How to Start Networked Robotics Projects Using NS2

To start a Networked Robotics project in NS2 that requires modeling the simulation in which robots communicate through the network for attaining combined tasks. In robotics networks, these simulations are generally utilised for learning communication protocols, performance, and scalability. Below is a brief procedure to get started:

Steps to Start Networked Robotics Projects in NS2

1. Understand Networked Robotics

• What is Networked Robotics?
  • It has numerous robots to interact and organize over a network for executing exploration, surveillance, or search-and-rescue tasks.
• Applications:
  • Cooperative task execution.
  • Autonomous navigation.
  • Swarm robotics.
  • Sensor data sharing.

2. Prepare Your Environment

• Install NS2:
  • We can set up NS2 on a Linux-based system:

sudo apt-get update

sudo apt-get install ns2 nam

• • Confirm the installation by executing sample scripts.
• Familiarize Yourself:
  • Focus on the TCL scripting (used for simulations) fundamentals and know NS2 structure that integrates the TCL for scripting and C++ for protocol modifications.

3. Define the Scope of the Project

• Choose an Objective:
  • Instances:
    • Collaborative task execution by leveraging networked robots.
    • Mobility-aware routing protocols.
    • Efficient robot communication.
• Identify Metrics:
  • Detect the performance parameters such as throughput, delay, energy consumption, packet loss, and so on.

4. Simulate Robots as Network Nodes

• It denotes the robots like mobile nodes including certain interaction protocols in NS2.
• Describe the robot mobility and behavior:
  • In NS2, replicate the robotic movement (e.g., Random Waypoint, Gauss-Markov) to utilise Mobility Models.

5. Create the Network Topology

• Nodes:
  • Robots are denoted by nodes.
• Links:
  • Make use of wireless interaction links such as Wi-Fi, ZigBee.
• Traffic Patterns:
  • Describe the data exchanges among robots like sensor data, task updates.

6. Write the TCL Script

• Basic Network Structure:
  • Make a robots network including wireless links.
• Example: Simple Robot Communication

# Create simulator

set ns [new Simulator]

# Create trace and animation files

set tracefile [open trace.tr w]

set namfile [open output.nam w]

$ns trace-all $tracefile

$ns namtrace-all $namfile

# Define nodes (robots)

set robot1 [$ns node]

set robot2 [$ns node]

set robot3 [$ns node]

# Add wireless link parameters

$ns node-config -adhocRouting DSDV -llType LL -macType Mac/802_11 \

-ifqType Queue/DropTail/PriQueue -ifqLen 50 \

-antType Antenna/OmniAntenna -propType Propagation/TwoRayGround \

-phyType Phy/WirelessPhy -channelType Channel/WirelessChannel

# Set robot positions and mobility

$robot1 set X_ 10

$robot1 set Y_ 20

$robot1 set Z_ 0

$robot2 set X_ 30

$robot2 set Y_ 40

$robot2 set Z_ 0

$robot3 set X_ 50

$robot3 set Y_ 60

$robot3 set Z_ 0

# Add traffic (sensor data exchange)

set udp [new Agent/UDP]

$ns attach-agent $robot1 $udp

set sink [new Agent/Null]

$ns attach-agent $robot2 $sink

$ns connect $udp $sink

set cbr [new Application/Traffic/CBR]

$cbr attach-agent $udp

$cbr set packetSize_ 512

$cbr set rate_ 100Kb

# Schedule events

$ns at 1.0 “$cbr start”

$ns at 10.0 “finish”

# Run simulation

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exit 0

}

$ns run

7. Enable Mobility

• Replicate the movement of robots to utilise NS2’s mobility patterns.
• Example: Random Waypoint Mobility

$robot1 setdest 50 50 10

$robot2 setdest 100 100 20

$robot3 setdest 150 150 15

8. Implement Protocols

• We can apply or change the existing protocols:
  • DSDV, AODV, and DSR: It is routing protocols used for mobile networks.
• Tailor the protocols for integrating robotic behavior or communication policies.

9. Run the Simulation

• Run the TCL script simulation in NS2:

ns your_script.tcl

• Examine the results:
  • Trace file (.tr): It has comprehensive event records.
  • NAM file (.nam): It is used to envision the simulation.

10. Analyze Results

• Make use of AWK, Python, or MATLAB tools to examine the trace files.
• We can estimate the simulation performance parameters like:
  • Energy consumption.
  • Packet delivery ratio.
  • Latency between robots.

11. Enhancements

• Multi-Robot Cooperation:
  • Add more robots and simulate collaborative tasks.
• Obstacle Avoidance:
  • Replicate the environments including obstacles and then experiment the routing protocols.
• Energy Efficiency:
  • Execute energy-aware routing protocol for long-term networked robots.
• Fault Tolerance:
  • Experiment how the network adjusts the tolerance to node failures.

12. Applications of Networked Robotics

• Search-and-Rescue:
  • Mimic robots that are organizing to determine the survivors within disaster scenarios.
• Surveillance:
  • Observe the analysis areas to utilise robots including cameras or sensors.
• Agriculture:
  • Replicate the robots which are interacting for enhancing the farming tasks.

Example: Swarm Robotics Simulation

Replicate the swarm robots to distribute sensor data for area exploration.

# Define nodes (robots)

set num_robots 10

for {set i 0} {$i < $num_robots} {incr i} {

set robot($i) [$ns node]

$robot($i) set X_ [expr $i * 10]

$robot($i) set Y_ [expr $i * 20]

$robot($i) set Z_ 0

}

# Connect robots and define traffic

for {set i 0} {$i < $num_robots-1} {incr i} {

set udp($i) [new Agent/UDP]

$ns attach-agent $robot($i) $udp($i)

set sink($i) [new Agent/Null]

$ns attach-agent $robot([expr $i+1]) $sink($i)

$ns connect $udp($i) $sink($i)

}

13. Document Your Work

• It provides detailed insights like:
  • Define the project objective.
  • We can create Network topology.
  • We need to utilise or alter the protocols.
  • Then, examine the simulation outcomes.

We have showcased a basic simulation method with sample coding for replicating and analysing the Networked Robotics Projects using NS2 tools. You can customize the simulation to the project’s needs, we will guide you.