How to plot position(x y z) and velocity of fixed frames(end-effector) in rqt ??

asked 2017-01-21 10:37:02 -0500

217 ●52 ●61 ●73

updated 2017-04-13 01:39:37 -0500

hi . i need answer to complete my Master's thesis. i want plot position and velocity of end effector that have fixed joint using rqt. How to plot position(x y z) and velocity of fixed frames(end-effector) in rqt ?? can you write a very very very simple examlpe for that ?? like two link and one joint arm . and plot position(x y z) of second link in rqt ??

UR5 straight line motion

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Please stop editing your question just to put it back on the first page.

NEngelhard ( 2017-04-13 01:43:45 -0500 )edit

can you write a very very very simple examlpe for that ?? for god doing that , please !

zakizadeh ( 2017-04-13 04:33:48 -0500 )edit

You don't show that you tried to do it yourself, you don't even care about writing correctly. Why should someone else do your work?

NEngelhard ( 2017-04-13 05:52:20 -0500 )edit

i tried . but i just need examlpe for that . i cant find any sample , like two link and one joint arm . and plot position(x y z) of second link in rqt

zakizadeh ( 2017-04-13 14:03:55 -0500 )edit

You were told how to do it several times: get a tf client, use it to get your translation, publish your values on separate float-topics.

NEngelhard ( 2017-04-13 14:49:16 -0500 )edit

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answered 2017-01-21 10:48:45 -0500

gvdhoorn
86574 ●283 ●1432 ●1054 http://cor.tudelft.nl/

updated 2017-01-21 12:34:32 -0500

A fixed joint has no element in the /joint_states/position array, as it cannot change from 0.0 (it's fixed, after all).

You could probably use the pose of your EEF as tracked by TF. Something like rosrun tf tf_echo CHAIN_START CHAIN_END (where CHAIN_START could be base_link and CHAIN_END the frame that represents your EEF) should give you the transform.

Edit:

how can i plot velocity of fixed joint ??

There is no entry in any of the arrays in a JointState message for fixed joints. Again: they are fixed. No velocity, acceleration or effort for these joints.

Note: I'm describing the typical situation (such as with joint_state_publisher with gui:=true). Whether all drivers do the same thing I cannot say, but it wouldn't make sense to me to publish joint values for something like a fixed joint.

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how can i plot pose for my fixed joint(joint_U26_1) like rqt_plot /turtle1/pose/x:y ??

what is a turtle1 ??

zakizadeh ( 2017-01-21 20:47:52 -0500 )edit

Joints don't have poses, only links have poses (every link becomes a TF frame). Plotting TF frames is slightly involved. See #q58793 for some hints.

gvdhoorn ( 2017-01-22 04:02:55 -0500 )edit

Some other options:

gvdhoorn ( 2017-01-22 04:05:58 -0500 )edit

how use this command ?? rxplot /tf/transforms[0]/transform/translation/x thats not working .

zakizadeh ( 2017-01-22 10:45:03 -0500 )edit

rxplot is now rqt_plot.

gvdhoorn ( 2017-01-22 15:20:01 -0500 )edit

rqt_plot /tf/transforms[0]/transform/translation/x not working .

can i use this page?? what can i do ?

zakizadeh ( 2017-01-22 20:57:43 -0500 )edit

what about this one??

zakizadeh ( 2017-01-23 10:34:41 -0500 )edit

That page still works with JointState messages, which do not typically include fixed joints. You'll have to plot TF frames, not JointState msgs. The pkgs I linked in my earlier comment could help you with that.

gvdhoorn ( 2017-01-23 10:53:54 -0500 )edit

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How to plot position(x y z) and velocity of fixed frames(end-effector) in rqt ??

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