ROS2 Example Applications

AWS RoboMaker version notice

This tutorial was created and is based on AWS RoboMaker as of July 2019. Please refer to the official documentation for the latest and most accurate information, as there may have been updates or changes since then.

ROSbot - introduction

ROSbot 2.0 is autonomous, open source robot platform. It can be used as a learning platform for Robot Operating System as well as a base for a variety of robotic applications such as research robots, inspection robots, custom service robots etc.

Unboxing

What's in the box:

• carrying case
• ROSbot 2.0 (with optional 3D camera and LiDAR already assembled)
• Wi-Fi 2.4GHz antenna
• 3x 18650 Li-Ion rechargeable batteries
• universal charger with power adapter
• charging cable
• microSD card with the software for ROSbot
• USB to Ethernet adapter

Rear panel description

In the picture below you can see names of the elements from the rear panel of the ROSbot.

Hardware setup

1. Mounting the batteries

Your ROSbot is assembled, but to get it ready to work, you need to provide a power supply and attach the antenna.

To mount the batteries turn ROSbot upside down and follow these steps:

1. Unscrew battery cover mounted with two screws.
2. Remove the battery cover.
3. Place batteries accordingly to the polarization symbols (do it carefully!), keeping the black strip under the batteries.
4. Place battery cover and mount it with screws.

2. Batteries charging guide

1. Connect the power adapter to the charger and the output cable between charger and ROSbot (2 connectors on charger side, 1 black connector to ROSbot charging port).

After this step is complete your charger should look like this:

2. Use the first two buttons to select “LiPo BATT” mode and press [Start] button.
3. Use arrows to select “LiPo CHARGE” mode.
4. Press [Start] - the current value should start blinking. Use arrows to set the current to 1.5A.
5. Press [Start] again - the voltage value should start blinking. Select “11.1V(3S)” using arrows.
6. Press and hold [Start] for 2 seconds. The charger should now ask for confirmation. Press [Start] again. The charging process should begin now.
7. When charging is finished (after about 3 hours), the charger will generate a loud “beep” sound and will finish charging at the same time.

The picture below is a visualization of the mentioned steps.

3. Attaching the antenna

To attach the antenna, screw it to the antenna connector on the ROSbot rear panel.

Flashing image with ROS2 support

ROSbots are shipped with ROS1 support. In order to enable working with ROS2 support, it is necessary to flash image with ROS2.

1. Extract SD card from ROSbot, by pushing card carefully until it is released back by card holder, then pull it out. You can find SD card slot on ROSbot right side.
2. Download image for Tinkerboard from here .
3. Extract downloaded image (For this process we recommend using 7zip)
4. Flash the extracted image onto SD card (For this process we recommend using Etcher but any image writing tool will be good):

• If you want to replace the included card, remember that you need to use at least 16 GB capacity and 10 speed class micro SD card.
• Download Etcher and install it.
• Connect an SD card reader with the SD card inside.
• Open Etcher and select from your hard drive .img file that you extracted.
• Select the SD card you wish to write your image to.
• Review your selections and click Flash! to begin writing data to the SD card.
• Wait until the process is finished.
• Use Unmount drive on linux on Remove device safely on Windows, wait until system confirms that you can unplug card reader.

5. Insert SD card back to ROSbot

Troubleshooting

It may happen that process of flashing SD card will fail, this may prevent ROSbot from booting properly. Possible symptoms of faulty flashing process are:

• Blank screeen after powering up the ROSbot.
• ROSbot begins to boot, but freeze at some moment.
• ROSbot is booting into text-only mode.
• ROSbot is booting into graphical mode but it is not responding. If above signs are observed, it will be necessary to repeat card flashing process.

Connecting to Wi-Fi network

ROSbot is basically a computer running Ubuntu, so let's configure it like a standard PC computer.

1. Plug in a display with HDMI, mouse and keyboard into USB port in the rear panel of ROSbot.
2. Turn on the robot and wait until it boots.
3. Use networking menu located on top-right of the screen to connect to a Wi-Fi network.
4. When connection is active, use networking menu again and choose Connection Information to find device IP address.
5. Note the ROSbot IP address, you will need it later.

Choosing the location

You can chose to work with AWS services on servers located in various location across world. You are free to choose the server closest to your location, although in tutorials we refer to us-east-1. Whichever location you will choose, you must keep it while following through the whole manual.

To choose location, go to AWS Management console and find location dropdown menu next to your username in top right corner. From the menu choose US East (N. Virginia) us-east-1.

For more information regarding regions please check the documentation.

Configure AWS Environment

Before we use AWS RoboMaker to build and deploy the tutorial applications, we must first set up the AWS environment. To simplify the configuration, we will use AWS CloudFormation. CloudFormation enables us to use a template file to define the configuration of our environment. We will use CloudFormation to create a bucket in Amazon S3, as well as to create the necessary permissions in AWS Identity and Access Manager (IAM) that AWS RoboMaker requires to simulate and deploy our robot applications.

