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How to use ur_modern_driver in gazebo #176
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The driver cannot be used with Gazebo, as it doesn't simulate a UR controller, but only a robot mechanism.
It would just state that it will not work, so I doubt that would be very useful. |
You might have more luck with That can be used with |
Hi, @gavanderhoorn , |
Hi, @gavanderhoorn , |
Using You should then be able to provide that with appropriate input and control it. As to whether that is simple: I don't know. That will depend on your experience and a lot of other factors. |
Btw:
be careful with sentences that start with |
Hi, @gavanderhoorn , |
Hi, @gavanderhoorn , |
The UR controller exposes a velocity control interface (ie: you can directly control joint velocity). That is what the driver uses. |
Hi, @gavanderhoorn , |
For gazebo you'll want to make sure you load the correct controller from
If you use the correct hardware interface in the xacro, that is not necessary. |
I tried to load the velocity controller for UR in gazebo, and then I found that I should adjust the PID parameters for the controller, but I didn't know how to got the right parameters. Do you have any suggestions? |
No, unfortunately not, other than try to use the regular way of tuning parameters of a PID. I haven't used it myself so I cannot guide you. But a note: as soon as you start using actual controllers (so not just transparent pass-through), tuning parameters is going to be needed there is no way around it. |
Oh, I see. Thank you very much. |
which "velocity control interface" are you now referring to here? The real one robot+controller, or the simulated one? |
The real one robot + controller, i.e. the velocity control mode in ur_modern_driver. |
That would be something only UR can authoritatively answer, but I would expect the answer to be "no". Why would it have to be position based? The internal controller can just look at dx/dt and increase/descrease motor current to achieve a desired rotational velocity. |
That is a position controller implemented using velocity control. Input: position setpoint To control joint velocity, use the |
You need to pass a |
Oh, I see. I think I've figured out the problem. |
Yes (and make sure to use the appropriate hardware interface in the xacro), but please understand that all of that has nothing to do with |
Ok, Thank you~ |
@geweihgg have you had any luck? |
@nag92 , yes, changing the controllers from position_controllers/JointTrajectoryController to velocity_controllers/JointVelocityController is ok, then we can tune the PID parameters with rqt_gui. |
Would I be able to take a look at your code? |
Yes, I'll show you the code tomorrow~ |
@nag92 , the JointVelocityController codes are listed bellow:
And if you want to control the arm with JointPositionController, you can add it into the controller.yaml file. |
@geweihgg Thanks in advance! |
Hi,
I think you can try to tune the PID params for velocity controller.
GeWei
发自我的 iPad
…------------------ Original ------------------
From: Abbyls <notifications@github.com>
Date: Fri,Oct 25,2019 9:09 PM
To: ros-industrial/ur_modern_driver <ur_modern_driver@noreply.github.com>
Cc: geweihgg <249806873@qq.com>, Mention <mention@noreply.github.com>
Subject: Re: [ros-industrial/ur_modern_driver] How to use ur_modern_driver in gazebo (#176)
@geweihgg
Hi, I am also trying to use velocity control for the ur in the gazebo. However, the velocity control cannot work well, there is always gravity pull the links falling down. And in the beginning of loading the gazebo, the robot arm can not stand up at a target pose.
Have you encountered this problem? Could you give me some suggestions?
Thanks in advance!
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Hi GeWei, Could you give me some guidance for tuning the PID for the velocity controller? |
I think this issue is not related with Please see the following open issues: So far, unfortunately, we couldn't find a proper solution for this problem, please follow and comment the previously mentioned discussions. |
Hi,
I want to use ur_modern_driver to publish joint speed commands to control the ur5 arm in gazebo, so I clone this repository and catkin_make it. Then I rewrite the ur5.launch file to load ur_modern_driver/config/ur5_controllers.yaml, and spawn it. But some errors occur like this:
Can you help me?
Um... Maybe a clear tutorial on how to use ur_modern_driver with ur5 in gazebo is perfect.
Thank you very much.
GeWei
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