A submillimetric 3-DOF force sensing instrument with integrated fiber Bragg grating for retinal microsurgery.
A submillimetric 3-DOF force sensing instrument with integrated fiber Bragg grating for retinal microsurgery.
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DOI：
10.1109/tbme.2013.2283501
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发表时间：
2014-02
期刊：
影响因子：
--
通讯作者：
Iordachita I
中科院分区：
文献类型：
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作者：
He X;Handa J;Gehlbach P;Taylor R;Iordachita I
玻璃体视网膜手术需要非常精细的运动控制，以对眼睛内部脆弱的组织进行精确的操作。除了生理性手部颤抖、疲劳、动觉反馈差和患者运动之外，力感应的缺失也是主要的技术挑战之一。之前的二自由度 (DOF) 力传感仪器已展现出强大的力测量性能。主要的设计挑战是采用高灵敏度轴向力传感。本文报道了基于光纤布拉格光栅（FBG）传感器的亚毫米三自由度力传感拾取仪器的开发。四个 FBG 传感器的配置旨在最大化轴向力和横向力传感之间的解耦。超弹性镍钛诺挠曲件旨在实现高轴向力灵敏度。开发了用于重复性测试、校准和验证的自动校准系统。实验结果表明 FBG 传感器的重复精度为 1.3 pm。用于计算横向力的线性模型提供了准确的全局估计。虽然轴向力的线性模型仅在顶角为 30° 的圆锥区域内局部准确，但二阶多项式模型可以为轴向力提供有用的全局估计。结合横向力的线性模型和轴向力的非线性模型，三自由度力传感仪器可以提供亚毫牛顿的轴向力分辨率和四分之一毫牛顿的横向力分辨率。随机样本验证表明力传感器可以提供一致且准确的三维力测量。
Vitreoretinal surgery requires very fine motor control to perform precise manipulation of the delicate tissue in the interior of the eye. Besides physiological hand tremor, fatigue, poor kinesthetic feedback, and patient movement, the absence of force sensing is one of the main technical challenges. Previous two degrees of freedom (DOF) force sensing instruments have demonstrated robust force measuring performance. The main design challenge is to incorporate high sensitivity axial force sensing. This paper reports the development of a sub-millimetric 3-DOF force sensing pick instrument based on fiber Bragg grating (FBG) sensors. The configuration of the four FBG sensors is arranged to maximize the decoupling between axial and transverse force sensing. A super-elastic nitinol flexure is designed to achieve high axial force sensitivity. An automated calibration system was developed for repeatability testing, calibration, and validation. Experimental results demonstrate a FBG sensor repeatability of 1.3 pm. The linear model for calculating the transverse forces provides an accurate global estimate. While the linear model for axial force is only locally accurate within a conical region with a 30° vertex angle, a second-order polynomial model can provide a useful global estimate for axial force. Combining the linear model for transverse forces and nonlinear model for axial force, the 3-DOF force sensing instrument can provide sub-millinewton resolution for axial force and a quarter millinewton for transverse forces. Validation with random samples show the force sensor can provide consistent and accurate measurement of three dimensional forces.