Building a High-Performance Robot Communication System with DDS

Building a High-Performance Robot Communication System with DDS Modern robots may have dozens of processes distributed across CPUs, edge computers, and embedded devices. ROS 2 uses DDS (Data Distribution Service) as its underlying communication technology. Understanding DDS helps you design robot systems that remain responsive as message traffic grows. The Communication Model Instead of connecting every process directly: Camera ---> Perception LiDAR ---> Perception IMU ---> Localization | v Planning | v Control ROS 2 nodes communicate through DDS topics and discovery. A simplified model is: Publisher | v DDS DataWriter | v Topic | v DDS DataReader | v Subscriber Why DDS Is Useful for Robotics DDS provides mechanisms for: Discovery Reliability Durability Deadline management History Resource limits Data delivery policies These features are important because different robot data has different requirements. A camera stream may prioritize low latency. A configuration message may prioritize reliability. High-Performance Design Avoid treating every topic identically. For example: Data Typical Priority Camera frames Low latency LiDAR scans High throughput IMU Low latency Robot commands Reliability Configuration Reliability + durability Diagnostics Reliability Reduce Copying Large sensor messages can consume substantial CPU and memory bandwidth. Good practices include: Avoid unnecessary serialization/deserialization. Reuse buffers where possible. Keep image resolution appropriate for the workload. Compress only when bandwidth savings justify CPU cost. Separate high-rate sensor topics from low-rate metadata. Separate Data Paths A useful architecture is: +--> Vision Camera ----------+ | LiDAR -----------+--> Perception --> Planning --> Control | IMU -------------+ Diagnostics ---------------------> Monitoring Configuration ------------------> Lifecycle Manager Not all traffic needs the same QoS or processing path. Measuring Performance Do not optimize based on intuition alone.