AbsoluteLib V2

AbsoluteLib is an FRC utility library for Team 4308. It provides reusable subsystems + wrappers with a focus on "same code in real + sim".

• Vendor install: https://team4308.github.io/absolutelib/lib/absolutelib.json
• Docs site: https://team4308.github.io/absolutelib/
• JavaDoc site: https://team4308.github.io/absolutelib/docs/javadoc

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Installation (WPILib Vendor JSON)

1. WPILib VS Code → Ctrl+Shift+P
2. WPILib: Manage Vendor Libraries
3. Install new library (online)
4. Paste:

   https://team4308.github.io/absolutelib/lib/absolutelib.json
   

Required Vendor Dependencies

Before building, install all required libraries:

• Rev Hardware Client
• AdvantageKit
• PathPlannerLib
• Phoenix6-Replay (6 and 5)
• PhotonLib
• REVLib
• Studica
• ThriftyLib
• YAGSL

Note: Your build WILL fail if you don't add these vendordeps.

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What You Get

Wrappers

• MotorWrapper: TalonFX (Phoenix6), TalonSRX/VictorSPX (Phoenix5), SparkMax (REV) unified API
• EncoderWrapper: Unified encoder access (CANCoder, SparkMax encoder, etc.)

Subsystems

• Arm: Multi-joint arm with IK support (2+ DOF arms with inverse kinematics)
• Pivot: Single-joint rotational control (PID + FF, optional Smart Motion)
• Elevator: Linear elevator control (PID + FF, optional Smart Motion)
• EndEffector: Base class for intakes, claws, and manipulators

Simulation

• ArmSimulation: Physics sim for multi-DOF arms
• PivotSimulation: Physics sim via SingleJointedArmSim
• ElevatorSimulation: Physics sim via ElevatorSim

Vision / LEDs

• Vision: PhotonVision wrapper + multi-camera support for pose estimation
• leds/*: Addressable LED patterns and simulation helpers

Math Utilities

• ChineseRemainderSolver: Generic CRT solver + turret anti-windup (shortest-path rotation within cable limits)
• DoubleUtils: Clamping, normalization, range mapping
• Vector2 / Vector3: Lightweight vector math

Trajectory System (2026 REBUILT)

• TrajectorySolver: Complete trajectory solving for turret shooters with obstacle avoidance
• ShooterSystem: Integrated state machine for managing shots, tracking, and fallback strategies
• FlywheelGenerator: Automated flywheel configuration generation and optimization
• FlywheelSimulator: Physics-based flywheel and ball exit velocity simulation
• ProjectileMotion: Projectile physics with air resistance, drag, and Magnus effect
• ObstacleConfig: Collision-aware field obstacle definition (e.g., 2026 hub)
• SolverConstants: Runtime-tunable constants for all solver behavior
• GamePieces: Predefined game pieces including 2026 REBUILT ball

Example Code

Under ./example/example-2026-Imported you can find full robot code for all subsystems + simulation.

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Full Simulation: How It Works

AbsoluteLib simulations follow this pattern:

1. Subsystem computes output (PID + FF) → produces a voltage or percent output
2. Subsystem applies output to motor (real hardware OR sim state)
3. In SIM: subsystem passes the same computed voltage into the simulation object
4. Simulation updates position/velocity and writes them back into:
   • Encoder sim position
   • Motor controller sim state (when supported)

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Subsystem Examples

MotorWrapper (Unified API)

import ca.team4308.absolutelib.wrapper.MotorWrapper;
import ca.team4308.absolutelib.wrapper.MotorWrapper.MotorType;

public class ShooterIO {
    // Control TalonFX, SparkMax, or TalonSRX with the same API
    private final MotorWrapper leader = new MotorWrapper(MotorType.TALONFX, 10);
    private final MotorWrapper feeder = new MotorWrapper(MotorType.SPARKMAX, 11);

    public void runVolts(double volts) {
        leader.setVoltage(volts);
    }

    public void stop() {
        leader.stop();
        feeder.stop();
    }
}

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Pivot Subsystem (Arm/Wrist)

Single-joint rotational subsystem with PID control and simulation.

