Stairs and ramps ascent and descent: how to design feasible gait patterns for a powered lower-limb exoskeleton

In recent years, powered exoskeletons have witnessed a surge in usage for rehabilitation purposes in clinical environments. Mainly used for walking on flat terrains, they are evolving to handle advanced scenarios as stairs and ramps to allow a wider range of activities. To do so, a valid tool is necessary to find effective and safe trajectories for different challenges. This paper proposes an iterative approach for designing the movement patterns for powered lower-limb exoskeletons by means of basis function interpolation. This approach has been used to define different trajectories to address ascending and descending stairs and ramps. Besides, the mathematical definition of the resulting basis function is presented. The outcome of this study has been successfully tested on real scenarios with the support of a group of nine healthy subjects wearing the TWIN lower-limb exoskeleton.