Last updated: March 25, 2024

Edge-Computing-Enabled Low-Latency Communication for a Wireless Networked Control System

Official implementation for the paper "Edge-Computing-Enabled Low-Latency Communication for a Wireless Networked Control System"

Description

We implemented a testbed in which a remote server receiving camera image information from an Autonomous Mobile Robot (AMR) creates a control command for moving the AMR and sends it back to the AMR. When the camera image information is transmitted to the server that performs edge computing, frequent transmission of camera information may adversely affect the performance of the entire system by increasing the load of the network. To solve this problem, two improvements were studied.

1. Transmitted image information is preprocessed in AMR and only a very small amount of data is transmitted.
2. Instead of transmitting video information at regular intervals, video information is transmitted only when surprising information comes in.

(The mobile robot deployed in the testbed is manufactured by Waveshare Electronics and integrated with a Raspberry Pi 3B+.)

Watch the video Description: This video showcases the Autonomous Mobile Robot successfully following a designated path and presents the results of Improvement #2, highlighting its enhanced performance.

Implementation setup on the remote vehicle

The Raspberry Pi is moving towards a 64-bit operating system. Within a year or so, the 32-bit OS will be fully replaced by the faster 64-bit version.

Step #1: Installation of Raspberry Pi OS

1. Dowmload and install the Raspberry Pi Imager into your computer
2. Run the Raspberry Pi Imager in your computer
3. Pluge in the sd card that you want to write the OS on
4. Select the operating system that you want to install
5. Select your sd card
6. Click write to write the OS into your sd card

Step #2: Enable Interfaces for AlphaBot2

More detalits about the Alphabot2 can be obtainet on the Link here

Type the following command in terminal.

sudo raspi-config

1. Choose Interfacing Options -> Camera -> Yes -> Yes -> OK
2. Choose Interfacing Options -> SPI -> Yes -> OK
3. Choose Interfacing Options -> VNC -> Yes -> OK
4. Choose Interfacing Options -> I2C -> Yes -> OK
5. Choose Interfacing Options -> SERIAL -> No -> Yes -> OK

sudo apt update
sudo apt install fonts-wqy-zenhei
pip install rpi_ws281x

Step #3: Download the EC-LLC-WNCS project

Download Project from our repository link to repo using command:

git clone https://github.com/sihsch/EC-LLC-WNCS

Step #4: Installing the requarments for the lineFollower project

We assume you have followed all the procedures from the biggining till here. Now we will install the necessary library to enable run our project. Navigate into the cloned repository directory using the cd command:

cd EC-LLC-WNCS\local
pip install -r requirements.txt

Syntax	Description (Local side)
AlphaBot2.py	contain the functionality to move the AlphaBot
full_local.py	All the computation is performed by the mobile robot
full_local_display.py	All the computation is performed at the mobile robot, and this will display what the mobile robot camera sees
remote_sender.py	offloads all the computation to the server
remote_sender_api.py	offloads all the computation to the server
edgelv1.py	Pre-process the image before offloading it to the server
edgelv1_sender_api.py	Pre-process the image before offloading it to the server
edgelv2.py	Pre-process the image before offloading it to the server
edgelv2_sender_api.py	Pre-process the image before offloading it to the server
edgelv3.py	Pre-process the image before offloading it to the server
edgelv3_sender_api.py	Pre-process the image before offloading it to the server
adaptive_sender.py	The mobile robot offloads the information to the server only when a threshold is violated
adaptive_sender_sender_api.py	The mobile robot offloads the information to the server only when a threshold is violated
requirements.txt	To install dependencies

