Building Gazebo Harmonic Plugin

General
1

Dear reader,

I want to migrate an existing plugin for a vacuum gripper from Gazebo-classic to Gazebo Harmonic. I have created a CMakeLists.txt for this:

cmake_minimum_required(VERSION 3.8)
project(ros_industrial_actuators)

cmake_minimum_required(VERSION 3.10.2 FATAL_ERROR)

# Find dependencies
find_package(ament_cmake REQUIRED)
find_package(ament_cmake_python REQUIRED)

#============================================================================
# Find gz-cmake
#============================================================================
find_package(gz-cmake3 REQUIRED)

#--------------------------------------
# Find gz-common
#--------------------------------------
gz_find_package(gz-common5
                 COMPONENTS profiler
                 REQUIRED)
set(GZ_COMMON_VER ${gz-common5_VERSION_MAJOR})

#--------------------------------------
# Find gz-plugin
#--------------------------------------
gz_find_package(gz-plugin2 REQUIRED COMPONENTS register)
set(GZ_PLUGIN_VER ${gz-plugin2_VERSION_MAJOR})

#--------------------------------------
# Find gz-msgs
#--------------------------------------
gz_find_package(gz-msgs10 REQUIRED)
set(GZ_MSGS_VER ${gz-msgs10_VERSION_MAJOR})


#--------------------------------------
# Find gz-sim
#--------------------------------------
gz_find_package(gz-sim8 REQUIRED)
set(GZ_SIM_VER ${gz-sim8_VERSION_MAJOR})

#============================================================================
# Configure the project
#============================================================================
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

#gz_configure_project(VERSION_SUFFIX)


#============================================================================
# Set project-specific options
#============================================================================
set (DRI_TESTS TRUE CACHE BOOL "True to enable DRI tests")

option(ENABLE_PROFILER "Enable Gazebo Profiler" FALSE)

if(ENABLE_PROFILER)
  add_definitions("-DGZ_PROFILER_ENABLE=1")
else()
  add_definitions("-DGZ_PROFILER_ENABLE=0")
endif()


add_library(VacuumGripper vacuum_gripper/VacuumGripper.cc)
set_property(TARGET VacuumGripper PROPERTY CXX_STANDARD 17)


target_link_libraries(VacuumGripper
  PRIVATE
    gz-common${GZ_COMMON_VER}::gz-common${GZ_COMMON_VER}
    gz-plugin${GZ_PLUGIN_VER}::gz-plugin${GZ_PLUGIN_VER}
    gz-sim${GZ_SIM_VER}::gz-sim${GZ_SIM_VER}
)

install(TARGETS
  VacuumGripper
  DESTINATION lib/${PROJECT_NAME}
)
install(TARGETS
  ARCHIVE DESTINATION lib
  LIBRARY DESTINATION lib
  RUNTIME DESTINATION bin
)

# Install models
install(DIRECTORY models
  DESTINATION share/${PROJECT_NAME}/
)

# Install launch
install(DIRECTORY launch
  DESTINATION share/${PROJECT_NAME}/
)

# Python package installation
ament_python_install_package(${PROJECT_NAME})

# Python installation
install(PROGRAMS
  ros_industrial_actuators/vacuum_gripper.py
  launch
  DESTINATION lib/${PROJECT_NAME}
)

# Install package.xml
install(FILES package.xml
  DESTINATION share/${PROJECT_NAME}
)

ament_package()

The CMakeLists.txt is compiled correctly.

I have also created a model.sdf file:

<?xml version="1.0"?>
<sdf version="1.6">
  <model name="vacuum_gripper">
    <static>true</static>

    <plugin
      filename="VacuumGripper"
      name="vacuum_gripper::VacuumGripper">
    </plugin>
  </model>
</sdf>

When loading the vacuum_gripper.sdf the following error message is given:

[gazebo-5] [Err] [SystemLoader.cc:92] Failed to load system plugin [VacuumGripper] : Could not find shared library.

Unfortunately I am unable to fill in the CMakeLists.txt correctly.

I used Gazebo Sim: Create System Plugins as a reference for this plugin.

Who can help me with this? Thanks in advance for your answer.
Gerard

2

Apparently, the tutorial is missing a key piece: the GZ_SIM_SYSTEM_PLUGIN_PATH variable, where you have to add your lib folder. I’ll create an issue for that.

3

Issue created: Tutorial for custom plugins is missing reference to GZ_SIM_SYSTEM_PLUGIN_PATH · Issue #2850 · gazebosim/gz-sim · GitHub . If you’d like, you can try to put together a pull request adding that information. It’s not that difficult! :slight_smile:

4

Thanks Martin,
Could you be a bit more specific. I am not an expert in creating CMakelists.txt files. Do you mean:

set(GZ_SIM_SYSTEM_PLUGIN_PATH DESTINATION lib/${PROJECT_NAME})

Unfortunately this does not work.

Thanks in advance,
Kind regards,
Gerard

5

No, this is not a cmakelists thing. It is an environment variable you have to set in the terminal where you launch Gazebo.

6

Thanks! This works.

Kind regards Gerard