Development of a Torque Sensor for Robot Actuators With Overload Protection

This study proposes the development of a one-axis torque sensor that can be integrated into robotic joint actuators, featuring an innovative structural design with enhanced overload protection. The developed torque sensor employs a strain gauge-based measurement principle and adopts a binocular structure to induce stress concentration, thereby improving signal sensitivity. In particular, a dedicated stopper mechanism is incorporated into the design to limit deformation and prevent irreversible damage under excessive torque loads. This mechanism plays a critical role in preventing plastic deformation, thereby ensuring long-term structural stability and extending the operational lifespan of the sensor. Finite Element Analysis (FEA) was conducted to simulate the deformation and stress distribution of the torque sensor, leading to the optimization of key design parameters. Based on the simulation results, a physical prototype was fabricated, and experimental validation was performed to evaluate the sensor’s performance. The experimental results showed strong agreement with the FEA outcomes, confirming the validity of the proposed design and demonstrating the effectiveness of the overload protection feature implemented in the sensor. Furthermore, the sensor maintains a compact form factor compatible with CPDS-type high-reduction actuators, while offering enhanced reliability and robustness against unexpected mechanical stress. The findings of this study contribute to the development of high-performance torque sensors suitable for applications in robotics, industrial automation, and precision control systems, and highlight the feasibility of sensor designs with built-in mechanical safety features.