A KAF powered lower-limb orthosis for assisting elderly or
impaired people walking and climbing stairs is presented in [72].
The knee f/e is actuated with a pneumatic muscle, while the ankle
joints are passive. A hybrid controller based on gait phases has
been designed. In stance phase, the desired knee support torque is
calculated with an inverse model of the orthosis. During leg swing,
a reference trajectory extracted from a healthy person is used to
lead the knee extension. Each state is activated by shoe pressure
sensors and the assistance transition between these two states is
smoothed with two anti-windup compensators