Simulating Intake

Info

You are reading the documentation for a Beta version of maple-sim. API references are subject to change in future versions.

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0. Overview

Intakes, or mechanisms that extend from the robot to collect game pieces from the field, are simulated by the IntakeSimulation class.

The intake is modeled as a 2D shape attached to one side of the robot's chassis. Intakes are represented as rectangles with a fixed width.

When deactivated, the rectangle is removed from the collision space, representing the intake retracting back into the robot’s frame.

When activated, the rectangle is added to the robot's collision space in the physics engine, simulating an intake that extends outward for a certain length.

This class simulates an idealized "touch it, get it" intake, meaning that when the intake is turned on, game pieces of the specified type are immediately collected upon contact — regardless of whether they are pushed towards the intake.

Tip

This simulation is intended for testing code and does not exactly replicate how your real intake mechanism works.

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1. Creating Intake Simulation

You need to create an instance of IntakeSimulation in your IntakeIOSim.

// subsystems/intake/IntakeIOSim.java
public class IntakeIOSim {
    private final IntakeSimulation intakeSimulation;
    public IntakeIOSim(AbstractDriveTrainSimulation driveTrain) {
        // Here, create the intake simulation with respect to the intake on your real robot
        this.intakeSimulation = new IntakeSimulation(...);
    }
}

In-The-Frame (ITF) IntakesOver-The-Bumper (OTB) IntakesCustom Shape Intakes

this.intakeSimulation = IntakeSimulation.InTheFrameIntake(
        // Specify the type of game pieces that the intake can collect
        "Note",
        // Specify the drivetrain to which this intake is attached
        driveTrainSimulation,
        // Specify width of the intake
        Meters.of(0.7),
        // The intake is mounted on the back side of the chassis
        IntakeSimulation.IntakeSide.BACK,
        // The intake can hold up to 1 note
        1);

this.intakeSimulation = IntakeSimulation.OverTheBumperIntake(
        // Specify the type of game pieces that the intake can collect
        "Note",
        // Specify the drivetrain to which this intake is attached
        driveTrainSimulation,
        // Width of the intake
        Meters.of(0.7),
        // The extension length of the intake beyond the robot's frame (when activated)
        Meters.of(0.2),
        // The intake is mounted on the back side of the chassis
        IntakeSimulation.IntakeSide.BACK,
        // The intake can hold up to 1 note
        1);

this.intakeSimulation = new IntakeSimulation(
        // Specify the type of game pieces that the intake can collect
        "Note",
        // Specify the drivetrain to which this intake is attached
        driveTrainSimulation, 
        // Our intake has a custom shape of a triangle (shape is specified in chassis frame-of-reference)
        new Triangle(new Vector2(0, 0), new Vector2(0.2, 0), new Vector2(0, 0.2)),
        // The intake can hold up to 1 note
        1);

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2. Using intake simulation

Next, implement the methods defined by the IntakeIO interface.

Intakes can be turned on and off by calling startIntake() and stopIntake(). Most intakes detect game pieces inside the mechanism (usually with a beam breaker sensor). You can simulate this by checking gamePiecesInIntakeCount.

public class IntakeIOSim implements IntakeIO {
    ...

    @Override // Defined by IntakeIO
    public void setRunning(boolean runIntake) {
        if (runIntake)
            intakeSimulation.startIntake(); // Extends the intake out from the chassis frame and starts detecting contacts with game pieces
        else
            intakeSimulation.stopIntake(); // Retracts the intake into the chassis frame, disabling game piece collection
    }

    @Override // Defined by IntakeIO
    public boolean isNoteInsideIntake() {
        return intakeSimulation.getGamePiecesAmount() != 0; // True if there is a game piece in the intake
    }

    @Override // Defined by IntakeIO
    public void launchNote() {
        // if there is a note in the intake, it will be removed and return true; otherwise, returns false
        if (intakeSimulation.obtainGamePieceFromIntake())
            ShooterIOSim.launchNote(); // notify the simulated flywheels to launch a note
    }
}

Tip

As shown in the code above, you can notify FlyWheelIOSim (the simulated flywheel mechansim) to shoot the note out when the note is passed to the shooter from the intake. See Simulating GamePiece Projectiles for more details.

If you want to simulate how the note moves inside the intake/feeder, you can take the indefinite integral of the intake/feeder voltage over time since the note entered the intake. This gives an approximation of the note's position in the feeder.

An example of simulating an intake together with flywheels can be found here.