PupperPy

Codename: CERBARIS

Software for the control and management of the Stanford Pupper Robot

Project maintained by nubs01 Hosted on GitHub Pages — Theme by mattgraham

Starting from a brand new Raspberry Pi 4

To start setting up the robot, I recommend plugging the raspberry pi into USB 3 power and a monitor, keyboard and mouse. This will make initial setup much easier.

To start with, you will need to install the lastest Raspberry Pi OS (Raspbian Buster) onto a fresh SD card. And you can follow the basic raspberry Pi setup instructions.

To connect to eduroam

An important note is that the newest Raspbian OS (Raspbian Buster) has issues connecting to Brandeis’s eduroam network. In order to get eduroam to connect you must run the downgrade_wpa_supplicant.sh script, and then setup the eduroam network credentials in the wpa_supplicant file. As such, the easiest way to get started is to put the downgrade_wpa_supplicant.sh and wpa_supplicant.conf files onto a USB drive. Then you can boot up the raspberry pi with your SD card and after the initial setup:

open a terminal
cd to the usb drive: cd /media/pi/name_of_usb/
downgrade wpa_supplicant: sudo bash downgrade_wpa_supplicant.sh
add robotics eudroam credential: sudo cp wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf

Now when you reboot the pi, it should automatically connect to eduroam. If using a different wireless network, you will have to add it to /etc/wpa_supplicant/wpa_supplicant.conf manually.

Setting up Cerbaris

Now that you have internet access you can clone the PupperPy repository and follow along in the setup_script.sh.

I recommend creating a folder in your home folder for all of your code so as not to pollute the home directory. For our project this was the pupper_code folder.

DO NOT run the setup script. It is not designed to be executed. Instead simply follow along and run each line or block of code as needed. The important steps are:

(optional) change username & hostname
enable ssh, camera via raspi-config
install all necessary software and python packages
grab all necessary git repositories
setup network interfaces for use with UDPComms
edit /boot/config.txt for I2C communication and camera settings
install pi gpio daemon
run installs for the git repositories
(optional) make symlinks for services
- required for basic PS4 control of pupper
- not needed for our autonomous control

Running Cerbaris

Once setup is complete and you have installed the PuppyPy package through pip:

cd /path/to/PupperPy
pip install -e pupperpy

You can now run the robot and all necessary processes with one command:

sudo python3 /path/to/PupperPy/pupperpy/run_cerbaris.py

After running this line you can connect the PS4 controller by holding the power and share buttons simultaneously until you see a double-blinking white light. The light will turn green when connected.

To activate the robot press the Left Bumper (L1).
To stop to robot press the Left Trigger (L2).
You can monitor the status of the robot on the web interface at https://cerbaris.netlify.app

Creating new behaviors

The control class provides a easy framework for creating and implementing new behaviors. All you need to do is inherit the Control class and override the update_behavior function.

from pupperpy.CommandInterface import Control

class NewControl(Control):
    def __init__(self, target='tennis_ball'):
        super().__init__(target=target)
        self.hokey_pokey_ticks = 0
        self._last_turn = None

    def update_behavior(self):
        obj, pos, cv = self.get_sensor_data()
        if self.hokey_pokey_ticks > 0 & self.hokey_pokey_ticks < 300:
            self.do_the_hokey_pokey()
            return
        elif self.hokey_pokey_ticks >= 300:
            self.turn_stop()
            self.move_forward()
            return

        if obj['left']:
            self.hokey_pokey_ticks = 0
            self.do_the_hokey_pokey()

    def do_the_hokey_pokey(self):
        if self._last_turn is None:
            self.turn_left()
            self._last_turn = 'left'
            self.hokey_pokey_ticks += 1
            return

        if self.hokey_pokey_ticks % 40 == 0:
            if self._last_turn == 'left':
                self.turn_right()
                self._last_turn = 'right':
            else:
                self.turn_left()
                self._last_turn = 'left'

        self.hokey_pokey_ticks += 1

Now you just make a copy of run_cerbaris.py and put your new class in place of Control()