Dielectric-elastomer-based capacitive force sensing with tunable and enhanced sensitivity

Designing capacitive force sensors with an enhanced and in situ tunable sensitivity is important in many fields such as robotic grippers but has been challenging. Existing capacitive force sensors mainly rely on ingenious but complex structural designs, posing tremendous difficulty in fabrication and usually featuring a fixed sensitivity. We present a facile design of capacitive tactile force sensor with an enhanced and tunable sensitivity using electro-mechanically responsive dielectric elastomer as the sensing medium. Dielectric elastomer exhibits tunable mechanical properties when subject to voltage and pre-stretch: increasing voltage and pre-stretch level leads to a more compliant response to the external pressure. Effectively, the sensitivity of the dielectric elastomer sensor can be continuously increased over one order of magnitude by properly exerting voltage and pre-stretch to the dielectric elastomer tactile sensor.