Resetting iCub in Gazebo from C++

[serena-ivaldi]

Hi all

we are trying to make the iCub in Gazebo learn by reinforcement learning some WB behaviors that frequently fail and cause the robot to fall/crash in Gazebo I was looking for the correct procedure to send the reset() to the world in Gazebo and to the controlBoards of the iCub but I cannot find the information.

Could you help us?

We are calling that from C++.

If we manually reset Gazebo (with CTRL+R) the world is reset, the iCub ports are still there but we basically loose the connection with the iCub motor controllers and we cannot move it anymore.

Thanks!

@lothas

[traversaro]

Hi @serena-ivaldi , which version of Gazebo are you using? As documented in http://robotology.gitlab.io/docs/gazebo-yarp-plugins/master/troubleshooting.html , we had problems in the past with the reset world of Gazebo < 7.2 . And recently @diegoferigo experienced problems with the latest Gazebo 7 (I guess Gazebo 7.8), and he had to update to Gazebo 8 to get the reset world to work.

[diegoferigo]

Adding more details, the only issue still present with Gazebo 8 is the following:

[ERROR]An hardware fault occurred on joint  2  torque too big!

But on this version, removing iCub and adding it again does work, Gazebo 7 always crashed (cc @nunoguedelha).

For what concern the C++ side, let's wait someone with more experience (than me at least) in dealing with its code.

[traversaro]

The hardware fault error is when a joint has a torque value bigger than 2000 Nm . https://github.com/robotology/gazebo-yarp-plugins/blob/93644b645efc56ce124e65b80f64b92dcc1a7cdb/plugins/controlboard/src/ControlBoardDriver.cpp#L69 .

[lothas]

We are running Gazebo 7.7. Right now we are solving the issue by creating and destroying all the ports between two resets, but this is not optimal.

[traversaro]

What you mean "creating and destroying all the ports" ?

[lothas]

Opening and connecting the ports, starting the threads etc. Then doing the opposite.

[traversaro]

Mhh, are you using the YARP_CLOCK enviromental variable and the libgazebo_yarp_clock.so plugin?

[lothas]

No. What would I use that for? I've attached the code below. icub_yarp_gazebo.txt

So we call connectGazebo(), run an episode, then disconnectGazebo() and reset Gazebo (CTRL+r). Rinse and repeat.