PDF(Pubmed)
Abstract：
Conventional passive ankle foot orthoses (AFOs) have not seen substantial advances or functional improvements for decades, failing to meet the demands of many stakeholders, especially the pediatric population with neurological disorders. Our objective is to develop the first comfortable and unobtrusive powered AFO for children with cerebral palsy (CP), the DE-AFO. CP is the most diagnosed neuromotor disorder in the pediatric population. The standard of care for ankle control dysfunction associated with CP, however, is an unmechanized, bulky, and uncomfortable L-shaped conventional AFO. These passive orthoses constrain the ankle\'s motion and often cause muscle disuse atrophy, skin damage, and adverse neural adaptations. While powered orthoses could enhance natural ankle motion, their reliance on bulky, noisy, and rigid actuators like DC motors limits their acceptability. Our innovation, the DE-AFO, emerged from insights gathered during customer discovery interviews with 185 stakeholders within the AFO ecosystem as part of the NSF I-Corps program. The DE-AFO is a biomimetic robot that employs artificial muscles made from an electro-active polymer called dielectric elastomers (DEs) to assist ankle movements in the sagittal planes. It incorporates a gait phase detection controller to synchronize the artificial muscles with natural gait cycles, mimicking the function of natural ankle muscles. This device is the first of its kind to utilize lightweight, compact, soft, and silent artificial muscles that contract longitudinally, addressing traditional actuated AFOs\' limitations by enhancing the orthosis\'s natural feel, comfort, and acceptability. In this paper, we outline our design approach and describe the three main components of the DE-AFO: the artificial muscle technology, the finite state machine (the gait phase detection system), and its mechanical structure. To verify the feasibility of our design, we theoretically calculated if DE-AFO can provide the necessary ankle moment assistance for children with CP-aligning with moments observed in typically developing children. To this end, we calculated the ankle moment deficit in a child with CP when compared with the normative moment of seven typically developing children. Our results demonstrated that the DE-AFO can provide meaningful ankle moment assistance, providing up to 69% and 100% of the required assistive force during the pre-swing phase and swing period of gait, respectively.
摘要：
传统的被动踝足矫形器（AFO）几十年来没有看到实质性的进步或功能改善，未能满足许多利益相关者的需求，尤其是患有神经系统疾病的儿科人群。我们的目标是为脑瘫（CP）儿童开发第一个舒适且不显眼的动力AFO，DE-AFO。CP是儿科人群中诊断最多的神经运动障碍。与CP相关的踝关节控制功能障碍的护理标准，然而,是一个非机械化的，笨重,和不舒服的L形常规AFO。这些被动矫形器限制了脚踝的运动，并经常导致肌肉废用萎缩，皮肤损伤,和不良的神经适应。虽然动力矫形器可以增强脚踝的自然运动，他们对笨重的依赖，嘈杂,和刚性致动器如直流电动机限制了它们的可接受性。我们的创新,DE-AFO，作为NSFI-Corps计划的一部分，从与AFO生态系统中185个利益相关者的客户发现访谈中收集的见解中脱颖而出。DE-AFO是一种仿生机器人，它采用由称为介电弹性体（DE）的电活性聚合物制成的人造肌肉来辅助脚踝在矢状平面中的运动。它包含一个步态相位检测控制器，使人造肌肉与自然步态周期同步，模仿天然踝关节肌肉的功能。这种装置是第一个利用轻量级的，紧凑型,软,和纵向收缩的无声人造肌肉，通过增强矫形器的自然感觉来解决传统致动AFO的局限性，comfort,和可接受性。在本文中,我们概述了我们的设计方法，并描述了DE-AFO的三个主要组成部分：人造肌肉技术，有限状态机(步态相位检测系统)，以及它的机械结构。为了验证我们设计的可行性，我们从理论上计算了DE-AFO是否可以为CP与典型发育儿童中观察到的力矩对齐的儿童提供必要的踝关节力矩辅助。为此,我们计算了一名患有CP的儿童的踝关节矩缺陷与7名典型发育儿童的规范矩相比.我们的结果表明，DE-AFO可以提供有意义的踝关节力矩辅助，在摆动前阶段和步态摆动期间提供高达69％和100％的所需辅助力，分别。
