Undulatory Swimming vs Propeller Based


Bio-inspired underwater robots have several benefits compared to traditional underwater vehicles. Indeed, underwater robots using bio-inspired manners to generate thrust benefit from outstanding properties such as great agility and efficiency as opposed to propeller based thrust. Furthermore, it is generally agreed that bio-inspired swimming are more environmentally friendly towards marine ecosystem than propelled motors.

This semester project aims to characterize in terms of efficiency the underwater snake robot called Envirobot developed at the BioRobotics Laboratory of EPFL. Envirobot being a bio-inspired robot that generates thrust with undulatory swimming, the obtained efficiency will be compared to the one generated by a propelled motor.

First of all, a research of the state of the art through literature in the field of characterization of bio-inspired underwater robots was conducted. This allowed us to gain precise knowledge on type of measurements needed to characterize an underwater robot. An overview of static set-ups used to acquire measurement data for bio-inspired underwater robots was also carried on. A static set-up specially sized for Envirobot was then designed and manufactured.

Finally, multiple experiments were conducted to measure the thrust force, the velocity, the acoustic noise and the power consumption of Envirobot for different amplitudes, frequencies and amplitude low (percentage of the maximum amplitude on the first front module and which linearly increases on each modules to the tail) during eel-like swimming. The cost of transport and propulsive efficiency of the underwater snake robot was also computed. Thrust force and power consumption of Envirobot and the T200 propelled motor were compared together.

Static Set-up


Experimental Results

Blue Robotics – T200 Propelled Thruster

BioRob – Envirobot