Schematic snapshots of the micropenguin gait under an orientation-switching control strategy. The dark and transparent structures show the current and previous orientations of the micropenguin at a certain position, respectively. Yellow curved arrows indicate the magnetic torques ( τ ) that facilitate the flippers closing and opening. Red curved arrows indicate the micropenguin rotation. The magnetic torques under the magnetic actuation field ( B x ) close the micropenguin flippers to generate a forward movement (phases 1–2 and 3–4) while the elastic torques under the magnetic base field ( B z ) open the flippers for shape recovery (phases 2–3 and 4–1) after the micropenguin rotates 90° along the y axis. From phases 1–4, the micropenguin moves along the +x , −z , +x and +z directions sequentially. The base field (2 mT) is necessary to keep the micropenguin’s orientation.
