Amphibious 3D active cord mechanism "HELIX" with helical swimming motion

There is the possibility to generate a very efficient locomotion strategy for a snake-like robot by introducing full-body helical motion. This paper proposes a new kind of propulsion principle for the underwater active cord mechanism, in which the helical motion is created by distortion of each articulated body segment, while keeping the whole body helically. This paper also discusses about the design of a new mechanical prototype to realize a hermetic underwater 3D active cord mechanism, used to verify the effectiveness of the newly proposed propulsion principle.