Development of soft actuator: mechanism with vibration element using dielectric elastomer to generate large displacement

Abstract

An electric active polymer (EAP) using a dielectric elastomer is superior in the points of view of generated stress and strain, response velocity, and energy efficiency. On the other hand, it is well known that a high polymer material has creep properties. There is no research about creep of a dielectric elastomer actuator (DEA) as far as we know. It is necessary to get a clear grasp of the creep properties of a DEA in order to design a DEA. The purpose of our research was to investigate the creep characteristics and propose a mechanism of a DEA that can generate a large displacement without creep deformation. At first, a sample element of a DEA was made and tested. As a result, it was found that creep deformation was generated and accumulated by the repeated actions. Secondly, an element structure of a DEA was proposed. The element had two driven areas on opposite sides and these two areas are actuated alternately. Therefore, the proposed element worked as a vibration element. The repeated fatigue tests of the proposed vibration element gave proof of the effectiveness against creep deformation. At last, a unit mechanism of a DEA was proposed. The proposed unit mechanism was a combination of the vibration element and a ratchet mechanism. Through a performance test of the proposed experimental unit mechanism, it was confirmed that the mechanism was able to be driven and the transport velocity was changed by changing the drive frequency of the vibration element.