🤖 AI Summary
This study addresses performance degradation in critical ROS 2 nodes caused by backpressure from slow subscribers on reliable DDS topics. We propose a proxy-based decoupling architecture featuring a novel dual-write mechanism and a health probe classifier with hysteresis. By splitting topics and isolating traffic via parallel reliable and best-effort channels, the system adaptively throttles non-critical data streams to prevent backpressure propagation. Experimental results demonstrate that under severe interference, publisher throughput remains stable at 30 Hz, while the p95 tail latency for critical subscribers decreases from 15 seconds to under 2 milliseconds. These findings confirm that the proposed approach effectively preserves both system real-time responsiveness and overall throughput in the presence of heterogeneous subscriber behaviors.
📝 Abstract
In ROS 2 systems using DDS, a single slow subscriber on a RELIABLE topic can cause backpressure that degrades throughput and latency for all subscribers sharing the same publisher, including safety-critical local nodes. We present Adaptive Bridge, a proxy-based decoupling layer that isolates critical subscribers from noncritical ones through topic splitting and adaptive rate control. The proxy subscribes to the original topic and republishes onto two independent DDS writers, one RELIABLE for critical consumers and one BEST_EFFORT for noncritical consumers, breaking the causal chain of backpressure propagation. A probe-based classifier monitors subscriber health with hysteresis and adjusts noncritical rate limits in real time. We evaluate the system under Gilbert-Elliot bursty wireless loss using a reproducible Docker-based harness. Results show the bridge reduces critical subscriber tail latency from up to 15 seconds to under 2 milliseconds at p95 and preserves publisher throughput at 30 Hz regardless of impairment severity.