**4.2.2 Experimental results**

The result of this experiment is shown by Fig. 14. The red line is the fingertip force. The black line and the blue line is the value of the encoder in MP1. The black line is the compensated data, and the blue line is the raw data. As shown in Fig. 14, the impact force is measured. This has a reason that the DIP and PIP joints of the finger extended to the stopper and the skidding mechanism of the DIP and PIP joints are inactive. Thus, the impact force is not alleviated.

Fig. 14. Transition of fingertip force contacted against rigid object

The angular difference is 1.5 [deg.] between the first tap and the second tap in the compensated data. The angular difference is 0.5[deg.] between the second and the third. After multi-cycle experiments, the angular difference is 2 [deg.] at a maximum by one tap. This compensating method has cumulative difference but is practical. Depending on the desired accuracy of control system, the values of encoders should be reset with a bump against the stopper. The results show that this compensating method is effective.
