Robust Interaction Control of a Dielectric Elastomer Actuator With Variable Stiffness

This paper presents an interaction control algorithm for a dielectric\nelastomer membrane actuator. The proposed method permits efficient exploitation\nof the controllable stiffness of the material, allowing to use the membrane as\na "programmable spring" in applications such as robotic manipulation or haptic\ndevices. To achieve this goal, we propose a design algorithm based on robust\ncontrol theory and linear matrix inequalities. The resulting controller permits\nto arbitrarily shape the stiffness of the elastomer, while providing robust\nstability and performance with respect to model nonlinearities. A self-sensing\ndisplacement estimation algorithm allows implementation of the method without\nthe need of a deformation sensor, thus reducing cost and size of the system.\nThe approach is validated on an experimental prototype consisting of an\nelastomer membrane preloaded with a bistable biasing spring.\n