T=0.74 (s), V=0.09 (m/s)



As a lateral perturbation, an impulse of approx. 0.56 (Kgm/s) that pushed the center of the body to the right was applied by a pendulum at the stance phase onset of the left foreleg.



The reason why Kotetsu ketp walking against a lateral perturbation:
where LF, LH, RF and RH mean left foreleg, left hind leg, right foreleg and right hind leg, respectively. The suffix st and sw mean the stance phase onset and the swing phase onset, respectively.


After impact, incorrect phase transitions (LH-sw, LF-sw [those swing phase were very short]) were followed.

But afterwards, correct phase transitions (LH-st, LF-st, RH-sw, RF-sw, RH-st, RF-st, LH-sw, LF-sw, ......) were followed, since ACMexc was employed. That is, since the threshold (XLO) of LF and RF was increased by ACMexc, the leg load of LF and RF became less than XLO. As a result, the stance-to-swing phase transitions of LF and RF were triggered.

Finally, the gait returned to the correct order and Kotetsu kept walking.

WMV 4M