README.md

FRC-2022

Team 254's 2022 FRC robot code for Sideways. Sideways' code is written in Java and is based off of WPILib's Java control system.

The code is divided into several packages, each responsible for a different aspect of the robot function. This README explains setup instructions, the function of each package, and some of the variable naming conventions used. Additional information about each specific class can be found in that class' Java file.

Setup Instructions

General

1. Clone this repo
2. Run ./gradlew to download gradle and needed FRC/Vendor libraries
3. Run ./gradlew tasks to see available options
4. Enjoy!

Visual Studio Code (Official IDE)

1. Get the WPILib extension for easiest use from the VSCode Marketplace - Requires Java 11 or greater
2. In .vscode/settings.json, set the User Setting, java.home, to the correct directory pointing to your JDK 11 directory

IntelliJ

1. Run ./gradlew idea
2. Open the FRC-2022-Public.ipr file with IntelliJ

Eclipse

1. Run ./gradlew eclipse
2. Open Eclipse and go to File > Open Projects from File System...
3. Set the import source to the FRC-2022-Public folder then click finish

Basic Gradle Commands

• Run ./gradlew deploy to deploy to the robot in Terminal (*nix) or Powershell (Windows)
• Run ./gradlew build to build the code. Use the --info flag for more details
• Run ./gradlew test to run all of the JUnit tests

Code Highlights

• Field-Centric Swerve Drive

  Standard field-centric control of a swerve drivebase using odometry, encoders and gyro along with Swerve Setpoint Generation to impose Kinematic constraints on the drivebase for more controlled movements to reduce wheel-slip and improve Shoot-On-The-Move.

• Superstructure with Two-Sided Intake, Automatic Wrong Ball Rejection, Super Eject, Automatic Turret Tracking

  The robot uses a state machine to control the intakes and serializers on both sides of the robot. It uses banner sensors to determine the locations of the ball in the robot and REV Color Sensors wired to a Teensy to determine ball color. After detecting a wrong color ball, the robot determines the eject setpoints based on its position and orientation on the field. Throughout the match, the robot always follows the vision target with the turret using Motion Profiling.

• Shooting on the Move

  The robot uses a Sin Map (Utilizing Trigonometry for both Shooter RPM and Hood Angle). We break Shooter RPM into a horizontal and vertical component and use a linear regression to map the robot's distance from goal to a Shooter RPM. To compensate for motion, the robot calculates a feedforward based on its tangential and radial velocity about the goal.

• Feedforward + Proportional Feedback Controller for Autonomous Path Following

  The robot generates pre-computed trajectories using a Quintic Hermite Spline. To follow trajectories, the robot is first commanded the precomputed velocity at the current timestamp. It then computes the longitudinal error along the path and uses a proportional controller to reduce it. The robot time-parametrizes heading based on the total timing of the trajectory and uses a separate proportional controller to reach heading setpoints.

• Fully Automated Climb

  The robot uses a state machine for the endgame climb to move mechanisms in a controlled fashion. Transitions between states are determined using encoder positions, time in state, and gyro measurements.

Package Functions

• com.team254.frc2022

  Contains the robot's central functions and holds a class with all numerical constants used throughout the code (see Constants.java). For example, the Robot class controls all routines depending on the robot mode. In addition, the RobotState class keeps track of the current position of the robot's various frames of reference.

• com.team254.frc2022.auto

  Handles the execution of autonomous routines and contains the actions and modes packages.

• com.team254.frc2022.auto.actions

  Contains all actions used during the autonomous period, which all share a common interface, Action (also in this package). Examples include driving paths, auto aiming the turret, and deploying and retracting intakes. Actions interact with the subsystems, which in turn interact with the hardware.

• com.team254.frc2022.auto.modes

  Contains all autonomous modes. Autonomous modes consist of a list of autonomous actions executed in a specific order.

• com.team254.frc2022.controlboard

  Contains code for the driver to use either joysticks or gamepad and the operator to use a gamepad. Also contains a wrapper class specifically for Xbox controllers (see XboxController.java).

• com.team254.frc2022.loops

  Contains codes for loops, which are routines that run periodically on the robot, such as for calculating robot pose, processing vision feedback, or updating subsystems. All loops implement the Loop interface and are handled (started, stopped, added) by the Looper class, which runs at 100 Hz. The Robot class has one main looper, mEnabledLooper, that runs all loops when the robot is enabled.

• com.team254.frc2022.paths

  Contains the TrajectoryGenerator class which contains the trajectories that the robot drives during autonomous mode. Each Trajectory is composed of a list of Waypoint objects and headings.

• com.team254.frc2022.planners

  Contains the DriveMotionPlanner class which controls the drivebase as it follows a trajectory during the autonomous period.

• com.team254.frc2022.shooting

  Contains the ShootingUtil helper class which takes in the current target range and robot state and returns parameters for an ideal shot for both stationary and shooting on the move.

• com.team254.frc2022.states

  Contains multiple classes representing LED states used in the Superstructure class.

• com.team254.frc2022.subsystems

  Contains code for subsystems, which are consolidated into one central class per subsystem, all of which extend the Subsystem abstract class. Each subsystem uses state machines for control and is a singleton, meaning that there is only one instance of each. Subsystems also contain an enabled loop, a read periodic inputs method, and a write periodic outputs method, which are controlled by the SubystemManager class.

• com.team254.lib.control

  Contains classes used for the robot's path following and alternative teleoperated driver modes.

• com.team254.lib.drivers

  Constains a set of custom classes for motor controllers, color sensors, and solenoids for simplifying motor configuration, reducing CAN Bus usage, and checking motors.

• com.team254.lib.geometry

  Contains a set of classes that represent various geometric entities.

• com.team254.lib.motion

  Contains all motion profiling code used for autonomous driving. Trapezoidal motion profiles are used for smooth acceleration and minimal slip.

• com.team254.lib.physics

  Contains classes to represent physical states of a swerve drive, a swerve's effective wheelbase, and a DC motor.

• com.team254.lib.spline

  Contains classes to generate and time parameterize splines for smooth autonomous paths.

• com.team254.lib.swerve

  Contains various drive controllers and classes used for forward and inverse kinematics.

• com.team254.lib.trajectory

  Contains multiple classes used for representing and following Trajectory objects.

• com.team254.lib.trajectory.timing

  Contains multiple classes for generating time-parameterized trajectories that obey physical robot constraints.

• com.team254.lib.util

  Contains a collection of assorted utilities classes used in the robot code. Check each file for more information.

• com.team254.lib.vision

  Contains various classes that help with tracking and storing information about vision targets.

• com.team254.lib.wpilib

  Contains parent classes of the main Robot class that get rid of loop overrun and watchdog print messages that clutter the console.

Variable Naming Conventions

• k*** (i.e. kDriveWheelbaseMeters): Final constants, especially those found in the Constants.java file
• m*** (i.e. mPathFollower): Private instance variables