Francesco Roscia, Michele Focchi, Andrea Del Prete, Darwin G. Caldwell, and Claudio Semini
Corresponding author's email: francesco.roscia@iit.it
This repository is a reduced version of Locosim (preprint) and it is intended for reproducing simulations and experiments presented in the manuscript Reactive Landing Controller for Quadruped Robots.
The Reactive Landing Controller addresses the problem of landing on a flat horizontal surface for a quadruped robot. It has been designed for satisfying the following requirements:
(R1) no bounces after landing;
(R2) the trunk must not hit the ground;
(R3) the robot must reach a stable standing state;
(R4) once landed, the feet must not slip.
It uses only proprioceptive measures for torque-controlled quadruped robots, without requiring prior knowledge of either the distance to the landing surface or the flight time.
Check out our Youtube video.
Locosim is composed by a roscontrol node called ros_impedance_controller (written in C++) that interfaces the Python ros node (where the controller is written) to a Gazebo simulator.
Locosim is compatible with Ubuntu 16/18/20. The installation instructions have been generalized accordingly. You need replace few strings with the appropriate values according to your operating systems as follows:
| Ubuntu 16: | Ubuntu 18: | Ubuntu 20: |
|---|---|---|
| PYTHON_PREFIX = Python | PYTHON_PREFIX = Python3 | PYTHON_PREFIX = Python3 |
| PYTHON_VERSION = 2.7 | PYTHON_VERSION = 3.5 | PYTHON_VERSION = 3.8 |
| ROBOTPKG_PYTHON_VERSION=py27 | ROBOTPKG_PYTHON_VERSION=py35 | ROBOTPKG_PYTHON_VERSION=py38 |
| PIP_PREFIX = pip | PIP_PREFIX = pip3 | PIP_PREFIX = pip3 |
| ROS_VERSION = kinetic | ROS_VERSION = bionic | ROS_VERSION = noetic |
NOTE: ROS is no longer supported on Ubuntu 22 (only ROS2) hence is not possible to install Locosim on Ubuntu 22.
setup your source list:
sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main" > /etc/apt/sources.list.d/ros-latest.list'
Set up your keys:
curl -sSL 'http://keyserver.ubuntu.com/pks/lookup?op=get&search=0xC1CF6E31E6BADE8868B172B4F42ED6FBAB17C654' | sudo apt-key add -
install ROS main distro:
sudo apt-get install ros-ROS_VERSION-desktop-full
install ROS packages:
sudo apt-get install ros-ROS_VERSION-urdfdom-py
sudo apt-get install ros-ROS_VERSION-srdfdom
sudo apt-get install ros-ROS_VERSION-joint-state-publisher
sudo apt-get install ros-ROS_VERSION-joint-state-publisher-gui
sudo apt-get install ros-ROS_VERSION-joint-state-controller
sudo apt-get install ros-ROS_VERSION-gazebo-msgs
sudo apt-get install ros-ROS_VERSION-control-toolbox
sudo apt-get install ros-ROS_VERSION-gazebo-ros
sudo apt-get install ros-ROS_VERSION-controller-manager
sudo apt install ros-ROS_VERSION-joint-trajectory-controller
Add robotpkg as source repository to apt:
sudo sh -c "echo 'deb [arch=amd64] http://robotpkg.openrobots.org/packages/debian/pub $(lsb_release -sc) robotpkg' >> /etc/apt/sources.list.d/robotpkg.list"
sudo sh -c "echo 'deb [arch=amd64] http://robotpkg.openrobots.org/wip/packages/debian/pub $(lsb_release -sc) robotpkg' >> /etc/apt/sources.list.d/robotpkg.list"
Register the authentication certificate of robotpkg:
sudo apt install -qqy lsb-release gnupg2 curl
curl http://robotpkg.openrobots.org/packages/debian/robotpkg.key | sudo apt-key add -
You need to run at least once apt update to fetch the package descriptions:
sudo apt-get update
Now you can install Pinocchio and the required libraries:
sudo apt install robotpkg-PINOCCHIO_PYTHON_VERSION-eigenpy
sudo apt install robotpkg-PINOCCHIO_PYTHON_VERSION-pinocchio
sudo apt-get install robotpkg-PINOCCHIO_PYTHON_VERSION-quadprog
NOTE: If you have issues in installing robotpkg libraries you can try to install them through ROS as:
sudo apt-get install ros-ROS_VERSION-LIBNAME
sudo apt-get install PYTHON_PREFIX-scipy
sudo apt-get install PYTHON_PREFIX-matplotlib
sudo apt-get install PYTHON_PREFIX-termcolor
sudo apt install Python3-pip
Now that you installed all the dependencies you are ready to get the code, but first you need to create a ros workspace to out the code in:
mkdir -p ~/ros_ws/src
cd ~/ros_ws/src
Now you need to call the following line manually (next you will see that it will be done automatically in the .bashrc)
source /opt/ros/ROS_VERSION/setup.bash
cd ~/ros_ws/
catkin_make
cd ~/ros_ws/src/
Now you can clone the repository inside the ROS workspace you just created:
git clone https://github.com/mfocchi/climbing_robots.git
now recompile again (then this step won't bee needed anymore if you just work in Python unless you do not modify / create additional ROS packages)
cd ~/ros_ws/
catkin_make install
the install step install the ros packages inside the "$HOME/ros_ws/install" folder rather than the devel folder. This folder will be added to the ROS_PACKAGE_PATH instead of the devel one.
