Actuation design and implementation for lower extremity human exoskeletons.

摘要

Heavy objects are typically transported by vehicles, carts, and other wheeled devices. However, many environments, such as rocky slopes and staircases, pose significant challenges to wheeled vehicles. Within these settings, legged locomotion becomes an attractive method of transportation, since legs can adapt to a wide range of extreme terrains. But autonomous walking robots have significant difficulty in balancing and navigating in rough, unpredictable terrain. Lower extremity human exoskeletons seek to avoid many of the limitations of autonomous legged robots by adding a human operator to the system. By combining the strength capabilities of robotics with the navigational intelligence and adaptability of humans, exoskeletons allow people to carry heavy loads over rough, unstructured, and uncertain terrains. This dissertation focuses on design and implementation of the actuation system for the exoskeleton. Since the exoskeleton is inherently human-sized, its actuation must support human-scale payloads without becoming excessively heavy or large, as to impede or cause discomfort to the operator. Additionally, because the exoskeleton operates autonomously, minimizing power consumption is critical to the robot's success.; Specifically, this dissertation covers the hydraulic and electric actuation developed for the lower extremity exoskeletons along with a novel power regeneration scheme that generates power normally dissipated by human locomotion. The hydraulic exoskeleton (BLEEX) is the first autonomous, load carrying lower extremity exoskeleton to ever successfully walk. The electrically actuated exoskeleton attempts to provide more joint power, but consume less power than the hydraulic actuation. Both actuation schemes are designed based on Clinical Gait Analysis (CGA) data. In an attempt to further improve power efficiency, a new power regeneration concept is developed and tested on a 3rd generation electro-hydraulically actuated exoskeleton. Unlike other attempts to generate power from human walking, this method only regenerates power that is typically dissipated by human muscles. Overall, this dissertation introduces new actuation design methods for high-powered legged robotics with a focus on compactness and power efficiency.