The biomechanical complexity of the human shoulder, while critical for functionality, poses a challenge for objective assessment during sensorimotor rehabilitation. With built-in sensing capabilities, robotic exoskeletons have the potential to serve as tools for both intervention and assessment. The bilateral upper-extremity Harmony exoskeleton is capable of full shoulder articulation, forearm flexion-extension, and wrist pronation-supination motions. The goal of this paper is to characterize Harmony's anatomical joint angle tracking accuracy towards its use as an assessment tool. We evaluated the agreement between anatomical joint angles estimated from the robot's sensor data and optical motion capture markers attached to the human user. In 9 healthy participants we examined 6 upper-extremity joint angles, including shoulder girdle angles, across 4 different motions, varying active/passive motion of the user and physical constraint of the trunk. We observed mostly good to excellent levels of agreement between measurement systems with CMCip > 0.65 for shoulder and distal joints, magnitudes of average discrepancies varying from 0.43° to 16.03° and width of LoAs ranging between 9.44° and 41.91°. Slopes were between 1.03 and 1.43 with r > 0.9 for shoulder and distal joints. Regression analysis suggested that discrepancies observed between measured robot and human motions were primarily due to relative motion associated with soft tissue deformation. The results suggest that the Harmony exoskeleton is capable of providing accurate measurements of arm and shoulder joint kinematics. These findings may lead to robot-assisted assessment and intervention of one of the most complex joint structures in the human body.

中文翻译：

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使用 Harmony 外骨骼评估上肢关节角度


人类肩部的生物力学复杂性虽然对功能至关重要，但对感觉运动康复过程中的客观评估提出了挑战。凭借内置的传感功能，机器人外骨骼有潜力作为干预和评估的工具。双侧上肢 Harmony 外骨骼能够进行全肩关节、前臂屈伸和腕部旋前-旋后运动。本文的目标是表征 Harmony 的解剖关节角度跟踪精度，以将其用作评估工具。我们评估了根据机器人传感器数据估计的解剖关节角度与附着在人类用户身上的光学运动捕捉标记之间的一致性。我们在 9 名健康参与者中检查了 6 个上肢关节角度，包括肩带角度、4 种不同的运动、用户不同的主动/被动运动以及躯干的物理约束。我们观察到肩部和远端关节的 CMCip > 0.65 测量系统之间的一致性基本良好到极好，平均差异幅度在 0.43° 到 16.03° 之间变化，LoA 宽度在 9.44° 到 41.91° 之间变化。肩关节和远端关节的斜率在 1.03 和 1.43 之间，r > 0.9。回归分析表明，测量的机器人和人类运动之间观察到的差异主要是由于与软组织变形相关的相对运动造成的。结果表明 Harmony 外骨骼能够提供手臂和肩关节运动学的精确测量。这些发现可能会导致机器人辅助评估和干预人体最复杂的关节结构之一。