Home | Tutorials | Wiki | Issues
Ask Your Question
0

Conversion from URDF to SDF using gzsdf issues

asked 2016-11-21 13:38:48 -0500

this post is marked as community wiki

This post is a wiki. Anyone with karma >75 is welcome to improve it.

Hi,

My question is two-fold.

(i) I have a URDF which has parallel linkages and multijoint definitions. I noticed that having a child link with multiple parent links gave unexpected behavior when using the joint_state_publisher gui to move the joints: I could only use one actuator joint to move the head I am trying to control. The xacro file is in this link.

(ii) I tried to export my URDF model to gazebo and in light of this, I wrote a separate file as was done in the rrbot example that adds a gazebo element for each link and joint. So I include the superchick_gazebo file within my superchick.xacro file and when I try to load it in gazebo, I notice that all my links come out correctly but the joints are not well placed as they are in rVIZ :

model

Here's what the interpreted sdf looked like in Gazebo.

gazebo

In my terminal, I noticed warnings such as

Warning [parser_urdf.cc:346] attempted to add visual to link [base_panel], but it already exists under group [lump::panel_12_oc]
Warning [parser_urdf.cc:346] attempted to add visual to link [base_panel], but it already exists under group [lump::panel_3_oc]
Warning [parser_urdf.cc:346] attempted to add visual to link [base_panel], but it already exists under group [lump::panel_9_oc]
Warning [parser_urdf.cc:317] attempted to add collision to link [base_panel], but it already exists under group [lump::panel_12_oc]
Warning [parser_urdf.cc:317] attempted to add collision to link [base_panel], but it already exists under group [lump::panel_3_oc]
Warning [parser_urdf.cc:317] attempted to add collision to link [base_panel], but it already exists under group [lump::panel_9_oc]
Warning [parser_urdf.cc:346] attempted to add visual to link [table_top], but it already exists under group [lump::base_panel]
Warning [parser_urdf.cc:346] attempted to add visual to link [table_top], but it already exists under group [lump::panel_12_oc]
Warning [parser_urdf.cc:346] attempted to add visual to link [table_top], but it already exists under group [lump::panel_3_oc]
Warning [parser_urdf.cc:346] attempted to add visual to link [table_top], but it already exists under group [lump::panel_9_oc]
Warning [parser_urdf.cc:317] attempted to add collision to link [table_top], but it already exists under group [lump::base_panel]
Warning [parser_urdf.cc:317] attempted to add collision to link [table_top], but it already exists under group [lump::panel_12_oc]
Warning [parser_urdf.cc:317] attempted to add collision to link [table_top], but it already exists under group [lump::panel_3_oc]
Warning [parser_urdf.cc:317] attempted to add collision to link [table_top], but it already exists under group [lump::panel_9_oc]
Warning [parser_urdf.cc:346] attempted to add visual to link [table_top], but it already exists under group [lump::big_bladder_link]
Warning [parser_urdf.cc:317] attempted to add collision to link [table_top], but it already exists under group [lump::big_bladder_link]
Warning [parser_urdf.cc:346] attempted to add visual to link [table_top], but it already exists under group [lump::left_bladder]
Warning [parser_urdf.cc:317] attempted to add collision to link [table_top], but it already exists under group [lump ...
(more)
edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
0

answered 2016-11-22 09:39:39 -0500

nkoenig gravatar image

SDF supports parallel linksages, but URDF does not. Everything in URDF must be a tree, not a graph. I think you can work around this by using <gazebo> reference elements in your URDF file.

edit flag offensive delete link more

Comments

I already did but it doesn't help. To improve my visuals, I stripped the links that were giving warnings of their collision elements and removed the other two actuators. I now have a simplified model but I still get `Error [Model.cc:640] can't have two joint with the same name Exception [Model.cc:641] can't have two joint with the same name Error [Model.cc:134] LoadJoint Failed [INFO] [WallTime: 1479872980.124301] Spawn status: SpawnModel: Successfully spawned model `

lakehanne gravatar imagelakehanne ( 2016-11-22 21:36:43 -0500 )edit

You have an err that says a model can't have two joints with the same name. Try resolving that error by changing joint names.

nkoenig gravatar imagenkoenig ( 2016-11-23 11:29:00 -0500 )edit
Login/Signup to Answer

Question Tools

1 follower

Stats

Asked: 2016-11-21 13:38:48 -0500

Seen: 331 times

Last updated: Nov 23 '16