Journal of Bionic Engineering (2025) 22:1039–1048https://doi.org/10.1007/s42235-025-00700-0

Sea Turtle-inspired Magnetic Soft Robot Demonstrates Versatile Landto-Submerged Locomotion

Yida Guo1  · Jia Zhu2  · Yutong Wang1  · Lei Zhang1  · Shichuan Wang1  · Binhong Dou1  · Shenghao Yang1  · Bing Li1  · Fuzhou Niu3  · Chonglei Hao1

1 School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen 518055, China 

2 School of Intelligent Manufacturing and Smart Transportation, Suzhou City University, Suzhou 215000, China 

3 School of Mechanical Engineering, Suzhou University of Science and Technology, Suzhou 215009, China

Abstract 

Soft robots capable of navigating complex environments hold promise for minimally invasive medical procedures and micromanipulation tasks. Here, we present a magnetically controlled multi-legged soft robot inspired by green sea turtle locomotion. Our designed robot, featuring six magnetized feet, demonstrates stable motion within a magnetic field strength range of 1.84–6.44 mT. Locomotion displacement scales linearly with field strength, while velocity correlates with frequency, reaching approximately 25 mm/s at 10 Hz. The robot navigates dry, semi-submerged, and fully submerged conditions, climbs slopes up to 30°, and maneuvers through U-shaped bends. Additionally, we demonstrate the robot's capability to smoothly transition between terrestrial and aquatic environments, demonstrating its amphibious locomotion performance. This adaptability to diverse environments, coupled with precise magnetic control, opens new possibilities for soft robotics in confined and complex spaces. Our findings provide a framework for designing highly maneuverable small-scale soft robots with potential applications ranging from targeted drug delivery to environmental sensing in challenging terrains. 

Keywords Bio-inspiration · Soft robot · Terrestrial-aquatic locomotion · Magnetically controlled robot