Novel dielectric elastomer sensors for compression load detection

Beside their application in actuation and energy harvesting, dielectric elastomers (DE) have also strong capabilities for stretch-sensing based on capacitive measurements. However, for compression detection the simple state-of-the-art DE films are too insensitive. In order to close this gap, a novel class of DE sensors for compression measurements has been developed. The new sensor mats consist of two flexible elastomer profiles, between which an elastomer film is squeezed, converting the compression to a stretch load. With this mechanism, very high sensitivities of the capacitive measurement under compression load are achieved. Furthermore, various parameters which influence the characteristics of the sensor mat have been identified. Most relevant are the shape of the profiles, the number and design of the electrode layers as well as the hardness of the profiles and of the elastomer film. The high variability of the sensor mat design offers farreaching possibilities to tune the characteristics of the compressions sensor in terms of the dependence of capacitance on the load force. The basic principles of the design of the new compression sensor mats are outlined and various examples of such flexible sensors are introduced in this paper.