ss24-solo12-control

This repository supports the development and control of the SOLO12 robot from the Open Dynamic Robot Initiative, leveraging the ros2_control framework. It includes essential packages for robot description, control, and simulation, providing a foundational structure to work with SOLO12 in ROS 2.

Installing this repository

After cloning the repository, go to your source workspace and execute the following commands to import the necessary repositories and to install all dependencies:

rosdep install --from-paths src --ignore-src -r -y

What is ros2_control?

In short, ros2_control is a control framework for ROS 2. But actually, it is much more—it's the kernel of the ROS 2 system that controls robots:

• It abstracts hardware and low-level control for other frameworks such as MoveIt2 and Nav2.
• It provides resource access management.
• It controls the lifecycle of robots and their hardware.

For more details, check this presentation.

Repository Structure

The repository is structured around the following main components:

1. Robot Description (solo12_description)

This package contains the URDF and XACRO files, defining the kinematics, visual, and collision properties of the SOLO12 robot.

2. Bringup Package (solo12_bringup)

This package is responsible for launching the system, loading robot description files, and starting the necessary controllers.

Usage

To launch the system, execute the following command:

ros2 launch solo12_bringup solo12.launch.py

This will bring up the SOLO12 system. For more detailed information, including available launch arguments, please refer to the solo12_bringup package.

View the Robot in Rviz2

To view the SOLO12 robot model and move its joints using the Joint State Publisher GUI, execute the following command:

ros2 launch solo12_description view_solo12.launch.py

This will load the robot's URDF and allow interaction with the robot's joints through Rviz2.

Using ros2_control with SOLO12

The ros2_control framework abstracts hardware and low-level control, providing resource management and lifecycle control for the robot. Key components of the framework include:

• Controller Manager: Manages and loads controllers.
• Controllers: Send commands to control the robot's joints.
• Resource Manager: Manages hardware interfaces and resources.
• Hardware Interface: Interfaces with physical or simulated hardware.

Mock Hardware Plugin

For simpler testing and development, you can use the Mock Hardware Plugin to simulate robot hardware. This allows testing controllers and setup configurations without needing real hardware or simulation.

To run the system with mock hardware, use:

ros2 launch solo12_bringup solo12.launch.py 

Testing Controllers

ros2 launch solo12_bringup controllers.launch.py

This will launch the joint_trajectory_controller and publish goals using trajectory_msgs.msg.JointTrajectoryPoint.

NOTE: Delay between spawning controllers is usually not necessary, but may be useful when starting a complex setup. Adjust this for your specific use case.

Troubleshooting

After executing the command:

ros2 launch solo12_bringup solo12.launch.py

You might encounter the following warning:

[WARNING] [launch_ros.actions.node]: Parameter file path is not a file: /path/to/source/install/solo12_bringup/share/solo12_bringup/config/solo12_controllers.yaml

Fixing the Warning

To resolve this issue, follow these steps:

1. Locate the solo12_controllers.yaml file from your source directory.

2 .Copy it to the specified location:

cp /path/to/source/solo12_bringup/config/solo12_controllers.yaml /path/to/source/install/solo12_bringup/share/solo12_bringup/config/

Ensure you replace /path/to/source/ with the actual path where the solo12_controllers.yaml file is located. This should resolve the warning and allow you to proceed with launching and using the SOLO12 robot system.

Reference

https://github.com/ros-controls/roscon2022_workshop

Packages Overview

• solo12_bringup: Handles the system startup and controller management.
• solo12_description: Defines the robot's URDF and XACRO files.

For more detailed information about each package, please refer to the README files within the respective directories.

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