To deploy the template, sign in to the CloudFormation console. Follow the steps to deploy the template:

1. Click the Create Stack button and select With new resources from the drop down.

2. In Step 1: Specify template in section Prerequisite - Prepare template select Template is ready, then in section Specify template select Amazon S3 URL and type in the following text field: https://robomaker-rosbot-samples.s3.amazonaws.com/rosbot_tutorial_template.yaml. Proceed with Next button.

3. In Step 2: Specify stack details in section Stack name type rosbot-stack, then proceed with Next button.

4. In Step 3: Configure stack options leave all settings default and proceed with Next button.
5. In Step 4: Review scroll to last section named Capabilities then check I acknowledge that AWS CloudFormation might create IAM resources with custom names.. Proceed with Create stack button.
6. You will be redirected to stacks list, wait until your stack is created.
7. When stack creation is finished, click stack name to open its details, then choose tab Outputs, in the table you will see three rows, note the three Key/Value pairs as you will need them later in this guide.

ROSbot setup in RoboMaker

ROSbot need some system modifications before Greengrass will be able to run and deploy applications. To configure ROSbot:

1. Sign in to the AWS RoboMaker console.
2. In the left navigation pane, choose Fleet Management and then choose Robots.
3. Choose Create robot.
4. In section General:

• In the Name field, type ROSbot.
• From the Architecture dropdown menu choose ARMHF.

5. In section AWS Greengrass group details:

• From the Greengrass setup method dropdown menu choose Use manual setup method.
• From the AWS Greengrass group dropdown menu choose Create new.
• In the AWS Greengrass prefix field type ROSbot.
• From the IAM role dropdown menu choose ROSbotDeploymentRole.

6. Proceed with Create, you will be redirected to Download your Core device page.

7. Choose Download button next to Download and store your Core's security resources, you will get ROSbot-setup.zip file.

• File needs to be uploaded to ROSbot. The upload process will vary, depending on your host operating system.

On Linux

Navigate to directory where the file is downloaded, by default it should be ~/Downloads.

cd ~/Downloads

• Copy file to your ROSbot, you will need to substitute ROSBOT_IP with device address you noted earlier:

scp ROSbot-setup.zip husarion@ROSBOT_IP:ROSbot-setup.zip

On Windows

You will need an SCP client, download and install WinSCP.

Start WinSCP, you will see the login dialog:

• From File protocol dropdown menu choose: SFTP.
• In Host name field provide rosbot IP address that you noted earlier, it is the value which we described as ROSBOT_IP.
• In Port number field provide 22.
• In User name field provide husarion.
• In Password field provide husarion.

When all fields are filled up, click Login button to connect, you will see file manager view.

In the left tab navigate to directory where you downloaded the ROSbot-setup.zip file. In the right tab navigate to /home/husarion directory.

Drag and drop the ROSbot-setup.zip to the right tab.

When the transfer is finished, close the window.

ROSbot setup on device

You will need to make some system configurations on device. Depending on your host system, you can connect to your ROSbot with different methods:

On Linux

Open terminal and start ssh connection, you will need to substitute ROSBOT_IP with device address you noted earlier:

ssh husarion@ROSBOT_IP

Proceed to Device setup section.

On Windows

Press WinKey + r then type mstsc.

You will see a window appear:

Type in your device IP address and click connect.

You will see the ROSbot desktop, from the top menu, choose the Applications -> Terminal.

Device setup

• Unzip ROSbot security resources:

cd ~
sudo unzip ROSbot-setup.zip -d /greengrass

• Download and flash low level firmware:

wget https://husarion-robomaker-downloads.s3-eu-west-1.amazonaws.com/firmware.bin
sudo stm32loader -c tinker -e -v -w firmware.bin

• Restart ROSbot to apply changes.

At this moment, ROSbot is ready to start AWS GreenGrass and accept incoming deployments.

• Connect with ROSbot again, open terminal and start the GreenGrass:

sudo /greengrass/ggc/core/greengrassd start

• Start MicroXRCEAgent for communication with CORE2 controller board:

sudo MicroXRCEAgent serial --dev /dev/ttyS1 -b 500000

• Reset the controller board with reset button on ROSbot back panel.

• Leave the ROSbot turned on, it will wait for deployment.

Creating a RoboMaker IDE

Application will be built using the RoboMaker environment. To create the IDE:

1. Sign in to the AWS RoboMaker console

2. On the left, expand Development, choose Development environments, and then choose Create environment.
3. In General section:

• In the Name field type rosbot_env.
• From the Pre-installed ROS distribution dropdown menu choose ROS2 Dashing (Beta).
• From the Instance type dropdown menu choose m4.large. You can select different instance type to improve bundling performance.

