This paper introduces a novel shape-sensing approach for Concentric Tube Steerable Drilling Robots (CT-SDRs) based on Optical Frequency Domain Reflectometry (OFDR). Unlike traditional FBG-based methods, OFDR enables continuous strain measurement along the entire fiber length with enhanced spatial resolution. In the proposed method, a Shape Sensing Assembly (SSA) is first fabricated by integrating a single OFDR fiber with a flat NiTi wire. The calibrated SSA is then routed through and housed within the internal channel of a flexible drilling instrument, which is guided by the pre-shaped NiTi tube of the CT-SDR. In this configuration, the drilling instrument serves as a protective sheath for the SSA during drilling, eliminating the need for integration or adhesion to the instrument surface that is typical of conventional optical sensor approaches. The performance of the proposed SSA, integrated within the cannulated CT-SDR, was thoroughly evaluated under free-bending conditions and during drilling along multiple J-shaped trajectories in synthetic Sawbones phantoms. Results demonstrate accurate and reliable shape-sensing capability, confirming the feasibility and robustness of this integration strategy.

翻译：本文提出了一种基于光学频域反射（OFDR）的同轴管可转向钻探机器人（CT-SDR）形状传感新方法。与传统基于光纤布拉格光栅（FBG）的方法不同，OFDR可沿整个光纤长度实现连续应变测量，且具有更高空间分辨率。在所提方法中，首先通过将单根OFDR光纤与扁平镍钛诺丝集成，制作形状传感组件（SSA）。随后将校准后的SSA穿过并容纳于柔性钻探仪器的内部通道中，该仪器由CT-SDR的预成型镍钛诺管引导。在此配置下，钻探仪器在钻进过程中充当SSA的保护套，无需像传统光学传感器方法那样集成或粘附于仪器表面。本文在自由弯曲条件下，以及在合成Sawbones体模中沿多条J形轨迹钻进过程中，对集成于空心CT-SDR中的所提SSA性能进行了全面评估。结果展示了准确可靠的形状传感能力，证实了该集成策略的可行性与鲁棒性。