Control Unitree A1 with ROS (via WiFi and Ethernet)

[staycoolish]

Hello,

I am trying to control Unitree A1 using ROS. When I connect to the robot using its WiFi (Unitree), I can use the unitree_legged_sdk package. For instance, I can run

sudo ./example_walk

and the robot moves. However, I want to control the robot using ROS, and there is no detailed tutorial for this purpose.

First of all, I connected to the robot using both WiFi and Ethernet. I can ping both of the connections (I can already verify that WiFi works, because for sudo ./example_walk I use it):

ping 192.168.123.201 for ethernet
ping 192.168.123.105 for WiFi

Then, I try to use ROS for controlling the robot. I first launch this file:
roslaunch unitree_legged_real real.launch ctrl_level:=highlevel

When I do that, no error is given, and I get the following output:

started roslaunch server http://staycoolish-PC:33983/

SUMMARY
========

PARAMETERS
 * /control_level: highlevel
 * /firmwork: 3_2
 * /robot_name: a1
 * /rosdistro: noetic
 * /rosversion: 1.15.14

NODES
  /
    node_lcm_server (unitree_legged_real/lcm_server_3_2)

auto-starting new master
process[master]: started with pid [5894]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 6d4ce3ea-0e70-11ed-ab0d-1300bbba5118
process[rosout-1]: started with pid [5904]
started core service [/rosout]
process[node_lcm_server-2]: started with pid [5907]
UDP Initialized. Port: 8080 
LCM Initialized. Subscribe channel: LCM_High_Cmd, Publish channel: LCM_High_State
[Loop Start] named: UDP_Send, period: 2(ms), run at cpu: 3 
[Loop Start] named: UDP_Recv, period: 2(ms), run at cpu: 3 
[Loop Start] named: LCM_Recv, period: 2(ms), cpu unspecified
[Loop Start] named: control_loop, period: 2(ms), cpu unspecified

However, something strange happens, no node is created. When I check with rosnode list, the only node is /rosout. Therefore, when I run the code

rosrun unitree_legged_real example_walk

nothing happens.

What is the right way for using ROS? Or, what am I missing?

Thank you,

[MYBOTSHOP_Support]

Dear all,

thanks for your topic.

Just a few general questions:

• Are you having a QUADRUPED A1 Basic or Explorer?
• When you have purchased it / which Software Version is running on it?
• Do you have access to docs.quadruped.de?

@Sohail May you can assist him as well?

[staycoolish]

Thanks for your interest:

It is the Basic version. There are two computers on it: One main computer (Ubuntu 16.04 is installed, but ROS is not installed), and a Raspberry Pi (I didn’t check the OS version and whether ROS is installed, because the robot is controlled via the other computer, as far as I know). It is purchased around 2 years ago, but this is the first time it is used except for using with the remote controller.

I don’t have access to http://docs.quadruped.de/ , but I think I have downloaded and read maybe all of your tutorials already, at least the ones that are on your website. We purchased the robot from Unitree, via a local distributor. Unfortunately, their support is quite limited (local distributor has no people working with ROS, and Unitree is not very responsive), and I couldn’t get any response for the issues I opened on their Github pages. To be honest, I noticed that your website is the most comprehensive and helpful place for this robot, and that is why I ask my question here. I do believe though, there is no good resource for ROS connection of A1. Thus, hopefully my question would be useful for your customers as well.

Thank you,

[Sohail]

Hi @staycoolish,

On your pc that is connected to the robot. You must run it as a super user i.e.

sudo su

Next source the environment where the A1 package is usually in the catkin_ws in the same super user terminal, (replace unitree with your username)

source /home/unitree/catkin_ws/devel/setup.bash

Finally run the roslaunch file with

roslaunch unitree_legged_real real.launch ctrl_level:=highlevel

Also we have like a software stack that has this if you are interested in purchasing one of the newer versions

[staycoolish]

Thanks a lot @Sohail !

I luckily solved the problem, but the reason was really strange, and I couldn’t really understand why. Nonetheless, it can happen to the others as well. When I try to run anything from the unitree_legged_real package, these are the options:

And when I look at the CMakeLists.txt inside the unitree_legged_real package, I see that there are 5 executables defined inside it (I took a screenshot but I can only upload 1, so :D):

Those 5 options in that package are:

lcm_server_3_2
position_lcm
velocity_lcm
torque_lcm
walk_lcm

Therefore, the remaining are actually unrelated to unitree_legged_real:

CMakeLists.txt
control_via_keyboard (this one is for Go1 as far as I know, and I installed the 3.2.1 version of unitree_ros_to_real -version for A1-, so I don’t know why it is even there)
velocity_mode.cpp, walk_mode.cpp, position_mode.cpp, torque_mode.cpp are the codes for the functions velocity_lcm, walk_lcm, position_lcm, torque_lcm. Those .cpp files should not be shown when rosrun is used.
…
and the remaining ones

That’s why nothing was happening when I write

rosrun unitree_legged_real example_walk , because example_walk is not related to that package.

I tried all the available 5 functions: lcm_server_3_2 does not work, it says Segmentation fault (core dumped) . The rest (position_lcm, velocity_lcm, torque_lcm, walk_lcm) work, walk_lcm requires high level control mode from real.launch; the other require low level control mode. I connected the ethernet cable to the robot’s main computer, didn’t try WiFi yet. Overall, thanks for your help, applying the steps you said, the robot worked successfully.

I am working in a university, and my supervisor wants me to control the robot (high level or low level) by myself. I believe it is preferable if we write our own code, but in case we buy a new Unitree A1, I will let him know about your software What is its difference by the way, from the codes provided by Unitree?

[Sohail]

We build upon Unitree’s existing SDK to provide specific ROS interface and drivers such walking odometry purely hardware based, joint_state_publishers, etc.