month = {05/2017},
	pages = {421-426},
	publisher = {IEEE},
	address = {Singapore},
	abstract = {<p><span style="color: rgb(51, 51, 51); font-family: sans-serif; font-size: 15px;">Rigid haptic devices enable humans to physically interact with virtual environments, and the range of impedances that can be safely rendered using these rigid devices is quantified by the Z-Width metric. Series elastic actuators (SEAs) similarly modulate the impedance felt by the human operator when interacting with a robotic device, and, in particular, the robot{\textquoteright}s perceived stiffness can be controlled by changing the elastic element{\textquoteright}s equilibrium position. In this paper, we explore the K-Width of SEAs, while specifically focusing on how discretization inherent in the computer-control architecture affects the system{\textquoteright}s passivity. We first propose a hybrid model for a single degree-of-freedom (DoF) SEA based on prior hybrid models for rigid haptic systems. Next, we derive a closed-form bound on the K-Width of SEAs that is a generalization of known constraints for both rigid haptic systems and continuous time SEA models. This bound is first derived under a continuous time approximation, and is then numerically supported with discrete time analysis. Finally, experimental results validate our finding that large pure masses are the most destabilizing operator in human-SEA interactions, and demonstrate the accuracy of our theoretical K-Width bound.</span></p>},
	isbn = {978-1-5090-4633-1},
	issn = {978-1-5090-4633-1},
	doi = {10.1109/ICRA.2017.7989054},
	url = {http://ieeexplore.ieee.org/abstract/document/7989054/},
	attachments = {https://mahilab.rice.edu/sites/default/files/publications/Losey_ICRA_2017.pdf},
	author = {Dylan P. Losey and Marcia K. O{\textquoteright}Malley}
}
