@inproceedings{howard2011constraint Author = {Howard, M. and Braun, D.J. and Vijayakumar, S.}, Title = {Constraint-based equilibrium and stiffness control of variable stiffness actuators}, Year = {2011}, Pages = {5554--5560}, Booktitle = {Robotics and Automation (ICRA), 2011 IEEE International Conference on}, Organization = {IEEE} }