The THKAF walking assistance device described in [37] aims at
aiding elderly and impaired people. Its actuation system is placed
in a backpack, with transmission employing flexible shafts: the
torques effectively applied to the active joints – knee and ankle
– are calculated on the basis of the shaft twist angle. The desired
joints angles and torques are referred to gaits data of healthy
people. Rather than tracking only one kind of desired signal, only
angles or only torques, the actuators’ final outputs are determined
by hybridizing the joints angles controller and torques controller
with a certain ratio (experimentally chosen).
Walking experiments have been carried out with both healthy
subjects and paralyzed subjects [38]. EMG activities measured
from healthy subjects showed decreased muscular activities with
respect to normal walking without the orthosis. In the experiments
with paralytic patients, the device only applied assistance to their
ankle joints. Still, their hip kinematics were found to be affected:
averagely, the hip f/e motion was decreased by about 7.4% than
non-assistance walking, while the maximum hip internal/external
rotation angle was reduced 15% compared with non-assistance
walking