SPIRAL: Self-Play Incremental Racing Algorithm for Learning in Multi-Drone Competitions
Onur Akgün
TL;DR
SPIRAL addresses autonomous drone racing in multi-agent settings by introducing a self-play incremental learning framework, modeled as a decentralized MDP with agent $i$ observing $S_i$, taking actions $A_i$, transitioning via $P_i$, receiving rewards $R_i$, and discount factor $\gamma$, and aims to maximize $J_i(\pi_i)=E[\sum_{t=0}^{T} \gamma^t R_i(s_{i,t},a_{i,t},s'_{i,t+1})]$. It combines a high-level 4D continuous action space $(p^{x},p^{y},p^{z},\psi)$ with a PID-generated low-level control, and a composite reward that balances progress, collisions, orientation, and lap-time objectives, enabling a staged self-play curriculum. SPIRAL trains in three stages (single-drone, 1v1, and 2v2) using PPO, where opponents evolve from the agent's best past policies, and can integrate with DRL libraries; experiments on a six-gate circuit show that SPIRAL yields fastest lap times but lower reliability relative to a game-theoretic planner, demonstrating a speed-reliability trade-off. The framework is scalable and data-efficient, offering a new path toward robust, adaptive multi-agent drone racing with potential extensions toward safety constraints and explicit cooperative behavior.
Abstract
This paper introduces SPIRAL (Self-Play Incremental Racing Algorithm for Learning), a novel approach for training autonomous drones in multi-agent racing competitions. SPIRAL distinctively employs a self-play mechanism to incrementally cultivate complex racing behaviors within a challenging, dynamic environment. Through this self-play core, drones continuously compete against increasingly proficient versions of themselves, naturally escalating the difficulty of competitive interactions. This progressive learning journey guides agents from mastering fundamental flight control to executing sophisticated cooperative multi-drone racing strategies. Our method is designed for versatility, allowing integration with any state-of-the-art Deep Reinforcement Learning (DRL) algorithms within its self-play framework. Simulations demonstrate the significant advantages of SPIRAL and benchmark the performance of various DRL algorithms operating within it. Consequently, we contribute a versatile, scalable, and self-improving learning framework to the field of autonomous drone racing. SPIRAL's capacity to autonomously generate appropriate and escalating challenges through its self-play dynamic offers a promising direction for developing robust and adaptive racing strategies in multi-agent environments. This research opens new avenues for enhancing the performance and reliability of autonomous racing drones in increasingly complex and competitive scenarios.
