Introduction

Here are the ROS simulation packages of Unitree robots, You can load robots and joint controllers in Gazebo, so you can do low-level control(control the torque, position and angular velocity) on the robot joints. Please watch out that the Gazebo simulation cannot do high-level control, namely walking. Besides of these simulation functions, you can also control your real robots in ROS by the unitree_legged_real package. For real robots, you can do high-level and low-level control by our ROS packages.

Packages:

Robot description: go1_description, a1_description, aliengo_description, laikago_description

Robot and joints controller: unitree_controller

Basic message function: unitree_legged_msgs

Simulation related: unitree_gazebo, unitree_legged_control

Dependencies

• ROS melodic or ROS kinetic(has not been tested)
• Gazebo8

Build

If your ROS is melodic:

sudo apt-get install ros-melodic-controller-interface  ros-melodic-gazebo-ros-control ros-melodic-joint-state-controller ros-melodic-effort-controllers ros-melodic-joint-trajectory-controller

Else if your ROS is kinetic:

sudo apt-get install ros-kinetic-controller-manager ros-kinetic-ros-control ros-kinetic-ros-controllers ros-kinetic-joint-state-controller ros-kinetic-effort-controllers ros-kinetic-velocity-controllers ros-kinetic-position-controllers ros-kinetic-robot-controllers ros-kinetic-robot-state-publisher ros-kinetic-gazebo8-ros ros-kinetic-gazebo8-ros-control ros-kinetic-gazebo8-ros-pkgs ros-kinetic-gazebo8-ros-dev

And open the file unitree_gazebo/worlds/stairs.world. At the end of the file:

<include>
    <uri>model:///home/unitree/catkin_ws/src/unitree_ros/unitree_gazebo/worlds/building_editor_models/stairs</uri>
</include>

Please change the path of building_editor_models/stairs to the real path on your PC.

Then you can use catkin_make to build:

cd ~/catkin_ws
catkin_make

If you face a dependency problem, you can just run catkin_make again.

Detail of Packages

unitree_legged_control:

It contains the joints controllers for Gazebo simulation, which allows users to control joints with position, velocity and torque. Refer to "unitree_ros/unitree_controller/src/servo.cpp" for joint control examples in different modes.

unitree_legged_msgs:

ros-type message, including command and state of high-level and low-level control. It would be better if it be compiled firstly, otherwise you may have dependency problems (such as that you can't find the header file).

The description of robots:

Namely the description of Go1, A1, Aliengo and Laikago. Each package include mesh, urdf and xacro files of robot. Take Laikago as an example, you can check the model in Rviz by:

roslaunch laikago_description laikago_rviz.launch

unitree_gazebo & unitree_controller:

You can launch the Gazebo simulation by the following command:

roslaunch unitree_gazebo normal.launch rname:=a1 wname:=stairs

Where the rname means robot name, which can be laikago, aliengo, a1 or go1. The wname means world name, which can be earth, space or stairs. And the default value of rname is laikago, while the default value of wname is earth. In Gazebo, the robot should be lying on the ground with joints not activated.

Stand controller

After launching the gazebo simulation, you can start to control the robot:

rosrun unitree_controller unitree_servo

And you can add external disturbances, like a push or a kick:

rosrun unitree_controller unitree_external_force

Position and pose publisher

Here we showed how to control the position and pose of robot without a controller, which should be useful in SLAM or visual development.

Then run the position and pose publisher in another terminal:

rosrun unitree_controller unitree_move_kinetic

The robot will turn around the origin, which is the movement under the world coordinate. And inside of the source file move_publisher, we also offered the method to move robot under robot coordinate. You can change the value of def_frame to coord::ROBOT and run the catkin_make again, then the unitree_move_publisher will move robot under its own coordinate.