Page 257 - Handbook of Biomechatronics

252 Georgios A. Bertos and Evangelos G. Papadopoulos

Bertos (2006) and Bertos et al. (2005) identified values (for n ¼7 sub-
jects) of the dynamic system using steady-state identification techniques.
The variance account for VAF% of the model to the data was 85%–95%.
The results for one representative subject are shown in Figs. 6–8 (Bertos
et al., 2005).

1
0.9
0.8
Damping ratio zeta ( ) 0.6
0.7
0.5
0.4
0.3
0.2
0.1
0
0 0.5 1 1.5 2 2.5
Average walking speed v (m/s)
Fig. 6 Estimated damping ratio zeta vs average walking speed v. (From Bertos, G.A.,
Childress, D.S., Gard, S.A., 2005. The vertical mechanical impedance of the locomotor system
during human walking with applications in rehabilitation. In: IEEE 9th International Con-
ference on Rehabilitation Robotics. IEEE, New York, pp. 380–383.)

15,000

Stiffness k (N/m) 10,000

5000

0
0 0.5 1 1.5 2 2.5
Average walking speed v (m/s)
Fig. 7 Estimated stiffness k vs average walking speed v. (From Bertos, G.A., Childress, D.S.,
Gard, S.A., 2005. The vertical mechanical impedance of the locomotor system during
human walking with applications in rehabilitation. In: IEEE 9th International Conference
on Rehabilitation Robotics. IEEE, New York, pp. 380–383.)