Deformation Mapping in Dielectric Elastomer Actuators using Electrical Impedance Tomography

Dielectric elastomer actuators commonly use flexible conductive electrodes to apply an electric potential for actuation. Depending on the material used, these electrodes often possess predictable piezo-resistive properties. Combining electrical impedance tomography (EIT) with a dielectric elastomer actuator (DEA) is investigated in this work to map compressive forces occurring throughout the electrode surfaces. This technology could allow for enhanced closed-loop control of electroactive actuators, extending their already extensive set of applications. This deformation mapping system also has the potential to be used with other piezoresistive materials, opening up more applications requiring a large hardness range and pressure sensitivity. With the material used in this work, the DEA-EIT device has an inherent trade-off between actuation and pressure mapping accuracy driven by the compliant electrode thickness of the DEA. The DEA-EIT device exhibited actuation strains of 2.5 % with a mean centre-of-mass error from a range of loads applied were 7.9 +/- 0.7 mm for 2 mm thick DEA electrodes. It is proposed that future work on custom hardware could be devised for the DEA-EIT system so the sensing and actuation can occur concurrently in real-time. Real-time control mean that applications requiring human-like manipulation can be designed, ranging from biomedical implant devices to agricultural processing equipment.