Printed soft angular/torque sensors using carbon black-silicone composite

This paper aims to propose the need for soft and flexible sensors that actually measure the turning angle and torque of a joint. Conventional rigid angular/torque sensors have compatibility issues in wearable applications due to its bulkiness, non-compliance and high rigidity.

The sensing element of the sensor is based on carbon black (CB)/Ecoflex composite, deposited via extrusion printing technique. A simple finite element analysis was used to explain the non-linearity and non-symmetricity behaviours of the sensor.

This prototype can measure the angular rotation up to ±180° and a maximum torque value of 0.6 Nm. The geometry of the printed CB/Ecoflex composite as piezoresistive trace has a significant effect on the output (resistance change) response.

This research explored an extrusion printing techniques that allow customization to construct a soft piezoresistive strain sensor, which can be used as an angular/torque sensor.