🚀 𝗦𝗰𝗶𝗲𝗻𝗰𝗲 𝗔𝗱𝘃𝗮𝗻𝗰𝗲𝘀 2026: Inertia-Driven Amphibious “Leglessbot” with Asymmetric Microundulatory Fin Arrays 🤖🌊

Thrilled to share our latest #𝗦𝗰𝗶𝗲𝗻𝗰𝗲𝗔𝗱𝘃𝗮𝗻𝗰𝗲 work on a 𝗰𝗲𝗻𝘁𝗶𝗺𝗲𝘁𝗲𝗿-𝘀𝗰𝗮𝗹𝗲, 𝗳𝘂𝗹𝗹𝘆 𝘀𝗲𝗮𝗹𝗲𝗱, 𝗹𝗲𝗴𝗹𝗲𝘀𝘀 𝗮𝗺𝗽𝗵𝗶𝗯𝗶𝗼𝘂𝘀 𝗿𝗼𝗯𝗼𝘁 that can crawl on sand, jump, and steerably swim – powered by a 𝘀𝗶𝗻𝗴𝗹𝗲 𝘃𝗮𝗿𝗶𝗮𝗯𝗹𝗲-𝗼𝘂𝘁𝗽𝘂𝘁 𝘃𝗼𝗶𝗰𝗲-𝗰𝗼𝗶𝗹 𝗺𝗼𝘁𝗼𝗿 (𝗩𝗖𝗠).

At small scales, reliable 𝘸𝘢𝘵𝘦𝘳𝘱𝘳𝘰𝘰𝘧 𝘴𝘦𝘢𝘭𝘪𝘯𝘨 is tough: transmissions and active mechanisms mean moving parts and dynamic seals that are fragile and 𝘭𝘦𝘢𝘬-𝘱𝘳𝘰𝘯𝘦. We wanted an amphibious robot that stays sealed and robust – yet still supports multiple locomotion modes.

🧠✨ 𝗪𝗵𝗮𝘁 𝘄𝗲 𝗱𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗱:

An 𝗶𝗻𝗲𝗿𝘁𝗶𝗮-𝗱𝗿𝗶𝘃𝗲𝗻 𝗮𝗰𝘁𝘂𝗮𝘁𝗶𝗼𝗻 + 𝗽𝗮𝘀𝘀𝗶𝘃𝗲 𝗽𝗿𝗼𝗽𝘂𝗹𝘀𝗶𝗼𝗻 𝗱𝗲𝘀𝗶𝗴𝗻 that:

🔹 Uses a variable-output VCM inside a fully sealed rigid shell (no external moving parts)

🔹 Switches among three modes: jumping, full-stroke vibration (land), and small-stroke vibration (water)

🔹 Uses asymmetric, tilted passive fins for frequency-tuned steering in water (IDMP)

🔹 Explains hydrodynamics via aquatic tests, high-speed PIV, and CFD

All of this – 𝗼𝗻𝗲 𝗺𝗮𝗶𝗻 𝗹𝗶𝗻𝗲𝗮𝗿 𝗮𝗰𝘁𝘂𝗮𝘁𝗼𝗿 + 𝗽𝗮𝘀𝘀𝗶𝘃𝗲 𝗳𝗶𝗻𝘀. No exposed legs, gears, or propellers – making sealing and durability much easier at the centimeter scale.

🎯 𝗞𝗲𝘆 𝗥𝗲𝘀𝘂𝗹𝘁𝘀:

✅ 24-g prototype (57.5 × 36 × 36 mm) with a fully enclosed shell

✅ ~1.4 BL/s (~78 mm/s) on dry sand; 41.6 mm/s on flat ground

✅ Jump height up to 17.16 mm at 15 V; continuous “tumbler” jumping

✅ Load carrying: 960 g (~40× body weight) and escape under 5-kg loads

✅ In water: min turning radius 5.6 mm; straight swim at 35/44/60 Hz (~32/35/28 mm/s); peak yaw -22°/s (30 Hz) or 16°/s (40 Hz)

💡 𝗪𝗵𝘆 𝗶𝘁 𝗺𝗮𝘁𝘁𝗲𝗿𝘀:

This work shows how inertia + mode-switchable actuation can bridge the 𝗺𝗼𝗺𝗲𝗻𝘁𝘂𝗺-𝗳𝗿𝗲𝗾𝘂𝗲𝗻𝗰𝘆 𝘁𝗿𝗮𝗱𝗲-𝗼𝗳𝗳, enabling jumping and swimming in the same tiny robot. Passive asymmetric fins turn simple reciprocation into steerable thrust – 𝘄𝗶𝘁𝗵 𝗻𝗼 𝗮𝗱𝗱𝗲𝗱 𝗮𝗰𝘁𝘂𝗮𝘁𝗼𝗿𝘀.

🌱 𝗪𝗵𝗮𝘁’𝘀 𝗻𝗲𝘅𝘁?

Future work will focus on improving environmental adaptability via 𝘧𝘦𝘦𝘥𝘣𝘢𝘤𝘬 𝘤𝘰𝘯𝘵𝘳𝘰𝘭 and adaptive structures, and optimizing energy efficiency + onboard power 𝘮𝘪𝘯𝘪𝘢𝘵𝘶𝘳𝘪𝘻𝘢𝘵𝘪𝘰𝘯.

Special shoutout to the team –

Lingqi Tang, Yongzun Yang (co-first authors), Bing Li, Bingfu Zhang, Qiguang He, Hongliang Ren, Yao Li – for making this project possible.

🔗 Paper link: https://lnkd.in/gFDfZYKq

🔖 #ScienceAdvances #Robotics #AmphibiousRobots #Microrobots #InertiaDriven #Locomotion #VCM #PIV #CFD