FLHex: a flapped-paddle hexapod for all-terrain amphibious locomotion

This paper presents the design of a versatile mechanism that can enable new directions in amphibious, all-terrain locomotion. The simple, passive, flapped-paddle can be integrated with several structures that are well-suited for locomotion in terrestrial applications. The flapped-paddle overcomes a serious limitation of the conventional flipper where the net lateral forces generated during oscillatory motion in aquatic environments averages out to zero. The flapped-paddle and its mounting, collectively, rests in natural positions in the aquatic environment so as to maximize hydrodynamic force utilization and consequently the propulsive efficiency. The simplicity of the design enabled us to develop a simulation model that concurs well with experimental results. The results reported in the paper are based on integrating the flapped-paddle with the curved leg of the RHex hexapod robot.