Modeling approaches for electroactive polymers

Abstract

The focus of this paper is on the modeling of dielectric elastomer actuators and generators. One of the effects that is rarely considered in modeling of these systems is the influence of the materials' specific resistance on the performance. The non-ideal electrical properties of both elastomer and electrode material will cause undesired parasitic effects. Although for most laboratory scale prototypes these effects are hardly recognizable, they may however play an important role for larger structures and especially for dynamic applications. Therefore, an analytical model is developed and presented in this paper which can give helpful instructions for the design and fabrication process of EAP-systems. It is proven to be valid by means of the finite element method and subsequently extended for more complex systems.

Where the rubber meets the hand: Unlocking the sensing potential of dielectric elastomers

“…In other words, the capacitor behaves like a composition of smaller capacitors in parallel. Due to the high resistance of typical DE electrodes (up to 100 s of kΩs), they have shown to behave like an electrical transmission line . At this granular level, they are represented by chains of smaller capacitors and resistors in a ladder network (Fig.…”

Stretch not flex: programmable rubber keyboard

“…Rather than using n sensors to distinguish n positions, we demonstrate how to segregate and localize the internal capacitance change in two dimensions without adding any additional wires or hardware (figure 2). The method is based a distributed transmission line model [13,[24][25][26][27] which separates the DE into smaller constituent sections that can be sensed independently.…”

Achieving Super Sensitivity in Capacitive Strain Sensing by Electrode Fragmentation

“…A dielectric capacitor (DEC) is a deformable and flexible thin film usually comprising an elastomer sandwiched between compliant electrodes . Accordingly, many studies have been conducted to explain the propagation behavior of an electrical signal in a typical DEC with a high electrode resistance. − They deduced that at radio frequency (RF) and for high-resistance electrodes, the electrical model of a dielectric capacitor can be considered as a transmission line model. Graf and Maas discussed the implications of electrode resistance and contact placement on the DE capacitor performance.…”

“…A capacitor-based DE between two resistive electrodes can be represented as distributed R–C chains at high frequencies . Such distributed transmission line models have been applied to DE actuators by discretizing actuators or sensors into R–C elements. ,, Xu et al , utilized the transmission line model for sensing local pressure on a single DE sensor by observing the capacitance variation and simultaneously applying sinusoidal excitation signals with different frequencies.…”