Figure 2. Commercial finger images (top) and kinematic models of finger joint coupling mechanism (bottom). (a) Vincent (Vincent Systems), (b) iLimb and iLimb Pulse (Touch Bionics), (c) Bebionic v2 and Bebionic (RSL Steeper), and (d) Michelangelo (Otto Bock). ??1 = angle of metacarpal phalange joint, ??2 = angle of proximal interphalange joint.