Advisor(s)

Vladimir Vantsevich

Committee Member(s)

Gregg Janowski
Lee Moradi
Roy Koomullil
Thomas Way

Document Type

Dissertation

Date of Award

6-18-2026

Degree Name

Doctor of Philosophy (PhD)

School

School of Engineering

Department

Engineering

Abstract

This dissertation introduces topographical mobility as a quantitative framework for assessing off-road unmanned ground vehicle performance based on geometric interaction between the vehicle and terrain. Rather than relying on conventional discrete indices, the proposed formulation evaluates mobility directly from vehicle and terrain geometry, expressing vehicle capability in terms of radius constraints implied by its dimensions and suspension state. On the vehicle side, longitudinal and lateral mobility radii are derived analytically from vehicle geometry—wheelbase, track width, ground clearance, and lowest underbody point location—quantifying the minimum terrain radius negotiable without underbody interference. Suspension state is shown to alter longitudinal mobility radius by up to 29%, motivating configuration-aware assessment. The mobility cross extends these planar constraints into a three-dimensional clearance envelope defined as the intersection of orthogonal cylinders, unifying longitudinal and lateral requirements into a single geometric representation. On the terrain side, a perception-to-decision pipeline integrates LiDAR and IMU to reconstruct elevation maps from which terrain passability radii are computed via local surface fitting and directional curvature analysis. The deterministic demand-capability test classifies a location as topographically mobile only if, for all tested headings, terrain passability radii meet or exceed vehicle mobility radii, and clearance and slope constraints are satisfied. Validation through simulation and outdoor UGV experiments demonstrate that the framework produces stable, physically interpretable mobility masks under real sensing conditions, correctly identifying immobile regions corresponding to sharp terrain features. The modular structure provides a foundation for topographical mobility assessment of off-road ground vehicles under real terrain conditions. Key words: Topographical mobility; mobility radius; off-road; mobility cross; suspension state.

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