Wei Yuyang, Zou Zhenmin, Qian Zhihui, Ren Lei, Wei Guowu
IEEE Trans Neural Syst Rehabil Eng. 2023;31:606-619. doi: 10.1109/TNSRE.2022.3229165. Epub 2023 Feb 1.
Human finger joints are conventionally simplified as rigid joints in robotic hand design and biomechanical hand modelling, due to their anatomic and morphologic complexity. However, our understanding of the effect of the finger joint configuration on the resulting hand performance is still primitive. In this study, we systematically investigate the grasping performance of the hands with the conventional rigid joints and the biomechanical flexible joints based on a computational human hand model. The measured muscle electromyography (EMG) and hand kinematic data during grasping are used as inputs for the grasping simulations. The results show that the rigid joint configuration currently used in most robotic hands leads to large reductions in hand contact force, contact pressure and contact area, compared to the flexible joint configuration. The grasping quality could be reduced up to 40% and 36% by the rigid joint configuration in terms of algebraic properties of grasping matrix and finger force limit respectively. Further investigation reveals that these reductions are caused by the weak rotational stiffness of the rigid joint configuration. This study implies that robotic/prosthetic hand performance could be improved by exploiting flexible finger joint design. Hand contact parameters and grasping performance may be underestimated by the rigid joint simplification in human hand modelling.
由于人类手指关节的解剖结构和形态复杂，在机器人手设计和生物力学手部建模中，通常将其简化为刚性关节。然而，我们对指关节构型对最终手部性能影响的理解仍很原始。在本研究中，我们基于一个计算人体手部模型，系统地研究了具有传统刚性关节和生物力学柔性关节的手的抓握性能。抓握过程中测量的肌肉肌电图（EMG）和手部运动学数据被用作抓握模拟的输入。结果表明，与柔性关节构型相比，目前大多数机器人手中使用的刚性关节构型会导致手部接触力、接触压力和接触面积大幅降低。就抓握矩阵的代数性质和手指力限制而言，刚性关节构型可使抓握质量分别降低高达40%和36%。进一步研究表明，这些降低是由刚性关节构型的弱旋转刚度引起的。本研究表明，通过采用柔性手指关节设计可以提高机器人/假肢手的性能。在人体手部建模中，刚性关节简化可能会低估手部接触参数和抓握性能。
