Bio-inspired tail oscillation enables robot fast crawling on deformable granular terrains

2025-09-15

AI Summary

Terrestrial robots exhibit low locomotion efficiency on deformable granular terrains (e.g., sand, mud) due to high resistive forces and poor substrate engagement. Method: Inspired by mudskippers, this work proposes a tail-oscillation–mediated substrate fluidization mechanism: active tail oscillation locally fluidizes the granular medium to reduce resistance, coupled with a design principle matching tail morphology to surface strength. Using a bio-inspired wheeled–flipper robot platform, we integrate tail motion control, in-situ shear force measurement, and multi-terrain interaction modeling to systematically characterize tail–substrate coupled dynamics. Contribution/Results: Experiments demonstrate a 67% increase in crawling speed and a 46% reduction in body drag force on soft granular media. The approach significantly enhances mobility efficacy on deformable substrates, establishing a novel paradigm and transferable design principles for bioinspired efficient locomotion over soft terrain.

Technology Category

• Intelligent Robots: Manipulation
• Machine Learning: Bio-inspired Learning
• Computer Vision: Low Level & Physics-based Vision

Application Category

• Web Mining and Content Analysis: Robustness and generalizability of Web mining methods
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines

Abstract

Deformable substrates such as sand and mud present significant challenges for terrestrial robots due to complex robot-terrain interactions. Inspired by mudskippers, amphibious animals that naturally adjust their tail morphology and movement jointly to navigate such environments, we investigate how tail design and control can jointly enhance flipper-driven locomotion on granular media. Using a bio-inspired robot modeled after the mudskipper, we experimentally compared locomotion performance between idle and actively oscillating tail configurations. Tail oscillation increased robot speed by 67% and reduced body drag by 46%. Shear force measurements revealed that this improvement was enabled by tail oscillation fluidizing the substrate, thereby reducing resistance. Additionally, tail morphology strongly influenced the oscillation strategy: designs with larger horizontal surface areas leveraged the oscillation-reduced shear resistance more effectively by limiting insertion depth. Based on these findings, we present a design principle to inform tail action selection based on substrate strength and tail morphology. Our results offer new insights into tail design and control for improving robot locomotion on deformable substrates, with implications for agricultural robotics, search and rescue, and environmental exploration.

Problem

• Enhancing robot crawling speed on deformable granular terrains
• Reducing body drag through bio-inspired tail oscillation
• Optimizing tail morphology and control for substrate fluidization

Innovation

• Tail oscillation fluidizes substrate reducing resistance
• Tail morphology influences oscillation strategy effectiveness
• Design principle for tail action based on substrate