etasl_ros_control

This project integrates eTaSL with ROS Control.

eTaSL is a task specification language for reactive control of robot systems developed by KU Leuven. It is a language that allows you to describe how your robotic system has to move and interact with sensors. This description is based on a constraint-based methodology. Everything is specified as an optimization problem subject to constraints.

More information on eTaSL can be found here.

Build etasl_ros_control from source.

For now, etasl_ros_control is only supported on Linux:

• Ubuntu 16.04 / ROS Kinetic

Follow all the instructions to install ROS Kinetic. Please make sure you have followed all steps and have the latest versions of packages installed:

rosdep update
sudo apt-get update
sudo apt-get dist-upgrade

Source installation requires wstool:

sudo apt-get install python-wstool

Optionally create a new workspace, you can name it whatever:

mkdir ~/etasl_ros_control_ws
cd ~/etasl_ros_control_ws

Next, source your ROS workspace to load the necessary environment variables.

source /opt/ros/kinetic/setup.bash

This will load the ${ROS_DISTRO} variable, needed for the next step.

Download and build etasl_ros_control

By default we will assume you are building on the latest branch, we currently use master as our master branch.

Pull down the required repositories and build from within the root directory of your catkin workspace:

wstool init src
wstool merge -t src https://raw.githubusercontent.com/tingelst/etasl_ros_control/master/etasl_ros_control.rosinstall
wstool update -t src
rosdep install -y --from-paths src --ignore-src --rosdistro ${ROS_DISTRO}
catkin_init_workspace src
catkin_make --cmake-args -DCMAKE_BUILD_TYPE=Release

Source the catkin workspace

Setup your environment - you can do this every time you work with this particular source install of the code, or you can add this to your .bashrc (recommended):

source ~/etasl_ros_control_ws/devel/setup.bash # or .zsh, depending on your shell

Getting started

If you haven’t already done so, make sure you’ve completed the steps above.

Launch the examples

There are three launch files available: One using the KUKA KR6 R900 sixx Agilus robot, one using the UR10 robot with Gazebo, and one showing how to setup multiple controllers that each load a separate task specification.

Launch the example using the KUKA Agilus:

roslaunch etasl_ros_control_examples example_kuka_kr6r900sixx.launch

Launch the example using the UR10:

roslaunch etasl_ros_control_examples example_ur10_gazebo.launch

You can visualize the trajectory by adding a Marker in RViz: Add -> Marker -> OK

Multiple controllers

Launch the example using multiple controllers:

roslaunch etasl_ros_control_examples example_multiple_controllers.launch

This example loads three controllers, one joint trajectory controller, and two eTaSL controllers. The joint trajectory controller (position_trajectory_controller) is started, while the two eTaSL controllers are loaded. To switch to the first eTaSL controller (etasl_controller) you can use:

rosservice call /controller_manager/switch_controller [etasl_controller] [position_trajectory_controller] 2

Then, to switch to the second eTaSL controller (etasl_controller_2), you can use

rosservice call /controller_manager/switch_controller [etasl_controller_2] [etasl_controller] 2

And, finally back to the joint trajectory controller:

rosservice call /controller_manager/switch_controller [position_trajectory_controller] [etasl_controller_2] 2

SMACH for discrete controller switching

The multiple controllers can be used in a SMACH example.

Launch the smach example:

roslaunch etasl_ros_control_examples example_smach.launch

Acknowledgements

• The expressiongraph and eTaSL projects have been developed by KU Leuven.
• The above installation instructions are modified from the MoveIt! installation instructions found here.