A small-sized underactuated biologically inspired aquatic robot

This extended abstract introduces the biologically inspired swimming robot URMELE light. The robot embodies the strategy of massive under-actuation. Propulsion is generated using a central module with one single actuator and coupled passive, compliant tail modules. Therewith this robot differs from other modular swimming robots like e.g. AmphiBot [3] or ACM-R5 [6] which feature motor-gear combinations in each module without defined in- and inter-module compliance. It also differs from fish-like robots like e.g. MT1, a robot which generates propulsion by a single drive and a "C-bending" tail structure [8] due to the explicit use of spring elements for locomotion. The swimming behavior of URMELE light is changeable: we aim at a shift between as well anguilliform as thunniform swimming modes due to tunable compliant elements. Therewith URMELE light could be used as reproducibly displaceable experimental platform for investigation of swimming abilities of fishes, e.g. energy efficiency of different swimming modes. Aside it may serve as a mobile sensing unit for control of water quality (e.g. detection and tracking of oil or chemicals) with minimized environmental disturbances. Currently URMELE light performs a thunniform swimming mode.