Unitree ROS real (package)

Description

The ROS package that runs on Unitree A1 NX and expose all functionality of Unitree A1 to ROS network.

Installation

1. Make sure you can access your ROS system. or source /opt/ros/kinetic/setup.bash

2. Make sure your system has lcm installed and optionally realsense-ros installed.

3. Setup your ROS workspace on your robot (A1) where you want to run the neural network.

   mkdir -p unitree_ws/src
   cd unitree_ws
   catkin_make

4. Download unitree_legged_sdk v3.3.1 and extract it under unitree_ws/src/

5. Clone this repository to unitree_ws/src/ by

   cd unitree_ws/src
   git clone https://github.com/Tsinghua-MARS-Lab/unitree_ros_real.git

6. Run catkin_make under the workspace folder

   cd ../
   catkin_make

   If error occurrs related to message file, you can run catkin_make again or temporarily stop the package unitree_legged_real from compiling, then compile unitree_legged_real after the message files are generated.

Usage

Important NOTE: Keep the emergency stop button in your hand or connect your robot using a stoppable power source if you run this package for the first time.

Launch the ROS robot node

1. Make sure your ROS system is accessable and unitree_ws is sourced (e.g. source unitree_ws/devel/setup.bash)

2. Make a detail check on the options in unitree_legged_real/launch/robot.launch.

3. Make sure your robot has all motor powered off, or pressing R2 + B on your remote control for A1.

4. Make sure all joints on the robot are not at the mechanical limit. (Or the safety guard will stop the node)

5. Launch the ROS node by

   • If you want only see the robot states but not reacting any motor command.

     roslaunch unitree_legged_real robot.launch

   • If you want to start the robot node and responding to motor command

     roslaunch unitree_legged_real robot.launch dryrun:=false

Control the robot using ROS network

1. Make sure you have another terminal with ROS access and unitree_ws workspace access. Make sure the ROS robot node is running.

2. Checkout robot state topic and command topic. Just publish and subscribe through these two topics.

   If you did not change anything in robot.launch, you will see /a112138/low_state as robot proprioception state and /a112138/legs_cmd as where the robot recieve the motor commands (defined in the same order as the SDK)

Check Robot state in rviz

1. Launch the robot node by

   roslaunch unitree_legged_real robot.launch publish_joint_state:=true publish_imu:=true

2. Launch the odom node by

   roslaunch unitree_legged_real odom.launch

3. Visualize in another terminal in the same ROS network that have access to a compiled unitree_ws workspace and GUI running. (a.k.a a laptop connected to A1's ROS network)

   roslaunch a1_description a1_rviz.launch

Interfaces and functions

• Only one process to handle robot proprioceptive command and states.
• A configurable rosnode namespace, just like xiaomi Cyberdog (/mi3065353)
• publish HighState / LowState on a given frequency
• publish HighCmd / LowCmd publish every time upd.send()
• Mandatory safe protection just before upd.send()

In HIGHLEVEL

• service for change mode (use ROS constant in service file)
• service for change gaitType (use ROS constant in service file)
• subscribe Twist message for x, y, yaw moving
• subscribe Twist message for position, euler angle positioning
• subscribe Float32 message for set body height

In LOWEVEL

• subscribe customized motor message for each joint

Perception system

• publish Twist message filtered IMU rpy euler angle, linear speed (kalman filter, etc)
• publish Transform message for each joint position of the robot
• publish Transform message for Robot base odometry

• publish aligned realsense RGB-D camera image and camera Transform (intrinsic parameters)

  (Usually it is two topics: image_raw and camera_info for RGB and for Depth)