Matjaz Mihelj Tobias Nef Robert Riener ARMin II - 7 DoF rehabilitation robot: mechanics and kinematics. 4120-4125 2007 conf/icra/2007 ICRA http://dx.doi.org/10.1109/ROBOT.2007.364112 db/conf/icra/icra2007.html#MiheljNR07