Automatic virtual impedance adaptation of a knee exoskeleton for personalized walking assistance
Automatic virtual impedance adaptation of a knee exoskeleton for personalized walking assistance
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DOI：
10.1016/j.robot.2019.01.013
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发表时间：
2019-04-01
影响因子：
4.3
通讯作者：
Zhang, Wenlong
中科院分区：
文献类型：
--
作者：
Chinimilli, Prudhvi Tej;Qiao, Zhi;Zhang, Wenlong
本文试图解决的问题，在线调制的虚拟阻抗的辅助机器人的基础上实时步态和活动的测量，个性化的援助，为不同的用户在不同的状态。在这项工作中，智能鞋和惯性传感器被引入到测量地面接触力和膝关节运动学，分别。提出了一种基于实时动作识别和步态相位检测的膝关节辅助装置自动阻抗调谐方法。本文考虑的活动是水平，上坡和下坡行走。一个高斯混合模型（GMM）映射的模糊可能性的各种活动和步态阶段所需的虚拟阻抗的KAD。虚拟阻抗的先验估计是使用人体膝关节阻抗来定义的，该人体膝关节阻抗是通过在不同用户上收集的行走数据来识别的。AIT方法被集成到KAD的基于阻抗的高级控制器中，用于在站立阶段提供帮助。最后，为了评估所提出的算法在站立阶段的益处，将EMG传感器放置在三名参与者的股内侧肌群上。将该方法与恒定阻抗和有限状态机两种基本方法进行了比较，结果表明，该方法的阻抗参数和机器人辅助力矩的轮廓更加平滑，股内侧肌的肌肉活动减少。还注意到，参与者在KAD的帮助下减少了他们的步长并增加了步行节奏。(C)2019 Elsevier B.V.版权所有。
This paper attempts to address the problem of online modulation of virtual impedance for an assistive robot based on real-time gait and activity measurements to personalize the assistance for different users at different states. In this work, smart shoes and inertial sensors are introduced to measure ground contact forces and knee joint kinematics, respectively. An automatic impedance tuning (AIT) approach is presented for a knee assistive device (KAD) based on real-time activity recognition and gait phase detection. The activities considered in this paper are level, uphill, and downhill walking. A Gaussian mixture model (GMM) is employed to map the fuzzy likelihood of various activities and gait phases to the desired virtual impedance of the KAD. The prior estimate of virtual impedance is defined using human knee impedance identified with the walking data collected on different users. The AIT approach is integrated into the high-level impedance-based controller of the KAD for assistance during the stance phase. Finally, to evaluate the benefit of the proposed algorithm in stance phase, an EMG sensor is placed on the vastus medialis muscle group of three participants. The proposed approach is compared with two baseline approaches: constant impedance and finite state machine, and the results demonstrate that the profiles of impedance parameters and robot assistive torque are smoother and the muscle activity of vastus medialis is reduced. It is also noticed that the participants reduce their step lengths and increase walking cadence with assistance from the KAD. (C) 2019 Elsevier B.V. All rights reserved.