World Joints

[methylDragon]

Should we be forcing blue to be fixed at the origin in Gazebo with the world joint?

That stops the model from being moved around which might be inconvenient if people want to simulate the robot somewhere else in a simulated world.

[wuphilipp]

Humm yes, that's true. Without fixing the robot to the world frame the robot tends to float away in the zero gravity world. We have the zero gravity gazebo world to simulate the control interface a user would have, where the hardware interface provides the gravity compensation.

I agree though that it is inconvenient. Maybe we can add a parameter that allows the user to choose if they want the extra joint?

[brentyi]

Perhaps we should move towards re-enabling gravity in the Gazebo world?
It might be a little less clean for use on the real robot, but one option would be to move the gravity compensation code from the controller manager level to the controller level.

[wuphilipp]

Alright sounds good. I've gone ahead and made these two pull requests which should address this.
#76
berkeleyopenarms/blue_simulator#12

Let me know what you all think!