Flatness-based Control for Dielectric Elastomer Transducers

This paper examines two essential aspects to achieve position controlled operation of dielectric elastomer transducers (DETs) via a still emerging and hardly tested approach using flatness-based control methods. Firstly, a model of the DET for the electrical and mechanical behavior is derived and the required parameters are determined experimentally. Secondly, the flatness-based controller is derived theoretically and then designed using the analytically found relations along with identified parameters. For experimental validation, the designed controller was compared with a PI-controller, optimized for a short settling time. As final outcome of this paper, the approach of flatness-based position control leads to significant improvements regarding the settling time of 7ms, compared to 25ms with the PI-controller. Furthermore, a desired trajectory with multiple properties can be specified, making the approach suitable for a wide range of applications and also ensures a safety operation by limiting the high voltage driving input and its slew rate. In addition, a stacked DET based on 320 layers, each with a film thickness of 20 mm, was used for the first time and the DET was driven by a new self developed linear HV amplifier.