Simulation of human walking with powered orthosis for designing practical assistive device

To design a powered assistive orthosis for human walking, we have simulated walking motion with an orthosis. The model dynamics of the coupled human-orthosis is represented by a 10-rigid-link system. In this model there exist rotational joints at lumbar, both thighs and both legs for orthosis, and each joints are controlled by a couple of central pattern generators (CPG) which imitates neuronal system in the spinal cord of mammals. The CPG controller modeled by 18 oscillators which have the sensory feedbacks and generates the joint torques to move the skeletal model of the coupled human-orthosis. This means that we use five actuators for controlling orthosis in the both of sagittal and frontal plane. The parameters of the CPG and the connecting gains are optimized by using a genetic algorithm. We have achieved the successful simulation of stable walking against disturbances with this model. The simulation results indicate the possibility of a practical assistive orthosis with five active joints for stable walking.