NexvioraDocumented target: Ubuntu 24.04 · ROS 2 Jazzy · Gazebo Harmonic where used. Browser labs tested; ROS/Ubuntu/hardware execution not performed here.
What you will understand
- Navigate a dedicated directory.
- Run a unit-aware Python calculation.
- Read a C++ calculation.
Prerequisites: Meet the robot: sense, decide, act and its stated environment.
The idea, made clear.
Terminal commands act in a working directory. Relative paths resolve from there; absolute paths begin at the filesystem root. Keep exercises in your own directory, separate from system files. Inspect a path before writing or deleting files, and do not treat sudo as a universal fix for permission errors.
Python makes small calculations and ROS nodes approachable. C++ provides compiled binaries, explicit types and detailed resource control. Start with inputs, units and outputs rather than trying to master both languages immediately. Read error messages from the final line upward and fix the underlying cause.
Wheel angular speed in radians per second differs from revolutions per minute. Convert at boundaries and include units in variable names. A plausible number with the wrong units still describes the wrong command. Small numerical assertions catch mistakes before software reaches a motor.
Try it, step by step.
Create a directory
These commands create your exercise folder.
mkdir -p ~/nexviora_robotics
cd ~/nexviora_robotics
pwdExpected: A path ending in nexviora_robotics.
Convert wheel speed
Save as wheel_speed.py and run python3 wheel_speed.py.
import math
radius_m = 0.05
rpm = 60.0
rad_s = rpm * 2 * math.pi / 60
print(f"rim speed: {radius_m * rad_s:.3f} m/s")Expected: rim speed: 0.314 m/s
Compare C++
Save as speed.cpp; compile with g++ -std=c++17 speed.cpp -o speed, then run ./speed.
#include <iostream>
int main() {
const double radius_m = 0.05;
const double speed_rad_s = 6.283185307;
std::cout << radius_m * speed_rad_s << " m/s\n";
}Expected: Approximately 0.314159 m/s.
If something goes wrong
- File not found
- Check pwd, ls and filename spelling.
- Permission denied
- Use an account-owned folder before considering privileged commands.
Check your understanding
Make it yours
Assert that 120 RPM converts to approximately 4π rad/s.
Optional progress stays in this browser. No account needed.
Go to the source documentation
Commands are educational examples for the stated environment, not a transcript of local ROS execution. Verify actual behavior on your machine.