Design and Optimization of a Joint Torque Sensor for Lightweight Robots

Force detection is an important indicator of a robot's interaction with the working environment. Therefore, accurate and sensitive torque sensor design and development are important. This study proposed a robot joint torque sensor design and optimization based on a strain gauge and through-hole spoke structure topology to detect the external force with high sensitivity and low noise. A through-hole spoke type with a novel inclination sensing surface (ISS) was proposed, and the optimization design improved the strain gauge placement position and focused stress arrangement. Three optimization objectives were desired to enhance the joint torque sensor sensitivity with guaranteed stiffness. A sensor signal processing circuit was also introduced to obtain low-noise output signal performance. The experimental results showed that the joint torque sensor had a high sensitivity of 1.65 mV/Nm before amplification. This sensor was compared with a previous study and a commercial torque sensor. The prototype torque sensor indicated high sensitivity and low error.