Wearable Haptic Array of Flexible Electrostatic Transducers

We demonstrate a wearable flexible electrostatic transducer (FET) matrix that conforms to the skin and can be used to generate complex haptic signals. The transducers consist of a pair of flexible electrodes that are attracted based on electrostatic force. We designed and built a 2 by 2 matrix of transducers from a pair of flexible films, with the design optimized for indentation into the skin. A transducer with a 10 mm by 10 mm footprint and a height of 2 mm effectively generated perceptible stimulus on the skin when operated at 150 V–250 V. Three psychophysical experiments were carried out to evaluate the properties of the new device as a wearable haptic display. Experiment 1 showed that the matrix of transducers was able to linearly boost perceived intensity when compared to a single transducer. Experiment 2 indicated that it was possible to indistinguishably replicate multi-frequency signals delivered to one transducer using multiple transducers that each operated at one of the frequencies. In Experiment 3, four movement-based stimulation patterns were designed using tactile illusion, and the identification rates were significantly above chance level. Our findings demonstrate that the compact, flexible, and scalable transducer array is well suited as a new type of actuator for wearable haptics research and applications.