Step #4: Installing the requarments for the lineFollower project

We assume you have followed all the procedures from the biggining till here. Now we will install the necessary library to enable run our project. Navigate into the cloned repository directory using the cd command:

cd EC-LLC-WNCS\remote
pip install -r requirements.txt

Syntax	Description (Remote side)
PID.py	PID algorithm for smoothly tracking the line
imgProcessing.py	For extracting useful information from the image
remote_receiver.py	Receive an image from (remote_sender.py), process it, and return a control command
remote_receiver_api.py	Receive an image from (remote_sender.py), process it, and return a control command
edge1_receiver.py	Receive semi-processed information from (edgelv1.py), finalize the processing, and return a control command
edge1_receiver_api.py	Receive semi-processed information from (edgelv1.py), finalize the processing, and return a control command
edge2_receiver.py	Receive semi-processed information from (edgelv2.py), finalize the processing, and return a control command
edge2_receiver_api.py	Receive semi-processed information from (edgelv2.py), finalize the processing, and return a control command
edge3_receiver.py	Receive semi-processed information from (edgelv3.py), finalize the processing, and return a control command
edge3_receiver_api.py	Receive semi-processed information from (edgelv3.py), finalize the processing, and return a control command
adaptive_receiver.py	Receive from (adaptive_sender.py) communication
adaptive_receiver_api.py	Receive from (adaptive_sender.py) communication
requirements.txt	To install dependencies

Step #5: How to Run the Source Code

This project consists of two main components: a server-side script and a corresponding client-side script. The server-side script listens for incoming connections, while the client-side script initiates a connection to the server. Both scripts are designed to work together to facilitate communication between the server and the client.

Usage Instructions

Before running the code, please ensure that you have the IP address of the server handy. You will need this IP address to establish a connection between the server and the client.

Step #5: Socket-based approach.

Remote {Server-Side Setup}

1. Navigate to the server-side directory.

2. Run the server-side script using the following command:

   python remote_receiver.py
   

   This command starts the server-side script, which will begin listening for incoming connections.

Local {Client-Side Setup}

1. Navigate to the client-side directory.

2. Run the client-side script using the following command, replacing {server IP address} with the actual IP address of the server:

   python remote_sender.py -ip {server IP address}
   

   This command initiates a connection to the server using the specified IP address.

Once the server and client scripts are running, they will be able to communicate with each other as intended.

Step #5: Rest-API based approach.

Remote {Server-Side Setup}

1. Navigate to the server-side directory.

2. Run the server-side script using the following command:

   python remote_receiver_api.py
   

   This command starts the server-side script, which will begin listening for incoming connections.

Local {Client-Side Setup}

1. Navigate to the client-side directory.

2. Run the client-side script using the following command, replacing {server IP address} with the actual IP address of the server:

   python remote_sender_api.py -ip {server IP address}
   

   This command initiates a connection to the server using the specified IP address.

Once the server and client scripts are running, they will be able to communicate with each other as intended.

Additional Information

• When using the REST API version, you can run the code on different networks, but you will need to configure port forwarding on the server side. Port forwarding allows external requests to access the specific port on your local network where the REST API server is running. This enables clients from external networks to communicate with your server over the internet. However, it's crucial to ensure that proper security measures are implemented, such as firewall settings and authentication mechanisms, to protect your server from unauthorized access and potential security risks when enabling port forwarding.

• Make sure that both the server and the client are connected to the same network if you are running them locally.

Stopping the Code

To ensure smooth stopping of the code execution, follow these steps:

Server-Side Stopping

1. On the server-side terminal where remote_receiver.py is running, press Ctrl + C.

   This action will gracefully terminate the server-side script, closing any open connections and releasing resources.

Client-Side Stopping

1. After stopping the server-side script, return to the terminal where remote_sender.py is running on the local side.

2. Press Ctrl + C to terminate the client-side script.

   By stopping the client-side script after the server-side script, you ensure that the connection is properly closed, preventing any unexpected behavior or resource leaks.

Following these steps will help you stop the code execution smoothly and avoid any potential issues.

Citation

If you use this code for your research, please cite:

@Article{electronics12143181,
AUTHOR = {Mtowe, Daniel Poul and Kim, Dong Min},
TITLE = {Edge-Computing-Enabled Low-Latency Communication for a Wireless Networked Control System},
JOURNAL = {Electronics},
VOLUME = {12},
YEAR = {2023},
NUMBER = {14},
ARTICLE-NUMBER = {3181},
URL = {https://www.mdpi.com/2079-9292/12/14/3181},
ISSN = {2079-9292},
DOI = {10.3390/electronics12143181}
}

Contact

For any inquiry please contact us at our email addresses: danielmtowe@sch.ac.kr or dmk@sch.ac.kr