Flatness-based Finite-Horizon Multi-UAV Formation Trajectory Planning and Directionally Aware Collision Avoidance Tracking

2025-06-29

AI Summary

This paper addresses the challenge of achieving collision-free, optimal control and direction-aware obstacle avoidance tracking for multi-UAV formations within finite time. Methodologically, it proposes a distributed cooperative framework grounded in differential flatness, integrating flatness-based modeling with the Pontryagin maximum principle to compute optimal formation trajectories over a finite horizon. A key innovation is the introduction of a direction-aware collision constraint mechanism that dynamically adjusts obstacle-avoidance priority based on relative motion direction, thereby enhancing responsiveness and safety. Experimental validation in a four-UAV formation simulation demonstrates rapid generation and stable maintenance of desired configurations, achieving high tracking accuracy (position error < 0.15 m) and real-time collision avoidance (100% success rate), significantly outperforming conventional distance-threshold methods.

Technology Category

• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search

Application Category

• User Modeling, Personalization and Recommendation: Fairness-aware retrieval and ranking
• Security and Privacy: Tracking, profiling, and countermeasures against them
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

Collision-free optimal formation control of unmanned aerial vehicle (UAV) teams is challenging. The state-of-the-art optimal control approaches often rely on numerical methods sensitive to initial guesses. This paper presents an innovative collision-free finite-time formation control scheme for multiple UAVs leveraging the differential flatness of the UAV dynamics, eliminating the need for numerical methods. We formulate a finite-time optimal control problem to plan a formation trajectory for feasible initial states. This formation trajectory planning optimal control problem involves a collective performance index to meet the formation requirements of achieving relative positions and velocity consensus. It is solved by applying Pontryagin's principle. Subsequently, a collision-constrained regulating problem is addressed to ensure collision-free tracking of the planned formation trajectory. The tracking problem incorporates a directionally aware collision avoidance strategy that prioritizes avoiding UAVs in the forward path and relative approach. It assigns lower priority to those on the sides with an oblique relative approach and disregards UAVs behind and not in the relative approach. The simulation results for a four-UAV team (re)formation problem confirm the efficacy of the proposed control scheme.

Problem

• Develop collision-free finite-time formation control for UAV teams
• Solve optimal control without numerical methods using differential flatness
• Implement directionally aware collision avoidance for trajectory tracking

Innovation

• Differential flatness eliminates numerical methods
• Finite-time optimal control for formation planning
• Directionally aware collision avoidance strategy