AckermannSteering System does not publish Tf

[andyblarblar]

Enviornment

OS: Ubuntu 20.04
Used with ROS2 Galactic over ign_bridge

Details

It appears that the AckermannSteering system does not publish tf alonside its odometry output, which means that this plugin is unusable for use with slamtoolbox, as no odom->base_footprint transform is generated.

This does not occur with the DiffDrive system plugin, which does produce such an output, here in source:

gz-sim/src/systems/diff_drive/DiffDrive.cc

Line 618 in d6e69d0

this->tfPub.Publish(tfMsg);

For refrence, here is where that line would be in the ackermann system, which simply publishes odom:

gz-sim/src/systems/ackermann_steering/AckermannSteering.cc

Line 671 in d6e69d0

this->odomPub.Publish(msg);

It belive that simply pasting the tf code from the DiffDrive system over to the AckermannSteering system should solve this problem, but I'm not too familar with the ignition ecosystem.