4. In Networking section:

• From the VPC dropdown menu choose the default value.
• In the Subnets dropdown list choose the first subnet. You can select different subnet if necessary.

5. Choose Create to create the AWS Cloud9 development environment, you will be redirected to new browser tab with environment opened.

Running RoboMaker sample applications on ROSbot

Below section will guide you through running sample applications provided by AWS RoboMaker.

Running the Hello World sample application

We are basing on Hello World sample application with some modifications for running on ROSbot.

To deploy application, you will use RoboMaker environment created in previous step:

• Go to AWS RoboMaker home console.

• On the left, expand Development, choose Development environments, and then choose rosbot_env.

• Open the development environment with Open environment button.

• In the IDE, go to bash tab and clone the "Hello World" sample application repository in ~/environment/ directory:

cd ~/environment/
git clone https://github.com/husarion/aws-robomaker-sample-application-helloworld.git

• Start the configuration script. You need to provide the S3 bucket name and the ARN of the IAM role that was created by CloudFormation earlier. The parameters to the script should be set to the corresponding values provided in the output of your CloudFormation stack:

cd ~/environment/aws-robomaker-sample-application-helloworld/rosbot_deploy/
./start_deployment_job.bash <S3Bucket> <ROSbotDeploymentRole>

The script will install all dependencies, configure project, build and set the deployment job.

When the script is done with its job, you can observe the deployment process:

• Sign in to the AWS RoboMaker console.
• In the left navigation pane, choose Fleet Management and then choose Deployments.
• When new deployment will appear, open it by clicking its name.
• Wait until deployment status changes to Succeed - ROSbot will start to spin in place.

Running the Cloud Watch sample application

We are basing on Cloud Watch sample application with some modifications for running on ROSbot.

Before you start with application deployment, first you need to set access permissions for ROSbot to enable it with Cloud Watch metrics uploads.

Open IAM console and in the left panel choose Access management -> Users, then choose button Add user.

In User name field provide 'ROSbotLoggerUser', mark Programmatic access checkbox and proceed with button Next: Permissions

Choose Attach existing policies directly and check policies:

• AWSRoboMakerFullAccess
• CloudWatchFullAccess
• AWSGreengrassFullAccess

You may use filter to find required policies, proceed with Next: Tags and Next: Review. Verify that you have AWS access type set to Programmatic access - with an access key and in Permissions summary table you have three policies.

Proceed with Create user button.

In confirmation window, you receive Access key ID and hidden Secret access key, click Show to view it. Note both keys, they will be required in next step. You can close dialog window with Close button.

Connect with ROSbot and open terminal, you will create AWS access configuration for ROSbot.

• Create a directory for storing configuration and credentials:

  sudo -u ggc_user mkdir /home/ggc_user/.aws

• Create a configuration file:

  sudo -H -u ggc_user nano config

  In file paste following content, adjust value of region depending on your zone.

  [default]
  region=********

• Create a credentials file:

  sudo -H -u ggc_user nano credentials

  In the file paste the following content and adjust values according to the keys that you created in previous step:

  [default]
  aws_access_key_id=************
  aws_secret_access_key=*****************
  region=********

ROSbot is ready for publishing Cloud Watch metrics, start Greengrass daemon and MicroXRCEAgent if they are not running already.

To deploy application, you will use RoboMaker environment created in previous step:

• Go to AWS RoboMaker home console.

• On the left, expand Development, choose Development environments, and then choose rosbot_env.

• Open the development environment with Open environment button.

• In the IDE, go to bash tab and clone the Cloud Watch sample application repository in ~/environment/ directory:

cd ~/environment/
git clone https://github.com/husarion/aws-robomaker-sample-application-cloudwatch.git

• Start the configuration script. You need to provide the S3 bucket name and the ARN of the IAM role that was created by CloudFormation earlier. The parameters to the script should be set to the corresponding values provided in the output of your CloudFormation stack:

cd ~/environment/aws-robomaker-sample-application-helloworld/rosbot_deploy/
./start_deployment_job.bash <S3Bucket> <ROSbotDeploymentRole>

The script will install all dependencies, configure project, build and set the deployment job.

When the script is done with its job, you can observe the deployment process:

• Sign in to the AWS RoboMaker console.
• In the left navigation pane, choose Fleet Management and then choose Deployments.
• When new deployment will appear, open it by clicking its name.
• Wait until deployment status changes to Succeed - ROSbot will publish metrics into Cloud Watch.

To view metrics, go to Cloud Watch console, then choose Metrics in left panel. Choose AWSRoboMakerFleetManagement -> RobotName, category, robot_id. You can mark chosen statistics to plot them on a graph, you can inspect memory usage, cpu usage or system uptime.

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by Łukasz Mitka, Husarion

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