Kulkarni Priya, Agrawal Sunil K
P. Kulkarni and S. K. Agrawal are with the Robotics and Rehabilitation Laboratory, Department of Mechanical Engineering, Columbia University, New York, NY 10027 USA.
S. K. Agrawal is with the Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, New York, NY 10032 USA.
IEEE ASME Trans Mechatron. 2024 Aug;29(4):3092-3099. doi: 10.1109/tmech.2024.3402614. Epub 2024 Jun 5.
Cervical traction is a common and effective treatment for degenerative disk diseases and pain in the cervical spine. However, the manual or mechanical methods of applying traction to the head-neck are limited due to variability in the applied forces and orientation of the head-neck relative to the shoulder during the procedure. Current robotic neck braces are not designed to provide independent rotation angles and independent vertical translation, or traction, to the brace end-effector connected to the head, making them unsuitable for traction application. This work proposes a novel architecture of a robotic neck brace, which can provide vertical traction to the head while keeping the head in a prescribed orientation, with flexion and lateral bending angles. In this paper, the kinematics of the end-effector attached to the head relative to a coordinate frame on the shoulders are described as well as the velocity kinematics and force control. The paper also describes benchtop experiments designed to validate the position control and the ability of the brace to provide a vertical traction force. It was shown that the maximum achievable end-effector orientations are 16° in flexion, 13.9° in extension, and ± 6.5° in lateral bending. The kinematic model of the active brace was validated using an independent motion capture system with a maximum root mean square error of 2.41°. In three different orientations of the end-effector, neutral, flexed, and laterally bent, the brace was able to provide a consistent upward traction force during intermittent force application. In these configurations, the force error has standard deviations of 0.55, 0.29, and 0.07N, respectively. This work validates the mechanism's ability to achieve a range of head orientations and provide consistent upward traction force in these orientations, making it a promising intervention tool in cases of cervical disk degeneration.
颈椎牵引是治疗椎间盘退变疾病和颈椎疼痛的一种常见且有效的方法。然而，对头颈部进行牵引的手动或机械方法存在局限性，因为在操作过程中，施加的力以及头颈部相对于肩部的方向存在变化。目前的机器人颈部支具并非设计用于为连接头部的支具末端执行器提供独立的旋转角度、独立的垂直平移或牵引，因此它们不适用于牵引应用。这项工作提出了一种新型的机器人颈部支具架构，该架构能够在保持头部处于规定方向（具有前屈和侧屈角度）的同时为头部提供垂直牵引。本文描述了连接到头部的末端执行器相对于肩部坐标系的运动学，以及速度运动学和力控制。本文还描述了旨在验证位置控制以及支具提供垂直牵引力能力的台式实验。结果表明，末端执行器可实现的最大前屈角度为16°，后伸角度为13.9°，侧屈角度为±6.5°。使用独立的运动捕捉系统对主动支具的运动学模型进行了验证，最大均方根误差为2.41°。在末端执行器的三种不同方向（中立、前屈和侧屈）下，支具在间歇性施加力的过程中能够提供一致的向上牵引力。在这些配置中，力误差的标准差分别为0.55N、0.29N和0.07N。这项工作验证了该机制能够实现一系列头部方向，并在这些方向上提供一致的向上牵引力，使其成为颈椎间盘退变病例中有前景的干预工具。
