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Transmission and track chain [closed]

asked 2015-02-12 01:44:16 -0500

Myzhar gravatar image

I added a "transmission" block in the URDF to describe the model of the tracks of my robot... My tracks are triangular, with an active sprocket and two passive sprockets. The active sprocket is rotated according to joint state message in my "control node". I expected that this kind of description resulted in a automatic joint state update of the passive sprockets in Rviz, but I think to have not understood very well how "transmission" works.

Does transmission work only in Gazebo?

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Closed for the following reason the question is answered, right answer was accepted by Myzhar
close date 2015-02-17 09:26:28.301026

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answered 2015-02-12 04:16:15 -0500

Adolfo Rodriguez T gravatar image

If you mean ros_control's transmissions, only simple reducers are supported in Gazebo.

It sounds like you need to implement a custom transmission type. Is this what you are trying to do?. If so, what is exactly the behavior you want to produce: That the active sprocket triggers motion of the two passive ones, or do you also want to move some sort of track geometries?.

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I would like to move the passive sprockets according to the angular position of the active respecting the radius ratio propagated by the track chain. I was going to create a subscriber to the joint_state message submitted by the "active" sprockets, but it does not seems a good solution to me.

Myzhar gravatar image Myzhar  ( 2015-02-14 08:50:53 -0500 )edit

If you just want the passive sprockets to move as a linear function of the active one, consider using mimic joints (look for <mimic> element documentation).

Adolfo Rodriguez T gravatar image Adolfo Rodriguez T  ( 2015-02-17 04:14:25 -0500 )edit

Great!!! It is just what I was searching for!!! Thank you very much

Myzhar gravatar image Myzhar  ( 2015-02-17 06:54:03 -0500 )edit

Glad to hear!. Please mark the question as answered if it is indeed the case.

Adolfo Rodriguez T gravatar image Adolfo Rodriguez T  ( 2015-02-17 08:06:42 -0500 )edit

Hey, for the record. To mark a question as answered, you don't need to close it and provide a reason. There's a checkmark icon to the left of every answer. Once you click on it, it becomes green, and the question is considered answered. You can only accept one answer (when there are more than one).

Adolfo Rodriguez T gravatar image Adolfo Rodriguez T  ( 2015-02-19 04:33:40 -0500 )edit

Done... I thought that closing it was the most complete way. Thank you again

Myzhar gravatar image Myzhar  ( 2015-02-19 05:06:58 -0500 )edit

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Asked: 2015-02-12 01:44:16 -0500

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Last updated: Feb 12 '15