Actuation Timing Perception of a Powered Ankle Exoskeleton and Its Associated Ankle Angle Changes During Walking
Actuation Timing Perception of a Powered Ankle Exoskeleton and Its Associated Ankle Angle Changes During Walking
复制标题
动力踝外骨骼的驱动时序感知及其行走过程中相关的踝关节角度变化
DOI：
10.1109/tnsre.2022.3162213
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发表时间：
2022
影响因子：
4.9
通讯作者：
Stirling, Leia
中科院分区：
文献类型：
--
作者：
Peng, Xiangyu;Acosta-Sojo, Yadrianna;Wu, Man I.;Stirling, Leia
机器人踝外骨骼具有扩展人类能力的潜力，驱动时间是其控制器设计中的关键参数之一。虽然许多实验已经研究了实现不同目标功能（例如最小化代谢成本）的最佳驱动时间值，但用户对控制参数的感知研究越来越受到关注，因为它提供了人们在使用设备时的舒适度、协调性和信任度的信息，并为感觉运动系统如何检测外骨骼行为变化提供了基础。本研究的目的是评估人们在行走过程中对外骨骼驱动时间变化及其相关的外骨骼踝关节角度变化的敏感性。参与者（n =15）之前很少或没有踝关节外骨骼的经验，并进行了心理物理实验，以表征他们的驱动时间的刚显着差异（JND）阈值。参与者穿着双侧主动踝关节外骨骼，在跑步机上行走时比较不同驱动时间和低峰值扭矩（0.225 Nm/kg）的扭矩曲线。参与者的平均时间JND为2.8±0.6%步幅周期。个体对驱动时间的敏感性不同，外骨骼踝关节角度变化也不同。踝关节角度变化的差异可能是由踝关节刚度的差异和步行时提供的不同踝关节扭矩来解释的。研究结果揭示了人们如何感知外骨骼控制参数的变化，并显示了外骨骼使用的个体差异。在本研究中发现的驱动定时JND也可以帮助确定必要的控制器精度。
Robotic ankle exoskeletons have the potential to extend human ability, and actuation timing serves as one of the critical parameters in its controller design. While many experiments have investigated the optimal actuation timing values to achieve different objective functions (e.g.minimizing metabolic cost), studies on users’ perception of control parameters are gaining interest as it gives information on people’s comfort, coordination, and trust in using devices, as well as providing foundations on how the sensorimotor system detects the exoskeleton behavior changes. The purpose of this study was to evaluate people’s sensitivity to changes in exoskeleton actuation timing and its associated exoskeleton ankle angle changes during walking. Participants (n =15) with little or no prior experience with ankle exoskeletons were recruited and performed a psychophysical experiment to characterize their just-noticeable difference (JND) thresholds for actuation timing. Participants wore a bilateral active ankle exoskeleton and compared pairs of torque profiles with different actuation timings and low peak torque (0.225 Nm/kg) while walking on the treadmill. The mean timing JND across participants was 2.8±0.6% stride period. Individuals exhibited different sensitivity towards actuation timing, and their associated exoskeleton ankle angle changes also varied. The variance in ankle angle changes might be explained by their differences in ankle stiffness and different ankle torques provided during walking. The results provide insights into how people perceive the changes in exoskeleton control parameters and show individual differences in exoskeleton usage. The actuation timing JND found in this study can also help determine the necessary controller precision.