EAGER: Developing and Bio-Inspired Assembly of Highly Scalable Electromagnetic Soft Actuators for Active Elbow Brace

EAGER：用于主动肘部支架的高度可扩展电磁软执行器的开发和仿生组装

• 批准号: 1840834
• 负责人: Amir Jafari
• 金额: $ 18.99万
• 依托单位: University of Texas at San Antonio
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1840834&HistoricalAwards=false
• 关键词: EAGER; Developing; Bio; Inspired; Assembly

Neurologically impaired people such as stroke patients often need assistance in moving their joints. However, current wearable rehabilitation and assistive devices are either 1) powerful and active but bulky and made of rigid elements such as exoskeletons and artificial limbs, or 2) flexible but passive with limited functionality such as joint braces. In spite of recent advances in soft robotics, there is still no soft actuator (motion-generating device) that is portable, i.e. can be operated by on-board power sources, scalable to be adapted to different joint sizes and still have the short response time and high output force-to-size ratio needed to assist joint motions. To address this need, the goal of this project is to design, fabricate and evaluate a novel Electromagnetic Soft Actuator (ESA) that can be easily powered by on-board batteries and can produce linear force and contraction in a manner that mimics the behavior of the contractile filaments (Actin and Myosin) inside a sarcomere (the basic human muscle actuation unit). The ESA is highly scalable and can be miniaturized to create an artificial sarcomere when assembled in parallel and in series. A series of artificial sarcomeres will create an ExoFiber. As the primary activation unit, each artificial sarcomere will be electrically excited separately. The ExoFibers straps will then be embedded into joint braces to make them active. Being activated based on the principle of electromagnetism, the ExoFibers can be quickly energized to generate force and motion. The performance of an ExoFibers-actived brace for the human elbow joint will be evaluated in a small-scale pilot study in humans with and without elbow disabilities. Findings will advance the next generation of flexible, powerful and portable active braces through scalable soft actuators for joint motion assistance and rehabilitation applications and will lay the foundations for interdisciplinary research on the design and analysis of soft actuator networks with dynamic system and materials design and rehabilitation therapy. Education and outreach impact will be achieved through the development of a new graduate level class in Soft Rehabilitation Robotics and working with the UTSA Center for Excellence in Engineering Education (CE3) and iTEC to involve students from underrepresented groups from San Antonio in the project.This exploratory project investigates the possibility of fabricating an Electromagnetic Soft Actuator (ESA) that can be powered by on-board batteries, can produce linear force and contraction in a manner that mimics the behavior of the contractile actin and myosin filaments inside a sarcomere and can be miniaturized to create an artificial sarcomere when assembled in a bioinspired parallel and series pattern. The artificial sarcomeres can be networked into ExoFibers that can be embedded in a human elbow brace that can be used for rehabilitation or as an assistive device. The Research Plan is organized under two aims. AIM 1 is focused on design and fabrication. The ESA design consists of two antagonistic solenoids with a spring linkage in between and an internal ferromagnetic core built with soft materials. By injecting electric current into micro-coils, two antagonistic electromagnetic fields will be induced, resulting in repulsive or attractive forces that stretch or compress the springy linkage. The artificial sarcomere and ExoFibers designs will be assembled using ESAs that have been bioprinted to facilitate ease of production. The number of ESAs assembled in parallel will determine the output source and the number of ESAs in series defines the overall contraction. AIM 2 is focused on development and evaluation of dynamic properties of an active brace, i.e., brace embedded with an ExoFiber. Experimental platforms will be set up to test performance at three levels: single ExoFiber, active brace, and human elbow. The output performance can be defined in terms of: 1) contraction length, output force, linear stiffness and bandwidth for ExoFiber, 2) flexion range, torque, angular stiffness and bandwidth for active brace, and 3) flexion range and comfort and ease of use with a human elbow. The active brace level will be evaluated while the brace is placed on a bioprinted arm model. The human elbow level will be evaluated by conducting a small-scale pilot study in two cohorts of adults: healthy individuals and subjects with elbow weakness, decreased range of motion, or stiffness due to stroke. Participants will be asked to perform three types of exercises: 1) to hold their arm at 5 different flexion-extension stationary angles while suddenly perturb by a 2Nm torque, 2) to flex and extend their arm while holding a 2Kg weight at two different speeds (slow and normal) and 3) to flex their arm while working against a constant torque of 2Nm.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

