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Universal_Robots_ROS_Driver

Universal Robots have become a dominant supplier of lightweight, robotic manipulators for industry, as well as for scientific research and education. The Robot Operating System (ROS) has developed from a community-centered movement to a mature framework and quasi standard, providing a rich set of powerful tools for robot engineers and researchers, working in many different domains.

Universal Robot e-Series family

With the release of UR’s new e-Series, the demand for a ROS driver that supports the new manipulators and the newest ROS releases and paradigms like ROS-control has increased further. The goal of this driver is to provide a stable and sustainable interface between UR robots and ROS that strongly benefit all parties.

It is the core value of Universal Robots, to empower people to achieve any goal within automation. The success criteria of this driver release is to follow this vision, by providing the ROS community with an easy to use, stable and powerful driver, that empowers the community to reach their goals in research and automation without struggling with unimportant technical challenges, instability or lacking features.

Acknowledgement

This driver is forked from the ur_modern_driver.

rosin_logo

Supported by ROSIN - ROS-Industrial Quality-Assured Robot Software Components.
More information: rosin-project.eu

eu_flag

This project has received funding from the European Union’s Horizon 2020
research and innovation programme under grant agreement no. 732287.

It was developed in collaboration between Universal Robots and the FZI Research Center for Information Technology.

How to report an issue

Create an issue on the Issue Board using the default template.

Features

  • Works for all CB3 (with software version >= 3.7) and e-Series (software >= 5.1) robots and uses the RTDE interface for communication, whenever possible.
  • Factory calibration of the robot inside ROS to reach Cartesian targets precisely.
  • Realtime-enabled communication structure to robustly cope with the 2ms cycle time of the e-Series. To use this, compile and run it on a kernel with the PREEMPT_RT patch enabled. (See the Real-time setup guide on how to achieve this)
  • Transparent integration of the teach-pendant. Using the URCaps system, a program is running on the robot that handles control commands sent from ROS side. With this, the robot can be paused, stopped and resumed without restarting the ROS driver. This will in the future also enable the usage of ROS-components as part of a more complex UR-program on the teach pendant. This is currently not yet supported, as we are still missing to exit control from ROS side. Expect this to come in future releases.
  • Use the robot's speed-scaling. When speed scaling is active due to safety constraints or the speed slider is used, this gets correctly handled on the ROS side, as well slowing down trajectory execution accordingly.
    Note: Other ros-controllers based on a position interface can be used with this driver, but may behave wrong if the speed slider isn't set to 100% or if speed scaling slows down the robot. Also, the pausing function can only be used if the default scaled trajectory controller is used.

Please see the external feature list for a listing of all features supported by this driver.

Contents

This repository contains the new ur_robot_driver and a couple of helper packages, such as:

  • controller_stopper: A small external tool that stops and restarts ros-controllers based on the robot's state. This can be helpful when the robot is in a state where it won't accept commands sent from ROS.
  • ur_calibration: Package around extracting and converting a robot's factory calibration information to make it usable by the robot_description.
  • ur_controllers: Controllers introduced with this driver, such as speed-scaling-aware controllers.
  • ur_robot_driver: The actual driver package.

Requirements

This driver requires a system setup with ROS. It is recommended to use Ubuntu 18.04 with ROS melodic, however using Ubuntu 16.04 with ROS kinetic should also work.

To make sure that robot control isn't affected by system latencies, it is highly recommended to use a real-time kernel with the system. See the real-time setup guide on information how to set this up.

Building

# source global ros
$ source /opt/ros/<your_ros_version>/setup.bash
# create a catkin workspace
$ mkdir -p catkin_ws/src && cd catkin_ws
$ catkin_make
$ cd src
# clone the driver
$ git clone <this_repository_url>
# clone fork of the description to use the calibration feature
$ git clone -b calibration_devel https://github.com/fmauch/universal_robot.git
# install dependencies
$ rosdep install --from-path . -y --ignore-src
# build the driver
$ cd ..
$ catkin_make
# source the workspace
$ source devel/setup.bash

Setting up a UR robot for ur_robot_driver

Prepare the robot

For using the ur_robot_driver with a real robot you need to install the externalcontrol-1.0.urcap which can be found inside the resources folder of this driver.

Note: For installing this URCap a minimal PolyScope version of 3.7 or 5.1 (in case of e-Series) is necessary.

For installing the necessary URCap and creating a program, please see the individual tutorials on how to setup a CB3 robot or how to setup an e-Series robot.

To setup the tool communication on an e-Series robot, please consider the tool communication setup guide.

Prepare the ROS PC

For using the driver make sure it is installed (either by the debian package or built from source inside a catkin workspace).

Extract calibration information

Each UR robot is calibrated inside the factory giving exact forward and inverse kinematics. To also make use of this in ROS, you first have to extract the calibration information from the robot.

Though this step is not necessary to control the robot using this driver, it is highly recommended to do so, as otherwise endeffector positions might be off in the magnitude of centimeters.

For this, there exists a helper script:

$ roslaunch ur_calibration calibration_correction.launch \
robot_ip:=<robot_ip> target_filename:="${HOME}/my_robot_calibration.yaml"

For the parameter robot_ip insert the IP address on which the ROS pc can reach the robot. As target_filename provide an absolute path where the result will be saved to.

We recommend keeping calibrations for all robots in your organization in a common package. See the package's documentation for details.

Quick start

Once the driver is built and the externalcontrol URCap is installed on the robot, you are good to go ahead starting the driver. (Note: We do recommend, though, to calibrate your robot first.)

To actually start the robot driver use one of the existing launch files

$ roslaunch ur_robot_driver <robot_type>_bringup.launch robot_ip:=192.168.56.101

where <robot_type> is one of ur3, ur5, ur10, ur3e, ur5e, ur10e. Note that in this example we load the calibration parameters for the robot "ur10_example".

If you calibrated your robot before, pass that calibration to the launch file:

$ roslaunch ur_robot_driver <robot_type>_bringup.launch robot_ip:=192.168.56.101 \
kinematics_config:=$(rospack find ur_calibration)/etc/ur10_example_calibration.yaml

If the parameters in that file don't match the ones reported from the robot, the driver will output an error during startup, but will remain usable.

For more information on the launch file's parameters see its own documentation.

Once the robot driver is started, load the previously generated program on the robot panel and execute it. From that moment on the robot is fully functional. You can make use of the pause function or even stop the program. Simply press the play button again and the ROS driver will reconnect.

To control the robot using ROS, use the action server on

/scaled_pos_traj_controller/follow_joint_trajectory

Use this with any client interface such as MoveIt! or simply the rqt_joint_trajectory_controller gui:

rosrun rqt_joint_trajectory_controller rqt_joint_trajectory_controller