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A small confusion about topics

asked 2021-02-03 16:52:07 -0600

Momit gravatar image

Hello I am new to ros, I See people always use cmd_vel topic for geometry msgs. My confusion is, what is the reason of always using cmd_vel? Can't we use other topic name? Or there are some existing topics like msg, such as ros have existing msg type like Twist, odom, pose etc. If ros 2 also have some existing topics, what are they? how to find them? (Sorry for bad English).

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I didn't get the second part of your question. ('or there are .....')

skpro19 gravatar image skpro19  ( 2021-02-04 15:08:14 -0600 )edit

Thanks everyone ๐Ÿ˜Š

Momit gravatar image Momit  ( 2021-02-06 14:22:47 -0600 )edit

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answered 2021-02-04 09:20:12 -0600

crnewton gravatar image

controllers subscribe to /cmd_vel to read their velocity command. you can use whatever topic name you want, but the controller is most likely not subscribed to the topicname you came up with. You can view all the topics with rostopic list as described in the documentation.

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answered 2021-02-04 15:07:16 -0600

First of all, there's a small correction. People usually used cmd_vel topic for [geometry_msgs/Twist] messages.

We can use any topic name we want. Using the name cmd_vel is sort of a ROS convention.

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Asked: 2021-02-03 16:52:07 -0600

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Last updated: Feb 06 '21