**4. Experiments**

102 The Future of Humanoid Robots – Research and Applications

Fig. 8 shows the relation between the clenched angle of an adjustment nut and the skidding torque. From Fig. 8, the skidding torque is adjustable from maximum to minimum of motor torque. In other word, this finger is able to be adjusted as a hard finger or a passive finger.

Torque Limiter Mechanism has some advantages on the operation of the Universal Robot Hand II. The behavior of the finger with the mechanism is shown in Fig. 9 and Fig. 10. The PIP joint and the DIP joint are normally located as shown in Fig. 9 (a). The DIP joint is flexed in conjunction with PIP joint as same degrees. It is thought that excess overload is operated at the distal phalanx. As shown in Fig. 9 (b). If torque by the external force exceeds setup skidding torque, modules of drive gearing are turned over toward the direction of fending off the force to the mechanical stopper as one structure. This mechanism doesn't only make the actuators to be protected against the overload, but also support the external force

Flexible grasp with Torque Limiter Mechanism is as shown by Fig. 10. Typically, a robot finger takes the form in Fig. 10 (a) in case of grasping a thin object. This is because that the

mechanistically without output power of actuators by the position of particularity.

Fig. 9. Overloaded operation with torque limiter mechanism

Fig. 8. Angle of adjustment nut vs skidding torque

**3.2 Advantages in finger behavior** 
