Simplified propulsive model for biomimetic robot fish and its experimental validation

As a combination of bio-mechanism and engineering technology, robot fish has become a multidisciplinary research that mainly involves both hydrodynamics-based control and actuation technology. This paper presents a simplified propulsive model for carangiform propulsion, which is a swimming mode suitable for high speed and high efficiency. The carangiform motion is modeled as an N-joint oscillating mechanism that is composed of two basic components: the streamlined fish body represented by a planar spline curve and its lunate caudal tail by an oscillating foil. The speed of fish's straight swimming is adjusted by modulating the joint's oscillating frequency, and its orientation is tuned by different joint's deflection. The results from actual experiment showed that the proposed simplified propulsive model could be a viable candidate for application in aquatic swimming vehicles.