Response time and dynamic range for a dielectric elastomer actuator

Dielectric elastomer actuators have attractive applications in many promising fields, such as artificial muscles, soft robots, micro air vehicles, etc. Quasi-static and steady-state analysis has been intensively studied in most of the existing works. However, quantitative evaluation of the response time for dielectric elastomer actuators is still unknown. Especially, with the extension of traditional operation domain to a wide frequency range, lacking the knowledge about the response time of a dielectric elastomer actuator may hinder further development of this technology. In this work, we theoretically and experimentally investigate the transient behavior of a circular dielectric elastomer actuator undergoing in-plane deformation. The response time of the actuator under a step voltage is proposed, which demonstrates that small, light and hard actuator with less damping effect reacts faster, and the response time of the commonly used VHB dielectric elastomer actuator is in the order of hundred milliseconds. Based on the transient response under harmonic voltage load, the dynamic range of a dielectric elastomer actuator and its relation to the response time are analyzed. The measured dynamic range for a circular actuator fabricated by pre-stressed commercial VHB4905 shows good consistency with theoretical prediction and verifies the influence of response time on its dynamic range. The results obtained herein are useful for optimizing the configuration and selecting proper materials of the dielectric elastomer actuator with desired operating frequency range.