Move_base action sever

Hello everybody!

I am trying to run the move demo that ubiquity provides and just keeps sending the “Move service not available” message.
I have done the basic verification of operation guide and everything seems fine.
Keeping in mind I am new to ROS, can you help me to troubleshoot?
Thank you very much for your availability!

Best regards,
Catarina

Hi @CatarinaPenacho,

In order to use the move demo, you need to have some kind of navigation system running.

roslaunch magni_nav move_basic.launch will bring one up that relies entirely on odometry, and will allow you to run to move demo, but will not have the best accuracy.

Rohan
Ubiquity Robotics

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Hi Rohan,
Is there another navigation package that offers a better accuracy than move_basic? I have been researching about this topic for a while and did not find anything.
Do you recommend programming it myself? Keeping in mind that I am not experienced in ROS.

Best regards,
Catarina

The accuracy of move_basic is going to be limited by the accuracy of the localization of the robot. If the robot doesn’t have a good idea of where it is or how far it has moved, it cannot navigate accurately.

If you run move_basic without any localization system, you are relying only on the odometry of the wheels, which is prone to inaccuracy and drift. We recommend our fiducial localization system, which estimates the position of the robot using ‘fiducial’ markers on the ceiling. https://learn.ubiquityrobotics.com/fiducials

Rohan

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I will chime in here to say that move_basic itself is a layer above the navigation stack.
Move basic goes to a new pose only within the limits that you set in it’s launch file.

I have found that an in development version of navigation is very much better than the limits that move_basic uses. So what happens is navigation may have great accuracy to within a couple cm of final location but move_basic may think that is ‘close enough’.

My overall message here is to point out that there is the navigation stack itself and then there is the control program above it (in this case move basic) that may think ‘good enough is good enough’ and may be completely happy with 5cm final X-Y part of the desired waypoint pose. .

I hope this helps isolate the layers and how they think for your usage.

Mark