Can Robot Models for simulations be used in all ROS versions?

Question

I'm having trouble in simulating robots in gazebo as most models use ROS indigo in their documentaries as well as in Ros.org domentaries; basically all robots I've encountered so far.

Such as (fetch robot):

sudo apt-get install ros-indigo-fetch-gazebo-demo

which prints out this Error:

indigo-fetch-gazebo-demo

Reading package lists... Done

Building dependency tree

Reading state information... Done

E: Unable to locate package ros-indigo-fetch-gazebo-demo

so I tried just changing indigo to my current version (Melodic_

sudo apt-get install ros-melodic-fetch-gazebo-demo

but the same error prints out:

melodic-fetch-gazebo-demo

Reading package lists... Done Building

dependency tree Reading state

information... Done

E: Unable to locate package ros-melodic-fetch-gazebo-demo

Am I doing anything wrong?

or the model just hasn't been updated for melodic? (if so, what robot models are for melodic?)

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Originally posted by JerelVelarde on ROS Answers with karma: 3 on 2018-10-12

Post score: 0

Answer 1

The issue you are running into is not one of whether the simulation works, but whether the simulations have been released as debian (ie: .deb) packages for a specific OS and ROS release.

Seeing as you tagged this melodic, I'm going to assume you are running Ubuntu Bionic.

On a Bionic machine you cannot install packages built for ROS Indigo -- that version of ROS just isn't supported on Ubuntu Bionic (see REP-3).

And since fetch_gazebo_demo (the ROS package) has not been released for Melodic, trying to install it using apt-get will also not work: the debian package simply doesn't exist (see status_page/ros_melodic_default.html?q=fetch_).

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Now as to the question of whether simulations (and I'm assuming Gazebo simulations here) created for ROS Indigo will work on ROS Melodic: the question is more subtle than that. ROS Indigo installed Gazebo 2.2 by default (see REP-3 again). ROS Melodic comes with Gazebo 9 (see REP-3).

There are quite a few changes between these two versions of Gazebo (and about 6 major versions), both in terms of the API and ABI as well as the dynamic behaviour of the simulator and the things that are simulated (Gazebo 9 has become a lot more realistic in its simulation than Gazebo 2 ever was).

So even while things (ie: plugins or Gazebo models) may work (ie: load) perhaps after fixing some incompatible things, the behaviour they exhibit in Gazebo 9 vs Gazebo 2 may be so different that we can no longer state that they "work".

Note that I'm not referring to the Fetch packages that you mention -- I don't know whether they work -- but wanted to address your question in general.

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Originally posted by gvdhoorn with karma: 86574 on 2018-10-12

This answer was ACCEPTED on the original site

Post score: 1

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Original comments

Comment by JerelVelarde on 2018-10-13:
Thanks, had a hint that thsi would be the issue. however I'm having issues with models for melodic; for example the fetch robot, I found this bot under the melodic robots category but in the documentations the instructions are all for indigo :(

Comment by gvdhoorn on 2018-10-14:
That would be something to "complain" about to Fetch. They are the ones who release those packages. I don't own one of those robots, so I don't know, but you could look around to see whether someone forked their pkgs to make them compatible with Melodic.