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Iterative Motion Planning in Multi-agent Systems with Opportunistic Communication under Disturbance

Neelanga Thelasingha, Agung Julius, James Humann, James Dotterweich

TL;DR

This work targets uncertainty and asymmetric knowledge in multi-agent motion planning under opportunistic communication. It develops a rigorous mathematical framework using a multi-agent transition system $S=(X,T)$ and a Task Site Assignment (TSA) planner, introducing plan and eigen trajectories along with projection operators to model information delays. A key contribution is the n-step recoverability concept, providing conditions under which disturbances can be corrected and task satisfaction guaranteed, even with asynchronous replanning and limited communications. The authors also propose planning algorithms that enforce synchronization constraints and handle disturbances, yielding bounded performance degradation. Experimental validation on a UAV–UGV coordination task demonstrates the feasibility and effectiveness of the approach in realistic mobility and energy-constrained settings.

Abstract

In complex multi-agent systems involving heterogeneous teams, uncertainty arises from numerous sources like environmental disturbances, model inaccuracies, and changing tasks. This causes planned trajectories to become infeasible, requiring replanning. Further, different communication architectures used in multi-agent systems give rise to asymmetric knowledge of planned trajectories across the agents. In such systems, replanning must be done in a communication-aware fashion. This paper establishes the conditions for synchronization and feasibility in epistemic planning scenarios introduced by opportunistic communication architectures. We also establish conditions on task satisfaction based on quantified recoverability of disturbances in an iterative planning scheme. We further validate these theoretical results experimentally in a UAV--UGV task assignment problem.

Iterative Motion Planning in Multi-agent Systems with Opportunistic Communication under Disturbance

TL;DR

This work targets uncertainty and asymmetric knowledge in multi-agent motion planning under opportunistic communication. It develops a rigorous mathematical framework using a multi-agent transition system and a Task Site Assignment (TSA) planner, introducing plan and eigen trajectories along with projection operators to model information delays. A key contribution is the n-step recoverability concept, providing conditions under which disturbances can be corrected and task satisfaction guaranteed, even with asynchronous replanning and limited communications. The authors also propose planning algorithms that enforce synchronization constraints and handle disturbances, yielding bounded performance degradation. Experimental validation on a UAV–UGV coordination task demonstrates the feasibility and effectiveness of the approach in realistic mobility and energy-constrained settings.

Abstract

In complex multi-agent systems involving heterogeneous teams, uncertainty arises from numerous sources like environmental disturbances, model inaccuracies, and changing tasks. This causes planned trajectories to become infeasible, requiring replanning. Further, different communication architectures used in multi-agent systems give rise to asymmetric knowledge of planned trajectories across the agents. In such systems, replanning must be done in a communication-aware fashion. This paper establishes the conditions for synchronization and feasibility in epistemic planning scenarios introduced by opportunistic communication architectures. We also establish conditions on task satisfaction based on quantified recoverability of disturbances in an iterative planning scheme. We further validate these theoretical results experimentally in a UAV--UGV task assignment problem.

Paper Structure

This paper contains 16 sections, 4 theorems, 4 equations, 5 figures, 1 table, 3 algorithms.

Key Result

Theorem 17

For a multi-agent transition system $S$ of $N_A$ agents, let $\Xi_k$ be the task site assignment at any time step $k$. Given a plan $\tau^k_{plan}$ that is generated from Algorithm alg:planning, and assuming perfect execution, the realized trajectory after $k$, $\zeta(k+)$, satisfies $\Xi_k$. That i

Figures (5)

  • Figure 1: Planning - Execution Scheme
  • Figure 2: Communication architecture, UAV-UGV coalitions, permanent and opportunistic links. UGVs and bases are always in sync. UAVs establish links opportunistically at synchronization states with bases and UGVs in their coalitions.
  • Figure 3: Demonstration of plan execution with synchronization
  • Figure 4: Visualized execution trajectory with synchronization: (a) Task assignment is visiting the road. All agents are at dept A and in sync (b) UAV 0's plan is shown. As it is not in sync, the plan only changes beyond the sync state (c) UAV 0's plan changed beyond the sync state (d) A disturbance occurred and a recovery trajectory was planned for UAV 0.
  • Figure 5: Disturbance vs. Task time. Aborted instances and Theorem \ref{['theo:Distrubed_satisfaction']} condition satisfaction are also shown.

Theorems & Definitions (15)

  • Definition 3: Trajectory
  • Definition 5: Projection
  • Definition 6: Task Site Assignment
  • Definition 10: Realized Trajectory
  • Definition 12: Perfect Execution
  • Definition 13: Task site update
  • Definition 14: Synchronization states
  • Definition 15: Opportunistic Synchronization
  • Theorem 17: Task Satisfaction
  • Definition 18: Disturbance
  • ...and 5 more