IEEE Trans Neural Syst Rehabil Eng. 2021;29:629-640. doi: 10.1109/TNSRE.2021.3064463. Epub 2021 Mar 15.
Misalignments between powered exoskeleton joints and the user's anatomical joints are inevitable due to difficulty locating the anatomical joint axis, non-constant location of the anatomical joint axis, and soft-tissue deformations. Self-aligning mechanisms have been proposed to prevent spurious forces and torques on the user's limb due to misalignments. Several exoskeletons have been developed with self-aligning mechanisms based on theoretical models. However, there is no experimental evidence demonstrating the efficacy of self-aligning mechanisms in lower-limb exoskeletons. Here we show that a lightweight and compact self-aligning mechanism improves the user's comfort and performance while using a powered knee exoskeleton. Experiments were conducted with 14 able-bodied subjects with the self-aligning mechanism locked and unlocked. Our results demonstrate up to 15.3% increased comfort and 38% improved performance when the self-aligning mechanism was unlocked. Not surprisingly, the spurious forces and torques were reduced by up to 97% when the self-aligning mechanism was unlocked. This study demonstrates the efficacy of self-aligning mechanisms in improving comfort and performance for sit-to-stand and position tracking tasks with a powered knee exoskeleton.
由于难以定位解剖关节轴、解剖关节轴位置不恒定以及软组织变形，动力外骨骼关节与用户解剖关节之间的错位是不可避免的。已经提出了自对准机构来防止由于错位而对用户肢体产生的虚假力和扭矩。已经基于理论模型开发了几种具有自对准机构的外骨骼。然而，没有实验证据表明自对准机构在下肢外骨骼中的有效性。在这里，我们展示了一种轻巧紧凑的自对准机构可以提高使用动力膝关节外骨骼的用户的舒适度和性能。对 14 名身体健康的受试者进行了实验，其中自对准机构锁定和解锁。我们的结果表明，当自对准机构解锁时，舒适度提高了高达 15.3%，性能提高了 38%。毫不奇怪，当自对准机构解锁时，虚假力和扭矩降低了高达 97%。这项研究证明了自对准机构在提高动力膝关节外骨骼进行坐站和位置跟踪任务时的舒适度和性能方面的有效性。
