{"action":"created","issue":{"url":"https://api.github.com/repos/robotology/icub-support/issues/622","repository_url":"https://api.github.com/repos/robotology/icub-support","labels_url":"https://api.github.com/repos/robotology/icub-support/issues/622/labels{/name}","comments_url":"https://api.github.com/repos/robotology/icub-support/issues/622/comments","events_url":"https://api.github.com/repos/robotology/icub-support/issues/622/events","html_url":"https://github.com/robotology/icub-support/issues/622","id":311554176,"number":622,"title":"Issue with neck joints acceleration measurement","user":{"login":"gabrielenava","id":12396934,"avatar_url":"https://avatars0.githubusercontent.com/u/12396934?v=4","gravatar_id":"","url":"https://api.github.com/users/gabrielenava","html_url":"https://github.com/gabrielenava","followers_url":"https://api.github.com/users/gabrielenava/followers","following_url":"https://api.github.com/users/gabrielenava/following{/other_user}","gists_url":"https://api.github.com/users/gabrielenava/gists{/gist_id}","starred_url":"https://api.github.com/users/gabrielenava/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/gabrielenava/subscriptions","organizations_url":"https://api.github.com/users/gabrielenava/orgs","repos_url":"https://api.github.com/users/gabrielenava/repos","events_url":"https://api.github.com/users/gabrielenava/events{/privacy}","received_events_url":"https://api.github.com/users/gabrielenava/received_events","type":"User","site_admin":false},"labels":[{"id":483426990,"url":"https://api.github.com/repos/robotology/icub-support/labels/iCubGenova04%20(green)","name":"iCubGenova04 (green)","color":"0e8a16","default":false}],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":7,"created_at":"2018-04-05T10:23:53Z","updated_at":"2018-04-05T19:04:38Z","closed_at":null,"author_association":"NONE","body":"By looking at the `joint accelerations` estimation from the port `yarp read ... /icub/head/stateExt:o`, one can see that the measured joint acceleration on the neck joints suddenly goes to a crazy value (-5493.17747357782 [deg/s^2]) as you can see in the picture:\r\n\r\n![screenshot from 2018-04-05 12-26-56](https://user-images.githubusercontent.com/12396934/38361135-abd63ebe-38cc-11e8-9772-e6ebad531345.png)\r\n\r\nand this is a plot of the head joints accelerations (from stateExt):\r\n\r\n![screenshot from 2018-04-05 12-47-12](https://user-images.githubusercontent.com/12396934/38362004-9f1cfdb8-38cf-11e8-929c-2018618f135c.png)\r\n\r\nthis is affecting the estimation of the joint torques and external forces that is done by taking into account joints position, velocity and acceleration. This is the result: fake estimated external forces forces are wrongly estimated all over the robot:\r\n\r\n![out](https://user-images.githubusercontent.com/12396934/38360973-1f2e23d2-38cc-11e8-96a0-7f6420ee1192.gif)\r\n\r\n\r\nIt is not clear to me if this issue is related to the neck encoders or to the computation of the joint acceleration. \r\n\r\n"},"comment":{"url":"https://api.github.com/repos/robotology/icub-support/issues/comments/379043695","html_url":"https://github.com/robotology/icub-support/issues/622#issuecomment-379043695","issue_url":"https://api.github.com/repos/robotology/icub-support/issues/622","id":379043695,"user":{"login":"DanielePucci","id":5045846,"avatar_url":"https://avatars0.githubusercontent.com/u/5045846?v=4","gravatar_id":"","url":"https://api.github.com/users/DanielePucci","html_url":"https://github.com/DanielePucci","followers_url":"https://api.github.com/users/DanielePucci/followers","following_url":"https://api.github.com/users/DanielePucci/following{/other_user}","gists_url":"https://api.github.com/users/DanielePucci/gists{/gist_id}","starred_url":"https://api.github.com/users/DanielePucci/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/DanielePucci/subscriptions","organizations_url":"https://api.github.com/users/DanielePucci/orgs","repos_url":"https://api.github.com/users/DanielePucci/repos","events_url":"https://api.github.com/users/DanielePucci/events{/privacy}","received_events_url":"https://api.github.com/users/DanielePucci/received_events","type":"User","site_admin":false},"created_at":"2018-04-05T19:04:38Z","updated_at":"2018-04-05T19:04:38Z","author_association":"NONE","body":"@randaz81 \r\nThanks for clarifying. For the sake of completeness, may you point the line of code where calculations occur? "}}
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