SimpleDrive

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

 1package frc.robot.commands.driveCommands;
 2
 3//WPI imports
 4import edu.wpi.first.wpilibj2.command.CommandBase;
 5
 6//RobotContainer import
 7import frc.robot.RobotContainer;
 8
 9//Subsystem imports
10import frc.robot.subsystems.DriveTrain;
11
12/**
13 * SimpleDrive class
14 * <p>
15 * This class drives a motor at 50% speed until the command is ended
16 */
17public class SimpleDrive extends CommandBase
18{
19    //Grab the subsystem instance from RobotContainer
20    private static final DriveTrain drive = RobotContainer.drive;
21
22    /**
23     * Constructor
24     */
25    public SimpleDrive()
26    {
27        addRequirements(drive); // Adds the subsystem to the command
28    }
29
30    /**
31     * Runs before execute
32     */
33    @Override
34    public void initialize()
35    {
36
37    }
38
39    /**
40     * Called continously until command is ended
41     */
42    @Override
43    public void execute()
44    {
45        drive.setMotorSpeed(0.5); // Set motor speed to 50%
46    }
47
48    /**
49     * Called when the command is told to end or is interrupted
50     */
51    @Override
52    public void end(boolean interrupted)
53    {
54        drive.setMotorSpeed(0.0); // Stop motor
55    }
56
57    /**
58     * Creates an isFinished condition if needed
59     */
60    @Override
61    public boolean isFinished()
62    {
63        return false;
64    }
65
66}

  • 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.