Gait planning and double support phase model for functional electrical stimulation-based walking

Joint or segment angle trajectories of able-bodied persons are often recorded or mimicked as reference trajectories for walking restoration in paraplegia. In this paper, lower limb segment angle trajectories are computed from simple mathematical models developed to represent functional electrical stimulation (FES) and a novel brace based walking. The new models incorporate the double support and single support phases of walking. Dynamic optimization is utilized to design walking trajectories that minimize muscle activations and arm reaction forces generated from the walker. Compared to the voluntary walking trajectories, the new trajectories are more representative of FES-based walking as only a limited number of muscle are stimulated to compute walking trajectories.