import ca.team4308.absolutelib.subsystems.Pivot;
import ca.team4308.absolutelib.subsystems.simulation.PivotSimulation;
import ca.team4308.absolutelib.wrapper.MotorWrapper;
import ca.team4308.absolutelib.wrapper.EncoderWrapper;
import edu.wpi.first.math.system.plant.DCMotor;

public class Wrist extends Pivot {
    public Wrist() {
        super(new Pivot.Config()
            .withLeader(new MotorWrapper(MotorWrapper.MotorType.TALONFX, 15))
            .withEncoder(EncoderWrapper.canCoder(20, 1.0)) // 1.0 = ratio derived from gearbox
            .gear(50.0)
            .limits(-90, 90)
            .pid(0.02, 0.0, 0.0)
            .ff(0.0, 0.15, 0.0, 0.0)
            .enableSimulation(true)
            .withSimulation(new PivotSimulation.Config()
                .gearbox(DCMotor.getFalcon500(1), 1)
                .gearRatio(50.0)
                .armLength(0.30)
                .armMass(2.0)
                .limits(Math.toRadians(-90), Math.toRadians(90))
                .startAngle(0.0)
            )
        );
    }

    public Command goToStow() { return setPosition(0.0); }
    public Command goToScore() { return setPosition(45.0); }
}

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Arm Subsystem (Multi-Joint IK)

Multi-DOF arm with inverse kinematics for Cartesian (x,y) positioning.

import ca.team4308.absolutelib.subsystems.Arm;
import ca.team4308.absolutelib.wrapper.MotorWrapper;
import ca.team4308.absolutelib.wrapper.EncoderWrapper;

public class ExampleArm {
    private final Arm arm = new Arm();
    private final Arm.Joint shoulder;

    public ExampleArm() {
        // Shoulder setup
        MotorWrapper shoulderMotor = new MotorWrapper(MotorType.TALONFX, 30);
        EncoderWrapper shoulderEncoder = EncoderWrapper.ofMechanismRotations(
            shoulderMotor::getPosition, 
            val -> shoulderMotor.asTalonFX().setPosition(val),
            1.0 / Math.PI // Conversion factor
        );

        Arm.JointConfig shoulderConfig = Arm.JointConfig.builder()
            .minAngleRad(-Math.PI / 2)
            .maxAngleRad(Math.PI / 2)
            .metersToRadians(2 * Math.PI)
            .linkLengthMeters(1.0)
            .build();

        shoulder = arm.addJoint(shoulderMotor, null, shoulderEncoder, shoulderConfig);
        shoulder.setPositionPID(32, 0, 0);
        shoulder.setFeedforwardGains(0.1, 0.1, 0.1, 0.1);

        // ... Add Elbow joint similarly ...

        arm.enableSimulation(true);
        arm.initialize();
    }

    // Modern IK control: Move end-effector to (x,y)
    public Command moveToPoint(double x, double y) {
        return runOnce(() -> arm.setGoalPose(x, y));
    }
}

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Vision (PhotonVision + Pose Estimation)

Seamless simulation-compatible vision integration.

import ca.team4308.absolutelib.vision.Vision;
import edu.wpi.first.apriltag.AprilTagFieldLayout;
import edu.wpi.first.apriltag.AprilTagFields;

public class VisionSubsystem {
    private final Vision vision;

    public VisionSubsystem(SwerveDrive drive) {
        AprilTagFieldLayout layout = AprilTagFieldLayout.loadField(AprilTagFields.k2025ReefscapeAndyMark);
        
        var frontCam = new Vision.VisionCamera(
            "FrontCam",
            layout,
            new Rotation3d(0, 0, 0),
            new Translation3d(0.30, 0.0, 0.20), // Camera offset from center
            VecBuilder.fill(0.8, 0.8, 2.0),    // Single tag trust
            VecBuilder.fill(0.3, 0.3, 1.0)     // Multi-tag trust
        );

        vision = new Vision(drive::getPose, drive.field, layout, frontCam);
    }

    // Call in periodic to update odometry
    public void updatePose(SwerveDrive drive) {
        vision.updatePoseEstimation(drive);
        vision.updateVisionField(); // Updates SmartDashboard field
    }
}

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Trajectory System (2026 REBUILT)

The layout for 2026 includes a powerful ShooterSystem state machine that integrates the TrajectorySolver with lookup tables and real-time physics.

