{"action":"opened","issue":{"url":"https://api.github.com/repos/ThomasTimm/ur_modern_driver/issues/47","repository_url":"https://api.github.com/repos/ThomasTimm/ur_modern_driver","labels_url":"https://api.github.com/repos/ThomasTimm/ur_modern_driver/issues/47/labels{/name}","comments_url":"https://api.github.com/repos/ThomasTimm/ur_modern_driver/issues/47/comments","events_url":"https://api.github.com/repos/ThomasTimm/ur_modern_driver/issues/47/events","html_url":"https://github.com/ThomasTimm/ur_modern_driver/issues/47","id":153765968,"number":47,"title":"Overshoot with position-based ros_control interface (servoj)","user":{"login":"miguelprada","id":678580,"avatar_url":"https://avatars.githubusercontent.com/u/678580?v=3","gravatar_id":"","url":"https://api.github.com/users/miguelprada","html_url":"https://github.com/miguelprada","followers_url":"https://api.github.com/users/miguelprada/followers","following_url":"https://api.github.com/users/miguelprada/following{/other_user}","gists_url":"https://api.github.com/users/miguelprada/gists{/gist_id}","starred_url":"https://api.github.com/users/miguelprada/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/miguelprada/subscriptions","organizations_url":"https://api.github.com/users/miguelprada/orgs","repos_url":"https://api.github.com/users/miguelprada/repos","events_url":"https://api.github.com/users/miguelprada/events{/privacy}","received_events_url":"https://api.github.com/users/miguelprada/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2016-05-09T12:33:17Z","updated_at":"2016-05-09T12:33:17Z","closed_at":null,"body":"I've had similar experience to what @andreaskoepf describes in #46. Working with the `ros_control` version of the driver, I switched to using the `PositionJointInterface`-based joint trajectory controller because I was suffering from pretty big stability issues when using the `VelocityJointInteface`-based joint trajectory controller (I reckon that this can be alleviated by tuning the PID parameters in the latter, but I figured that using the former was a quicker way to avoid the issue altogether).\r\n\r\nWhen using the position interface in the driver, I see pretty noticeable overshoot, whether I use the `joint_trajectory_controller` in `ros_controllers` or other custom position controllers I've implemented myself. I don't think this comes from the controllers themselves, since the same controllers don't show this behavior when used to control a LWR. Since the `ur_modern_driver` does nothing more than forwarding the command from the controller to the servoing thread in the UR, I'm guessing this is some artifact of using `servoj`.\r\n\r\nHas anyone else seen this effect and played a bit with the parameters to `servoj` to try to improve its performance?"}}