Decentralized Scalable Exploration via Emergent Adaptive Lévy Walks on Minimal-Sensing Platforms

Wai Lun Leong, Teo Swee Huat Rodney
National University of Singapore
IROS 2026, Pittsburgh

SDLW in Action

SDLW turns four local range readings into sensor-adaptive, map-free exploration for decentralized nano-UAV teams.

Open Arena

SDLW coverage with four robots.

Rooms and Corridors

SDLW responds to structured geometry.

Cluttered Arena

SDLW maintains reactive exploration among obstacles.

Abstract

Efficient autonomous exploration with palm-sized nano-UAVs remains challenging due to severe limitations in sensing, computation, and flight endurance. We present a lightweight sensor-driven Lévy walk (SDLW) controller for aerial robots weighing under 50 grams and equipped with sparse local sensing. The method combines discrete Lévy step-length sampling with a sensor-reactive heading policy using directional range measurements. Each robot independently samples its Lévy exponent from a uniform prior to diversify exploration without inter-robot communication for exploration control. Each robot then selects headings using a von Mises distribution that biases motion toward open directions while preserving superdiffusive exploration properties. The controller operates at constant computational cost, enabling scalable multi-UAV exploration. Simulation results show coverage improvements of 79.6% in open arenas, 43.1% in rooms-and-corridors layouts, and 13.6% in cluttered environments, with collision reductions of 13.0%, 7.1%, and 1.4%, respectively, relative to a uniform-heading Lévy walk baseline. This work provides a practical framework for scalable multi-robot exploration on minimal-sensing, resource-constrained nano-UAVs.

Method: Sense, Bias, Walk

Sense

Each nano-UAV reads four local directional ranges: front, left, right, and back. SDLW uses this sparse local sensing without global localization, map building, or exploration communication.

Bias

A sensor-weighted resultant sets the mean direction of a von Mises heading distribution. Its normalized strength measures directional imbalance in the range readings. A stronger normalized resultant produces broader angular sampling around the mean direction, while a weaker resultant produces more concentrated sampling.

Walk

Each robot samples a discrete Lévy exponent independently from a uniform prior and executes heavy-tailed motion segments. The resulting controller remains map-free, decentralized, and constant-time.

Three SDLW stages: four range readings, stochastic headings biased toward open space, and a straight discrete Lévy motion segment.
SDLW combines four directional range readings, stochastic headings biased toward open space, and straight discrete Lévy motion segments.

Experimental Results

Our experiments show that SDLW accelerates coverage accumulation relative to Uniform Heading Lévy Walk (UHLW) across the Open, Rooms and Corridors, and Cluttered (50 obstacles) arenas. SDLW improves mean coverage by 79.6%, 43.1%, and 13.6%, respectively, while reducing mean collision events by 13.0%, 7.1%, and 1.4%, respectively. These results demonstrate the benefit of sensor-adaptive headings across environments with varied geometric complexity.

Published coverage-over-time plot for the Open arena.
Coverage over time in the Open arena for SDLW and UHLW across team sizes.
Published coverage-over-time plot for the Rooms and Corridors arena.
Coverage over time in the Rooms and Corridors arena for SDLW and UHLW across team sizes.
Published coverage-over-time plot for the Cluttered arena.
Coverage over time in the Cluttered arena for SDLW and UHLW across team sizes.
Published grouped bar chart of collision events per trial by arena and team size.
Collision events per trial across arenas and team sizes; error bars show standard error.

BibTeX

@inproceedings{leong2026decentralized,
  title={Decentralized Scalable Exploration via Emergent Adaptive L{\'e}vy Walks on Minimal-Sensing Platforms},
  author={Leong, Wai Lun and Teo, Swee Huat Rodney},
  booktitle={2026 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  year={2026},
  address={Pittsburgh, PA, USA},
  doi={10.48550/arXiv.2607.25195},
  url={https://arxiv.org/abs/2607.25195}
}