PIDSubsystem.h

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// 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.
 
#pragma once
 
#include <frc/controller/PIDController.h>
 
#include "frc2/command/SubsystemBase.h"
 
namespace frc2 {
/**
 * A subsystem that uses a PIDController to control an output.  The controller
 * is run synchronously from the subsystem's periodic() method.
 *
 * This class is provided by the NewCommands VendorDep
 *
 * @see PIDController
 */
class PIDSubsystem : public SubsystemBase {
 public:
  /**
   * Creates a new PIDSubsystem.
   *
   * @param controller the PIDController to use
   * @param initialPosition the initial setpoint of the subsystem
   */
  explicit PIDSubsystem(frc::PIDController controller,
                        double initialPosition = 0);
 
  void Periodic() override;
 
  /**
   * Sets the setpoint for the subsystem.
   *
   * @param setpoint the setpoint for the subsystem
   */
  void SetSetpoint(double setpoint);
 
  /**
   * Gets the setpoint for the subsystem.
   *
   * @return the setpoint for the subsystem
   */
  double GetSetpoint() const;
 
  /**
   * Enables the PID control.  Resets the controller.
   */
  virtual void Enable();
 
  /**
   * Disables the PID control.  Sets output to zero.
   */
  virtual void Disable();
 
  /**
   * Returns whether the controller is enabled.
   *
   * @return Whether the controller is enabled.
   */
  bool IsEnabled();
 
  /**
   * Returns the PIDController.
   *
   * @return The controller.
   */
  frc::PIDController& GetController();
 
 protected:
  /// PID controller.
  frc::PIDController m_controller;
 
  /// Whether PID controller output is enabled.
  bool m_enabled{false};
 
  /**
   * Returns the measurement of the process variable used by the PIDController.
   *
   * @return the measurement of the process variable
   */
  virtual double GetMeasurement() = 0;
 
  /**
   * Uses the output from the PIDController.
   *
   * @param output the output of the PIDController
   * @param setpoint the setpoint of the PIDController (for feedforward)
   */
  virtual void UseOutput(double output, double setpoint) = 0;
};
}  // namespace frc2