神经受损的人（例如中风患者）通常需要帮助来移动关节。然而，当前的可穿戴康复和辅助设备要么是：1）功能强大、主动，但体积庞大，由外骨骼和假肢等刚性元件制成；2）灵活，但被动，功能有限，如关节支架。 尽管软机器人技术最近取得了进展，但仍然没有便携式的软致动器（运动产生装置），即可以通过机载电源操作、可扩展以适应不同的关节尺寸，并且仍然具有辅助关节运动所需的短响应时间和高输出力尺寸比。 为了满足这一需求，该项目的目标是设计、制造和评估一种新型电磁软致动器（ESA），该致动器可以轻松地由板载电池供电，并能够以模仿肌节（基本人体肌肉致动单元）内收缩丝（肌动蛋白和肌球蛋白）行为的方式产生线性力和收缩。 ESA 具有高度可扩展性，在并联和串联组装时可以小型化以创建人工肌节。一系列人工肌节将产生外纤维。作为主要激活单元，每个人工肌节将分别受到电激发。然后，ExoFibers 带子将嵌入关节支架中，使其活动起来。 ExoFibers基于电磁原理被激活，可以快速通电产生力和运动。 用于人类肘关节的 ExoFibers 主动支架的性能将通过一项针对有或没有肘部残疾的人类的小规模试点研究进行评估。研究结果将通过用于关节运动辅助和康复应用的可扩展软执行器推动下一代灵活、强大和便携式主动支架的发展，并将为软执行器网络与动态系统和材料设计和康复治疗的设计和分析的跨学科研究奠定基础。 通过开发新的软康复机器人研究生课程，并与 UTSA 工程教育卓越中心 (CE3) 和 iTEC 合作，让来自圣安东尼奥代表性不足群体的学生参与该项目，将实现教育和推广影响。这个探索性项目研究了制造电磁软致动器 (ESA) 的可能性，该电磁软致动器 (ESA) 可以由板载电池供电，可以产生线性力和 以模仿肌节内收缩肌动蛋白和肌球蛋白丝行为的方式收缩，并且当以仿生平行和串联模式组装时，可以小型化以创建人工肌节。 人造肌节可以联网成 ExoFibers，可以嵌入人体肘部支架中，用于康复或作为辅助装置。 该研究计划有两个目标。 AIM 1 专注于设计和制造。 ESA 设计由两个相对的螺线管（其间有弹簧连杆）和一个由软材料制成的内部铁磁芯组成。通过将电流注入微线圈，将感应出两个对抗的电磁场，从而产生排斥力或吸引力，从而拉伸或压缩弹性连杆。 人工肌节和 ExoFibers 设计将使用经过生物打印的 ESA 进行组装，以方便生产。 并联组装的 ESA 数量将决定输出源，串联的 ESA 数量决定整体收缩。 AIM 2 专注于主动支架（即嵌入 ExoFiber 的支架）动态特性的开发和评估。 将建立实验平台来测试三个级别的性能：单 ExoFiber、主动支架和人体肘部。输出性能可以通过以下方面来定义：1) ExoFiber 的收缩长度、输出力、线性刚度和带宽，2) 主动支架的弯曲范围、扭矩、角刚度和带宽，以及 3) 人类肘部的弯曲范围和舒适度以及易用性。 当支架放置在生物打印的手臂模型上时，将评估主动支架水平。 将通过对两组成年人进行小规模试点研究来评估人类肘部水平：健康个体和肘部无力、活动范围减少或因中风而僵硬的受试者。参与者将被要求进行三种类型的练习：1) 将手臂保持在 5 个不同的屈曲-伸展固定角度，同时突然受到 2Nm 扭矩的干扰；2) 在以两种不同的速度（慢速和正常）握住 2Kg 重物的同时弯曲和伸展手臂；3) 在以 2Nm 的恒定扭矩工作时弯曲手臂。该奖项反映了 NSF 的法定使命，并通过使用基金会的评估进行评估，认为值得支持。 智力价值和更广泛的影响审查标准。

项目成果

Energy and Force Optimization of a Network of Novel Electromagnetic Soft Actuators

新型电磁软执行器网络的能量和力优化

• DOI: 10.3390/en13143572
• 发表时间: 2020
• 期刊: Energies
• 影响因子: 3.2
• 作者: Ebrahimi, Nafiseh;Jafari, Amir
• 通讯作者: Jafari, Amir

Design Optimization of a Novel Networked Electromagnetic Soft Actuators System Based on Branch and Bound Algorithm

基于分支定界算法的新型网络化电磁软执行器系统设计优化

• DOI: 10.1109/access.2020.3005877
• 发表时间: 2020
• 期刊: IEEE Access
• 影响因子: 3.9
• 作者: Ebrahimi, Nafiseh;Guda, Teja;Alamaniotis, Miltiadis;Miserlis, Dimitrios;Jafari, Amir
• 通讯作者: Jafari, Amir

Design optimization of a solenoid-based electromagnetic soft actuator with permanent magnet core

• DOI: 10.1016/j.sna.2018.10.026
• 发表时间: 2018-12-01
• 期刊: SENSORS AND ACTUATORS A-PHYSICAL
• 影响因子: 4.6
• 作者: Ebrahimi, Nafiseh;Schimpf, Paul;Jafari, Amir
• 通讯作者: Jafari, Amir