Pose calculation in gazebosim tutorial

edit

I don't think there's a tutorial for it yet. Here's my attempt at a basic overview:

Transform

Poses in Gazebo represent a transform between two frames. They are defined by 6 values:

<pose> x y z roll pitch yaw </pose>

• Translation (x y z) is applied before rotation (roll pitch yaw)

• Fixed axis is used for the rotation

Reference frames

Currently poses are always defined with respect to a specific frame according to the element it belongs to. This is documented in the SDF specification for that element, see link -> pose for an example. I'll list some of the most used ones here as a quick reference:

• Model -> World
• Link -> Model
• Visual -> Link
• Collision -> Link
• Joint -> Child link
• Inertia (CoM) -> Link

Experimenting

I recommend you experiment with poses using the left panel and see how different poses affect your model.

1. Turn off gravity so your model stays in place: on the left panel, choose Physics and set all gravity elements to zero.

2. Insert a box, right click it and view it transparent, then also choose to view link origin. This will show the frame you're manipulating.

3. On the left panel, choose the box and input different poses to see how it moves with respect tot he world frame. Make sure the simulation is not paused.

Reference

You might want to look at the ignition math Pose class for a deeper insight.