Finally, run (you should do it any time you add a new ros package)
rospack profile
There are some additional utilities that I strongly suggest to install. You can find the list here.
gedit ~/.bashrc
copy the following lines (at the end of the .bashrc), remember to replace the string PYTHON_VERSION with the appropriate version name as explained in software versions section:
source /opt/ros/ROS_VERSION/setup.bash
source $HOME/ros_ws/install/setup.bash
export PATH=/opt/openrobots/bin:$PATH
export LOCOSIM_DIR=$HOME/ros_ws/src/reactive_landing_controller
export PYTHONPATH=/opt/openrobots/lib/PythonPYTHON_VERSION/site-packages:$PYTHONPATH
export PYTHONPATH=$LOCOSIM_DIR/robot_control:$PYTHONPATH
export PYTHONPATH=$LOCOSIM_DIR/landing_controller:$PYTHONPATH
export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:/opt/openrobots/share/
The .bashrc is a file that is automatically sourced whenever you open a new terminal.
NOTE: people with some operating systems like ARCH LINUX, might need to add "export ROS_IP=127.0.0.1" to the .bashrc.
Whenever you modify some of the ROS packages (e.g. the ones that contain the xacro fles inside the robot_description folder), you need to install them to be sure they are been updated in the ROS install folder.
cd ~/ros_ws/
catkin_make install
IMPORTANT!
The first time you compile the code the install folder is not existing, therefore won't be added to the PYTHONPATH with the command source $HOME/ros_ws/install/setup.bash, and you won't be able to import the package ros_impedance_controller. Therefore, only once, after the first time that you compile, run again :
source .bashrc
We recommend to use an IDE to run and edit the Python files, like Pycharm community. To install it, you just need to download and unzip the program:
https://download.jetbrains.com/Python/pycharm-community-2021.1.1.tar.gz
and unzip it inside the home directory.
We ask you to download this specific version (2021.1.1) that we am sure it works: newer versions seem to be failing to load environment variables.
To be able to keep the plots alive at the end of the program and to have access to variables, you need to "Edit Configurations..." and tick "Run with Python Console". Otherwise the plot will immediately close.
To run from a terminal we use the interactive option that allows when you close the program have access to variables:
$ Python3 -i $LOCOSIM_DIR/robot_control/base_controllers/climbingrobot_controller.py
to exit from Python3 console type CTRL+Z
- Some machines, do not have support for GPU. This means that if you run Gazebo Graphical User Interface (GUI) it can become very slow. A way to mitigate this is to avoid to start the Gazebo GUI and only start the gzserver process that will compute the dynamics, you will keep the visualization in Rviz. This is referred to planners that employ BaseController or BaseControllerFixed classes. In the Python code where you start the simulator you need to pass this additional argument as follows:
additional_args = 'gui:=false'
p.startSimulator(..., additional_args =additional_args)
- Another annoying point is the default timeout to kill Gazebo that is by default very long. You can change it (e.g. to 0.1s) by setting the _TIMEOUT_SIGINT = 0.1 and _TIMEOUT_SIGTERM = 0.1:
sudo gedit /opt/ros/ROS_VERSION/lib/PYTHON_PREFIX/dist-packages/roslaunch/nodeprocess.py
this will cause ROS to send a kill signal much sooner.
- if you get this annoying warning:
Warning: TF_REPEATED_DATA ignoring data with redundant timestamp for frame...
a dirty hack to fix it is to clone this repository in your workspace:
git clone --branch throttle-tf-repeated-data-error git@github.com:BadgerTechnologies/geometry2.git
If you want to record video of the simulations, you must:
- install ffmpeg (https://ffmpeg.org/)
- initialize Gazebo with camera_slow.world
If you do not want to run the Gazebo client, you can add 'gui:=False' as additional argument.
p.startController(world_name='camera_slow.world', additional_args=['gui:=False'])
If you need to create compile and install SLIP_dynamics_lib.so, you first need to download and install Boost. Then, you must type
cd landing_controller/controller/SLIP_dynamics
mkdir build & cd build
cmake ..
make installSLIP_dynamics_lib.so will be installed in landing_controller/controller folder.
Please move it to landing_controller/lib. It is imported by landingController.py.
Locosim simplifies the use of Go1. The robot_hardware_interface folder contains what you need for communicating to the
robot. Please refer to setupGo1.md for turning on the robot. In landing_controller/go1tests there are some toy example
describing how to use Locosim with the Go1 hardware.