Resonance-Optimized Dielectric Pump Demonstrator With Self-Sensing Based Pressure Feedback

Abstract This paper introduces a method for obtaining pressure feedback in a resonance-optimized dielectric elastomer-based pump, employing a self-sensing approach. Despite their increasing relevance, achieving energy-efficient control and optimized operation within various load ranges remains a significant challenge for dielectric elastomer-based pumps. As a result, dielectric elastomer-based pumps, regardless of their advantages such as silent operation, light weight and cheap base materials, have not yet found use in many everyday applications. In this work, the first step is taken to solve this problem with the help of a self-sensing approach and thus lays the foundation for the design of an energy-efficient control of dielectric elastomer-based pumps. To develop, investigate and validate the self-sensing approach a demonstrator is designed, which operates in resonance under maximum load conditions, thereby ensuring consistent attainment of the target pressure and efficient pump performance in this exact operating point. For lower load pressures, the pump is not yet optimized as the resonance shifts under these conditions, due to a pressure-dependent stiffness change of the entire system. Depending on the target volume, this may result in a longer duration to reach the target pressure with simultaneous increased energy consumption. Solving this issue is the missing step in making dielectric elastomer-based pumps suitable for everyday use. For designing an optimized control strategy across the entire load progression, and the resulting varying system stiffness when building up the target pressure, it is essential to always know the exact pressure at the target volume, as the system stiffness is proportional to this pressure. Conventional pumps have the same issue, which is often solved with the help of external pressure sensors. The target of this work is to exploit the advantages of dielectric elastomers and use their self-sensing capability. With this self-sensing approach, the final goal is to develop an independent actuator system that can work smart, and energy optimized without external sensors. In this work, the pressure generated within the target volume can be determined utilizing electrical characteristics’ measurements on the demonstrator, which works under the previously described conditions. With a real-time current measurement during operation, the pressure can be determined using a microcontroller. This approach is validated by additionally equipping the demonstrator with an external pressure sensor and investigation of the two feedback signals of the pressure in the target volume. Even without a specific control strategy, this already enables the use of dielectric elastomer-based pumps in applications that require various specific target pressures, such as pneumatic actuators, vacuum pumps, massage pillows and many other pressure-controlled applications.