Gerd Hirzinger Norbert Sporer Markus Schedl Jörg Butterfaß Markus Grebenstein Torque-Controlled Lightweight Arms and Articulated Hands: Do We Reach Technological Limits Now? 331-340 2004 23 I. J. Robotic Res. 4-5 http://ijr.sagepub.com/cgi/content/abstract/23/4-5/331 db/journals/ijrr/ijrr23.html#HirzingerSSBG04