Nature in engineering for monitoring the oceans: comparison of the energetic costs of marine animals and AUVs

Abstract

The range of physiological adaptations possessed by marine animals allowing them to successfully operate in the marine environment is a plentiful source of inspiration for the designers of Autonomous Underwater Vehicles. This chapter compares the total energetic cost of straight line swimming for both marine animals and AUVs, using cost of transport (COT) as a comparative metric. COT is a normalised measure of the energetic cost of transporting the animal's or vehicle's mass over a unit distance. It includes non propulsion power requirements as well as considering the energy lost by actuators and mechanical couplings and energy lost in the wake. Comparisons presented in this chapter show that marine animals typically have higher optimum COT than engineered systems of equivalent size. However parallels may be drawn, for example, to increase range both marine animals and AUVs appear to favour reducing non-propulsion power costs and travelling slowly to ensure operating at the minimum COT.

Model predictive control of a hybrid autonomous underwater vehicle with experimental verification

“…Therefore to achieve equivalent performance using Python compared to C++ requires a more powerful computer that will, in general, use more electrical power. The hotel load of Delphin2 at 50W is high for a vehicle of it's size [20]. As this vehicle is designed as a research platform, electrical power consumption is not of primary concern and instead the rate of software development takes precedent.…”

Nature in Engineering for Monitoring the Oceans (NEMO): An isopycnal soft bodied approach for deep diving autonomous underwater vehicles

“…Consequently, significant research effort has been applied to mimicking biological propulsion systems, for example see DLVCUUV robotic tuna [37], robotic dolphin [38], Finnegan robotic turtle [39], and soft-bodied robot fish [40]. However, current actuator efficiencies mean that the electric motor and propeller combination still provides a comparable level of total propulsion system efficiency, with comparatively easy control and design [41]. As such, a conventional propeller and brushless DC motor combination will be used to propel the NEMOdeep vehicle.…”

Mission based Optimum System Selector for Bio-inspired Unmanned Untethered Underwater Vehicles

“…However for BMSs with limited available data, the calculation is rather complicated. Therefore, a formulation of the physical factors associated with biological & engineered systems energy usage was presented for energetic cost comparison [1]. Since BMSs from many and various biological classes of species are investigated in this research, there were a number of principal challenges to be overcome.…”

“…As explained by Phillips et al [1], the energetic cost of transport for biological and engineered vehicles is calculated as: It is evident from literature that the definition of total efficiency is inconsistent when applied to BMSs and in some cases unclear; therefore to elaborate further on the definition of , this is given special treatment in Section V.…”