Design and Optimization of a Joint Torque Sensor for Robot Collision Detection

It is important to maintain safety and reliability during human-robot cooperations with a service robot. Collision should be monitored and detected in real time to avoid possible damages. In this paper, we propose the design and optimization of a novel strain-gauge-type joint torque sensor for robot collision detection. It features a thin structure, quick response, and high sensitivity. A holed spoke structure is proposed to transfer maximum stress position and improve stress distribution. To achieve the best sensitivity and stress evenness of the sensor, a mathematical optimization with two objective functions is formulated to topologically optimize the flexure spoke structure. Optimal structure parameters are thus obtained. Sensor signal processing is proposed based on the Wheatstone full bridge. Its corresponding hardware is designed and implemented to be integrated into the sensor. Calibration and evaluation are carried out to validate the sensor performance.