2020-12-28 02:45

Collision sometime with the ground

Hello everyone,

My environment

ROS Distro: [Indigo]
OS Version: e.g. Ubuntu 14.04
Source or Binary build?
If binary, which release version? install with : sudo apt-get install ros-indigo-moveit => ros-indigo-moveit is already the newest version.

Gazebo 7 (before Gazebo 2.2 and also the same issue)

Do someone has an idea why the robot collides with the ground using moveit ? I am doing reinforcement learning and everything is working well except that part. I can go everywhere I need to go in cartesian space or using joint space. The end is working well too. But sometime when I work close to the ground and go from (x = 0.5, y = 0.1, z = 0.1) to (x = 0.5, y = 0.2, z = 0.1), it touch the ground. The robot then (a kuka iiwa lbr 7) deformed itself with the constraint and finally reach the point in more than 5 to 10 sec. I know it can reach those points with others paths but I don't understand why it take this one. I am working (unfortunately) on Ubuntu 14, with ROS indigo. I am using as solver: RRTkConfigDefault or maybe a bit better RRTConnectkConfigDefault.

Screenshot from 2019-07-11 12:02:04

Normally the robot looks like that: Screenshot from 2019-07-09 17:51:57

I can give you more information if you need it.

Kind regards,



  • 点赞
  • 写回答
  • 关注问题
  • 收藏
  • 复制链接分享
  • 邀请回答


  • weixin_39939530 weixin_39939530 4月前

    Thank you very much for you answer! I am really sorry for this kind of mistake. To anyone, it is working now! Screenshot from 2019-07-15 14:57:56

    点赞 评论 复制链接分享
  • weixin_39525255 weixin_39525255 4月前

    I am really sorry for this kind of mistake.

    no need to apologise.

    点赞 评论 复制链接分享
  • weixin_39989941 weixin_39989941 4月前

    Thanks for reporting an issue. We will have a look asap. If you can think of a fix, please consider providing it as a pull request.

    点赞 评论 复制链接分享
  • weixin_39525255 weixin_39525255 4月前

    Do you model your environment in your urdf / does MoveIt 'know' there is a ground plane there?

    点赞 评论 复制链接分享
  • weixin_39939530 weixin_39939530 4月前

    Seriously ? Is it so simple and me so s...pid ? :D I should do it by adding in the Step 3: Add Virtual Joints of the setup assistant? Or how can I do in the URDF file ? Bur I had set the workinspace with z >0...

    点赞 评论 复制链接分享
  • weixin_39525255 weixin_39525255 4月前

    How do you expect the planners to 'know' about any obstacles if the robot is simply floating in empty space in the description that you give them?

    Or how can I do in the URDF file ?

    Add a flat box under the robot?

    点赞 评论 复制链接分享
  • weixin_39525255 weixin_39525255 4月前

    I'm going to close this as it's likely to be a user-side configuration issue.

    If it's not, we can re-open.

    Feel free to keep commenting on the issue of course.

    点赞 评论 复制链接分享