Conditional Max-Sum for Asynchronous Multiagent Decision Making

TL;DR

This paper introduces Conditional Max-Sum, a novel message-passing algorithm for asynchronous multiagent decision making in dynamic environments like lane-free traffic, improving coordination among automated vehicles.

Contribution

The paper proposes a new asynchronous message-passing algorithm, Conditional Max-Sum, and a realistic communication framework for Factor Graphs in multiagent systems.

Findings

Enhanced coordination in lane-free traffic scenarios.

Conditional Max-Sum outperforms standard Max-Sum in asynchronous settings.

Effective decision-making in complex multiagent environments.

Abstract

In this paper we present a novel approach for multiagent decision making in dynamic environments based on Factor Graphs and the Max-Sum algorithm, considering asynchronous variable reassignments and distributed message-passing among agents. Motivated by the challenging domain of lane-free traffic where automated vehicles can communicate and coordinate as agents, we propose a more realistic communication framework for Factor Graph formulations that satisfies the above-mentioned restrictions, along with Conditional Max-Sum: an extension of Max-Sum with a revised message-passing process that is better suited for asynchronous settings. The overall application in lane-free traffic can be viewed as a hybrid system where the Factor Graph formulation undertakes the strategic decision making of vehicles, that of desired lateral alignment in a coordinated manner; and acts on top of a rule-based method we devise that provides a structured representation of the lane-free environment for the factors, while also handling the underlying control of vehicles regarding core operations and safety. Our experimental evaluation showcases the capabilities of the proposed framework in problems with intense coordination needs when compared to a domain-specific baseline without communication, and an increased adeptness of Conditional Max-Sum with respect to the standard algorithm.