To simulate Networked Robotics projects using NS2 has a series of steps that includes generating a network that enable communication among the robots, sensors, and control centres. These simulations usually concentrate on aspects such as coordination, data sharing, control signal communication, and mobility. Networked robotics can be implemented in numerous areas like swarm robotics, teleoperation, or autonomous vehicles in a smart city environment.
Key Components of Networked Robotics Simulation:
- Robotic Nodes: Robots perform as mobile nodes that interact with each other or with a control centre.
- Control Centers: Central nodes that handles and observe the actions of robotic nodes.
- Sensor Nodes: Sensors attached to robots or placed in the environment to track conditions.
- Communication Channels: Wireless or wired communication for data and control signals among robots and control centers.
Here’s how to simulate a Networked Robotics project in NS2:
Steps to Simulate Networked Robotics Projects in NS2
- Install NS2
If NS2 is not installed, install it using the following steps:
sudo apt-get install ns2
- Define the Components
In a networked robotics system, robots perform as mobile nodes, a control center oversees their operation, and sensor nodes can be utilized for environmental monitoring.
- Define Network Topology
Configure a network topology in which each robot is signified as a mobile node. The control center performs as a fixed node that interacts with the robots to transmit control signals and receive data.
Example Network Topology:
- Robots (Mobile Nodes): Communicate with each other or the control center.
- Control Center (Fixed Node): gathers data from the robots and transmit control signals.
- Sensors (Fixed or Mobile Nodes): Track the environmental conditions, delivered input to the robots.
- TCL Script for Networked Robotics Simulation
4.1 Define Nodes
Each robot and control centre is a node in the network. Mobility for the robots will be defined later.
# Create the simulator object
set ns [new Simulator]
# Open trace and NAM files
set tracefile [open “networked_robotics.tr” w]
$ns trace-all $tracefile
set namfile [open “networked_robotics.nam” w]
$ns namtrace-all $namfile
# Define simulation parameters
set val(chan) Channel/WirelessChannel ;# Wireless channel for communication
set val(prop) Propagation/TwoRayGround;# Propagation model
set val(mac) Mac/802_11 ;# MAC protocol for wireless communication
set val(ifq) Queue/DropTail/PriQueue ;# Interface queue
set val(ll) LL;# Link layer
set val(ant) Antenna/OmniAntenna ;# Antenna model
set val(ifqlen) 50 ;# Interface queue length
set val(rp) AODV;# Routing protocol (ad-hoc)
# Node configuration
$ns node-config -adhocRouting $val(rp) \
-llType $val(ll) \
-macType $val(mac) \
-ifqType $val(ifq) \
-ifqLen $val(ifqlen) \
-antType $val(ant) \
-propType $val(prop) \
-channelType $val(chan)
# Create nodes for robots and control center
set robot1 [$ns node]
set robot2 [$ns node]
set robot3 [$ns node]
set control_center [$ns node] ;# Control center
# Set initial positions for robots and control center
$robot1 set X_ 50
$robot1 set Y_ 100
$robot1 set Z_ 0.0
$robot2 set X_ 150
$robot2 set Y_ 100
$robot2 set Z_ 0.0
$robot3 set X_ 250
$robot3 set Y_ 100
$robot3 set Z_ 0.0
$control_center set X_ 200
$control_center set Y_ 200
$control_center set Z_ 0.0
- Set up Communication Links
Describe wireless communication among robots and the control centre. Depending on the task, communication can be direct (robot to robot) or through the control centre (robot to control center).
5.1 Communication between Robots and Control Center
# Define communication between robots and control center
$ns duplex-link $robot1 $control_center 10Mb 20ms DropTail
$ns duplex-link $robot2 $control_center 10Mb 20ms DropTail
$ns duplex-link $robot3 $control_center 10Mb 20ms DropTail
5.2 Robot-to-Robot Communication (Optional)
If robots interact directly, utilize duplex links among the robot nodes.
# Define communication between robots
$ns duplex-link $robot1 $robot2 5Mb 15ms DropTail
$ns duplex-link $robot2 $robot3 5Mb 15ms DropTail
- Configure Traffic Patterns
We can utilize TCP for reliable communication (for commands or control signals) or UDP for sensor data transmission.
6.1 TCP Traffic for Control Signals
# TCP agent for control signals between control center and robot1
set tcp_robot1 [new Agent/TCP]
$ns attach-agent $robot1 $tcp_robot1
# TCP sink at the control center
set tcp_control_center [new Agent/TCPSink]
$ns attach-agent $control_center $tcp_control_center
# Connect the TCP agent to the sink
$ns connect $tcp_robot1 $tcp_control_center
# Define application traffic (e.g., control commands)
set app_robot1 [new Application/Traffic/CBR]
$app_robot1 attach-agent $tcp_robot1
$app_robot1 set packetSize_ 512
$app_robot1 set interval_ 0.05
$ns at 1.0 “$app_robot1 start”
6.2 UDP Traffic for Sensor Data
# UDP agent for sensor data from robot2 to control center
set udp_robot2 [new Agent/UDP]
$ns attach-agent $robot2 $udp_robot2
# UDP sink at the control center
set sink_udp_control [new Agent/Null]
$ns attach-agent $control_center $sink_udp_control
# Connect the UDP agent to the sink
$ns connect $udp_robot2 $sink_udp_control
# Define application traffic for sensor data
set app_robot2 [new Application/Traffic/CBR]
$app_robot2 attach-agent $udp_robot2
$app_robot2 set packetSize_ 512
$app_robot2 set interval_ 0.1
$ns at 2.0 “$app_robot2 start”
- Define Mobility for Robots
Robots in networked robotics frequently move autonomously. We can describe mobility models such as Random Waypoint or specific paths.
# Define mobility for robots
$ns at 1.0 “$robot1 setdest 100 200 10.0”
$ns at 2.0 “$robot2 setdest 200 150 15.0”
$ns at 3.0 “$robot3 setdest 300 100 12.0”
- Run the Simulation
Once the topology, traffic, and mobility are defined, execute the simulation:
ns networked_robotics.tcl
- Visualize the Simulation
We can utilize NAM (Network Animator) to envision the robot mobility and communication:
nam networked_robotics.nam
- Analyse Simulation Results
The created trace file (networked_robotics.tr) will encompass information on packet transmission, latency, losses, and other parameters. We can measure key performance indicators such as:
- End-to-End Delay: The time taken for a control signal or sensor data to reach its destination.
- Packet Delivery Ratio (PDR): The ratio of successfully delivered packets to the total packets sent.
- Throughput: Data transmission rate among the robots and the control centre.
- Mobility Impact on Communication: How robot movement impacts communication performance.
- Extend the Simulation
We can improve the simulation by adding:
- Collaborative Robotics (Swarm Robotics): Multiple robots performing together to complete a task, needs more complex communication protocols.
- Obstacle Detection and Avoidance: Execute techniques that replicate real-time obstacle detection and avoidance.
- Energy Efficiency: Replicate battery-powered robots and enhance communication for energy efficiency.
- Security Protocols: Incorporate encryption for secure communication among robots and control centres.
This project idea deliver a wide range of implementations using the Networked Robotics projects in NS2, helping you explore numerous contexts of the Networked Robotics projects performance in smart city scenarios. We plan to deliver the detailed instructions to this project to in further manual.
If you’re having a tough time with your Networked Robotics Project simulation in the ns2 tool, just let us know the details of your project. We’re here to help you get some fresh results! The simulation pros at phdprime.com can suggest the best topics for your Networked Robotics Projects, so you can get your work done with our team’s support and achieve amazing results.
