Modeling of Two-Dimensionally Maneuverable Jellyfish-Inspired Robot Enabled by Multiple Soft Actuators

Soft actuators, such as dielectric elastomer (DE) and ionic polymer metal composite (IPMC), can generate large deformation under electric stimuli, which makes them promising in biomimetic robotic jellyfish applications. Although dielectric elastomers and ionic polymer metal composites (IPMCs) have been used in jellyfish-inspired robots, respectively, there is no research that combines both of them to develop a jellyfish robot capable of two-dimensionally (2-D) maneuvering capability. In our previous work, a jellyfish robot fabricated with DE can achieve effective locomotion. However, the robot requires a big bell to provide propulsion and can only move vertically. The jellyfish-inspired robot developed in this article exhibits contracting muscle-like behavior using a DE membrane to generate a periodic contraction on its eight fins to provide a thrust force, which propels the robot to transit through underwater. The robot utilizes an IPMC to generate a bending moment, which directs the heading angle of its swimming. This article presents the design, modeling, and experimental characterization of the 2-D maneuverable jellyfish robot. The preliminary results show that the jellyfish-inspired robot can swim underwater effectively in the vertical direction with different sinusoidal input signals, the direction of the robot can be changed by bending the IPMC. The average speed of the robot is about 4.8 mm/s when a sinusoidal signal with 5 kV amplitude and 1.4 Hz frequency is applied to the DE actuator. The maximum average heading angle change can reach to 3.02
$^{\circ }$
by actuating IPMC without voltage applied to DE.