The Vanderbilt HK orthosis is designed to assist the hip and
knee f/e of SCI individuals [40]. To help the user keep ankle stable
during stance phase and avoid drop foot during swing phase,
the Vanderbilt orthosis could be mounted with a standard AFO.
For a safety reason, the knee joints are equipped with normally
locked brakes in case of power failure. The orthosis controller
consists of four motion states: standing, right forward, left forward,
sitting [41]. In each state, the joint angle are pre-programmed
based on recorded trajectories from a healthy subject wearing
the orthosis. Switching between states is initiated by user’s vocal
command.