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albertgoalbertgo Posts: 5 Apprentice
Hi all, I am trying to control the 2F gripper on a UR5e robot using ros. How can I go about doing this? I am able to control the UR5e robot itself using ros, but cannot seem to control the gripper.

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  • David_LevasseurDavid_Levasseur Posts: 175Beta Tester Beetle Handy
    Hello @albertgo, perhaps @jproberge can help you with that. He is very knowledgeable with ROS and Robotiq products. 
  • jprobergejproberge Posts: 36Tactile Sensor Beta Testers Crew

    Hello @albertgo ,


    Thanks for your question! I assume your 2F gripper is connected to the end effector's connector? If so, I must say that using ROS to interact with any tools mounted on the newest e-series robots seems indeed to be challenging at the moment.

    Indeed, when you choose to connect the gripper to the UR5e's wrist, you connect it directly to the UR5e's computer (control box). More precisely, the gripper becomes a UART device connected to the robot's computer (thus not directly accessible from the "external world"). So if your goal is to use our ROS package to control your gripper from an external computer, it therefore cannot "talk" directly with the gripper anymore. Also, the gripper unfortunately cannot be disconnected from within the UR control box without having to open and alter the computer's enclosure (of course, not recommended). Thus, it is not possible to connect your ROS machine to the gripper from the control box, which would have been great because it would have allowed one to take advantage of not using a long cable and not having to attach the said cable to the manipulator.

    For now however, this still seems to be the way to integrate any tool properly with ROS when using an e-series robot: using a long cable to connect your ROS machine to the gripper.

    In another vein, I've heard Universal Robots is planning to update their ROS driver such that their UART port (at the wrist) would be forwarded as a virtual serial port on the ROS machine, which would totally fix this issue (see this presentation: , page 15). Thus, maybe there's hope that this will be fixed in the near-future. I just checked now and it still look like "work in progress" at the moment.

    Please do not hesitate to reach out to me, should you have any other questions.

    Best regards,

    Jean-Philippe Roberge, 
    ROS Package Developper / Maintainer 
    [email protected]

  • jprobergejproberge Posts: 36Tactile Sensor Beta Testers Crew
    Also, if I may add two additional points...

    1) While there are no "plug-and-play" solutions at the moment, depending on how comfortable you are with Linux and how it is important for you not to have an external cable alongside the robot, you could consider to ssh into the robot's control box to write a simple relay script (in Bash or Python, for example) that would automatically listen to a specific pre-determined port and simply send everything it receives back to the gripper (which is accessible from the control box's computer).  While this might sound like an easy and a quick fix, I personally have never tried to implement this solution and I can easily imagine that it there would be many unforeseen challenges. Note that you would also need to use the TCP protocol in this case: your computer would have to send the Modbus RTU commands throughout a TCP link.

    2) If you choose to use an external cable alongside the robot, you will simply need a RS485<-->USB converter, as well as a 24 Volts DC power supply. You plug the end of the gripper's cable in the converter / power supply, and you plug the USB end of the converter directly to your ROS machine.

    Don't hesitate to reach out to me again, should you have any other questions!

    Best regards,

    Jean-Philippe Roberge, 
    ROS Package Developper / Maintainer 
    [email protected]

  • albertgoalbertgo Posts: 5 Apprentice
    How do you ssh into the robot?

  • jprobergejproberge Posts: 36Tactile Sensor Beta Testers Crew
    Hi @albertgo ,

    If they haven't change the login credentials for the newest eseries, then you should be able to ssh using the username "root" and the password "easybot". So in a terminal you would simply have to type:

    ssh [email protected][IP_ADDRESS_OF_YOUR_ROBOT]  ,

    then when asked for a password, simply enter "easybot" without the quotes.

    All the best,

    Jean-Philippe Roberge, 
    ROS Package Developper / Maintainer 
    [email protected]
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