Gathering Autonomous Mobile Robots Under the Adversarial Defected View Model

TL;DR

This paper addresses the challenge of guaranteeing finite-time gathering of autonomous robots in the Euclidean plane under adversarial visibility faults, proposing algorithms for both synchronous and asynchronous models with proven correctness.

Contribution

It introduces the first finite-time gathering algorithms under adversarial defected view models for both FSYNC and ASYNC settings, handling incomplete and dynamic observations.

Findings

Finite-time gathering in FSYNC model under (4, 2) defected view.

Finite-time gathering in ASYNC model under (N, K) defected view.

Algorithms work with non-rigid motion and coordinate axis agreement.

Abstract

This paper studies the gathering problem for a set of $N \ge 2$ autonomous mobile robots operating in the Euclidean plane under the distributed Look-Compute-Move model. We consider oblivious robots executing under the adversarial defected view model, in which an activated robot may observe only a restricted subset of robots due to adversarial visibility faults. Consequently, the information obtained during each Look phase may be incomplete and dynamically altered. The objective is to guarantee deterministic finite-time gathering at a location not known a priori despite such sensing restrictions. We present two distributed algorithms under distinct scheduling assumptions. In the fully synchronous (FSYNC) model, we prove finite-time gathering in the adversarial (4, 2) defected view setting, resolving a previously open case without requiring additional capabilities or coordinate agreement. In the asynchronous (ASYNC) model, we establish finite-time gathering under the general adversarial (N, K) defected view model, where an activated robot observes at most K of the other $N - 1$ robots for any $1 \le K < N - 1$. Both results hold under non-rigid motion. The proposed algorithm for the ASYNC model assumes agreement in the direction and orientation of one coordinate axis.