record time from rviz

hi, I am trying to record time from rviz in order to plot the velocity of an UR10 robot (using linux). I am totally new to ROS

Asked by Yosra Griri on 2019-01-23 11:41:57 UTC

Comments

Can you edit your question clarify what you mean by "record time"?

Asked by tfoote on 2019-01-23 16:59:43 UTC

RViz gives us ROS time right ? Well I am trying to track the robot and save a video of its movements which includes the time of course and if possible with the distance

Asked by Yosra Griri on 2019-01-24 03:31:10 UTC

What velocity are you trying to record? Joint angular velocities, end effector linear velocity or end effector 6DOF velocity? All of this can be done without RVIZ using the relevant topics.

Asked by PeteBlackerThe3rd on 2019-01-24 10:24:19 UTC

I am trying to get the cartesian ("linear") Velocity at a certain time.. I am so confused . I am a beginner to programming

Asked by Yosra Griri on 2019-01-24 10:45:47 UTC

Answers

You probably want to use rosbag.

It will allow you to save data from ROS topics and play the data again. If you are receiving joint states from the robot through a driver then you just have to record this and you will be able to get the speed of the robot etc.

Asked by VictorLamoine on 2019-01-24 10:21:28 UTC

Comments

I will try it thanks.

Asked by Yosra Griri on 2019-01-24 10:46:11 UTC

If you want to record the linear velocity of the end effector of your UR10 then you're going to have to program a simple node to do this yourself.

The python transform listener tutorial should be a good place to start. You'll want to look up the transform between the base frame and EE frame, then by comparing two different samples you can work out the change in position and change in time and therefore working out the velocity.

Hope this makes sense.

Asked by PeteBlackerThe3rd on 2019-01-24 11:30:04 UTC