Many robotic surgical systems have been developed with micro-sized biopsy forceps for tissue manipulation. However, these systems often lack force sensing at the tool side. This paper presents a vision-based force sensing method for micro-sized biopsy forceps. A miniature sensing module adaptive to common biopsy forceps is proposed, consisting of a flexure, a camera, and a customised target. The deformation of the flexure is obtained by the camera estimating the pose variation of the top-mounted target. Then, the external force applied to the sensing module is calculated using the flexure's displacement and stiffness matrix. Integrating the sensing module into the biopsy forceps, in conjunction with a single-axial force sensor at the proximal end, we equip the forceps with haptic sensing capabilities. Mathematical equations are derived to estimate the multi-modal force sensing of the haptics-enabled forceps, including pushing/pulling forces (Mode-I) and grasping forces (Mode-II). A series of experiments on phantoms and ex vivo tissues are conducted to verify the feasibility of the proposed design and method. Results indicate that the haptics-enabled forceps can achieve multi-modal force estimation effectively and potentially realize autonomous robotic tissue grasping procedures with controlled forces.

翻译：诸多机器人手术系统已配备微型活检钳用于组织操控，然而这些系统在器械末端普遍缺乏力觉感知能力。本文提出一种基于视觉的微型活检钳力学传感方法，设计了一种适配常规活检钳的微型传感模块，该模块由柔性铰链、相机及定制化靶标构成。通过相机获取顶部靶标的位姿变化解算柔性铰链形变，进而利用柔性铰链位移与刚度矩阵计算作用于传感模块的外部载荷。将该传感模块集成至活检钳，并联合近端单轴力传感器，赋予活检钳触觉感知能力。通过推导数学模型，实现力触觉赋能活检钳的多模态力传感，涵盖推拉力（模态I）与夹持力（模态II）的同步解耦。基于组织仿体与离体组织的系列实验验证了所提设计与方法的可行性，结果表明该力触觉赋能活检钳可有效实现多模态力估计，并有望实现基于力控的自主化机器人组织抓取流程。