# Timescale Separation Enables Deep Reinforcement Learning Control of Rotating Detonation Engine Mode Transitions

arXiv: https://arxiv.org/abs/2604.14398 · HTML: https://mlsanity.com/paper/2604.14398/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Placed in RL theory and sample complexity, one of 15 directions in Deep reinforcement learning methods.
- Builds on 13 of its 76 references that are in the map.
- First posted on arXiv 15 Apr 2026.

## Placed in

- Deep reinforcement learning methods / [RL theory and sample complexity](https://mlsanity.com/deeprl/rl-theory-and-sample-complexity/)

## Builds on (most cited first, 13 of 13)

- [A review on Deep Reinforcement Learning for Fluid Mechanics](https://mlsanity.com/paper/1908.04127/) (2019)
- [A Survey of Temporal Credit Assignment in Deep Reinforcement Learning](https://mlsanity.com/paper/2312.01072/) (2023)
- [Bridging RL Theory and Practice with the Effective Horizon](https://mlsanity.com/paper/2304.09853/) (2023)
- [Control Frequency Adaptation via Action Persistence in Batch Reinforcement Learning](https://mlsanity.com/paper/2002.06836/) (2020)
- [Effective control of two-dimensional Rayleigh--B'enard convection: invariant multi-agent reinforcement learning is all you need](https://mlsanity.com/paper/2304.02370/) (2023)
- [Controlling Rayleigh-B'enard convection via Reinforcement Learning](https://mlsanity.com/paper/2003.14358/) (2020)
- [Dynamic Decision Frequency with Continuous Options](https://mlsanity.com/paper/2212.04407/) (2022)
- [Multi-agent reinforcement learning for the control of three-dimensional Rayleigh-B'enard convection](https://mlsanity.com/paper/2407.21565/) (2024)
- [Dynamic Feature-based Deep Reinforcement Learning for Flow Control of Circular Cylinder with Sparse Surface Pressure Sensing](https://mlsanity.com/paper/2307.01995/) (2023)
- [Navigation in a simplified Urban Flow through Deep Reinforcement Learning](https://mlsanity.com/paper/2409.17922/) (2024)
- [A Reinforcement Learning Approach for Transient Control of Liquid Rocket Engines](https://mlsanity.com/paper/2006.11108/) (2020)
- [Data-driven Modeling of Rotating Detonation Waves](https://mlsanity.com/paper/2008.05586/) (2020)
- [Invariant Control Strategies for Active Flow Control using Graph Neural Networks](https://mlsanity.com/paper/2503.22775/) (2025)

## Abstract (arXiv)

Rotating detonation engines (RDEs) are a promising propulsion concept that may offer higher thermodynamic efficiency and specific impulse than conventional systems, but nonlinear phenomena, including transitions to oscillatory or chaotic propagation modes, can hinder practical operation. Deep Reinforcement Learning (DRL) has emerged as a promising method for controlling complex nonlinear dynamics such as those observed in RDEs. However, the multi-timescale nature of the RDE system makes direct application of DRL challenging. We address this challenge by reformulating the DRL problem in a moving reference frame that follows the detonation-wave pattern, making the wave structure appear quasi-steady to the agent. This reformulation enables scale separation between fast detonation propagation and slower operating-mode dynamics. We train DRL controllers to modulate spatially segmented injection pressure in a one-dimensional reduced-order RDE model and induce rapid transitions between different mode-locked states. Across a range of actuation periods, initial states, and target modes, controllers trained in the moving frame learn more reliably than those trained in a stationary frame and remain effective over a broader range of actuation periods. These results suggest that symmetry-aware moving reference frame formulations may be useful for related multiscale flow-control problems and that scale separation should be exploited whenever possible to enable DRL control of multi-timescale systems.