NoteBot: Fully retractable spoke-wheel robot based on a compliant mechanism

Abstract

This paper presents Notebot, a novel mobile robot featuring a fully retractable compliant spoke wheel (CSW) mechanism. The CSW, fabricated from SK-5 spring steel, enables significant wheel diameter deformation and compact storage within the robot body, minimizing the risk of creep and mechanical failure associated with compliant materials. A dynamic modeling, based on multi-body dynamics method was developed to analyze the force–displacement characteristics of the spokes according to the thickness. The optimal spoke thickness was determined through simulation and validated experimentally. The Notebot prototype demonstrated reliable performance, overcoming obstacles higher than the wheel center, traversing narrow gaps as small as 40 mm, and navigating uneven terrain with roughness up to 20 mm. In future work, by conducting an additional design and research climbing stability, enhanced the practicality of the robot and expand its capabilities are expected.