and standing [8]. Its hip and knee f/e are actuated, while ankle
d/p is passively actuated with a spring. A finite state machine is
used to determine the movements of the two exoskeleton legs.
During walking, one stride cycle is separated into four states: left
swing, left double stance, right swing, and right double stance.
Stance to swing transition is mainly triggered by the user moving
his/her crutches and shifting his/her body weight; swing to stance
transition is mainly triggered by heel strike detection. In sitting
down and standing up maneuvers, the two robotic legs are
actuated symmetrically with the same trajectory: even though,
each leg is controlled separately.