Gazebo URDF: two axis of rotation

asked 2016-11-18 16:13:10 -0500

nikku gravatar image

Hi. I'm using Ubuntu 14.04 ROS Indigo Gazebo 2.2

I'm setting up a 4-wheeled car simulation in Gazebo which should be able to interact with ROS. For that I want to have joints at the front wheels which allow them to rotate to travel forward as well as to be steered. Therefor the wheel-hinge-joint should have two axes of rotation which are perpendicular to each other.

How can I accomplish this?

I couldn't find any suitable joints in the URDF-ROS-Documentation.

Thanks

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Comments

Usually you would create one joint first, then create an infinitesimally small link, then the second joint.

JoshMarino gravatar imageJoshMarino ( 2016-11-18 21:28:35 -0500 )edit

Thanks. I will try that!

nikku gravatar imagenikku ( 2016-11-19 00:04:51 -0500 )edit

No need for an "infinitesimally small link", just make two joints that are at a 90 degree offset to each other.

I couldn't find any suitable joints in the URDF-ROS-Documentation.

So what kind of joint would you have liked to see? You wrote it yourself: it's just two revolute joints :).

gvdhoorn gravatar imagegvdhoorn ( 2016-11-19 03:57:31 -0500 )edit

Implemented in Gazebo SDF with revolute2 joint.

JoshMarino gravatar imageJoshMarino ( 2016-11-19 06:36:39 -0500 )edit

Well, yes. But that is SDF, not URDF. And that is also 'just' two revolute joints at an angle. From the SDF spec page:

revolute2: same as two revolute joints connected in series

so that is just a bit of convenience.

gvdhoorn gravatar imagegvdhoorn ( 2016-11-19 08:12:45 -0500 )edit