Tank Drive Solution

DriveSubsystem

package competition.subsystems.drive;

import com.ctre.phoenix.motorcontrol.FeedbackDevice;
import com.google.inject.Inject;
import com.google.inject.Singleton;

import competition.electrical_contract.ElectricalContract;
import xbot.common.command.BaseSubsystem;
import xbot.common.controls.actuators.XCANTalon;
import xbot.common.injection.wpi_factories.CommonLibFactory;
import xbot.common.injection.electrical_contract.CANTalonInfo;

@Singleton
public class DriveSubsystem extends BaseSubsystem {

    public final XCANTalon frontLeft;
    public final XCANTalon frontRight;

    private final double simulatedEncoderFactor = 256.0 * 39.3701; //256 "ticks" per meter, and ~39 inches in a meter

    @Inject
    public DriveSubsystem(CommonLibFactory factory, ElectricalContract electricalContract) {
        log.info("Creating DriveSubsystem");
        // instantiate speed controllers and sensors here, save them as class members

        this.frontLeft = factory
                .createCANTalon(new CANTalonInfo(1, true, FeedbackDevice.CTRE_MagEncoder_Absolute, true, simulatedEncoderFactor));
        this.frontRight = factory
                .createCANTalon(new CANTalonInfo(2, true, FeedbackDevice.CTRE_MagEncoder_Absolute, true, simulatedEncoderFactor));

        frontLeft.createTelemetryProperties(this.getPrefix(), "frontLeft");
        frontRight.createTelemetryProperties(this.getPrefix(), "frontRight");

        this.register();
    }

    public void tankDrive(double leftPower, double rightPower) {
        frontRight.simpleSet(rightPower);
        frontLeft.simpleSet(leftPower);
    }
    
    @Override
    public void periodic() {
        super.periodic();
        frontLeft.updateTelemetryProperties();
        frontRight.updateTelemetryProperties();
    }
}

• Question: Does the order of the drive command matter?

TankDriveWithJoysticksCommand

package competition.subsystems.drive.commands;

import com.google.inject.Inject;

import xbot.common.command.BaseCommand;
import competition.operator_interface.OperatorInterface;
import competition.subsystems.drive.DriveSubsystem;

//This first exercise is mostly completed for you. Take your time to read through it,
// review all the comments, and then complete it by adding in a bit more code of your own.

public class TankDriveWithJoysticksCommand extends BaseCommand {

    DriveSubsystem drive;
    OperatorInterface operatorInterface;

    @Inject
    public TankDriveWithJoysticksCommand(DriveSubsystem driveSubsystem, OperatorInterface oi) {
        drive = driveSubsystem;
        operatorInterface = oi;
        this.addRequirements(drive);
    }

    @Override
    public void initialize() {
        // This code is run one time, right when the command is started.
        // You don't need to write any code here for this exercise.
    }

    @Override
    public void execute() {
        // You need to get values from the joysticks and pass them into the motors.

        // Get values from the joysticks:
        // Here's how to get how far the left joystick's Y-axis is pushed:
        double leftValue = operatorInterface.gamepad.getLeftVector().y;
        double rightValue = operatorInterface.gamepad.getRightVector().y;
        // You'll need to get how far the RIGHT joystick's Y-axis is pushed as well.

        // Pass values into the DriveSubsystem so it can control motors:
        // right now, this just sends the left power to the left part of the drive.
        // You'll
        // need to give it a right power as well.
        drive.tankDrive(leftValue, rightValue);
    }

}