CAREER: Recovering and Enhancing Natural Locomotion in Changing Conditions with Powered Lower-Limb Prostheses and Orthoses

这个教师早期职业发展（Career）项目将研究控制动力假肢和矫形器（P&amp；O）设备的新方法，以帮助下肢截肢者和中风幸存者进行在家庭和社区中导航所需的行动活动。对于现有的P&amp；O设备，其机动性通常受到楼梯、斜坡和不平坦地形的限制。最先进的动力P&amp；O设备能够克服这些障碍，但目前大多数先进的控制方法都专门用于一组有限的特定预定义运动，例如步行、跑步、上下楼梯。现有的方法必须推断用户的意图，并切换到最接近匹配的预定义活动。即使用户的意图被正确理解，期望的动作也可能与任何预先确定的选项不匹配。相比之下，该项目启用的P&amp；O设备将为不断变化的各种任务提供机动性，包括应对变化和意外的斜坡和基础条件的能力。除了恢复自然功能外，所研究的控制方法还可以根据用户的体验调整物理环境。例如，使用者的表观重量和质量可以减少，以在物理治疗期间提供更高的稳定性，甚至可以增强自然能力。仅在美国，这项工作将显著提高近100万下肢截肢者的生活质量和工作效率，甚至更多的中风幸存者。综合教育计划将产生广泛的影响：1)提高K-12和大学生对残疾的认识和对STEM的兴趣；2)通过联合教育和研究促进工程和P&amp；O学生之间的相互理解；3)向P&amp；O学生传授STEM概念，以便在未来的临床实践中利用预计的P&amp；O技术。该项目支持从特定任务的运动学控制方法到任务不变的能量控制方法的范式转变，为动力P&amp；O设备提供帮助，可以帮助下肢截肢者和中风幸存者进行各种活动。该项目将通过能量整形来推进动力P&amp；O设备控制方面的知识，即在闭环中改变人体能量的参数和/或公式，以实现更理想的动力学。在这种方法中，可穿戴驱动器可以减少身体能量学中的质量/惯性参数，从而动态减轻中风患者的体重，否则在步态康复期间将由多个治疗师支持。动力假肢可以通过塑造人体的动量来为截肢者的运动提供支撑和推进。因此，该项目的目标是：1)了解如何使用可穿戴驱动器来塑造人体在运动过程中的能量；2)确定身体能量的具体变化，从而为动力假肢和动力腿矫形器（即外骨骼）提供有效的控制策略；3)了解不同的步态（即运动学模式）是如何从身体能量中产生的，以便为动力P&amp；O设备设计任务不变控制器。这种在动力学和控制方面的创新将使P&amp；O设备能够帮助人类进行连续的运动活动，这是基于预定义的、特定任务的关节运动学的最先进的控制策略无法实现的。

This Faculty Early Career Development (CAREER) project will investigate new ways to control powered prosthetic and orthotic (P&O) devices to assist lower-limb amputees and stroke survivors with the mobility activities needed to navigate their homes and communities. With existing P&O devices, mobility is often limited by stairs, slopes, and uneven terrains. State-of-the-art powered P&O devices are capable of overcoming these obstacles, but most current advanced control methods are specialized to a limited set of specific pre-defined motions -- for example, walking, running, and ascending or descending stairs. Existing approaches must infer the user's intention and switch to the most closely matching pre-defined activity. Even if user intention is correctly interpreted, the desired motion may not match any of the pre-determined options. In contrast, the P&O devices enabled by this project will provide mobility for a continuously changing variety of tasks, including the ability to respond to changing and unanticipated slope and footing conditions. In addition to restoring natural function, the investigated control approach can also adjust the physical environment as experienced by the user. For example, the apparent weight and mass of the user could be reduced to provide increased stability during physical therapy, or even to enhance natural capabilities. This work will significantly improve quality of life and productivity for nearly a million lower-limb amputees, and even more stroke survivors, in the US alone. The integrated education plan will have broad impact by 1) promoting disability awareness and increasing interest in STEM among K-12 and college students, 2) fostering mutual understanding between engineering and P&O students through joint education and research, and 3) educating P&O students in STEM concepts that will be needed to utilize the projected P&O technologies in their future clinical practice.This project supports a paradigm shift from task-specific, kinematic control approaches to task-invariant, energetic control approaches for powered P&O devices that can assist lower-limb amputees and stroke survivors across varying activities. This project will advance knowledge in the control of powered P&O devices through energy shaping, where the parameters and/or formula for the human body's energy are altered in closed loop to achieve more desirable dynamics. In this approach, wearable actuators could reduce mass/inertia parameters in body energetics to dynamically offload the weight of a stroke patient who otherwise would be supported by multiple therapists during gait rehabilitation. Powered prosthetic legs could provide support and propulsion during amputee locomotion by shaping the momentum of the human body. Accordingly, the goals of this project are to 1) understand how to use wearable actuators to shape the energetics of the human body during locomotion, 2) determine specific changes to body energetics that lead to effective control strategies for powered prosthetic legs and powered leg orthoses (i.e., exoskeletons), and 3) understand how different gaits (i.e., kinematic patterns) emerge from body energetics in order to design task-invariant controllers for powered P&O devices. This innovation in dynamics and control will enable P&O devices to assist humans in a continuum of locomotor activities, which cannot be achieved with state-of-art control strategies based on pre-defined, task-specific joint kinematics.