I. Introduction
Ionic polymer–metal composites (IPMCs) are innovative materials that can be exploited for emerging robotic, intelligent mechatronic, bioinpsired, and biomedical systems [1]–[5]. Due to their low driving voltage (<5 V), large strain, soft and flexible structure, and the ability to operate in an aqueous environment (such as water), IPMCs are suitable for many unique applications that include innovative propulsion systems in underwater autonomous systems [6]–[9]. Particularly, strips of IPMCs have been used to construct the legs (tentacles) of a jellyfish-like robot [10]. The walking speed of the jellyfish robot was controlled through the frequency of the input voltage applied to the IPMC-based legs. Likewise, the caudal fin to propel a robotic fish was created from an IPMC with an achievable peak swimming speed reported at 22 mm/s [11]. However, IPMC actuators can play a critical role in the development of highly-maneuverable biorobotic vehicles, e.g., the system described in [12].