WhoopLib: Open, PROS & VEXCode-Compatible SLAM/Motion Toolkit for VEX Robotics

VEX V5 Robotics Competition VRC
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Independent Project: WhoopLib is a student-led initiative and is not endorsed by or affiliated with Texas A&M University.

Pretense

Howdy,

I’m releasing WhoopLib as a free, open-source suite of templates to give the VEX community a practical, easy-to-learn foundation for advanced robotics and robot/computer interaction. It includes wheel and optional vision odometry, PID control, pure pursuit path following, and fusion of vision and wheel pose estimates via a Jetson Nano. The source is intentionally unbundled and editable to keep integration for VEXcode and PROS simple.

Competition use is the responsibility of each team; please verify legality against the current season’s rules. WhoopLib works with zero, one, or two pod odometry setups and offers an experimental vision fusion mode, which at present is most stable when paired with two pod odometry.

I’ve observed that with the library, the same code exhibits lower performance under PROS than under VEXcode. The root cause is under investigation, with differences in hardware interfacing being a leading hypothesis. I hope the community adopts, adapts, and helps improve it.

WhoopLibWhite
WhoopLibWhite2138×566 57 KB

A Simple SLAM Solution with both PROS and VEXCode support.

Features

Odometry & Pose Estimation

  • Visual odometry / pose estimation
  • Wheel odometry / pose estimation (inspired by JAR-Template)
  • Fusion odometry (visual + wheel) with rolling average filter

Control & Motion

  • WhoopController with auto-configuration for Split Arcade, Tank, Left Stick Arcade, and Right Stick Arcade
  • Path generation: Dubins curves (thanks to Andrew Walker) and Pure Pursuit
  • Point-to-point navigation (move between Point A and Point B)
  • High-level motion primitives: precise turning (by degrees / to face coordinates), forward/reverse movement with historical position memory for resilience
  • General PID controller with anti-windup (kR, aka “retracted windup”)
  • Slew rate limiter for motor movements
  • Motor voltage-to-speed linearization

Utilities & Abstractions

  • TwoDPose class simplifying linear algebra, modeled with similarities to Roblox’s CFrames
  • Units system (_in, _v, _mm, etc.)
  • Simplified MicroSD card file system
  • Autonomous selector with optional persistent saving via MicroSD

Documentation & Ecosystem

  • Comprehensive and continuously updated documentation for a low floor and high ceiling

Roadmap (Needs Maintainer)

  • Object Detection and Gridded Permanence system
  • Detecting other robots that impede the path of the robot, and drive around
  • Implementation of a Jetson Orion Nano instead of the End-Of-Line (EOL) Jetson Nano
  • Implementation of a better SLAM solution instead of relying on the EOL Realsense T265 Camera
  • Capability to Use Different Devices like Oak-D, etc. for Visual Odometry
  • Capability to Use Lidar
  • Virtual Highway system

Video Of WhoopLib

Here is a video of WhoopLib in motion on a robot from team WHOOP that has seen screentime on the Worlds 2024 stage:

As you see, the robot uses odometry for tracking, dubins-curves for path generation, pure pursuit for distance and rotation error, and two symbiotic PID’s that switch between point-turns and curvature turns.

Resources

Documentation on how to get started can be found here:

GitHub repository can be found here:

Acknowledgements

License

Distributed under the MIT License.

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@anon4126930
I edited your post.

You had a link to “VEX Robotics” which most would think would be the company I work for when in reality it’s a github account that seems to be pretending to be “VEX Robotics” and has nothing to do with us.

8 Likes
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Thank you for the fix, my mistake. Also thank you for updating the HTML error in the title.

:slight_smile:

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After looking further, I have found the core problem. Apparently, there is motor voltage linearization for VEXCode, but it did not apply for PROS. So the motors were less reactive in PROS.

This has been fixed:

void WhoopMotor::spin(double volts) {
// Linearizes the voltage. Visual representation of the linearization:
// https://www.desmos.com/calculator/anyejul5wg It attempts to make the voltage
// and motor power more linearly proportional
#if USE_VEXCODE
  vex::motor::spin(fwd, linearize_voltage(volts), voltageUnits::volt);
#else
  pros::Motor::move(linearize_voltage(volts) * VOLTAGE_TO_ANALOG_CONVERSION);
#endif
}