Conformal direct-print of piezoresistive polymer/nanocomposites for compliant multi-layer tactile sensors

A conformal, compliant and multi-layer tactile sensor was built layer by layer using a hybrid manufacturing process including conformal Direct-Print (DP) technology and layer by layer soft molding process with a developed piezoresistive polymer/nanocomposite. A multi-layer conformal skin structure of the sensor was created using the soft molding process along with a highly flexible rubber material. Two layers of sensing elements were designed, where the sensing elements in the lower sensing layer were orthogonally placed against those in the upper sensing layer so that the sensing elements in two layers could cross each other with an insulating layer between them. A conformal printing algorithm was developed to advance the capability of DP technology. Thus, all the sensing elements were printed uniformly within the conformal skin structure. Several experiments on position detection were performed to evaluate the performance of the fabricated conformal sensor. The results showed that the sensor can detect locations of external forces applied on the sensor surface due to the multiple layers of sensing elements. It is concluded that the suggested manufacturing methods and developed materials are promising tools to develop conformal, compliant tactile sensors.