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Published a new message that contains:

Open michaelblindnology opened this issue 3 years ago • 12 comments

michaelblindnology avatar May 18 '21 15:05 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.

michaelblindnology avatar May 18 '21 15:05 michaelblindnology

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

pavloblindnology avatar May 18 '21 17:05 pavloblindnology

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

DLu avatar May 18 '21 18:05 DLu

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 avatar May 18 '21 19:05 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.

mikeferguson avatar May 18 '21 19:05 mikeferguson

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 avatar May 19 '21 05:05 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 avatar May 19 '21 05:05 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?

pavloblindnology avatar May 19 '21 07:05 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 avatar May 19 '21 13:05 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.

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

pavloblindnology avatar May 21 '21 18:05 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.

DLu avatar May 26 '21 19:05 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.

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.

pavloblindnology avatar May 27 '21 06:05 pavloblindnology