Magnetically Actuated Simple Millirobots for Complex Navigation and Modular Assembly

• Published in: IEEE robotics and automation letters Vol. 5; no. 2; pp. 2957 - 2964
• Main Authors: Al Khatib, Ehab, Bhattacharjee, Anuruddha, Razzaghi, Pouria, Rogowski, Louis William, Kim, Min Jun, Hurmuzlu, Yildirim
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.04.2020; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Biomedical engineering; Coils; Comparative studies; design and control; Esophagus; Legged locomotion; Locomotion; Magnetic circuits; magnetically actuated robot; Millirobot; Modular structures; Modular units; motion control; Permanent magnets; Polylactic acid; Remote control; Robot kinematics; Task analysis; Three dimensional printing; Torque; Tumbling
• ISSN: 2377-3766; 2377-3766
• DOI: 10.1109/LRA.2020.2974389

Magnetic millirobots can be controlled remotely by external magnetic fields, making them promising candidates for biomedical and engineering applications. This letter presents a low-cost millirobot that is simple in design, easy to fabricate, highly scalable, and can be used as modular sub-units within complex structures for large-scale manipulation. The rectangular-shaped millirobots were 3D printed using a polylactic acid (PLA) filament, where two cylindrical permanent magnets were subsequently embedded at each end. Individual millirobots are highly agile and capable of performing a variety of locomotive tasks such as pivot walking, tapping, and tumbling. A comparative study is presented to demonstrate the advantages and disadvantages of each locomotion mode. However, among these modes of locomotion, pivot walking at millimeter length scale is demonstrated for the first time in this letter, and our experimental data shows that this is the fastest and the most stable of the motion modes examined. Further, we demonstrate that the millirobot could be deployed through an esophagus-like bent tube and a maze-like path with combined motion modes. Later, to extend the functionality of our millirobots, we present two systems utilizing multiple millirobots combined together: a stag beetle and a carbot. Using a powerful electromagnetic coil system, we conduct extensive experiments to establish feasibility and practical utility of the magnetically actuated millirobot.