Package edu.wpi.first.wpilibj.controller

Class PIDController

java.lang.Object
edu.wpi.first.wpilibj.controller.PIDController
public class PIDController
extends java.lang.Object
Implements a PID control loop.

  • Constructor Summary

    Constructors 
    Constructor Description
    PIDController​(double Kp, double Ki, double Kd)
    Allocates a PIDController with the given constants for Kp, Ki, and Kd and a default period of 0.02 seconds.
    PIDController​(double Kp, double Ki, double Kd, double period)
    Allocates a PIDController with the given constants for Kp, Ki, and Kd.

  • Method Summary

    Modifier and Type Method Description
    boolean atSetpoint()
    Returns true if the error is within the percentage of the total input range, determined by SetTolerance.
    double calculate​(double measurement)
    Returns the next output of the PID controller.
    double calculate​(double measurement, double setpoint)
    Returns the next output of the PID controller.
    void disableContinuousInput()
    Disables continuous input.
    void enableContinuousInput​(double minimumInput, double maximumInput)
    Enables continuous input.
    double getD()
    Get the Differential coefficient.
    double getI()
    Get the Integral coefficient.
    double getP()
    Get the Proportional coefficient.
    double getPeriod()
    Returns the period of this controller.
    double getPositionError()
    Returns the difference between the setpoint and the measurement.
    double getSetpoint()
    Returns the current setpoint of the PIDController.
    double getVelocityError()
    Returns the velocity error.
    void reset()
    Resets the previous error and the integral term.
    void setD​(double Kd)
    Sets the Differential coefficient of the PID controller gain.
    void setI​(double Ki)
    Sets the Integral coefficient of the PID controller gain.
    void setIntegratorRange​(double minimumIntegral, double maximumIntegral)
    Sets the minimum and maximum values for the integrator.
    void setP​(double Kp)
    Sets the Proportional coefficient of the PID controller gain.
    void setPID​(double Kp, double Ki, double Kd)
    Sets the PID Controller gain parameters.
    void setSetpoint​(double setpoint)
    Sets the setpoint for the PIDController.
    void setTolerance​(double positionTolerance)
    Sets the error which is considered tolerable for use with atSetpoint().
    void setTolerance​(double positionTolerance, double velocityTolerance)
    Sets the error which is considered tolerable for use with atSetpoint().

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • PIDController

      public PIDController​(double Kp, double Ki, double Kd)
      Allocates a PIDController with the given constants for Kp, Ki, and Kd and a default period of 0.02 seconds.
      Parameters:
      Kp - The proportional coefficient.
      Ki - The integral coefficient.
      Kd - The derivative coefficient.

    • PIDController

      public PIDController​(double Kp, double Ki, double Kd, double period)
      Allocates a PIDController with the given constants for Kp, Ki, and Kd.
      Parameters:
      Kp - The proportional coefficient.
      Ki - The integral coefficient.
      Kd - The derivative coefficient.
      period - The period between controller updates in seconds.

  • Method Details

    • setPID

      public void setPID​(double Kp, double Ki, double Kd)
      Sets the PID Controller gain parameters.

      Set the proportional, integral, and differential coefficients.

      Parameters:
      Kp - The proportional coefficient.
      Ki - The integral coefficient.
      Kd - The derivative coefficient.

    • setP

      public void setP​(double Kp)
      Sets the Proportional coefficient of the PID controller gain.
      Parameters:
      Kp - proportional coefficient

    • setI

      public void setI​(double Ki)
      Sets the Integral coefficient of the PID controller gain.
      Parameters:
      Ki - integral coefficient

    • setD

      public void setD​(double Kd)
      Sets the Differential coefficient of the PID controller gain.
      Parameters:
      Kd - differential coefficient

    • getP

      public double getP()
      Get the Proportional coefficient.
      Returns:
      proportional coefficient

    • getI

      public double getI()
      Get the Integral coefficient.
      Returns:
      integral coefficient

    • getD

      public double getD()
      Get the Differential coefficient.
      Returns:
      differential coefficient

    • getPeriod

      public double getPeriod()
      Returns the period of this controller.
      Returns:
      the period of the controller.

    • setSetpoint

      public void setSetpoint​(double setpoint)
      Sets the setpoint for the PIDController.
      Parameters:
      setpoint - The desired setpoint.

    • getSetpoint

      public double getSetpoint()
      Returns the current setpoint of the PIDController.
      Returns:
      The current setpoint.

    • atSetpoint

      public boolean atSetpoint()
      Returns true if the error is within the percentage of the total input range, determined by SetTolerance. This asssumes that the maximum and minimum input were set using SetInput.

      This will return false until at least one input value has been computed.

      Returns:
      Whether the error is within the acceptable bounds.

    • enableContinuousInput

      public void enableContinuousInput​(double minimumInput, double maximumInput)
      Enables continuous input.

      Rather then using the max and min input range as constraints, it considers them to be the same point and automatically calculates the shortest route to the setpoint.

      Parameters:
      minimumInput - The minimum value expected from the input.
      maximumInput - The maximum value expected from the input.

    • disableContinuousInput

      public void disableContinuousInput()
      Disables continuous input.

    • setIntegratorRange

      public void setIntegratorRange​(double minimumIntegral, double maximumIntegral)
      Sets the minimum and maximum values for the integrator.

      When the cap is reached, the integrator value is added to the controller output rather than the integrator value times the integral gain.

      Parameters:
      minimumIntegral - The minimum value of the integrator.
      maximumIntegral - The maximum value of the integrator.

    • setTolerance

      public void setTolerance​(double positionTolerance)
      Sets the error which is considered tolerable for use with atSetpoint().
      Parameters:
      positionTolerance - Position error which is tolerable.

    • setTolerance

      public void setTolerance​(double positionTolerance, double velocityTolerance)
      Sets the error which is considered tolerable for use with atSetpoint().
      Parameters:
      positionTolerance - Position error which is tolerable.
      velocityTolerance - Velocity error which is tolerable.

    • getPositionError

      public double getPositionError()
      Returns the difference between the setpoint and the measurement.
      Returns:
      The error.

    • getVelocityError

      public double getVelocityError()
      Returns the velocity error.

    • calculate

      public double calculate​(double measurement, double setpoint)
      Returns the next output of the PID controller.
      Parameters:
      measurement - The current measurement of the process variable.
      setpoint - The new setpoint of the controller.

    • calculate

      public double calculate​(double measurement)
      Returns the next output of the PID controller.
      Parameters:
      measurement - The current measurement of the process variable.

    • reset

      public void reset()
      Resets the previous error and the integral term. Also disables the controller.