Class ProfiledPIDController

  • All Implemented Interfaces:
    Sendable

    public class ProfiledPIDController
    extends Object
    implements Sendable
    Implements a PID control loop whose setpoint is constrained by a trapezoid profile. Users should call reset() when they first start running the controller to avoid unwanted behavior.
    • Constructor Detail

      • ProfiledPIDController

        public ProfiledPIDController​(double Kp,
                                     double Ki,
                                     double Kd,
                                     TrapezoidProfile.Constraints constraints)
        Allocates a ProfiledPIDController with the given constants for Kp, Ki, and Kd.
        Parameters:
        Kp - The proportional coefficient.
        Ki - The integral coefficient.
        Kd - The derivative coefficient.
        constraints - Velocity and acceleration constraints for goal.
      • ProfiledPIDController

        public ProfiledPIDController​(double Kp,
                                     double Ki,
                                     double Kd,
                                     TrapezoidProfile.Constraints constraints,
                                     double period)
        Allocates a ProfiledPIDController with the given constants for Kp, Ki, and Kd.
        Parameters:
        Kp - The proportional coefficient.
        Ki - The integral coefficient.
        Kd - The derivative coefficient.
        constraints - Velocity and acceleration constraints for goal.
        period - The period between controller updates in seconds. The default is 0.02 seconds.
    • Method Detail

      • setPID

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

        Sets the proportional, integral, and differential coefficients.

        Parameters:
        Kp - Proportional coefficient
        Ki - Integral coefficient
        Kd - Differential 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()
        Gets the proportional coefficient.
        Returns:
        proportional coefficient
      • getI

        public double getI()
        Gets the integral coefficient.
        Returns:
        integral coefficient
      • getD

        public double getD()
        Gets the differential coefficient.
        Returns:
        differential coefficient
      • getPeriod

        public double getPeriod()
        Gets the period of this controller.
        Returns:
        The period of the controller.
      • setGoal

        public void setGoal​(TrapezoidProfile.State goal)
        Sets the goal for the ProfiledPIDController.
        Parameters:
        goal - The desired goal state.
      • setGoal

        public void setGoal​(double goal)
        Sets the goal for the ProfiledPIDController.
        Parameters:
        goal - The desired goal position.
      • atGoal

        public boolean atGoal()
        Returns true if the error is within the tolerance of the error.

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

      • setConstraints

        public void setConstraints​(TrapezoidProfile.Constraints constraints)
        Set velocity and acceleration constraints for goal.
        Parameters:
        constraints - Velocity and acceleration constraints for goal.
      • getSetpoint

        public TrapezoidProfile.State getSetpoint()
        Returns the current setpoint of the ProfiledPIDController.
        Returns:
        The current setpoint.
      • atSetpoint

        public boolean atSetpoint()
        Returns true if the error is within the tolerance of the error.

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

      • 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 change in error per second.
      • calculate

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

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

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

        public double calculate​(double measurement,
                                TrapezoidProfile.State goal,
                                TrapezoidProfile.Constraints constraints)
        Returns the next output of the PID controller.
        Parameters:
        measurement - The current measurement of the process variable.
        goal - The new goal of the controller.
        constraints - Velocity and acceleration constraints for goal.
      • reset

        public void reset​(TrapezoidProfile.State measurement)
        Reset the previous error and the integral term.
        Parameters:
        measurement - The current measured State of the system.
      • reset

        public void reset​(double measuredPosition,
                          double measuredVelocity)
        Reset the previous error and the integral term.
        Parameters:
        measuredPosition - The current measured position of the system.
        measuredVelocity - The current measured velocity of the system.
      • reset

        public void reset​(double measuredPosition)
        Reset the previous error and the integral term.
        Parameters:
        measuredPosition - The current measured position of the system. The velocity is assumed to be zero.