Design of Strain Gauge Torque Sensor Used in the Modular Joint of Collaborative Robot

Abstract

With the characteristics of simple structure, good fabrication performance and stability, the disc strain gauge torque sensor is widely equipped in the collaborative robot to measure the modular joint output torque. The sensitivity and the stiffness are two important parameters of the torque sensor which influence robot torque control. However, the stiffness is paid less attention than the sensitivity during the robot design process. What is worse, some sensor design process improving the sensitivity weaken the stiffness unconsciously. In order to consider the sensitivity and the stiffness of the torque sensor during the design process simultaneously, the conflicting relationship between sensor sensitivity and the sensor stiffness about the measurement area thickness is established. With the guidance of the relationship the measurement area thickness is determined not only ensuring the sensitivity meet the safety demand but also improving the torque sensor has a higher stiffness. After designed a torque sensor model is made to detect the parameters. The experiment shows that the sensor has a good accuracy and the sensitivity is in accordance with the design.