Abstract In contrast to traditional designs that place actuators within the body, which makes replacement a demanding task, ZTUNA features a fully modular structure where each subsystem can be easily detached, reattached, and replaced for maintenance or reconfiguration. The fish consists of four independently designed modules: the head, middle, pectoral fins, and tail. These modules were developed with waterproofing and hydrodynamic behavior in mind. ZTUNA employs bio-inspired kinematics in the design of the pectoral fins and tail, enabling 3D maneuvers, and a buoyancy engine situated in its middle section to control depth. It operates in two swimming modes: a biomimetic swimming mode, which utilizes only the tail, and a faster pectoral-tail mode, achieving a maximum forward velocity of 14.6 cm/s and a vertical ascent rate of 6.31 cm/s. The motion analysis of the tail oscillations reveals a close similarity to that of real fish, demonstrating that the modularity of the design can be achieved without compromising its effectiveness.
Hamoud et al. (Tue,) studied this question.