Add TF2 Transform System

[Michi-Tsubaki]

Overview

This PR adds comprehensive TF2 (Transform) support to ROS2.jl, enabling coordinate frame transformations essential for robotics applications.

Changes

New Module: src/tf2.jl

• TransformListener: Query transformations between coordinate frames
• TransformBroadcaster: Publish dynamic coordinate transformations
• StaticTransformBroadcaster: Publish static coordinate transformations
• lookup_transform: Look up transform between frames
• can_transform: Check if transform is available
• send_transform: Send dynamic transform
• send_static_transform: Send static transform
• create_transform_stamped: Create TransformStamped message

New Example: examples/example_tf2.jl

Demonstrates TF2 usage with RViz visualization including:

• Static transform broadcasting (map → odom)
• Dynamic transform broadcasting (odom → base_link)
• Transform listener
• Integration with visualization markers

API Example

using ROS2

init()
node = ROSNode("tf_example")

# Broadcast transform
broadcaster = TransformBroadcaster(node)
transform = create_transform_stamped("map", "base_link", (1.0, 2.0, 0.0), (0.0, 0.0, 0.0, 1.0))
transform.header.stamp = to_msg_time(now())
send_transform(broadcaster, transform)

# Listen to transform
listener = TransformListener(node)
transform = lookup_transform(listener, "map", "base_link")

shutdown()

Testing

Tested with:

• ROS2 Humble on Ubuntu 22.04
• ROS2 Jazzy on Ubuntu 24.04
• Transform broadcasting and lookup
• RViz visualization

Dependencies

• tf2_ros (installed via apt with ROS2)
• geometry_msgs (installed via apt with ROS2)

Backward Compatibility

Fully backward compatible. All existing code continues to work without modifications.