A Data-Driven Reinforcement Learning Solution Framework for Optimal and Adaptive Personalization of a Hip Exoskeleton
NC State University（北卡罗来纳州立大学）；University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校）；Arizona State University（亚利桑那州立大学）；Hubei University of Technology（湖北工业大学）
Xikai Tu, Minhan Li, Ming Liu, Jennie Si, He, Huang
Robotic exoskeletons are exciting technologies for augmenting human mobility. However, designing such a device for seamless integration with the human user and to assist human movement still is a major challenge. This paper aims at developing a novel data-driven solution framework based on reinforcement learning (RL), without first modeling the human-robot dynamics, to provide optimal and adaptive personalized torque assistance for reducing human efforts during walking. Our automatic personalization solution framework includes the assistive torque profile with two control timing parameters (peak and offset timings), the least square policy iteration (LSPI) for learning the parameter tuning policy, and a cost function based on transferred work ratio. The proposed controller was successfully validated on a healthy human subject to assist unilateral hip extension in walking. The results showed that the optimal and adaptive RL controller as a new approach was feasible for tuning assistive torque profile of the hip exoskeleton that coordinated with human actions and reduced activation level of hip extensor muscle in human.
University of Michigan（密歇根大学）；Shanghai Jiao Tong University（上海交通大学）
Task-dependent controllers widely used in exoskeletons track predefined trajectories, which overly constrain the volitional motion of individuals with remnant voluntary mobility. Energy shaping, on the other hand, provides task-invariant assistance by altering the human body's dynamic characteristics in the closed loop. While human-exoskeleton systems are often modeled using Euler-Lagrange equations, in our previous work we modeled the system as a port-controlled-Hamiltonian system, and a task-invariant controller was designed for a knee-ankle exoskeleton using interconnection-damping assignme…
Friction Characterization of a Cable-Driven Differential Actuation System for Lower-Limb Exoskeletons
Institute of Mechanical Intelligence, Department of Excellence in Robotics and AI, Sant'Anna School of Advanced Studies（机械智能研究所、机器人及人工智能卓越系，圣安娜高等研究学院）；Wearable Robotics s.r.l.（可穿戴机器人有限公司）
Rutgers, The State University of New Jersey（新泽西州立大学罗格斯分校）
High-performance actuators are crucial to enable mechanical versatility of lower-limb wearable robots, which are required to be lightweight, highly backdrivable, and with high bandwidth. State-of-the-art actuators, e.g., series elastic actuators (SEAs), have to compromise bandwidth to improve compliance (i.e., backdrivability). In this paper, we describe the design and human-robot interaction modeling of a portable hip exoskeleton based on our custom quasi-direct drive (QDD) actuation (i.e., a high torque density motor with low ratio gear). We also present a model-based performance benchmark c…
University of Tsukuba Hospital（筑波大学附属医院）；University of Tsukuba（筑波大学）；Swiss Federal Institute of Technology in Lausanne（洛桑联邦理工学院）
We present a personal mobility device for lower-body impaired users through a light-weighted exoskeleton on wheels. On its core, a novel passive exoskeleton provides postural transition leveraging natural body postures with support to the trunk on sit-to-stand and stand-to-sit (STS) transitions by a single gas spring as an energy storage unit. We propose a direction-dependent coupling of knees and hip joints through a double-pulley wire system, transferring energy from the torso motion towards balancing the moment load at the knee joint actuator. Herewith, the exoskeleton maximizes energy tran…
New Jersey Institute of Technology（新泽西理工学院）；CFD Research Corporation（CFD研究公司）
In this paper, we present an integrated human-in-the-loop simulation paradigm for the design and evaluation of a lower extremity exoskeleton that is elastically strapped onto human lower limbs. The exoskeleton has 3 rotational DOFs on each side and weighs 23kg. Two torque compensation controllers of the exoskeleton are introduced, aiming to minimize interference and maximize assistance to human motions, respectively. Their effects on the wearer's biomechanical loadings are studied with a running motion and predicted ground reaction forces. It is found that the added weight of the passive exosk…
The Impact of Gait Pattern Personalization on the Perception of Rigid Robotic Guidance: A Pilot User Experience Evaluation
Cognitive Robotics Department, Delft University of Technology（代尔夫特理工大学认知机器人学系）；Department of Rehabilitation Medicine, Erasmus Medical Centre（伊拉斯姆斯医学中心康复医学系）；Department of Biomechanical Engineering, Delft University of Technology（代尔夫特理工大学生物力学工程系）；Institute of Automatic Control, RWTH Aachen University（亚琛工业大学自动控制研究所）；Department of Mechanical Engineering, FUM Center of Advanced Rehabilitation and Robotics Research (FUM CARE), Ferdowsi University of Mashhad（菲尔多西大学机械工程系先进康复与机器人研究中心）；Walker Department of Mechanical Engineering, University of Texas at Austin（德克萨斯大学奥斯汀分校沃克机械工程系）
A Multi-Layer Sim-to-Real Framework for Gaze-Driven Assistive Neck Exoskeletons
Kahlert School of Computing, University of Utah（犹他大学计算机学院）；Dept. of Mechanical Engineering, University of Utah（犹他大学机械工程系）；Robotics Center, University of Utah（犹他大学机器人中心）
University of Twente（特温特大学）；Delft University of Technology（代尔夫特理工大学）
Knowledge on joint impedance during walking in various conditions is relevant for clinical decision-making and the development of robotic gait trainers, leg prostheses, leg orthotics and wearable exoskeletons. Whereas ankle impedance during walking has been experimentally assessed, knee and hip joint impedance during walking have not been identified yet. Here we developed and evaluated a lower limb perturbator to identify hip, knee and ankle joint impedance during treadmill walking. The lower limb perturbator (LOPER) consists of an actuator connected to the thigh via rods. The LOPER allows to …
Human Locomotion Implicit Modeling Based Real-Time Gait Phase Estimation
Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education（生物力学与机械生物学重点实验室（北京航空航天大学）教育部）；Key Laboratory of Innovation and Transformation of Advanced Medical Devices, Ministry of Industry and Information Technology（先进医疗设备创新与转化重点实验室（工业和信息化部））；National Medical Innovation Platform for Industry-Education Integration in Advanced Medical Devices (Interdiscipline of Medicine and Engineering)（先进医疗设备产业教育融合国家级创新平台（医学与工程交叉学科））；School of Biological Science and Medical Engineering, Beihang University（生物科学与医学工程学院（北京航空航天大学））
