Enhanced flexible vibrotactile actuator based on dielectric elastomer with propylene carbonate

This paper proposes a flexible vibrotactile actuator based on a dielectric elastomer which is fabricated by mixing a PDMS-Ecoflex elastomer and PC (propylene carbonate) solution. The proposed flexible vibrotactile actuator is composed of a top electrode, an adhesive tape, the PDMS-Ecoflex-PC-based elastomer, and a bottom electrode. The applied electric field between two parallel electrodes (top and bottom electrodes) creates an electrostatic force in the actuator, resulting in the actuator being compressed. The performance of the vibrotactile actuator based on dielectric elastomers is affected by the mechanical and dielectric properties of the dielectric elastomer. So, in this paper, we experimentally optimize the design of the haptic actuator and then quantitatively evaluate the actuator. For evaluation, the six samples of PDMS-Ecoflex-PC elastomers having different mixing ratios are prepared and their material properties are investigated by experiments. We fabricate the haptic actuators based on PDMS-Ecoflex-PC elastomers and then measure the haptic behaviors of the proposed actuator as a function of the applied voltage amplitude and frequency. Furthermore, we inquire the response time of the proposed actuator. Maximum vibrational force of the optimized sample is about 0.556 N at 140 Hz which is strong enough to stimulate human finger, and the response time is 21 ms which is fast enough to obtain the touch feedback in real time. From the results, we show that the proposed vibrotactile actuator creates a variety of haptic sensations in real time.