Current minimally invasive surgical robots are lacking in force sensing that is robust to temperature and electromagnetic variation while being compatible with micro-sized instruments. This paper presents a multi-axis force sensing module that can be integrated with micro-sized surgical instruments such as biopsy forceps. The proposed miniature sensing module mainly consists of a flexure, a camera, and a target. The deformation of the flexure is obtained by the pose variation of the top-mounted target, which is estimated by the camera with a proposed pose estimation algorithm. Then, the external force is estimated using the flexure's displacement and stiffness matrix. Integrating the sensing module, we further develop a pair of haptics-enabled forceps and realize its multi-modal force sensing, including touching, grasping, and pulling when the forceps manipulate tissues. To minimize the unexpected sliding between the forceps' clips and the tissue, we design a micro-level actuator to drive the forceps and compensate for the motion introduced by the flexure's deformation. Finally, a series of experiments are conducted to verify the feasibility of the proposed sensing module and forceps, including an automatic robotic grasping procedure on ex-vivo tissues. The results indicate the sensing module can estimate external forces accurately, and the haptics-enabled forceps can potentially realize multi-modal force sensing for task-autonomous robotic surgery. A video demonstrating the experiments can be found at https://youtu.be/4UUTT_hiFcI.

翻译：当前微创手术机器人缺乏对温度和电磁变化鲁棒的力觉传感能力，且难以与微型器械兼容。本文提出一种可集成于活检钳等微型手术器械的多轴力觉传感模块。该微型传感模块主要由柔性机构、相机及靶标组成：通过顶部靶标的位姿变化获取柔性机构形变信息，并采用所提出的位姿估计算法由相机进行靶标位姿解算；进而基于柔性机构的位移与刚度矩阵实现外力估计。基于该传感模块，我们进一步开发了一对触觉感知力钳，并实现了包含接触、抓取及牵拉在内的多模态力觉感知功能。为最小化力钳夹爪与组织间的非预期滑动，我们设计了微米级驱动机构控制力钳运动，并对柔性机构形变导致的位移进行补偿。最后，通过系列实验验证了所提传感模块与力钳的可行性，包括离体组织上的自动化机器人抓取实验。结果表明，传感模块能精确估计外力，且该触觉感知力钳有望为任务自主的机器人手术实现多模态力觉感知。实验演示视频见https://youtu.be/4UUTT_hiFcI。