Add Tiago robot, configs and examples

[dnandha]

Add Tiago Single and Dual arm robots

1. Download this zip file and extract it into the main iGibson folder (the files will be automatically extracted to gibson2/data/assets/models/): tiago_modelv2.zip
2. Run Tiago examples:

• cd gibson2/examples/demo
• python tiago_example.py for loading Tiago Single and Dual arm and performing small motions (similar to existing robot_example.py)
• python tiago_dual_ik.py for inverse kinematics demo with Tiago Dual arm (similar to the existing ik_example.py, move target with arrow keys)

[fxia22]

Hi @dnandha , thanks for the contribution. Just by briefly looking at it I find that tiago_dual_hand.urdf is missing, and also in the urdfs some links don't have inertia frame, which doesn't work really well for pybullet since it will use a very large inertia matrix as default.

[dnandha]

Hi @fxia22, thanks for your comments. For the missing urdf please note that the PR was updated yesterday and a new zip file was uploaded ("...v2.zip"), it contains the tiago_dual_hand.urdf. As for the missing inertia frames we will be in contact with PAL robotics to get these issues fixed as the URDF's in this PR have been generated from the official xacro provided by PAL robotics (https://github.com/pal-robotics/tiago_dual_robot/blob/kinetic-devel/tiago_dual_description/robots/tiago_dual.urdf.xacro).

[sjauhri]

Created an issue in the PAL repository to fix the urdf inertias: pal-robotics/tiago_robot#12

[dnandha]

Update: We have removed unused links in the tiago_single.urdf to get rid of missing inertia warnings. Furthermore, PAL robotics has fixed the "0" inertia values with this commit. We have updated the assets for tiago to reflect the fixes: tiago_modelv3.zip.

[sjauhri]

Update: We improved the examples for tiago_dual_ik and tiago_single_ik

[sjauhri]

Update: We made minor improvements for better visualization (colors) of the tiago robot. Updated urdf assets: tiago_modelv4.zip