A Smooth and Safe Path Planning for an Active Lower Limb Exoskeleton

Abstract

The Probabilistic Foam method (PFM) is a path planner that ensures a volumetric region for safe maneuverability called bubble. This method generates paths bounded by a set of overlapped bubbles, called rosary. In this paper, we present an approach to obtain safe and smooth collision-free paths from PFM for a lower limb active exoskeleton, which is based on two main processes: The rosary adjustment and the path smoothing. The first process keeps the size of the bubbles more regular, while the second process guarantees a smooth and short path, satisfying the safe constraints imposed by the rosary. To evaluate these proposed approaches, we presented a simulation of the exoskeleton leg performing the swing phase movement in three different scenarios: overcoming an obstacle, walking up and down a step. The resulting planned paths were evaluated and compared, considering the path length and the path smoothness.