DDS-based fault tolerance for robotic data communication in ROS 2

Ruzmetov A.A., Khudaybergenov T.A. DDS-based fault tolerance for robotic data communication in ROS 2. Scientific and Technical Journal of Information Technologies, Mechanics and Optics, 2026, vol. 26, no. 4, pp. 806–815 (in Russian). doi: 10.17586/2226-1494-2026-26-4-806-815

Modern distributed robotic systems based on Robot Operating System 2 (ROS 2) critically depend on the quality of the network environment. However, when wireless communication channels, such as Wi-Fi, LoRa, and 4G/5G, are used, various forms of degradation occur, including packet loss, increased jitter, and micro-outages. Standard Data Distribution Service (DDS) mechanisms provide Quality of Service (QoS) metrics, but they do not define application-level adaptation logic. This work addresses the problem of ensuring continuous robot control under unstable communication conditions by developing an intelligent fault-tolerance layer. The authors propose a DDS-aware architecture that integrates QoS Monitor and Policy Engine components. The methodology is based on online monitoring of DDS events, such as DeadlineMissed and LivelinessChanged, as well as statistical analysis of a message delivery window. A finite-state algorithm for classifying the communication state was developed, along with mitigation mechanisms, including dual-path command delivery using primary and backup channels with deduplication based on serial numbers, and dynamic traffic prioritization. Experimental validation was carried out on a Linux-based testbed using tc netem for precise emulation of network degradation scenarios, including 10 % packet loss, delay with jitter, and micro-outages, at a communication frequency of 50 Hz. The comparative analysis demonstrated the superiority of the proposed method over the standard baseline approach. In the scenario with 10 % packet loss, the command delivery ratio, denoted as DR_c, increased from 99.81 % to 100 %, while the 95th percentile latency decreased from 115.52 ms to 3.51 ms. Under micro-outage conditions, the proposed solution completely eliminated control gaps by reducing the maximum blocking time, T_(blk, max), from 1.052 s to 0 s. The system demonstrated a stable recovery time T_rec of approximately 5 s which was determined by the hold-down policy used to prevent oscillations. The results confirm that application-level traffic redundancy and DDS event-based analysis can compensate for physical-layer communication limitations without modifying the ROS 2 core. Unlike standard approaches, the proposed method separates traffic classes, ensuring the delivery of critical control commands even under extreme telemetry degradation. A limitation of the method is the need for preliminary QoS profile configuration; however, this is compensated for by the high portability of the solution across different ROS Middleware implementations, including Fast DDS and Cyclone DDS. This work lays the foundation for the development of self-healing communication environments for mission-critical robotic applications. Robotic systems operating in dynamic and especially wireless environments are subject to communication degradation, including packet loss, increased latency, jitter, and short-term disconnections. These factors reduce the quality of telemetry and may lead to temporary failures in the delivery of control commands. In ROS 2, data exchange is implemented over DDS, which provides QoS policies and events; however, it does not define an application-level fault-tolerance policy. This article proposes a DDS-aware fault-tolerant communication layer for ROS 2 which includes a QoS Monitor and a Policy Engine. The Policy Engine classifies the communication state and triggers mitigation actions, including command prioritization, telemetry stream adaptation, and switching between preconfigured QoS profiles. A reproducible evaluation methodology is proposed for testing the system under artificially introduced communication channel degradations.

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