Shooter System Implementation

import ca.team4308.absolutelib.math.trajectories.*;
import ca.team4308.absolutelib.math.trajectories.shooter.*;

public class Shooter {
    private final ShooterSystem shooterSystem;
    private final TrajectorySolver solver;

    public Shooter() {
        // 1. Configure Solver
        TrajectorySolver.SolverConfig solverConfig = TrajectorySolver.SolverConfig.defaults()
            .toBuilder()
            .minPitchDegrees(47.5)
            .maxPitchDegrees(82.5)
            .build();
            
        solver = new TrajectorySolver(GamePieces.REBUILT_2026_BALL, solverConfig);
        // SWEEP mode finds best angle by testing candidates (thorough)
        // ITERATIVE mode is faster but less robust for complex obstacles
        solver.setSolveMode(TrajectorySolver.SolveMode.SWEEP);

        // 2. Configure Shooter Limits
        ShooterConfig config = ShooterConfig.builder()
            .pitchLimits(47.5, 82.5)
            .rpmLimits(0, 6000)
            .distanceLimits(0.5, 12.0)
            .safetyMaxExitVelocity(30.0)
            .build();

        // 3. Define Lookup Table (Fallback)
        ShotLookupTable table = new ShotLookupTable()
            .addEntry(1.0, 78.0, 1000)
            .addEntry(2.0, 72.0, 1300)
            .addEntry(4.0, 59.0, 2100)
            .addEntry(6.0, 52.0, 2700);

        // 4. Initialize System
        shooterSystem = new ShooterSystem(config, table, solver);
        shooterSystem.setMode(ShotMode.SOLVER_WITH_LOOKUP_FALLBACK);
    }
    
    public void periodic() {
        // Calculate shot based on current robot state
        ShotParameters shot = shooterSystem.calculate(
            distanceMeters, 
            currentFlywheelRpm, 
            robotVx, robotVy, 
            robotYawRadians
        );

        if (shot.valid) {
            // Apply shot.pitchDegrees and shot.rpm
        }
    }
}

Obstacle Avoidance

The 2026 solver can be configured to avoid field structures (like the Hub).

// Define Obstacle
ObstacleConfig hub = ObstacleConfig.builder()
    .position(4.03, 4.0)
    .baseSize(1.19)
    .wallHeight(1.83)
    .build();

// Add to Shot Input
ShotInput input = ShotInput.builder()
    .shooterPositionMeters(x, y, z)
    .targetPositionMeters(tx, ty, tz)
    .addObstacle(hub)
    .collisionCheckEnabled(true)
    .build();

Tuning & Debugging

All physics constants are runtime-tunable via SolverConstants:

SolverConstants.setVelocityBufferMultiplier(1.2); // 20% extra velocity buffer
SolverConstants.setDragCompensationMultiplier(1.0); // Air resistance factor

Enable debug logging to see exactly why shots are chosen or rejected:

solver.setDebugEnabled(true);
// Logs accepted/rejected candidates, physics calculations, and flight paths

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Updating AbsoluteLib in Your Robot Project

When a new version of AbsoluteLib is released, follow these steps to update:

Option 1: Automatic (Recommended)

1. WPILib VS Code → Ctrl+Shift+P
2. WPILib: Manage Vendor Libraries
3. Check for updates (online)
4. If AbsoluteLib shows an update, accept it.

This works because the vendor JSON URL points to the latest published version.

Option 2: Manual Re-install

1. WPILib VS Code → Ctrl+Shift+P
2. WPILib: Manage Vendor Libraries
3. Install new library (online)
4. Paste:

   https://team4308.github.io/absolutelib/lib/absolutelib.json
   

5. If prompted to replace the existing version, confirm.
6. Rebuild your project (Ctrl+Shift+P → WPILib: Build Robot Code).

Option 3: Direct JSON Edit

1. Open vendordeps/absolutelib.json in your robot project.
2. Update the "version" fields to the new version number.
3. Update the javaDependencies[0].version to match.
4. Rebuild.

Tip: After updating, always do a clean build (./gradlew clean build) to avoid stale cached artifacts.

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Releasing a New Version (For Maintainers)

To publish a new release of AbsoluteLib:

scripts\release.bat

This single script handles the entire release process:

1. Safety checks — verifies you're on master, inside the repo, and required files exist
2. Version bump — prompts for a new version and auto-updates gradle.properties and absolutelib.json
3. Backup — creates a timestamped local backup in .git-backup-cache/
4. Commit & push master — stages, commits, and pushes to the master branch
5. Gradle build — runs publishPagesRepo to generate Maven artifacts and Javadoc
6. Site staging — assembles the full GitHub Pages site (docs + Maven repo + Javadoc + vendor JSON)
7. Deploy gh-pages — force-pushes the built site to the gh-pages branch

No other scripts need to be run — release.bat replaces the old publish.bat and build-pages-site.bat scripts.

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Updating Libraries and WPILib Versions

1. WPILib — Go into the build.gradle file and change wpilibVersion to the year. You may also have to update WPILibRepositoriesPlugin only if they rework vendors.
2. Libraries — Also in the build.gradle file, scroll down to the dependencies block and update each package as needed.