edu.wpi.first.wpilibj
Class PIDController

java.lang.Object
  edu.wpi.first.wpilibj.PIDController

All Implemented Interfaces:

IDevice, IUtility

Direct Known Subclasses:

SendablePIDController

public class PIDController
extends java.lang.Object
implements IUtility

Class implements a PID Control Loop. Creates a separate thread which reads the given PIDSource and takes care of the integral calculations, as well as writing the given PIDOutput

Field Summary

static double

kDefaultPeriod

Constructor Summary

PIDController(double Kp, double Ki, double Kd, PIDSource source, PIDOutput output)
Allocate a PID object with the given constants for P, I, D, using a 50ms period.

PIDController(double Kp, double Ki, double Kd, PIDSource source, PIDOutput output, double period)
Allocate a PID object with the given constants for P, I, D

Method Summary

void	disable() Stop running the PIDController, this sets the output to zero before stopping.
void	enable() Begin running the PIDController
void	free() Free the PID object
double	get() Return the current PID result This is always centered on zero and constrained the the max and min outs
double	getD() Get the Differential coefficient
double	getError() Returns the current difference of the input from the setpoint
double	getI() Get the Integral coefficient
double	getP() Get the Proportional coefficient
double	getSetpoint() Returns the current setpoint of the PIDController
boolean	isEnable() Return true if PIDController is enabled.
boolean	onTarget() Return true if the error is within the percentage of the total input range, determined by setTolerance.
void	reset() Reset the previous error,, the integral term, and disable the controller.
void	setContinuous() Set the PID controller to consider the input to be continuous, Rather then using the max and min in as constraints, it considers them to be the same point and automatically calculates the shortest route to the setpoint.
void	setContinuous(boolean continuous) Set the PID controller to consider the input to be continuous, Rather then using the max and min in as constraints, it considers them to be the same point and automatically calculates the shortest route to the setpoint.
void	setInputRange(double minimumInput, double maximumInput) Sets the maximum and minimum values expected from the input.
void	setOutputRange(double minimumOutput, double maximumOutput) Sets the minimum and maximum values to write.
void	setPID(double p, double i, double d) Set the PID Controller gain parameters.
void	setSetpoint(double setpoint) Set the setpoint for the PIDController
void	setTolerance(double percent) Set the percentage error which is considered tolerable for use with OnTarget.

Methods inherited from class java.lang.Object

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

Field Detail

kDefaultPeriod

public static final double kDefaultPeriod

See Also:

Constant Field Values

Constructor Detail

PIDController

public PIDController(double Kp,
                     double Ki,
                     double Kd,
                     PIDSource source,
                     PIDOutput output,
                     double period)

Allocate a PID object with the given constants for P, I, D

Parameters:

Kp - the proportional coefficient

Ki - the integral coefficient

Kd - the derivative coefficient

source - The PIDSource object that is used to get values

output - The PIDOutput object that is set to the output value

period - the loop time for doing calculations. This particularly effects calculations of the integral and differential terms. The default is 50ms.

PIDController

public PIDController(double Kp,
                     double Ki,
                     double Kd,
                     PIDSource source,
                     PIDOutput output)

Allocate a PID object with the given constants for P, I, D, using a 50ms period.

Parameters:

Kp - the proportional coefficient

Ki - the integral coefficient

Kd - the derivative coefficient

source - The PIDSource object that is used to get values

output - The PIDOutput object that is set to the output value

Method Detail

free

public void free()

Free the PID object

setPID

public void setPID(double p,
                   double i,
                   double d)

Set the PID Controller gain parameters. Set the proportional, integral, and differential coefficients.

Parameters:

p - Proportional coefficient

i - Integral coefficient

d - 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

get

public double get()

Return the current PID result This is always centered on zero and constrained the the max and min outs

Returns:

the latest calculated output

setContinuous

public void setContinuous(boolean continuous)

Set the PID controller to consider the input to be continuous, Rather then using the max and min in as constraints, it considers them to be the same point and automatically calculates the shortest route to the setpoint.

Parameters:

continuous - Set to true turns on continuous, false turns off continuous

setContinuous

public void setContinuous()

Set the PID controller to consider the input to be continuous, Rather then using the max and min in as constraints, it considers them to be the same point and automatically calculates the shortest route to the setpoint.

setInputRange

public void setInputRange(double minimumInput,
                          double maximumInput)

Sets the maximum and minimum values expected from the input.

Parameters:

minimumInput - the minimum value expected from the input

maximumInput - the maximum value expected from the output

setOutputRange

public void setOutputRange(double minimumOutput,
                           double maximumOutput)

Sets the minimum and maximum values to write.

Parameters:

minimumOutput - the minimum value to write to the output

maximumOutput - the maximum value to write to the output

setSetpoint

public void setSetpoint(double setpoint)

Set 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

getError

public double getError()

Returns the current difference of the input from the setpoint

Returns:

the current error

setTolerance

public void setTolerance(double percent)

Set the percentage error which is considered tolerable for use with OnTarget. (Input of 15.0 = 15 percent)

Parameters:

percent - error which is tolerable

onTarget

public boolean onTarget()

Return true if the error is within the percentage of the total input range, determined by setTolerance. This assumes that the maximum and minimum input were set using setInput.

Returns:

true if the error is less than the tolerance

enable

public void enable()

Begin running the PIDController

disable

public void disable()

Stop running the PIDController, this sets the output to zero before stopping.

isEnable

public boolean isEnable()

Return true if PIDController is enabled.

reset

public void reset()

Reset the previous error,, the integral term, and disable the controller.