What Autonomous Is and How It Runs

Every FIRST Tech Challenge match begins with the Autonomous period: 30 seconds in which robots move only on code that the team wrote before the match. Nobody touches the gamepads. After a short transition (8 seconds), the 2-minute Driver-Controlled (TeleOp) period starts, and its final part is usually called the endgame.

Why autonomous matters

• In many seasons, tasks completed during Autonomous are worth extra points compared with doing the same task later.
• A good autonomous routine can leave your robot in a useful position for the start of Driver-Controlled.
• Autonomous is the clearest test of your engineering: the robot has to sense, decide and move with no human help.
• Your alliance partner depends on you. Two robots with predictable paths are far less likely to collide.

Here is the most important idea of this week: reliability beats ambition. A short routine that works every single time is worth more than a long one that works only sometimes. Start small, such as driving off the start line and parking, and add steps only when the earlier steps are dependable. Talk to your alliance partner before each match about where both robots will go; that is Gracious Professionalism and Coopertition in action.

How a robot knows where it is

During Autonomous there is no driver watching, so the robot needs sensors to measure what it is doing. These are the most common ones on FTC robots:

This week focuses on encoders and the IMU, because almost every robot already has them and together they are enough for a solid basic routine.

The life of an autonomous OpMode

1. 1
   INIT

   The driver selects your OpMode and presses INIT. Your code maps hardware, sets motor directions, resets encoders and prepares the IMU. The robot must not move yet.
2. 2
   Wait for start

   waitForStart() pauses your code until the driver presses START when the match begins.
3. 3
   Run

   Your code performs its moves one after another. Every loop should check opModeIsActive() so the robot stops when asked.
4. 4
   Stop

   The OpMode ends when your code finishes, when the driver presses STOP, or when the Autonomous timer runs out. Always set motor power to 0 at the end.

1package org.firstinspires.ftc.teamcode;
2
3import com.qualcomm.robotcore.eventloop.opmode.Autonomous;
4import com.qualcomm.robotcore.eventloop.opmode.LinearOpMode;
5import com.qualcomm.robotcore.hardware.DcMotor;
6import com.qualcomm.robotcore.util.ElapsedTime;
7
8@Autonomous(name = "Timed Drive Test", group = "Auto")
9public class TimedDriveTest extends LinearOpMode {
10    @Override
11    public void runOpMode() {
12        // INIT: runs after the driver presses INIT
13        DcMotor leftDrive = hardwareMap.get(DcMotor.class, "left_drive");
14        DcMotor rightDrive = hardwareMap.get(DcMotor.class, "right_drive");
15        leftDrive.setDirection(DcMotor.Direction.REVERSE);
16        ElapsedTime timer = new ElapsedTime();
17
18        telemetry.addData("Status", "Initialized, waiting for START");
19        telemetry.update();
20        waitForStart();
21
22        // RUN: drive forward for 1.5 seconds
23        timer.reset();
24        leftDrive.setPower(0.4);
25        rightDrive.setPower(0.4);
26        while (opModeIsActive() && timer.seconds() < 1.5) {
27            telemetry.addData("Time", "%.2f s", timer.seconds());
28            telemetry.update();
29        }
30
31        // STOP: always cut power at the end
32        leftDrive.setPower(0);
33        rightDrive.setPower(0);
34    }
35}