FakeSystem initial_value does not seem to work correctly

[AndyZe]

I am launching one of the common test packages from MoveIt, the Panda. The ros2_control xacro is here:

https://github.com/ros-planning/moveit_resources/blob/ros2/panda_moveit_config/config/panda.ros2_control.xacro

I saw this deprecation warning:

[ros2_control_node-5] [WARN] [1642614151.127346724] [fake_generic_system]: The usage of initial_position has been deprecated. Please use 'initial_value' instead.

So I tried updating initial_position to initial_value in that ros2_control xacro file. Yet, the robot does not move to the initial position like it used to.

[AndyZe]

I wonder if it's because these joints have 2 state interfaces: position and velocity.

[AndyZe]

@destogl can I ask how this feature is supposed to work? I don't see any usage example in ros2_control_demos.

Is it:

<state_interface name="position" initial_value="0.0"/>
<state_interface name="velocity" initial_value="0.0"/>

or

                <param name="initial_value">0.0</param>
                <command_interface name="position" />
                <state_interface name="position"/>
                <state_interface name="velocity"/>

I hope it's option 1. Option 2 wouldn't make sense if there are multiple state interfaces.

[AndyZe]

OK, I finally got it working like this:

                <param name="initial_position">${initial_positions['panda_joint4']}</param>
                <param name="initial_velocity">${initial_positions['panda_joint4']}</param>
                <command_interface name="position"/>
                <state_interface name="position"/>
                <state_interface name="velocity"/>

Will make a small PR to give a warning to the user.

[wmmc88]

@destogl can I ask how this feature is supposed to work? I don't see any usage example in ros2_control_demos.

Is it:

<state_interface name="position" initial_value="0.0"/>
<state_interface name="velocity" initial_value="0.0"/>

or

                <param name="initial_value">0.0</param>
                <command_interface name="position" />
                <state_interface name="position"/>
                <state_interface name="velocity"/>

I hope it's option 1. Option 2 wouldn't make sense if there are multiple state interfaces.

For anyone stumbling upon this looking for the new preferred syntax, there's an example in the test file:

ros2_control/hardware_interface/test/fake_components/test_generic_system.cpp

Line 259 in a362e2b

<param name="initial_value">2.78</param>

[AndyZe]

Thanks @wmmc88!