  Research on the co-optimization of soft robotic design and control requires
rapid means for real-world validation. Existing creation pipelines do not allow
for the swift prototyping of soft robots to quickly test various design
configurations and control policies. This work proposes a pipeline for rapid
iterative design and fabrication of a miniaturized modular
silicone-elastomer-based robotic fish. The modular design allows simple and
rapid iterations of robotic fishes with varying configurations to assist
current research efforts on the development of design optimization methods. The
proposed robotic fish can serve as a standardized test platform on which
performance metrics such as thrust and range of motion can be evaluated. We
further show the design of an underwater evaluation setup capable of measuring
input pressure, tail deformation, and thrust. Multiple robotic fish prototypes
with varying stiffness and internal pneumatic chamber configurations are
fabricated and experimentally evaluated. The presented flexible modular design
principle for the robot and its evaluation platform unlocks the possibilities
of more efficient soft robotic fish and will benefit research on design
optimization and underwater exploration in the future.
