Design and Development of a NiTiNOL Actuated, Crab-Like Milliscale Octabot

This paper introduces a novel design for a centimeter-scale side-crawling ‘Octabot’ robot inspired by crab locomotion. The robot imitates the crab's ability to crawl in two directions through the adduction and abduction of its legs, making this feature unique to the design. The prototype has been fabricated through smart composite microstructure technique. NiTiNOL wire has been used for actuation considering the advantage it offers in terms of power density, given the size constraint. Inverse and forward kinematics have been implemented to calculate the joint angles and leg trajectory, attributed to a 4% strain in the NiTiNOL wire. Control signals are pulsed at timed intervals to channels on either side for sequential adduction and abduction of legs. The Octabot has demonstrated a crawling speed of 2.5 mm/s.