Ontology in ROS

[Taha Elsenosy]

Is there any way to use owlready2 inside ROS (Robotic Operation System) to handle the ontology, if not, then can anyone guide me to find a way to do that?
Thanks

[Jiba]

Hi,

I've never used ROS, but if it has Python, Owlready should be useable on it.

Jiba

[Taha]

Thanks Jiba, I've worked with owlready in python, and yes ROS having python in it, but the implementation is different in ROS, I'll figure a way to solve it.

Many thanks,
Taha Elsenosy

[Hiba]

Hello
I think there is a way to integrate an ontology in ROS by using ARMOR but Indeed, I found many difficulties.

[Taha Elsenosy]

Thanks @Hiba

To be honest, i've worked with ARMOR, it has a lot of functionality to manipulating ontologies, but it still under developing, i found a lot of uncompleted functions related to SPARQL, so i moved to work with rdflib to make SPARQLs to the ontology

since that the owlready2 doesn't works with python 2.7, the version that ROS is already used.

I hope i can finish my task through these libraries.

Many thanks

[Hiba]

For me, I try to infer SWRL rules but still can't find a way to do it😒

[Taha Elsenosy]

The same problem i face, so i moved to work with rdflib, try it.

[Hiba]

Okey thanks a lot

[Lynsie]

@Taha how can you infer the swrl rules with rdflib plz?

[Taha Elsenosy]

Let me explain some staff, i thought that i can infer SWRL with rdflib, but i was wrong,
rdflib is just to querying and it doesn't has Reasoner to infer the ontology, so i was searching about that, then i found that it is possible to make SWRL rules using
pullet reasoner,

read this: https://stackoverflow.com/questions/31500701/how-to-use-swrl-builtin-in-owlapi-with-pellet?rq=1 and this: http://dior.ics.muni.cz/~makub/owl/ ,

for now, i'm still searching, but i think these links may help us.

Thanks.

[Taha]

@Lynsie
I found that owlready2 , owlready2 version 2 - 0.15 has a new version which can infer data property values when reasoning with Pellet

Try it.

[Lynsie]

Actually, i got an error while calling sync_reasoner()

[Taha]

Let me explain what you have to do to make things work,

First of all you should test the SWALLOW on protege first,
Then save the rule to your ontology
Load the ontology using owlready2 in python,
Notice that the SWRL works with PELLET reasoner,
But sync_reasoner() function runs the HermiT reasoner, so there won't be an inferred objects

Instead of that you should use sync_reasoner_pellet(), the functions  added to the newer version of owlready2, you have to make sure you installed this version

Read this carefully

https://owlready2.readthedocs.io/en/latest/reasoning.html#running-the-reasoner

If you still got errors, post it here.

Regards,

[Lynsie]

this is the error i got:
RuntimeError: cannot release un-acquired lock

[Jiba]

Hi,

A bug in Owlready causes this error to be raised instead of another, during reasoning.

You can either use Owlready 0.16 (just release) to find the real error, or call the reasoner outside a "with..." block.

The real error is probably that the ontology is inconsistent.

Jiba

[Lynsie]

Thank you Jiba for your quick reply.
Actually, I have installed Owlready 0.16 but i got OwlReadyJavaError. I tried two versions of java but the problem still persist.

[Lynsie]

Finally, I noticed that when I remove the SWRL rules from my ontology, the sync_reasoner_pellet() works.
I don't know how to fix this.

[Jiba]

Hi,

The OwlreadyJavaError means that an error occured in the Java reasoner. You need to check the Java error message (it should be displayed on the terminal).

If you send me your ontology, I can look at it.

Jiba

[Lynsie]

Could you send me your email, please, so that I can send you the ontology.

[Jiba]

My address is jiba (at) lesfleursdunormal.fr