Boxfish with multiple fins can maneuver in confined spaces with a near zero turning radius, and it has been found that its unusual boxy shape is responsible for a self-correcting mechanism that makes its trajectories immune to water disturbances. The microautonomous robotic ostraciiform aims to apply these features in a novel underwater vehicle design. Miniature underwater vehicles with these characteristics have a variety of applications, such as environmental monitoring, ship wreck exploration, inline pipe inspection, forming sensor networks, etc. This paper presents the research leading to the design and fabrication of a robotic ostraciiform. Tail fin hydrodynamics have been investigated experimentally using robotic flapper mechanisms to arrive at a caudal fin shape with optimal-shape-induced flexibility. Fluid simulation studies were utilized to arrive at the body shape that can result in a self-correcting vorticity generation. Finally, the robotic ostraciiform prototype was designed based on the previous results. The ostracifform locomotion is implemented with a pair of 2 DOF pectoral fins and a single DOF tail fin. The finalized body shape of the robot is produced by 3-D prototyping two separate halves.

This paper presents the design and fabrication of a robotic ostraciiform. The robot's design is inspired by the highly stable and fairly maneuverable boxfish. Boxfish with its multiple fins can maneuver in confined spaces with a near zero turning radius and it has been found that its unusual boxy shape is responsible for a self correcting mechanism that makes its trajectories immune to water disturbances. The Micro Autonomous Robotic Ostraciiform (MARCO) project aims to apply these features in a novel underwater vehicle design. Miniature underwater vehicles with these characteristics have a variety of applications, such as environmental monitoring, ship wreck exploration, inline pipe inspection, forming sensor networks, etc. Tail fin hydrodynamics have been investigated experimentally using robotic flapper mechanisms to arrive at a caudal fin shape with optimal shape induced flexibility. Fluid simulation studies were utilized to arrive at the body shape that can result in self correcting vorticity generation. The robotic ostraciiform prototype was designed based on the above results. Ostraciiform locomotion is implemented with a pair of 2-DOF pectoral fins and a single DOF tail fin. The finalized body shape of the robot is produced by 3D prototyping two separate halves.

Ostraciiform fish such as the boxfish are known for their ability to swim smoothly through turbulent waters of coral reefs and their excellent maneuverability. These characteristics are desirable in an micro underwater vehicle. Biologists have recently found that the boxfish's body shape generates self-correcting trimming forces by shedding counter rotating vortices to compensate for the instabilities in turbulent water. The purpose of this work is to study the effect of body shape on self-correcting vortex generation and use these results to design the outer body shape of a micro underwater vehicle mimicking a real boxfish. To this end, computer aided design and Engineering (CAD/CAE) tools such as solid modeling software and fluid flow simulation software were used for analysis and comparison of different body shapes. In this paper we present the numerical simulation results for two varieties of boxfish, namely the spotted boxfish the Buffalo trunkfish, and the results were used to derive key design guidelines for a suitable body shape that can exhibit the desired self-correcting mechanism. Based on the results an outer shape has been rapid prototyped in two halves that can be mounted on either side of the robot chassis

This paper presents the experimental studies and force measurements on the tail fin of a ostraciiform micro underwater vehicle mimicking a boxfish. Boxfish are known for their ability to swim smoothly through turbulent waters and exhibit excellent maneuverability, characteristics desirable in an micro under water vehicle. In this work an experimental setup consisting of a 3DOF robotic flapper and a beam deflection based force sensor is built to study the hydrodynamics of tail fin and pectoral fin and arrive at the optimal parameters of fin morphology and kinematics, such as fin shape, stiffness, and frequency. Results on optimal tail fin shape are reported