EugVal

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Everything posted by EugVal

  1. EugVal

    Gripper failed to calibrate

    Hello, In our lab we have the Baxter two finger gripper attached to a Sawyer. In the past couple of weeks , using the gripper_keyboard.py example in the intera_examples (from the intera_sdk ROS packages, https://github.com/RethinkRobotics/intera_sdk/blob/master/intera_examples/scripts/gripper_keyboard.py ) has been throwing the following error : "Calibration failed.". It is unclear why this has started happening after a couple of years of operation without issue. This is a problem because we then cannot use the gripper (The error happens in any script when instantiating the Gripper class in the intera python api for the first time : https://rethinkrobotics.github.io/intera_sdk_docs/5.1.0/intera_interface/html/index.html ). We noticed that running the gripper_keyboard.py over and over again generally results with it finally working after some time. Moreover, once it works, then it is not a problem again until the robot is rebooted. Any ideas what could be happening or how we could fix this? We are starting to suspect a hardware malfunction. Many thanks
  2. Hello, I am setting up the Sawyer in the Mujoco physics simulator, but I have some trouble finding information on the joint velocity controller. More specifically, I am interested to know what happens when we set joint velocities using the set_joint_velocities method on the Limb class . I assume it uses a PID contoller to convert the commanded velocities to low level signals on the arms, but I would like to know the process more precisely. For instance, what are the velocities mapped to and what is the type of controller and what are its corresponding gains? I am trying to understand how the actuation model works in a bit more detail so I can set up the simulation adequately, apologies if I missed some documentation somewhere that goes through the information I am looking for. Thanks!