Figure 3

The transradial prosthesis design. Five fingers are actuated by means of four DC brushed motors M1-4 all located inside the palm structure. Motor M1 drives thumb flexion/extension, M2 drives index flexion/extension, M3 actuates the middle, ring and little fingers simultaneously and M4 actuates the thumb abduction/adduction. The thumb axis angle with regard to the horizontal plane is highlighted (50 deg). The main printed circuit board (PCB) is placed on the motors.