Requirements of Dielectric Elastomer Actuator

The operational principle of the DE, elaborated in [Bar-Cohen (2004) Kim and Tadokoro (2007)], is briefly introduced in this section. When a voltage is supplied across a DE film coated with compliant electrodes on both sides, the film shrinks in thickness and expands in area accordingly, as is shown in Fig. 6.1. This is a field-induced deformation, and the electrostatic force as a result of the charges on the surface of the film, called the Maxwell stress, causes a contraction of the film along the thickness direction. Based on the simple electrostatic model, the effective pressure can be derived as follows [Pelrine et al. (1998)]  

DE actuators have broad applications in areas such as robots, mi-cro/milli devices as presented in [Bar-Cohen (2004) Carpi et al. (2007a) Kim and Tadokoro (2007)]. So far, many configurations of actuators have been proposed such as planar devices, tubes, rolls, folds, and stacks etc. Accordingly, a quick widening of the affordable range of robotic applications is expected to occur in the near future. However, the actuator performance 

The elastic energy density Us of the dielectric elastomer is calculated as follows [Pelrine et al. (2000)]  

Furthermore, the dissipation factor is one of the parameters used to clarify the performance of DE actuators. The dissipation factor can be calculated by the following formula [Bljdhe and Bloor (2005)]  

---