USTS: A High-Sensitivity and Stiff Torque Sensor for Advanced Robotic Joints

Robotic manipulators are pivotal in industries such as automotive, electronics, and shipbuilding, requiring advanced sensors to improve performance , precision, and safety. Among these, force and torque sensors are crucial for enabling robots to interact intelligently with dynamic environments. Traditional 6-axis force/torque sensors, while effective at the end-effector, have limitations in detecting forces at other parts of the manipulator, which can be crucial for safety in human-robot interaction. This study introduces the Ultra-Sensitive Torque Sensor (USTS), designed with a three-beam structure and four-bar linkage to enhance sensitivity while maintaining mechanical stiffness. The USTS design was optimized through Finite Element Analysis (FEA) and validated experimentally. Simulation results show a significant improvement in sensitivity and deflection, achieving a performance index 4.71 times higher than conventional sensors. Additionally, the USTS maintains a linearity error below 7.5%, offering precise and reliable torque measurements. The results indicate that the USTS is a promising solution for advanced robotic applications, particularly in collabora-tive environments where safety and accuracy are critical.