On Designing Compliant Actuators Based On Dielectric Elastomers for Robotic Applications

Abstract

The study of compliant actuators based on Dielectric Elastomers has been presented in a general framework which takes into account the interaction between the EDF and the film supporting frame. The key motivation of this work is based on the observation that a DELA presents an available thrust profile which can be heavily improved in terms of stiffness characteristics. Therefore, an easy methodology is needed to tailor the actuator stiffness to the application requirements. In conclusion, the main contributions of this chapter can be summarized as it follows: · A novel concept for the design of compliant frames has been proposed. The concept makes use of the stiffness properties of the slider-crank compliant mechanism. If suitably coupled with EDF of different geometries, such mechanism permits to adjust the DELA available thrust profile at the will of the designer. · A novel design methodology has been presented which allows to tailor the stiffness of the actuator to the application requirements, defining its structural and geometrical properties. The procedure is composed of two main sub-procedures, one allowing the design of the EDF, the other one allowing the design of the compliant frame. In particular, the first part of the procedure can be employed to size EDF which are shaped as lozenges or rectangles for which analytical models are available. It is not applicable to general DE geometries (which require resorting to FEM analysis or experiments). The second part of the procedure is general and can be used to size the compliant frames even if a mathematical model of the EDF is not directly available. · Three case studies have been presented concerning rectangular shaped EDF, lozenge shaped EDF, and conically shaped EDF. The response of the rectangular-shaped and