A Joint Torque Sensor for Robots

This paper describes the design of the elastic body of a new torque sensor to measure torsion moment faithfully in the presence of strong overhang and thrust forces as well as bending moments. This feature, in conjunction with high stiiness makes this sensor an ideal choice for robotic applications. The structure inherently exhibits minimum strain sensitivities and compliances to all non-torsional moments and forces such that their eeect can easily be cancelled in the Wheatstone bridge circuit. On the other hand, maximum possible local strain sensitivity near the material limit, and maximum torsional stiiness are achieved through the struc-ture's strain concentration characteristic. Several other important design criteria are also discussed, as well. The sensor geometry is analysed and further optimized using the nite element method. The sensor was constructed, and experimental data validated the nite element model and documented the sensor's performance.