Department of Robotics, Brain and Cognitive Sciences, Italian Institute of Technology, Genoa, Italy.
Ann Biomed Eng. 2011 Dec;39(12):2945-54. doi: 10.1007/s10439-011-0381-7. Epub 2011 Aug 24.
Modulation of arm mechanical impedance is a fundamental aspect for interaction with the external environment and its regulation is essential for stability preservation during manipulation. Even though past research on human arm movements has suggested that models of human finger impedance would benefit the study of neural control mechanisms and the design of novel hand prostheses, relatively few studies have focused on finger and hand impedance. This article touches on the two main aspects of this research topic: first it introduces a mechanical refinement of a device that can be used to effectively measure finger impedance during manipulation tasks; then, it describes a pilot study aimed at identifying the inertia of the finger and the viscous and elastic properties of finger muscles. The proposed wearable exoskeleton, which has been designed to measure finger posture and impedance modulation while leaving the palm free, is capable of applying fast displacements while monitoring the interaction forces between the human finger and the robotic links. Moreover, due to the relatively small inertia of the fingers, it allows us to meet some stringent specifications, performing relatively large displacements (45°) before the stretch reflex intervenes (25 ms). The results of measurements on five subjects show that inertia, damping, and stiffness can be effectively identified and that the parameters obtained are comparable with values from previous studies.
手臂机械阻抗的调节是与外部环境相互作用的基本方面，其调节对于在操作过程中保持稳定性至关重要。尽管过去对人类手臂运动的研究表明，人类手指阻抗模型将有益于神经控制机制的研究和新型手部假肢的设计，但相对较少的研究关注手指和手部阻抗。本文涉及该研究主题的两个主要方面：首先，它介绍了一种可以在操作任务中有效测量手指阻抗的设备的机械改进；然后，它描述了一项旨在识别手指惯性以及手指肌肉的粘性和弹性特性的初步研究。所提出的可穿戴式外骨骼旨在在保持手掌自由的情况下测量手指姿势和阻抗调节，能够施加快速位移，同时监测人手与机器人连杆之间的相互作用力。此外，由于手指的惯性相对较小，它允许我们满足一些严格的规范，在伸展反射介入（约 25 毫秒）之前执行相对较大的位移（约 45°）。对五个受试者的测量结果表明，可以有效地识别惯性、阻尼和刚度，并且获得的参数与先前研究中的值具有可比性。
