[robotpy][examples] Split examples and snippets (#8944)

This also updates the bazel scripts to behave more like the C++ and Java
examples, and updates the copybara scripts to be able to sync up
`mostrobotpy`

robotpyExamples/snippets/FlywheelBangBangController/robot.py

@@ -0,0 +1,108 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) FIRST and other WPILib contributors.
+# Open Source Software; you can modify and/or share it under the terms of
+# the WPILib BSD license file in the root directory of this project.
+#
+
+import wpilib
+import math
+
+import wpilib.simulation
+import wpimath
+import wpimath.units
+
+
+class MyRobot(wpilib.TimedRobot):
+    """
+    This is a sample program to demonstrate the use of a BangBangController with a flywheel to
+    control RPM.
+    """
+
+    kMotorPort = 0
+    kEncoderAChannel = 0
+    kEncoderBChannel = 1
+
+    # Max setpoint for joystick control in RPM
+    kMaxSetpointValue = 6000.0
+
+    # Gains are for example purposes only - must be determined for your own robot!
+    kFlywheelKs = 0.0001  # V
+    kFlywheelKv = 0.000195  # V/RPM
+    kFlywheelKa = 0.0003  # V/(RPM/s)
+
+    # Reduction between motors and encoder, as output over input. If the flywheel
+    # spins slower than the motors, this number should be greater than one.
+    kFlywheelGearing = 1.0
+
+    # 1/2 MR²
+    kFlywheelMomentOfInertia = (
+        0.5
+        * wpimath.units.lbsToKilograms(1.5)
+        * math.pow(wpimath.units.inchesToMeters(4), 2)
+    )
+
+    def __init__(self) -> None:
+        """Robot initialization function"""
+        super().__init__()
+
+        self.flywheelMotor = wpilib.PWMSparkMax(self.kMotorPort)
+        self.encoder = wpilib.Encoder(self.kEncoderAChannel, self.kEncoderBChannel)
+
+        self.bangBangControler = wpimath.BangBangController()
+
+        # Gains are for example purposes only - must be determined for your own robot!
+        self.feedforward = wpimath.SimpleMotorFeedforwardMeters(
+            self.kFlywheelKs, self.kFlywheelKv, self.kFlywheelKa
+        )
+
+        # Joystick to control setpoint
+        self.joystick = wpilib.Joystick(0)
+
+        # Simulation classes help us simulate our robot
+
+        self.gearbox = wpimath.DCMotor.NEO(1)
+
+        self.plant = wpimath.Models.flywheelFromPhysicalConstants(
+            self.gearbox, self.kFlywheelGearing, self.kFlywheelMomentOfInertia
+        )
+
+        self.flywheelSim = wpilib.simulation.FlywheelSim(self.plant, self.gearbox)
+        self.encoderSim = wpilib.simulation.EncoderSim(self.encoder)
+
+        # Add bang-bang controller to SmartDashboard and networktables.
+        wpilib.SmartDashboard.putData(self.bangBangControler)
+
+    def teleopPeriodic(self) -> None:
+        """Controls flywheel to a set velocity (RPM) controlled by a joystick."""
+
+        # Scale setpoint value between 0 and maxSetpointValue
+        setpoint = max(
+            0.0,
+            self.joystick.getRawAxis(0)
+            * wpimath.units.rotationsPerMinuteToRadiansPerSecond(
+                self.kMaxSetpointValue
+            ),
+        )
+
+        # Set setpoint and measurement of the bang-bang controller
+        bangOutput = (
+            self.bangBangControler.calculate(self.encoder.getRate(), setpoint) * 12.0
+        )
+
+        # Controls a motor with the output of the BangBang controller and a
+        # feedforward. The feedforward is reduced slightly to avoid overvelocitying
+        # the shooter.
+        self.flywheelMotor.setVoltage(
+            bangOutput + 0.9 * self.feedforward.calculate(setpoint)
+        )
+
+    def simulationPeriodic(self) -> None:
+        """Update our simulation. This should be run every robot loop in simulation."""
+        # To update our simulation, we set motor voltage inputs, update the
+        # simulation, and write the simulated velocities to our simulated encoder
+        self.flywheelSim.setInputVoltage(
+            self.flywheelMotor.getThrottle() * wpilib.RobotController.getInputVoltage()
+        )
+        self.flywheelSim.update(0.02)
+        self.encoderSim.setRate(self.flywheelSim.getAngularVelocity())