An Integrated Audio-Tactile Interface Based on Dielectric Elastomer Actuators for User Interaction

Due to their high actuation energy density, high stretchability and self-sensing capability, dielectric elastomer actuators (DEAs) and sensors are very attractive for the field of user interaction and communication. The possibility of using the same element to perform actuation (feedback) and sensing (user input detection), in particular, opens up possibilities towards highly integrated interaction elements. Here, we present an integrated prototype of a DEA user interface that can produce different feedbacks (acoustic, vibrotactile) in response to a user’s touch. Touch detection is achieved by means of capacitive sensing, whereas multi-sensory actuation (tactile and acoustic feedbacks) is produced leveraging on the dynamic modal response of the DEA membrane, whose different vibration modes are used to produce linear actuation (used to convey vibrotactile stimulations) at low frequencies, and structural vibrations (for generating sound) at higher frequencies. The prototype includes an acoustic enclosure, compact sensing/control electronics, and a custom-built low-cost compact high voltage (HV) power amplifier. We characterize the coupled system response (DEA + custom amplifier) in terms of linear actuation (in the range 0–180 Hz) and sound pressure output (in the range 500–2500 Hz) and compare results with those obtained with a commercially available HV bench power supply. The performance of the proposed system is comparable to that obtained with commercial electronics in terms of linear displacements and sound pressure level, while it introduces higher harmonic distortions in specific ranges of the acoustic response. The concept and results presented here represent a step forward towards further integration and down-scaling of DEA user interfaces.