Repository for utilities and tools necessary for setting up hardwares required for robotics subject

Overview

For developers, tutors or individuals who are keen

Setting up the Raspberry Pi (from scratch)

Download the Raspberry Pi Imager and follow the instructions:

• Flash Raspian Lite OS 64bit. Make sure that SD card is at least 16GB
• Before flashing the OS to the SD, ensure the following configurations are met:
  • hostname: robotic
  • Enable SSH with password authentication
  • Username: robotic
  • Password: admin
  • Enable locale settings

Insert the SD card into the Raspberry Pi and let it boot, which usually takes around 1 to 2 minutes. After that, connect it to a router and proceed with ssh-ing into it, using the above credentials. It is also important to have the ip address of the ethernet port to be static. To do so, follow the instructions from this guide. Follow this guide to install and configure docker onto the Raspberry Pi. Note that it is not necessary to install docker-compose since we do not rely on it in any of the scripts. Finally, clone this package to the Pi and put it somewhere convienient for youself.

How to build base image

robotic_base image can only be built on Ubuntu devices (currently supported on MacOS M1 only) and cannot be built on a raspberry pi due to missing dependencies. Therefore, the base image should be built on an Ubuntu device and then transfered onto the Pi for setting up containers.

You can also email the maintainer (Khoa - khoanguyendacdang2198@gmail.com) of this repository for a copy of the base image. To build the base image, follow the instructions:

On the Ubuntu device:

Create a folder built_images and build the image using the build.sh script

mkdir built_images
./build.sh

Save the base image into a file in built_images

docker save -o built_images/robotic_base dkhoanguyen/robotic_base:latest

Wait for the process to finish then copy that image onto the pi using scp

scp built_images/robotic_base robotic@<pi-ip-address>:/home/robotic/robotic_base

On the Raspberry Pi:

Navigate to /home/robotic/ and make sure that the file exists. Then run this command to load the image onto docker:

docker load -i robotic_base

Please make sure that there is sufficient space on the Pi for this operation. Once that done then the image should be available for use. You can double-check using docker image ls -a

Disabling wpa_supplicant

To facilitate the wifi access point setup, it is important to disable the wpa_supplicant on the Raspberry Pi by using these commands:

sudo systemctl mask wpa_supplicant.service
sudo mv /sbin/wpa_supplicant /sbin/no_wpa_supplicant
sudo pkill wpa_supplicant

Configuring Wifi Access Point

It is important to configure the Wifi Access Point before proceeding forward, as it creates a safe point for us to ssh in and debug the unit. It also provides a mean for non - ROS devices to communicate with the ROS network inside the Pi via websocket. To get started, we need to make the Wifi of each Pi to contain the uuid serial number. Obtain the serial number by running the following command:

cat /sys/firmware/devicetree/base/serial-number

The output should look something like this:

1000000aabbccdd

Copy the last 8 digits of the uuid and save it somewhere. After that, navigate to the config/rpi_wifi folder and open the file wificfg.json. It should look something like this:

{
    "dnsmasq_cfg": {
        "address": "/#/192.168.27.1",
        "dhcp_range": "192.168.27.100,192.168.27.150,1h",
        "vendor_class": "set:device,IoT"
    },
    "host_apd_cfg": {
        "ip": "192.168.27.1",
        "ssid": "rpi3_default",
        "wpa_passphrase": "robotics",
        "channel": "6"
    },
    "wpa_supplicant_cfg": {
        "cfg_file": "/etc/wpa_supplicant/wpa_supplicant.conf"
    }
}

Replace the rpi3_default in the ssid field by a combination of the word robotics_ and the 8 uuid characters that you've obtained from the previous step. The field should look like this:

"ssid": "robotics_aabbccdd",

Also change the passphrase to robotics if necessary. Save the file and navigate back to the root folder of the repo then run

./run_base.sh

Double check on your laptop or phone to see if the Wifi is available.

Run containers

We currently support the following robots:

• UR3 (CB and E series) with the onrobot grippers (RG2 only)
• Hans Cute
• Dobot Magician

UR3 series

Please double check your setup before proceeding:

• The following components should be present:
  • UR3 robot
  • Router
  • Raspberry Pi
• They must all be connected to the same network. The UR3 has to be configured with the External Control URCap to communicate with ROS. Please follow the instructions here to setup a CB series robot and here to setup an E series robot.

Once that is done, ssh into the Raspberry Pi and run: E series:

./run_ur3e.sh

CB series:

./run_ur3.sh

Please allow at least one minute for all containers to properly start and kick off all of the necessary components.