Evolutionary multiobjective design of a flexible caudal fin for robotic fish

Abstract

Robotic fish accomplish swimming by deforming their bodies or other fin-like appendages. As an emerging class of embedded computing system, robotic fish are anticipated to play an important role in environmental monitoring, inspection of underwater structures, tracking of hazardous wastes and oil spills, and the study of live fish behaviors. While integration of flexible materials (into the fins and/or body) holds the promise of improved swimming performance (in terms of both speed and maneuverability) for these robots, such components also introduce significant design challenges due to the complex material mechanics and hydrodynamic interactions. The problem is further exacerbated by the need for the robots to meet multiple objectives (e.g., both speed and energy efficiency). In this paper, we propose an evolutionary multiobjective optimization approach to the design and control of a robotic fish with a flexible caudal fin. Specifically, we use the NSGA-II algorithm to investigate morphological and control parameter values that optimize swimming speed and power usage. Several evolved fin designs are validated experimentally with a small robotic fish, where fins of different stiffness values and sizes are printed with a multi-material 3D printer. Experimental results confirm the effectiveness of the proposed design approach in balancing the two competing objectives.

Contest-Driven Soft-Robotics Boost: The RoboSoft Grand Challenge

“…This discipline is steeply growing, and from the seminal review paper of Trivedi et al (2008) the field was subject to several evolutions; to date, the most recent review paper on soft robotics (Rus and Tolley, 2015) identifies four possible application domains for soft robots: locomotion, manipulation, wearable, and soft cyborgs. This review agrees with our survey on the most relevant domains influenced by soft robotic, which identified three niches: (1) the terrestrial locomotion, where a great number of bio-inspired (Belanger et al, 2000;Mezoff et al, 2004;Lin et al, 2013;Umedachi et al, 2016) (inspired by worms, caterpillars, and their gaits) (Jayaram and Full, 2016) (insects) (Chrispell et al, 2013;Cicconofri and DeSimone, 2015) (snakes) or build from scratch robots (Kim et al, 2014;Li et al, 2016) are under development; (2) the underwater locomotion (Fiazza et al, 2010), mainly inspired by fishes (Clark et al, 2015), turtles (Song et al, 2016), crabs (Calisti et al, 2016), chephalopods (Arienti et al, 2013;Cianchetti et al, 2015), rays (Urai et al, 2015), or other aquatic animals; and (3) manipulation, either at the level of grippers (Manti et al, 2015;Fakhari et al, 2016;Shintake et al, 2016), arms Elango and Faudzi, 2015;Katzschmann et al, 2015;Deashapriya et al, 2016;Sun et al, 2016), or other devices (Deng et al, 2016).…”

High-performance electrified hydrogel actuators based on wrinkled nanomembrane electrodes for untethered insect-scale soft aquabots

“…This PDF file includes: Figs. S1 to S29 Tables S1 and S2 References (69)(70)(71)(72)(73)(74)(75)(76)(77)(78)(79)(80)(81)(82)(83) Other Supplementary Material for this manuscript includes the following: Movies S1 to S5…”

Design, modeling, and experimental validation of a concave‐shape pectoral fin of labriform‐mode swimming robot

“…The robot kinematics are given as in References and where ρ is the water density and Ψ is the angle between the x ‐axis of global coordinate and the x ‐axis of body coordinate. C D and C L are the drag and lift coefficients, respectively, while S denotes the projected surface area to the water such that where S outer and S inner are the surface areas of outer and inner radii, respectively, while r outer and r inner are the fin outer radius and fin inner radius, respectively.…”

“…The researchers in Reference proposed an evolutionary multiobjective optimization (EMO) approach to the design and control of flexible fins for robotic fish, in which they investigated fins of different stiffness values and sizes. In Reference , the authors mentioned the unmanned underwater vehicles (UUVs) by studying the hydrodynamics of UUVs, especially drag force since it is required to determine the total thrust.…”