profiledpidsubsystem.py

# 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.

from typing import Generic

from wpimath.trajectory import TrapezoidProfile

from .subsystem import Subsystem
from .typing import TProfiledPIDController, TTrapezoidProfileState


class ProfiledPIDSubsystem(
    Subsystem, Generic[TProfiledPIDController, TTrapezoidProfileState]
):
    """
    A subsystem that uses a :class:`wpimath.controller.ProfiledPIDController`
    or :class:`wpimath.controller.ProfiledPIDControllerRadians` to
    control an output. The controller is run synchronously from the subsystem's
    :meth:`.periodic` method.
    """

    def __init__(
        self,
        controller: TProfiledPIDController,
        initial_position: float = 0,
    ):
        """
        Creates a new Profiled PID Subsystem using the provided PID Controller

        :param controller:        the controller that controls the output
        :param initial_position:  the initial value of the process variable

        """
        super().__init__()
        self._controller: TProfiledPIDController = controller
        self._enabled = False
        self.setGoal(initial_position)

    def periodic(self):
        """Updates the output of the controller."""
        if self._enabled:
            self.useOutput(
                self._controller.calculate(self.getMeasurement()),
                self._controller.getSetpoint(),
            )

    def getController(
        self,
    ) -> TProfiledPIDController:
        """Returns the controller"""
        return self._controller

    def setGoal(self, goal):
        """Sets the goal state for the subsystem."""
        self._controller.setGoal(goal)

    def useOutput(self, output: float, setpoint: TTrapezoidProfileState):
        """Uses the output from the controller object."""
        raise NotImplementedError(f"{self.__class__} must implement useOutput")

    def getMeasurement(self) -> float:
        """
        Returns the measurement of the process variable used by the
        controller object.
        """
        raise NotImplementedError(f"{self.__class__} must implement getMeasurement")

    def enable(self):
        """Enables the PID control. Resets the controller."""
        self._enabled = True
        self._controller.reset(self.getMeasurement())

    def disable(self):
        """Disables the PID control. Sets output to zero."""
        self._enabled = False
        self.useOutput(0, TrapezoidProfile.State())

    def isEnabled(self) -> bool:
        """Returns whether the controller is enabled."""
        return self._enabled