Variable Stiffness Actuator article featured in Editor's Choice

© 2020 LIS / EPFL

© 2020 LIS / EPFL

Article on dielectric actuator with variable stiffness featured as Editor’s Choice in the journal Advanced Intelligent Systems. Editors' Choice articles are handpicked by the editorial team of Advanced Intelligent Systems to showcase the very best that the journal has to offer. Read it in open access at

Controlled stiffness is a solution to empower soft robots with the ability to apply large forces on their environments and sustain external loads without deformations. In this study, a compact, soft actuator composed of a shared electrode used for both electrostatic actuation and variable stiffness is described. The device operates as a dielectric elastomer actuator, while variable stiffness is provided by a shared electrode made of gallium. The fabricated actuator, namely variable stiffness dielectric elastomer actuator (VSDEA), has a compact and lightweight structure with a thickness of 930 μm and a mass of 0.7 g. It exhibits a stiffness change of 183×, a bending angle of 31°, and a blocked force of 0.65 mN. Thanks to the lightweight feature, the stiffness change per mass of the actuator (261× g−1) is 2.6 times higher than that of the other type of VSDEA that has no shared electrode.


Egor Piskarev, Jun Shintake, Vivek Ramachandran, Neil Baugh, Michael D. Dickey, Dario Floreano, Lighter and Stronger: Cofabricated Electrodes and Variable Stiffness Elements in Dielectric Actuators, Advanced Intelligent Systems, 2020,