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（PO）设备的新方法，以帮助下肢截肢者和中风幸存者进行必要的活动，以导航他们的家园和社区。使用现有的PO设备，移动性通常受到楼梯、斜坡和不平坦地形的限制。最先进的动力PO设备能够克服这些障碍，但目前大多数先进的控制方法专用于有限的一组特定的预定义运动-例如，步行，跑步和上下楼梯。现有的方法必须推断用户的意图，并切换到最匹配的预定义活动。即使用户意图被正确地解释，期望的运动也可能不匹配任何预定选项。相比之下，该项目启用的P O设备将为不断变化的各种任务提供移动性，包括响应变化和意外的斜坡和基脚条件的能力。除了恢复自然功能外，所研究的控制方法还可以调整用户所体验的物理环境。例如，可以减少使用者的表观重量和质量，以在物理治疗期间提供增加的稳定性，或者甚至增强自然能力。这项工作将显著改善近100万下肢截肢者的生活质量和生产力，甚至更多的中风幸存者，仅在美国。综合教育计划将产生广泛的影响，1）促进残疾人的意识和增加的兴趣，在K-12和大学生中的STEM，2）通过联合教育和研究，促进工程和P O学生之间的相互理解，和3）教育P O学生在STEM的概念，将需要在他们未来的临床实践中利用预计的P O技术。该项目支持从特定任务，运动控制方法的范式转变，任务不变，充满活力的控制方法的动力P O设备，可以帮助下肢截肢者和中风幸存者在不同的活动。该项目将通过能量整形来推进对动力PO设备的控制，其中人体能量的参数和/或公式在闭环中被改变以实现更理想的动态。在这种方法中，可穿戴致动器可以减少身体能量学中的质量/惯性参数，以动态地卸载中风患者的重量，否则中风患者在步态康复期间将由多个治疗师支撑。动力假肢可以通过塑造人体的动量，在截肢者运动期间提供支撑和推进力。因此，该项目的目标是：1）了解如何使用可穿戴致动器来塑造运动期间人体的能量学，2）确定身体能量学的具体变化，从而为动力假肢和动力腿矫形器（即，外骨骼），以及3）理解不同的步态（即，运动模式）从身体能量学中出现，以便设计用于动力PO设备的任务不变控制器。动力学和控制方面的这种创新将使PO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.