Package edu.wpi.first.math.controller

Class BangBangController

java.lang.Object
edu.wpi.first.math.controller.BangBangController
All Implemented Interfaces:
Sendable
public class BangBangController
extends Object
implements Sendable
Implements a bang-bang controller, which outputs either 0 or 1 depending on whether the measurement is less than the setpoint. This maximally-aggressive control approach works very well for velocity control of high-inertia mechanisms, and poorly on most other things.

Note that this is an *asymmetric* bang-bang controller - it will not exert any control effort in the reverse direction (e.g. it won't try to slow down an over-speeding shooter wheel). This asymmetry is *extremely important.* Bang-bang control is extremely simple, but also potentially hazardous. Always ensure that your motor controllers are set to "coast" before attempting to control them with a bang-bang controller.

  • Constructor Summary

    Constructors 
    Constructor Description
    BangBangController()
    Creates a new bang-bang controller.
    BangBangController​(double tolerance)
    Creates a new bang-bang controller.

  • Method Summary

    Modifier and Type Method Description
    boolean atSetpoint()
    Returns true if the error is within the tolerance of the setpoint.
    double calculate​(double measurement)
    Returns the calculated control output.
    double calculate​(double measurement, double setpoint)
    Returns the calculated control output.
    double getError()
    Returns the current error.
    double getMeasurement()
    Returns the current measurement of the process variable.
    double getSetpoint()
    Returns the current setpoint of the bang-bang controller.
    double getTolerance()
    Returns the current tolerance of the controller.
    void initSendable​(SendableBuilder builder)
    Initializes this Sendable object.
    void setSetpoint​(double setpoint)
    Sets the setpoint for the bang-bang controller.
    void setTolerance​(double tolerance)
    Sets the error within which atSetpoint will return true.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • BangBangController

      public BangBangController​(double tolerance)
      Creates a new bang-bang controller.

      Always ensure that your motor controllers are set to "coast" before attempting to control them with a bang-bang controller.

      Parameters:
      tolerance - Tolerance for atSetpoint.

    • BangBangController

      public BangBangController()
      Creates a new bang-bang controller.

      Always ensure that your motor controllers are set to "coast" before attempting to control them with a bang-bang controller.

  • Method Details

    • setSetpoint

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

    • getSetpoint

      public double getSetpoint()
      Returns the current setpoint of the bang-bang controller.
      Returns:
      The current setpoint.

    • atSetpoint

      public boolean atSetpoint()
      Returns true if the error is within the tolerance of the setpoint.
      Returns:
      Whether the error is within the acceptable bounds.

    • setTolerance

      public final void setTolerance​(double tolerance)
      Sets the error within which atSetpoint will return true.
      Parameters:
      tolerance - Position error which is tolerable.

    • getTolerance

      public double getTolerance()
      Returns the current tolerance of the controller.
      Returns:
      The current tolerance.

    • getMeasurement

      public double getMeasurement()
      Returns the current measurement of the process variable.
      Returns:
      The current measurement of the process variable.

    • getError

      public double getError()
      Returns the current error.
      Returns:
      The current error.

    • calculate

      public double calculate​(double measurement, double setpoint)
      Returns the calculated control output.

      Always ensure that your motor controllers are set to "coast" before attempting to control them with a bang-bang controller.

      Parameters:
      measurement - The most recent measurement of the process variable.
      setpoint - The setpoint for the process variable.
      Returns:
      The calculated motor output (0 or 1).

    • calculate

      public double calculate​(double measurement)
      Returns the calculated control output.
      Parameters:
      measurement - The most recent measurement of the process variable.
      Returns:
      The calculated motor output (0 or 1).

    • initSendable

      public void initSendable​(SendableBuilder builder)
      Description copied from interface: Sendable
      Initializes this Sendable object.
      Specified by:
      initSendable in interface Sendable
      Parameters:
      builder - sendable builder