A Compact Robotic Wrist with Embedded Torque Sensing for Peg-in-Hole Tasks

Abstract

This paper presents the design and experimental validation of a torque-controlled robotic wrist for peg-in-hole tasks. The proposed wrist features a serial pitch-yaw joint configuration that enhances dexterity while maintaining compactness. The design integrates stepper motors, harmonic geartrains, and compliant mechanisms to optimize torque output and control accuracy. A compliant pulley and a compliant cap are introduced, enabling embedded torque sensing without the need for external sensors, thereby reducing system complexity and improving response time. Experimental results demonstrate the effectiveness of the wrist in torque accuracy and misalignment correction during peg-in-hole assembly, highlighting the benefits of the compliant-driven torque sensing approach. Compared to existing robotic wrists, the proposed design achieves a higher torque density. The findings contribute to advancing robotic wrist technology, particularly in applications requiring precise force modulation, high dexterity, and adaptable compliance.