Week 04 — Gazebo Demo (Studio 2)

Lab handout (from Lab-Code)

Week 4 - Studio 4.1 - Gazebo Demo

The objective of this lab is to install the UR3e packages and have a working simulation of the robot in Gazebo.

Package Installation

There are two methods to do this:

1. Source Installation

Clone the following repositories in your workspace:

git clone -b humble https://github.com/UniversalRobots/Universal_Robots_ROS2_Driver.git
git clone -b humble https://github.com/UniversalRobots/Universal_Robots_ROS2_Gazebo_Simulation.git

Build and source the workspace

2. Pre-configured Docker Container

Find the Dockerfile in /Resources/Docker Container/humble_dockerfile.Dockerfile and build and run the container. This is the preferred method but it can lead to issues with Gazebo (looking into a foolproof solution - will be updated this week)

sudo docker build -t humble_image -f humble_dockerfile.Dockerfile .
sudo docker run -it humble_image

Troubleshooting - no joint trajcetory controller or controller interface

If you run into an issue with building packages due to missing a joint controller run:

sudo apt install ros-humble-joint-trajectory-controller

sudo apt install ros-humble-controller-interface

sudo apt install ros-humble-ur-*

sudo apt install ros-humble-control-*

sudo apt install ros-humble-ros2-control-*

Troubleshooting on Macs

Gazebo doesn’t directly support ARM64 architecture. As a result, we need to manually compile and install it.

Install necessary dependencies:

sudo apt-add-repository ppa:dartsim

sudo apt update

sudo apt install libdart-dev libdart-utils-dev libdart-external-ikfast-dev libsdformat9-dev libfreeimage-dev libprotoc-dev libprotobuf-dev protobuf-compiler freeglut3-dev libcurl4-openssl-dev libtinyxml-dev libtinyxml2-dev libtar-dev libtbb-dev libogre-1.9-dev libxml2-dev pkg-config qtbase5-dev libqwt-qt5-dev libltdl-dev libgts-dev libboost-thread-dev libboost-system-dev libboost-filesystem-dev libboost-program-options-dev libboost-regex-dev libboost-iostreams-dev libsimbody-dev libignition-common3-dev libignition-fuel-tools4-dev libignition-transport8-dev libignition-math6-dev libignition-msgs5-dev

Clone the Gazebo source code from GitHub:

cd ~/Downloads/

git clone https://github.com/osrf/gazebo

Modify the line 647 of SearchForStuff.cmake in Downloads/gazebo/cmake. Change from 9.8 to 9.7 as the default libsdformat version of ubuntu22 is 9.7.
Compile and install Gazebo:

cd ~/Downloads/gazebo
mkdir build && cd build
cmake ../
make -j3
sudo make install

Add Gazebo to your environment path by modifying .bashrc*:

export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH
export PATH=/usr/local/bin:$PATH
export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig:$PKG_CONFIG_PATH

In your workspace, add the gazebo_ros package:

cd ~/enme480_ws/src
git clone https://github.com/ros-simulation/gazebo_ros_pkgs
cd gazebo_ros_pkgs
git checkout ros2
cd ~/enme480_ws/src
git clone -b humble https://github.com/ros-controls/gazebo_ros2_control

Build and source your workspace

Running UR3 Demo on Gazebo

Launch the UR3e in Gazebo

ros2 launch ur_simulation_gazebo ur_sim_control.launch.py

It should open up two windows with UR3e arm in Gazebo & RViz.

Troubleshooting - Gazebo does not open up; waiting for controller

Run the following command in a seperate terminal before launching the previous command (in order to use this method, start and source 3 consoles, run this command, then the one above it then the last command on this page).

gazebo -s libgazebo_ros_init.so -s libgazebo_ros_factory.so myworld.world

To test if the simulation works, run the following command

ros2 launch ur_robot_driver test_joint_trajectory_controller.launch.py

This will keep moving the robot continously in multiple positions.

Assignment

Prepare a report answering the following questions and posting relevant screenshots 1. Screenshots of Gazebo & RViz with the UR3 in 3 different positions 2. Show the topics