robot2024

The code for our 2024 robot

How it works

What's a Kotlin?

• Java, but better
• No, seriously, it was made by JetBrains to make Java better again.
• Kotlin can interop with Java (i.e. Java code can call Kotlin, and vice versa).
• It's a lot easier to work with.

Why is half of the code still in Java then?

• You all know how to use Java, not Kotlin, therefore anything that may need to be changed on-the-fly (other than constants) have been kept in Java.

Spark Motor Stuff

SparkPIDController

• A lot of boilerplate for managing the speeds of each motor with PID.
• They use the integrated relative encoder as a feedback device by default.
• Can be set to use absolute encoders if they exist (ask assembly/control systems people)
• They can be managed by position or velocity setpoints.
  • To set a position setpoint, use the encoder values.
  • Set a scaling factor/zero offset on the encoder, THE PID CONTROLLER DOES NOT HAVE ONE
• SmartMotion also exists, but I don't know how it works yet. Will update.

Subsystems

Arm

• Both the arm pivot and extension is controlled via a position-based feedback loop

• This means that you set a position (angle degrees or ext percent) and the subsystem will try to meet that setpoint

  Arm Pivot

  • Setpoints are set via SparkPIDController's position setpoints
  • There are two motors controlling the arm, configured via a master (left) and slave (right) config

  Arm Extension

  • The extension is a bit different. You still set a percent setpoint but the code that "meets" the setpoint is handled separately, as SparkPIDController was being weird. See Arm.extendSetpoint() for more information.
  • There is only one motor being used for arm extension.
  • PID is not used.

Camera

• Still an untested work-in-progress. Will update this later, hopefully.

Drivetrain

• This needs a bit more explanation, so buckle up

  SwerveModule

  • There are four of these in a drivetrain, each with one turning and one driving motor
  • The angularOffset constructor parameter is the angle (rad) each module is offset by, relative to the front right one. These are +/- quarter circles and half circles
  • Modules have a desiredState, which includes the drive velocity and a rotation setpoint in radians
  • The desired states, once set, are first corrected then optimized before being set via the SparkPIDControllers

  Swerve

  • Swerve is a type of drivetrain where there are four wheels whose rotations and positions can be controlled separately.
  • To make the robot drive in a field-centric manner (i.e. forward is always field-north no matter which way the robot is facing), a gyroscope is used to measure the robot's current rotation, and fix motion accordingly

  Slew and rate-limiting

  • I did not write this (I copied it from whoever did write it), nor do I know how it works. It is off by default and the robot seems to work fine. if someone figures it out, update this, please.

  Drivetrain.drive()

  • Converts controller inputs to ChassisSpeeds, which when set, update the desired speeds using math
  • Don't ask, 99% of it is library code.

  Other Drivetrain stuff

  • resetGyro(): Makes it so that field-north is the direction the robot is facing
  • stop(): Kills the motors
  • lock(): Turns motors into an X-formation, effectively killing them

Notifier

• This subsystem houses the controllers and LED, and is used to notify the drivers of stuff using the XboxController's rumbling stuff.
• Pass in the Notifier subsystem as a constructor argument for commands, and call Notifer.notify() to buzz the driver's and operator's controllers for one second.

Climber

• Each climber has two ClimberModules, each of which has a servo to lock and unlock the climbers, and a motor
• One of the motors need to be inverted. Do not change that.
• I'm still working on an automatic climbing command, therefore the gyro and .bias() is not yet used

Shintake

• Shooter + Intake combined subsystem.
• Contains methods to set the intake and shooter motors.
• The shooter has two motors, right (master) and left (slave).
• A beam brake is used to check if the note is in place.

Led

• Contains both an AddressableLED and an AddressableLEDBuffer
• Write colors to the buffers, then write the buffer to the LED.