Fetch & Freight robot: sudo service robot stop

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Hi Everyone. I am newbie to ROS and my lab just have a fetch-freight robot. I was playing around with it, but get the error with rviz, so I tried to uninstall/reinstall ROS. But now, I can not use the remote control to control the robot, as well as I tried to run the command: "sudo service robot stop" ( http://docs.fetchrobotics.com/care_an... ) But I got the following error. robot: unrecognized service Please help. Thank you very much.