Performance Investigation on a Vibro-impact Capsule Robot Driven by a Multi-layer Dielectric Elastomer Actuator*

Vibro-impact capsule robots driven by dielectric elastomer actuators (DEAs) feature a simple structure and controllable bidirectional crawling capability. Despite the well-proven effectiveness of the multi-layer stacking technique in improving the output performance of the DEAs, whether this technique can also enhance the locomotion performance of the DEA-driven vibro-impact capsule robot remains unclear. In this work, a nonlinear dynamic model of the multi-layer-DEA-driven capsule robots is first developed. Together with experiments, this paper investigates the effects of DE layer number on the maximum velocities of the capsule robot. The study results show that increasing the number of layers in the DEA does not necessarily improve the maximum locomotion velocity of the capsule robot. In contrast, the maximum achievable velocity begins to reduce as the number of layers increases from two to three. This is mainly due to the different scaling effects of the impact force and the rebound force exerted by the DEA against the number of layers. The finding reported in this paper raises the necessity for developing novel solutions for enhancing the locomotion performance of the DEA-driven vibro-impact crawling capsule robot in the future.