Tendon-driven under-actuated robotic fingers provide advantages for dexterous manipulation through reduced actuator requirements and simplified mechanical design. However, achieving both high load capacity and adaptive compliance in a compact form remains challenging. This paper presents an under-actuated tendon-driven robotic finger (UTRF) featuring a synchronous tendon routing that mechanically couples all joints with fixed angular velocity ratios, enabling the entire finger to be actuated by a single actuator. This approach significantly reduces the number of actuators required in multi-finger hands, resulting in a lighter and more compact structure without sacrificing stiffness or compliance. The kinematic and static models of the finger are derived, incorporating tendon elasticity to predict structural stiffness. A single-finger prototype was fabricated and tested under static loading, showing an average deflection prediction error of 1.0 mm (0.322% of total finger length) and a measured stiffness of 1.2x10^3 N/m under a 3 kg tip load. Integration into a five-finger robotic hand (UTRF-RoboHand) demonstrates effective object manipulation across diverse scenarios, confirming that the proposed routing achieves predictable stiffness and reliable grasping performance with a minimal actuator count.

翻译：腱绳驱动的欠驱动机器人手指通过减少执行器数量和简化机械设计，为灵巧操作提供了优势。然而，在紧凑的形态下同时实现高负载能力和自适应柔顺性仍然具有挑战性。本文提出了一种采用同步腱绳布线的欠驱动腱绳驱动机器人手指（UTRF），该设计通过固定角速度比机械耦合所有关节，使得整个手指可由单个执行器驱动。该方法显著减少了多指手所需的执行器数量，在保持刚度或柔顺性的同时实现了更轻量、更紧凑的结构。推导了手指的运动学和静力学模型，并纳入腱绳弹性以预测结构刚度。制作了单指原型并在静态负载下进行了测试，结果显示平均挠度预测误差为1.0毫米（占手指总长度的0.322%），在3千克指尖负载下测得刚度为1.2×10^3 N/m。将其集成到五指机器人手（UTRF-RoboHand）中，展示了在不同场景下有效的物体操作能力，证实了所提出的布线方法以最少的执行器数量实现了可预测的刚度和可靠的抓取性能。