Annu Int Conf IEEE Eng Med Biol Soc. 2021 Nov;2021:6066-6069. doi: 10.1109/EMBC46164.2021.9629751.
Effective physical human-robot interaction (pHRI) depends on how humans can communicate their intentions for movement with others. While it is speculated that small interaction forces contain significant information to convey the specific movement intention of physical human-human interaction (pHHI), the underlying mechanism for humans to infer intention from such small forces is largely unknown. The hypothesis in this work is that the sensitivity to a small interaction force applied at the hand is affected by the movement of the arm that is affected by the arm stiffness. For this, a haptic robot was used to provide the endpoint interaction forces to the arm of seated human participants. They were asked to determine one of the four directions of the applied robot interaction force without visual feedback. Variations of levels of interaction force as well as arm muscle contraction were applied. The results imply that human's ability to identify and respond to the correct direction of small interaction forces was lower when the alignment of human arm movement with respect to the force direction was higher. In addition, the sensitivity to the direction of the small interaction force was high when the arm stiffness was low. It is also speculated that humans lower their arm stiffness to be more sensitive to smaller interaction forces. These results will help develop human-like pHRI systems for various applications.
有效的人机物理交互（pHRI）取决于人类如何与他人交流运动意图。虽然有人推测，小的交互力包含传达物理人机交互（pHHI）特定运动意图的重要信息，但人类从这种小力中推断意图的潜在机制在很大程度上是未知的。本工作的假设是，手所受的小交互力的敏感性受手臂运动的影响，而手臂运动又受手臂刚度的影响。为此，使用触觉机器人向坐姿人体参与者的手臂提供末端交互力。要求他们在没有视觉反馈的情况下确定机器人施加的交互力的四个方向之一。施加了不同水平的交互力和手臂肌肉收缩。结果表明，当人手臂运动相对于力方向的对齐程度较高时，识别和响应小交互力正确方向的能力较低。此外，当手臂刚度较低时，对小交互力方向的敏感性较高。有人推测，人类会降低手臂的刚度以提高对较小交互力的敏感性。这些结果将有助于为各种应用开发类人 pHRI 系统。
