[Python] ros2 control topic remapping inconsistency

Issue

When bringing up my gazebo simulation, the specified topic remaps for my ros2 controllers are not consistently remapping. It seems to be a toss up as to when the topic gets remapped. I'll provide more context as well as solutions I attempted bellow.

note: this issue only occurs when the dock is spawned alongside the robot, instances where the robot is spawned alone the topics remap correctly.

Context

I'm working on a simulation project which uses ros2_control to control a diff drive robot. In addition to this my dock is controlled using forward position controller. I have remapped the velocity command topics to '/cmd_vel' within my urdf for each robot.

Attempted Solutions

• Remapping topics within python launch files through the 'remappings' param
• Monitoring ros2 nodes on shutdown to ensure no remnants of previous runs are left hanging and potentially interfering with subsequent bring up attempts
• Changing Node launch order to start remapped topics first to subsequent nodes recognize the remapping

Code

remapping within robot_1 urdf (diff drive robot)

<gazebo>
<plugin filename="ign_ros2_control-system" name="ign_ros2_control::IgnitionROS2ControlPlugin">
<parameters>$(find test_robot_description)/config/test_robot_diff_drive_controller.yaml</parameters>
<ros>
<remapping>/diff_drive_base_controller/odom:=/robot_controller/odometry</remapping>
<remapping>/diff_drive_base_controller/cmd_vel_unstamped:=/cmd_vel</remapping>
</ros>
</plugin>
</gazebo>


Remapping within dock

<gazebo>
<plugin filename="ign_ros2_control-system" name="ign_ros2_control::IgnitionROS2ControlPlugin">
<parameters>$(find test_dock_robot_description)/config/dock_forward_controller.yaml</parameters>
<ros>
<namespace>dock</namespace>
<remappings>/robot_description:=/dock/robot_description</remappings>
<remappings>/joint_states:=/dock/joint_states</remappings>
<remappings>/position_forward_controller:=/dock/position_forward_controller</remappings>
</ros>
</plugin>
</gazebo>


portion of bring up responsible for ros2_controls in robot

joint_state_broadcaster_spawner = Node(
package='controller_manager',
executable='spawner',
arguments=[
'joint_state_broadcaster',
'--controller-manager',
'/controller_manager',
],
condition=UnlessCondition(
PythonExpression(
[
"'",
LaunchConfiguration('ros2_control'),
"' == 'None'",
]
)
),
)

diff_drive_controller_spawner = Node(
package='controller_manager',
executable='spawner',
arguments=[
'diff_drive_base_controller',
'--param-file',
controller_config,
],
condition=UnlessCondition(
PythonExpression(
[
"'",
LaunchConfiguration('ros2_control'),
"' == 'None'",
]
)
),
)


portion of bring up responsible for ros2_controls in dock

joint_state_broadcaster_spawner = Node(
package='controller_manager',
executable='spawner',
name='dock_spawner_joint_state_broadcaster',
arguments=[
'joint_state_broadcaster',
'-c',
'/dock/controller_manager',
'--param-file',
controller_param_file,
],
condition=UnlessCondition(
PythonExpression(
[
"'",
LaunchConfiguration('ros2_control'),
"' == 'None'",
]
)
),
)

forward_position_controller_spawner = Node(
package='controller_manager',
executable='spawner',
name='dock_spawner_forward_position_controller',
arguments=[
'forward_position_controller',
'-c',
'/dock/controller_manager',
'--param-file',
controller_param_file,
],
condition=UnlessCondition(
PythonExpression(
[
"'",
LaunchConfiguration('ros2_control'),
"' == 'None'",
]
)
),
)

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