ROS2 Node LEAPP Runtime

The ROS2 Node LEAPP Runtime runs a LEAPP bundle as standalone composable nodes. All data flows via ROS topics, enabling multi-model bundles and feedback self-loops.

Architecture

flowchart LR subgraph IG [Inference Graph] direction LR B[InputBuilderNode] --> C[TritonNode] C --> D[OutputBuilderNode] end i1(( )) --> B i2(( )) --> B D --> o1(( )) D --> o2(( ))

Key Components

InputBuilderNode

Subscribes to external ROS topics and converts messages to tensors using the MessageToTensorConverter registry. Runs the core InputBuilder for preprocessing (reordering, history stacking, reshaping) and publishes a bundled TensorList message.

TritonNode

Runs all neural network models via Triton Inference Server. The TritonNode supports Triton Ensembles, meaning it can run inference on a graph of ONNX files. The bundle configuration YAML is used to automatically generate the Triton model repository with individual ONNX model configurations and an ensemble config.pbtxt.

The model repository structure:

model_repo/
├── model_a/
│   ├── config.pbtxt
│   └── 1/model.onnx
├── model_b/
│   ├── config.pbtxt
│   └── 1/model.onnx
└── ensemble/
    └── config.pbtxt

OutputBuilderNode

Subscribes to the output TensorList from TritonNode, runs the core OutputBuilder for postprocessing, and publishes typed ROS messages using the TensorToMessageConverter registry.

Topic Connections

The launch file automatically sets up the topic connections:

• InputBuilderNode publishes on input_tensors

• TritonNode subscribes to input_tensors, runs ensemble inference, publishes on output_tensors

• OutputBuilderNode subscribes to output_tensors

Parameters

InputBuilderNode

Parameter	Type	Default	Description
config_path	string	""	Path to the LEAPP bundle configuration YAML (required).
publish_rate	double	50.0	Rate at which tensors are published in Hz.
source_to_topic.<source>	string	<source>	Map an input source name to a ROS topic.

OutputBuilderNode

Parameter	Type	Default	Description
config_path	string	""	Path to the LEAPP bundle configuration YAML (required).
output_to_topic.<name>	string	<name>	Map an output name to a ROS topic.