Robot adapts wheel shape to cross land mud sand and water
MOSS: Multimodal Origami Swamp Robot System
Robotics
Summary
Moving through wetlands and swamps is tricky because the ground changes from hard soil to soft mud and water. The authors created a small robot called MOSS with special wheels that can change shape to roll better depending on the terrain. When the wheels are compact, the robot moves efficiently on firm ground, and when expanded, it moves better on sand, mud, and even water. Tests showed these shape changes save energy and reduce slipping, helping MOSS travel across different natural environments smoothly.
What this means in practice
- •For environmental monitoring teams: Deploy robots that adapt wheel shape to efficiently survey wetland terrains varying between soil, mud, and water.
- •For robot design engineers: Incorporate shape-changing wheels to build compact amphibious robots capable of multi-terrain navigation without multiple platform changes.
Authors
T. Lan, A. Babgei, L. Romanello, M. Kovac, S. F. Armanini
Abstract
Robotic systems for environmental monitoring and ecological surveying in wetlands and swamps must operate across diverse terrestrial and aquatic conditions. Conventional fixed-geometry wheels cannot adapt their contact geometry to these varying conditions. This work presents MOSS (Multimodal Origami Swamp Robot System), a compact amphibious robotic platform with 3D-printed origami wheels. The compact crank mechanism switches the wheel between contracted and expanded configurations, changing its width, body diameter, and fin orientation simultaneously. The contracted configuration is better suited to efficient rolling on firmer ground, whereas the expanded configuration provides greater contact and terrain engagement on softer surfaces. MOSS was evaluated on soil, sand, mud with varying water content, and water, in addition to in-motion morphing and terrestrial-aquatic transition tests. The more energy-efficient wheel configuration depended on terrain. The contracted configuration achieved a lower cost of transport on firmer soil and mud, whereas the expanded configuration performed better on wetter mud, sand, and water, reducing the cost of transport by up to 29%. Expanded wheels also reduced slip in wet mud and reduced both slip and hub sinkage in sand. MOSS successfully completed configuration changes in $1.95 \pm 0.11$ s and demonstrated continuous locomotion across soil-mud-water transitions. Outdoor trials further demonstrated operation across natural deformable terrain and water. These results show that adaptive wheel geometry provides terrain-dependent locomotion benefits and enables a single compact platform to traverse substantially different terrestrial and aquatic conditions.