Published a new message that contains:

[michaelblindnology]

No description provided.

[michaelblindnology]

The new message: Path, which contains: current position, goal position, path length, and time left to goal.
The message published in the context of action feedback.

[mikeferguson]

How is this different from the paths published by the local/global planners?

[mikeferguson]

we should not be adding messages to move_base - there is a move_base_msgs package in a separate repo specifically so that users of nav do not have to build all of nav on remote machines that are monitoring outputs.

There is also a standard path message in nav_msgs, why not use that?

[michaelblindnology]

Hi,
I used my msg instead of nav_msg/Path, since I need

float32 dist_to_goal # Path distance left to goal (m)
float32 time_to_goal # Time left to goal to navigate along path (s)

[pavloblindnology]

@mikeferguson The idea of this message is to publish distance to goal along global plan plus estimated time needed to get to the goal.

[DLu]

It also probably makes more sense to make an action that publishes feedback, as opposed to creating a new topic just called feedback.

Also, I did something similar over with locomotor

[mikeferguson]

It also probably makes more sense to make an action that publishes feedback, as opposed to creating a new topic just called feedback.

It seems really late in the ROS1 lifecycle to be adding an entirely new action interface to move_base.

[mikeferguson]

The idea of this message is to publish distance to goal along global plan plus estimated time needed to get to the goal.

So, this looks quite non-generic: the estimate of distance remaining is straight-line (as opposed to the distance along the actual path) and the estimate of time remaining is quite likely inaccurate (it's just using the current speed, it has no idea what the future velocities might be, and the distance it's applied over is kinda wrong too as previously mentioned).

My suggestion would actually be to write a separate node (outside the nav stack) that subscribes to the plan already being published and computes the distance/time remaining and publishes it on a topic for your application.

[pavloblindnology]

The real distance along the path should be just computed instead of a straight line distance. Then, the time estimation based on max speed is the best we can do. Also, action is not suitable as goal can come through move_base_simple and/or 3rd party other than the action caller may need this info.

[pavloblindnology]

Also, I did something similar over with locomotor

I heard about robot_navigation, but never tried. Is there any documentation on it?
How does it compares to move_base_flex, which seems to be more documented and maintained?

[pavloblindnology]

It also probably makes more sense to make an action that publishes feedback, as opposed to creating a new topic just called feedback.

What about extending existing action feedback instead of publishing to a new message?

[mikeferguson]

What about extending existing action feedback instead of publishing to a new message?

You can't change the action feedback - that would change the MD5 checksum of the messages, which would break API/ABI.

[pavloblindnology]

What about extending existing action feedback instead of publishing to a new message?

You can't change the action feedback - that would change the MD5 checksum of the messages, which would break API/ABI.

@mikeferguson Understood. Is there any chance to have this merged if publishing to a new message?

[DLu]

Other than knowing what the current linear velocity is, is there any part of this that you can't derive from other published material? You can get the pose from TF and goal from current_goal.

[pavloblindnology]

Other than knowing what the current linear velocity is, is there any part of this that you can't derive from other published material? You can get the pose from TF and goal from current_goal.

Well, velocity and global plan can also be derived from other published material. But as for me, it's nice to have this functionality integrated. Just drop a goal in RViz and you start getting some important feedback. If this doesn't suit your vision in any way, please let me know, so that my team can plan another solution. Thanks.