Inverse Resistive Force Theory (I-RFT): Learning granular properties through robot-terrain physical interactions

Fuente: arXiv
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Main Authors: Liu, Shipeng, Xue, Feng, Zhang, Yifeng, Ponnusamy, Tarunika, Qian, Feifei
Format: Preprint
Published: 2026
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author Liu, Shipeng
Xue, Feng
Zhang, Yifeng
Ponnusamy, Tarunika
Qian, Feifei
author_facet Liu, Shipeng
Xue, Feng
Zhang, Yifeng
Ponnusamy, Tarunika
Qian, Feifei
contents For robots to navigate safely and efficiently on soft, granular terrains, it is crucial to gather information about the terrain's mechanical properties, which directly affect locomotion performance. Recent research has developed robotic legs that can accurately sense ground reaction forces during locomotion. However, existing tests of granular property estimation often rely on specific foot trajectories, such as vertical penetration or horizontal shear, limiting their applicability during natural locomotion. To address this limitation, we introduce a physics-informed machine learning framework, Inverse Resistive Force Theory (I-RFT), which integrates the Granular Resistive Force Theory model with Gaussian Processes to infer terrain properties from proprioceptively measured contact forces under arbitrary gait trajectories. By embedding the granular force model within the learning process, I-RFT preserves physical consistency while enabling generalization across diverse motion primitives. Experimental results demonstrate that I-RFT accurately estimates terrain properties across multiple gait trajectories and toe shapes. Moreover, we show that the quantified uncertainty over the terrain resistance stress map could enable robots to optimize foot design and gait trajectories for efficient information gathering. This approach establishes a new foundation for data-efficient characterization of complex granular environments and opens new avenues for locomotion strategies that actively adapt gait for autonomous terrain exploration.
format Preprint
id arxiv_https___arxiv_org_abs_2603_07796
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Inverse Resistive Force Theory (I-RFT): Learning granular properties through robot-terrain physical interactions
Liu, Shipeng
Xue, Feng
Zhang, Yifeng
Ponnusamy, Tarunika
Qian, Feifei
Robotics
For robots to navigate safely and efficiently on soft, granular terrains, it is crucial to gather information about the terrain's mechanical properties, which directly affect locomotion performance. Recent research has developed robotic legs that can accurately sense ground reaction forces during locomotion. However, existing tests of granular property estimation often rely on specific foot trajectories, such as vertical penetration or horizontal shear, limiting their applicability during natural locomotion. To address this limitation, we introduce a physics-informed machine learning framework, Inverse Resistive Force Theory (I-RFT), which integrates the Granular Resistive Force Theory model with Gaussian Processes to infer terrain properties from proprioceptively measured contact forces under arbitrary gait trajectories. By embedding the granular force model within the learning process, I-RFT preserves physical consistency while enabling generalization across diverse motion primitives. Experimental results demonstrate that I-RFT accurately estimates terrain properties across multiple gait trajectories and toe shapes. Moreover, we show that the quantified uncertainty over the terrain resistance stress map could enable robots to optimize foot design and gait trajectories for efficient information gathering. This approach establishes a new foundation for data-efficient characterization of complex granular environments and opens new avenues for locomotion strategies that actively adapt gait for autonomous terrain exploration.
title Inverse Resistive Force Theory (I-RFT): Learning granular properties through robot-terrain physical interactions
topic Robotics
url https://arxiv.org/abs/2603.07796