Abstract
Small-scale magnetic soft-bodied robots can be designed to operate based on different locomotion modes to navigate and function inside unstructured, confined and varying environments. These soft millirobots may be useful for medical applications where the robots are tasked with moving inside the human body. Here we cover the entire process of developing small-scale magnetic soft-bodied millirobots with multimodal locomotion capability, including robot design, material preparation, robot fabrication, locomotion control and locomotion optimization. We describe in detail the design, fabrication and control of a sheet-shaped soft millirobot with 12 different locomotion modes for traversing different terrains, an ephyra jellyfish-inspired soft millirobot that can manipulate objects in liquids through various swimming modes, a larval zebrafish-inspired soft millirobot that can adjust its body stiffness for efficient propulsion in different swimming speeds and a dual stimuli-responsive sheet-shaped soft millirobot that can switch its locomotion modes automatically by responding to changes in the environmental temperature. The procedure is aimed at users with basic expertise in soft robot development. The procedure requires from a few days to several weeks to complete, depending on the degree of characterization required.
Key points
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The protocol describes a sheet-shaped millirobot with 12 locomotion modes for traversing different terrains, a jellyfish-inspired millirobot for manipulating objects in liquids, a zebrafish-inspired millirobot for efficient swimming and a dual stimuli-responsive millirobot that can switch locomotion modes automatically by responding to the environmental temperature.
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Rigid-bodied robots lack deformation capabilities, limiting them to specific functions, whereas soft-bodied millibots display sophisticated locomotion strategies similar to those adopted by small-scale organisms.
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Code availability
The codes used for locomotion performance evaluation and optimization has been published in our previous papers and are available from the corresponding author on reasonable request.
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Acknowledgements
We thank the Max Planck Society, European Research Council Advanced Grant SoMMoR project (grant no. 834531) and the German Research Foundation Soft Material Robotic Systems (SPP 2100) Program (grant no. 497562474) for funding this project.
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Key references
Hu, W. et al. Nature 554, 81–85 (2018): https://doi.org/10.1038/nature25443
Ren, Z. et al. Sci. Adv. 7, eabh2022 (2021): https://doi.org/10.1126/sciadv.abh2022
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Ren, Z., Sitti, M. Design and build of small-scale magnetic soft-bodied robots with multimodal locomotion. Nat Protoc 19, 441–486 (2024). https://doi.org/10.1038/s41596-023-00916-6
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DOI: https://doi.org/10.1038/s41596-023-00916-6
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