PupperWholeBodyControl

Master repo for implementing Whole Body Control on the Stanford Pupper

Installation

> git clone [email protected]:makeller1/PupperWholeBodyControl.git

Note: You will need an SSH key on your GitHub profile. See: https://docs.github.com/en/authentication/connecting-to-github-with-ssh/adding-a-new-ssh-key-to-your-github-account

Setting up Catkin Workspace

The catkin workspace is used to compile the C++ code

1. Create folder for catkin workspace e.g. WBC_catkin_ws
2. Add new folder called src e.g. WBC_catkin_ws/src
3. In a terminal enter:

   sudo apt update
   sudo apt install python3-catkin-tools
   cd  WBC_catkin_ws
   catkin build
   

4. Move repo code to WBC_catkin_ws/src
5. Run one more time:

   catkin build
   

6. Source the catkin workspace by adding the following line to ~/.bashrc (hidden file in your home directory)

   source /home/user/WBC_catkin_ws/devel/setup.bash # Allows ros to find the specific executable inside the package

Installing gazebo_ros

Assuming you have the ros distro noetic,

sudo apt install ros-noetic-gazebo-ros

Building the WBC C++ code

1. Open a terminal and navigate to ~/WBC_catkin_ws/src/PupperWholeBodyControl/workstation/plugins
2. Create a folder called build

   mkdir build
   

3. Run

   cd build
   catkin build #build library containing PupperWBC.cpp and PupperModel.cpp
   cmake ..
   make -j
   

Running WBC in simulation

1. Build the WBC C++ code using the steps above
2. Add the following line to your .bashrc (or run in the current shell)

   # Point gazebo to plugin path
   export GAZEBO_PLUGIN_PATH=~/WBC_catkin_ws/src/PupperWholeBodyControl/workstation/plugins/build
   

3. Open a terminal and run

   roslaunch workstation load_pupper.launch
   

Running WBC on Pupper

1. Start ros by opening a terminal and running:

   roscore
   

2. Start the ros node (communication between C++ code and Python code) by running:

   rosrun workstation PupperNode
   

3. If you don't have a physical ethernet adapter (common on laptops), create a virtual one. This is required to communicate with the keyboard controller interface.

   cd ~/WBC_catkin_ws/src/PupperWholeBodyControl/workstation/src/PythonComms
   bash create_dummy_ethernet
   

4. Run keyboard controller:

   cd ~/WBC_catkin_ws/src/PupperWholeBodyControl/workstation/src/PythonComms/KeyboardController
   python3 keyboard_joystick.py
   

5. Start the python code that communicates with the keyboard controller, C++ code, and the pupper. Open a new terminal and enter:

   cd ~/WBC_catkin_ws/src/PupperWholeBodyControl/workstation/src/PythonComms
   python3 run_djipupper.py 
   

Note: the order of these steps is important.

Building and uploading the Teensy code

1. Open VS code
2. Install the PlatformIO extension
3. Open the PlatformIO tab and select "Open"
4. Select "Add Existing"
5. Navigate to the folder src/onboard
6. Select Open "onboard"
7. In the PlatformIO tab, select Project Tasks> teensy40 > Build

Zeroing the Pupper

The pupper is zeroed at initialization of run_djipupper.py.

1. Start run_djipupper.py and wait for prompt "Press enter to ZERO MOTORS".
2. Lay pupper flat with elbows and knees back (all feet pointing forward)
3. Rotate hips to raise legs
4. Rotate elbows to raise feet off the ground
5. Rotate hips to lower the legs until the end of the motors touch the ground
6. Rotate elbows to lower feet until they touch the ground (the motors should be rubbing against the ground at this point)
7. Press enter. If performed correctly, repeatability is < 1 deg

Updating pupper URDF

The Pupper URDF is generated with the xacro urdf macro. It is composed of four files:

1. pupper.urdf.xacro
2. right_leg.xacro
3. left_leg.xacro
4. motor.xacro

Modifications to any of these files do not take place until compiled as follows:

1. Open a terminal and navigate to ~/WBC_catkin_ws/src/PupperWholeBodyControl/workstation/pupper_description
2. Run

   rosrun xacro xacro pupper.urdf.xacro > pupper.urdf