MorphoBall: A Bio-Inspired Transformable Spherical Robot with Dual Terrestrial Gaits and Surface Swimming Capability
Jinyuan Liu, Guangzhi Tian, Yuqiang Jin, Ling Shi, Minglei Fu, Wen-An Zhang, Bo Chen
AI summary
Problem
Existing spherical and amphibious robots struggle with propulsion efficiency, locomotion versatility, and high structural complexity when navigating diverse terrains and water surfaces.
Approach
The robot morphs between a sealed spherical rolling mode and a differential-drive mode on land, while a biomimetic ciliary band provides passive damping on land and active surface propulsion in water, all regulated by a hierarchical model-based controller.
Key results
- Unified drive system enabling adaptive mobility across flat ground, slopes, and narrow passages.
- Dual-function ciliary band that limits roll tilt on land and enhances aquatic propulsion without extra actuators.
- Hierarchical control architecture achieving precise velocity, curvature, and tilt regulation.
- 34% faster mission completion compared to single-morphology strategies in indoor and outdoor tests.
Why it matters
Demonstrates how morphology adaptation can significantly enhance environmental adaptability and mission efficiency for mobile robots operating in dynamic, heterogeneous environments.
Abstract
MorphoBall is a bio-inspired, deformable spher- ical robot designed for multimodal locomotion across terres- trial and aquatic environments. By integrating a dual-mode drive system (spherical rolling and differential-drive) with a morphology-mediated propulsion mechanism, MorphoBall achieves adaptive mobility in diverse terrains, including flat ground, slopes, and water surfaces. A key innovation lies in the dual-function ciliary band, which provides both passive damping during terrestrial rolling and active propulsion during aquatic navigation. Model-based controllers are developed to regulate forward velocity, trajectory curvature, and roll tilt angle, demonstrating superior stability and responsiveness com- pared to baseline PID implementations. Experimental results validate MorphoBall’s ability to autonomously navigate struc- tured indoor environments and traverse unstructured outdoor terrains, achieving seamless mode transitions and completing missions 34% faster than single-morphology strategies. This work highlights the potential of morphology adaptation as a tool for enhancing environmental adaptability in mobile robotics.