SimpleDriveΒΆ

SimpleDrive is the command that controls the subsystem output. Commands can be called again and again which makes them perfect for autonomous routines.

Java

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package frc.robot.commands.driveCommands;

//WPI imports
import edu.wpi.first.wpilibj2.command.CommandBase;

//RobotContainer import
import frc.robot.RobotContainer;

//Subsystem imports
import frc.robot.subsystems.DriveTrain;

/**
 * SimpleDrive class
 * <p>
 * This class drives a motor at 50% speed until the command is ended
 */
public class SimpleDrive extends CommandBase
{
    //Grab the subsystem instance from RobotContainer
    private static final DriveTrain drive = RobotContainer.drive;

    /**
     * Constructor
     */
    public SimpleDrive()
    {
        addRequirements(drive); // Adds the subsystem to the command
    }

    /**
     * Runs before execute
     */
    @Override
    public void initialize()
    {

    }

    /**
     * Called continously until command is ended
     */
    @Override
    public void execute()
    {
        drive.setMotorSpeed(0.5); // Set motor speed to 50%
    }

    /**
     * Called when the command is told to end or is interrupted
     */
    @Override
    public void end(boolean interrupted)
    {
        drive.setMotorSpeed(0.0); // Stop motor
    }

    /**
     * Creates an isFinished condition if needed
     */
    @Override
    public boolean isFinished()
    {
        return false;
    }

}

  • Lines 4 - 10 are the imports required.

  • Line 20 grabs the instance of the DriveTrain subsystem defined and instantiated in RobotContainer.

  • Lines 25 - 28 are the constructor.

  • Line 27 says that this command requires the subsystem drive which is the handle for the subsystem DriveTrain.

  • Lines 33 - 37 is the initialize section of the command. In this case there is nothing to initialize so it is left blank.

  • Lines 42 - 46 is the execute section of the command. As long as the command is active anything in here will run every robot packet (20ms).

  • Line 45 is setting the motor speed to 0.5 which is equal to 50% speed.

  • Lines 51 - 55 is the end section of the command. When the command is scheduled to end or is interrupted this method is called.

  • Line 54 sets the motor speed to 0.0 this will stop the motor. It is a good idea to always add a stop motor instruction here unless its not required.

  • Lines 60 - 64 is the isFinished section of the command. This method can be called to check if the command is finished or not. Useful if you wanted to put a stop condition based on sensor feedback here. For example using the sharp sensor to sence distance and it hits the threshold.