Development of an Oblique Cone Dielectric Elastomer Actuator Module-Connected Vertebrate Fish Robot.

As a soft actuator for fish robots, an oblique cone dielectric elastomer actuator (DEA) module inspired by the structure of white muscles in fish was proposed in the authors' previous study. However, a mathematical model of an oblique cone DEA was not established, and designing a drive module that took into account its driving characteristics and passivity for integration into a fish robot remained a challenge. The purpose of this paper is to develop a vertebrate fish robot using multiple oblique cone DEA modules to achieve fish-like bending capability. First, an oblique cone DEA module was modeled for the design of a fish robot. The relationships among bending angle, blocking torque, driving voltage, and design parameters were established and confirmed by comparing the calculated and experimental results. Based on the modeling results, we designed an oblique cone DEA module-connected vertebrate fish robot. Finally, the experimental results of the fabricated fish robot demonstrated that the model-based design enabled flexible body swinging and swimming through a multiple-module-connected vertebrate structure.