Closed-loop control of a gait neuroprosthesis

For automatic control of a gait neuroprosthesis utilizing functional neuromuscular stimulation, a new supervisory finite-state controller, and an low-level closed-loop knee extension controller are introduced. Experimental results with complete thoracic spinal cord injured patients are presented. The objective is to provide users with increased control over their desired movement while reducing excessive muscle fatigue prominent in common open-loop systems. As little knowledge about the neuromuscular system is required, the parameters of the proposed control system can be adapted to individuals quickly. Muscle activation of the knee extensors can be reduced by 50% compared to open-loop systems.