910 reference: glossary

Every word here is one the task pages use, and each entry names the page that introduces it. Where the guide could have invented a friendlier word and did not, the reason is that the code, Pedro’s documentation and the Driver Station all use this one.

OpMode

One program the Driver Station can run. Each lesson is an OpMode, and its name in the list is the one in its @TeleOp or @Autonomous line. L020

Simulator

A robot that exists only in the laptop. It runs the same OpMode, so code can be tried before the real robot is near. L020

AdvantageScope

The program that shows what the code published. It can show it live or from a flight log, as numbers, as graphs, or as a robot on the field. The cheat sheet lists every name the lessons publish. L020

Flight log

The file a run writes. It holds every number the code published, so you can look at the run later. L020

TeleOp and Autonomous

The two kinds of OpMode. A TeleOp reads the gamepads; an autonomous runs on its own. L125 and L130 are the two autonomous lessons. L125

Driver Station

The phone or tablet that holds the gamepads and picks the OpMode. Lines printed with Tracker.printToDs show up there. L050

Drivetrain

The four motors and the code that decides what power each one gets. L040 sets the four powers itself. From L110 on, a lesson’s drivetrain is a class of its own. L090

Deadband

A band of stick readings near the middle that count as let go. Without one the robot creeps when nobody is touching it. L060

Method

A named piece of code you can use again. It takes numbers in and can give one back. L060

Squaring a stick

Making a small push mean a smaller power, by multiplying the stick by itself and putting the sign back. L060

Scaling the powers

Bringing two or four wheel powers down together when the biggest one is over 1. The robot still goes where it was asked. It only goes slower. L080

Strafe

Driving sideways without turning. L090

Mixing

Turning forward, sideways and turn into four wheel powers with four sums. L090

Mecanum

A wheel with rollers set at 45 degrees on its rim, which lets the robot drive sideways. The four wheels’ rollers make an X seen from above. L090

Commanded wheels

Four powers a lesson has set itself. The path follower cannot overrule them. It gets the wheels back when the lesson hands them back. L110

Array

Several numbers in a row, in one variable. wheels[FL] is one of them. L110

Follower

Pedro’s code that drives the robot along a path, or holds it at a pose. From L110 on it holds the drivetrain and the lessons reach past it. L110

Pose

Where the robot is and which way it faces: x, y and a heading. A pose is a place on the field, not a distance from the robot. L040

Heading

Which way the robot is facing, as an angle. Counter-clockwise counts up, and the code keeps it in radians even where a page says degrees. L090

Localizer

Whatever works out the pose. A robot can run more than one at a time. That is what L120 is for. L120

Shadow localizer

A second localizer that is read and logged but never steers anything. It is how two answers get compared on one run. L120

Encoder

The counter inside a drive motor that counts how far the motor has turned. L120

Dead reckoning

Working out where you are by adding up every step you took, with nothing to check it against. The drive encoders do it; the Pinpoint does it better. L120

Pinpoint

The odometry computer. It has its own two measuring wheels, and it works out the pose. The follower believes this one. L195 measures against it. L117

Path

A line or curve the follower drives along, with a heading to hold while it does. L125

Hold

Telling the follower to sit at one pose and stay there. If something pushes the robot, the follower puts it back. L130

Field relative

Sticks that mean the field. Push away from you and the robot moves away from you, whichever way its nose points. L140

Robot relative

Sticks that mean the robot’s own directions. Better for lining up against something. L150

Heading hold

Keeping the nose where the driver left it, and giving it straight back the moment the turn stick moves. L160

Instant command

A command that does its work and finishes in the same breath, rather than running for a while. A button press is usually one. L170

Feedforward

A guess at the power a wanted speed needs, made before anything is measured. Gets most of the way there at once. L190

Feedback

A correction worked out from two speeds: the one asked for and the one measured. It cleans up what the guess got wrong. L190

Ticks

What an encoder counts as a motor turns. A tick is a fixed fraction of a turn, so ticks become inches once you know how many make one. L195

Ticks per inch

How many ticks a wheel counts for an inch of travel. Measured, not looked up. L195

Turn radius

How far a wheel rolls each time the robot spins one radian. Measure from the middle of the robot to a wheel, once across and once along, and add the two. It turns a spin speed into a wheel speed. L195

Coast and brake

What a motor does at zero power. Braking holds the robot still; coasting lets the wheels roll, which is what a measurement you push by hand needs. L195