Propulsion

Warning

Made by Claude (AI) and NOT yet reviewed by a human. This code was written by Claude Code from the CompetitionBot2026 motor utilities. It has not been compiled against the real vendor libraries, run on a robot, or reviewed by a team member. The pure-math tests (MotorMathTest) pass; the Phoenix 6 / REVLib calls are unverified. Treat it as a draft: review it, build it, and test it on hardware before relying on it at an event. Remove this notice once someone has done that.

Team 4761's reusable robot code library. Anything we copy from one season's robot into the next belongs here instead.

Right now that is the motor wrappers:

Class	Hardware	Notes
SmartKrakenMotor	Kraken X60/X44 (any TalonFX)	Phoenix 6
SmartVortexMotor	NEO Vortex on a SPARK Flex	REVLib
SmartMotor	interface both implement	swap motors without touching commands
MotorMath	pure math (wrapping, limits, gear ratios)	unit tested

Installing in a robot project

The library ships as a WPILib vendordep served by JitPack.

VS Code: WPILib: Manage Vendor Libraries → Install new library (online) → paste

https://raw.githubusercontent.com/Team4761/Propulsion/main/Propulsion.json

By hand: copy Propulsion.json into your project's vendordeps/ folder.

GroundZero (our yearly template) already includes it.

The library declares WPILib, Phoenix 6 and REVLib as compileOnly, so your robot project must also have the Phoenix 6 and REVLib vendordeps installed (GroundZero does).

Using the motors

import frc.team4761.propulsion.motors.MotorMode;
import frc.team4761.propulsion.motors.SmartKrakenMotor;
import frc.team4761.propulsion.motors.SmartVortexMotor;

SmartKrakenMotor turret = SmartKrakenMotor.Builder.newInstance()
    .port(25)
    .PID(0.5, 0.0, 0.0)            // position gains
    .gearRatio(185.0 / 28.0)       // motor rotations per turret rotation
    .angleLimits(-80.0, 80.0)      // soft limits in turret degrees
    .mode(MotorMode.CONTINUOUS)
    .statorCurrentLimit(40.0)
    .build();

turret.set(45.0);                  // go to 45 degrees
turret.turn(-10.0);                // 10 degrees back from wherever it is
turret.isAtAngle(45.0, 1.0);

SmartVortexMotor roller = SmartVortexMotor.Builder.newInstance()
    .canId(43)
    .velocityPID(0.0002, 0.0, 0.0)
    .velocityFF(0.1, 0.0017)
    .build();

roller.setSpeed(3000.0);           // mechanism RPM
roller.setSpeedPercent(0.8);       // open loop
roller.stopTurning();

Units: everything is in mechanism degrees / RPM (after the gear ratio) unless the method name has Raw in it. gearRatio is motor rotations per mechanism rotation.

Closed-loop slots: position uses slot 0, velocity uses slot 1. If you only call PID(...), those gains are used for both.

Changes from the 2026 robot's frc.robot.util versions

Drop-in except for the package name (frc.team4761.propulsion.motors) and SmartKrakenMotor.MotorMode → MotorMode.

• Bug: builders defaulted the output range to [0, 0] and angle limits to [0, 0], so a motor built without outputRange(...) / angleLimits(...) could not move. Defaults are now full output and no limits.
• Bug: angleLimits(-1, -1) was a magic "no limits" value, which made a real limit of -1 degrees impossible. Limits are now off unless you call angleLimits.
• Bug: WRAPPED mode used Java's %, which returns negative angles, and then commanded that angle directly so the turret could spin the long way around. It now takes the shortest path.
• Bug: set() checked the limits against the unwrapped angle but commanded the wrapped one.
• Bug: SmartVortexMotor.setSpeedPercent multiplied the percent by the gear ratio, so any reduction above 1:1 slammed to full output.
• Bug: SmartVortexMotor.setSpeed used closed-loop velocity without ever configuring gains, so it did nothing. Gains and feedforward are now configurable.
• Kraken velocity control allocated a new VelocityDutyCycle every loop; it now reuses one.
• Added: inversion, brake/coast, current limits, CAN bus name, velocity feedforward, resetAngle, isAtAngle, getWrappedAngle, Vortex position control and getSpeedRPM/getAngle, and getMotor() as an escape hatch.
• Config failures and limit violations are reported to the Driver Station instead of java.util.logging (which nobody reads on the RIO).

Releasing a new version

The vendordep currently pins commit 4f390da501 (JitPack builds any commit hash). Once the code has been reviewed, cut a real release:

1. Bump the versions in build.gradle (WPILib / Phoenix / REVLib) at the start of each season.
2. Commit, then create a GitHub release with a tag like v0.1.0 (or git tag v0.1.0 && git push origin v0.1.0).
3. Open https://jitpack.io/#Team4761/Propulsion and click Get it on the tag to trigger the build (it also builds on first download).
4. Update version in Propulsion.json (both the top-level version and the dependency version, which is the tag name) and bump frcYear when the season changes.

Building locally

./gradlew build

Runs the MotorMath unit tests. The wrappers themselves need hardware (or sim) to test.