Design and control of multi-branch and multi-segment-based dielectric elastomer actuator and biomimetic applications

Dielectric elastomer actuators (DEAs) based on the dielectric elastomer minimum energy structure (DEMES) exhibit excellent dynamic shape deformation and fast response characteristics, making them widely applicable in flexible actuators, smart grippers, and biomimetic devices. While existing studies have explored the fundamental mechanisms of DEMES, most focus on simple structural types or single application scenarios. However, a systematic approach for designing, modeling, and computing versatile, complex DEAs remains underexplored. In this work, the nonlinear motion equations for an electroelastic cantilever plate are derived based on Hamilton's principle to capture the nonlinear behavior of DEAs. Multi-structured single-segment DEAs are designed to investigate the influence of the driven shape and geometric configuration of the frame on actuator performance. Additionally, complex deformations and grasping strategies for four-branch single-segment and six-segment DEAs are analyzed in detail, considering the actuation of individual branches and parts of each segment. An octopus-inspired variable-stiffness DEA is designed to grasp polygonal objects of varying sizes and shapes using diverse voltage control strategies. Different hand gestures are mimicked by independently controlling each segment and finger of a human hand-based DEA. The accuracy of the three-segment and six-segment DEMES is validated by comparison with rotary joint experiments and a microsatellite gripper, respectively. Additionally, a duty cycle voltage strategy that enables the variation of the flapping angle of a rotary joint to closely match real flight conditions is proposed. The results confirm the independence and controllability of multi-branch and multi-segment DEAs in complex tasks. This research offers new insights and methodologies to advance the field of flexible actuators, highlighting the vast application potential of DEAs in multi-task and multi-objective operations.