Package edu.wpi.first.wpilibj.simulation

Class SingleJointedArmSim

java.lang.Object

edu.wpi.first.wpilibj.simulation.LinearSystemSim<N2,N1,N1>

edu.wpi.first.wpilibj.simulation.SingleJointedArmSim

public class SingleJointedArmSim
extends LinearSystemSim<N2,N1,N1>

Represents a simulated single jointed arm mechanism.

Field Summary

Fields inherited from class edu.wpi.first.wpilibj.simulation.LinearSystemSim

m_measurementStdDevs, m_plant, m_u, m_x, m_y

Constructor Summary

Constructors

Constructor	Description
SingleJointedArmSim(LinearSystem<N2,N1,N1> plant, DCMotor gearbox, double gearing, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity)	Creates a simulated arm mechanism.
SingleJointedArmSim(LinearSystem<N2,N1,N1> plant, DCMotor gearbox, double gearing, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity, Matrix<N1,N1> measurementStdDevs)	Creates a simulated arm mechanism.
SingleJointedArmSim(DCMotor gearbox, double gearing, double jKgMetersSquared, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity)	Creates a simulated arm mechanism.
SingleJointedArmSim(DCMotor gearbox, double gearing, double jKgMetersSquared, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity, Matrix<N1,N1> measurementStdDevs)	Creates a simulated arm mechanism.

Method Summary

Modifier and Type	Method	Description
static double	estimateMOI(double lengthMeters, double massKg)	Calculates a rough estimate of the moment of inertia of an arm given its length and mass.
double	getAngleRads()	Returns the current arm angle.
double	getCurrentDrawAmps()	Returns the arm current draw.
double	getVelocityRadPerSec()	Returns the current arm velocity.
boolean	hasHitLowerLimit()	Returns whether the arm has hit the lower limit.
boolean	hasHitUpperLimit()	Returns whether the arm has hit the upper limit.
void	setInputVoltage(double volts)	Sets the input voltage for the arm.
protected Matrix<N2,N1>	updateX(Matrix<N2,N1> currentXhat, Matrix<N1,N1> u, double dtSeconds)	Updates the state of the arm.
boolean	wouldHitLowerLimit(double currentAngleRads)	Returns whether the arm would hit the lower limit.
boolean	wouldHitUpperLimit(double currentAngleRads)	Returns whether the arm would hit the upper limit.

Methods inherited from class edu.wpi.first.wpilibj.simulation.LinearSystemSim

clampInput, getOutput, getOutput, setInput, setInput, setInput, setState, update

Methods inherited from class java.lang.Object

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

Constructor Details

SingleJointedArmSim

public SingleJointedArmSim(LinearSystem<N2,N1,N1> plant, DCMotor gearbox, double gearing, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity)

Creates a simulated arm mechanism.

Parameters:

plant - The linear system that represents the arm.

gearbox - The type of and number of motors in the arm gearbox.

gearing - The gearing of the arm (numbers greater than 1 represent reductions).

armLengthMeters - The length of the arm.

minAngleRads - The minimum angle that the arm is capable of.

maxAngleRads - The maximum angle that the arm is capable of.

armMassKg - The mass of the arm.

simulateGravity - Whether gravity should be simulated or not.

SingleJointedArmSim

public SingleJointedArmSim(LinearSystem<N2,N1,N1> plant, DCMotor gearbox, double gearing, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity, Matrix<N1,N1> measurementStdDevs)

Creates a simulated arm mechanism.

Parameters:

plant - The linear system that represents the arm.

gearbox - The type of and number of motors in the arm gearbox.

gearing - The gearing of the arm (numbers greater than 1 represent reductions).

armLengthMeters - The length of the arm.

minAngleRads - The minimum angle that the arm is capable of.

maxAngleRads - The maximum angle that the arm is capable of.

armMassKg - The mass of the arm.

simulateGravity - Whether gravity should be simulated or not.

measurementStdDevs - The standard deviations of the measurements.

SingleJointedArmSim

public SingleJointedArmSim(DCMotor gearbox, double gearing, double jKgMetersSquared, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity)

Creates a simulated arm mechanism.

Parameters:

gearbox - The type of and number of motors in the arm gearbox.

gearing - The gearing of the arm (numbers greater than 1 represent reductions).

jKgMetersSquared - The moment of inertia of the arm, can be calculated from CAD software.

armLengthMeters - The length of the arm.

minAngleRads - The minimum angle that the arm is capable of.

maxAngleRads - The maximum angle that the arm is capable of.

armMassKg - The mass of the arm.

simulateGravity - Whether gravity should be simulated or not.

SingleJointedArmSim

public SingleJointedArmSim(DCMotor gearbox, double gearing, double jKgMetersSquared, double armLengthMeters, double minAngleRads, double maxAngleRads, double armMassKg, boolean simulateGravity, Matrix<N1,N1> measurementStdDevs)

Creates a simulated arm mechanism.

Parameters:

gearbox - The type of and number of motors in the arm gearbox.

gearing - The gearing of the arm (numbers greater than 1 represent reductions).

jKgMetersSquared - The moment of inertia of the arm; can be calculated from CAD software.

armLengthMeters - The length of the arm.

minAngleRads - The minimum angle that the arm is capable of.

maxAngleRads - The maximum angle that the arm is capable of.

armMassKg - The mass of the arm.

simulateGravity - Whether gravity should be simulated or not.

measurementStdDevs - The standard deviations of the measurements.

Method Details

wouldHitLowerLimit

public boolean wouldHitLowerLimit(double currentAngleRads)

Returns whether the arm would hit the lower limit.

Parameters:

currentAngleRads - The current arm height.

Returns:

Whether the arm would hit the lower limit.

wouldHitUpperLimit

public boolean wouldHitUpperLimit(double currentAngleRads)

Returns whether the arm would hit the upper limit.

Parameters:

currentAngleRads - The current arm height.

Returns:

Whether the arm would hit the upper limit.

hasHitLowerLimit

public boolean hasHitLowerLimit()

Returns whether the arm has hit the lower limit.

Returns:

Whether the arm has hit the lower limit.

hasHitUpperLimit

public boolean hasHitUpperLimit()

Returns whether the arm has hit the upper limit.

Returns:

Whether the arm has hit the upper limit.

getAngleRads

public double getAngleRads()

Returns the current arm angle.

Returns:

The current arm angle.

getVelocityRadPerSec

public double getVelocityRadPerSec()

Returns the current arm velocity.

Returns:

The current arm velocity.

getCurrentDrawAmps

public double getCurrentDrawAmps()

Returns the arm current draw.

Overrides:

getCurrentDrawAmps in class LinearSystemSim<N2,N1,N1>

Returns:

The aram current draw.

setInputVoltage

public void setInputVoltage(double volts)

Sets the input voltage for the arm.

Parameters:

volts - The input voltage.

estimateMOI

public static double estimateMOI(double lengthMeters, double massKg)

Calculates a rough estimate of the moment of inertia of an arm given its length and mass.

Parameters:

lengthMeters - The length of the arm.

massKg - The mass of the arm.

Returns:

The calculated moment of inertia.

updateX

protected Matrix<N2,N1> updateX(Matrix<N2,N1> currentXhat, Matrix<N1,N1> u, double dtSeconds)

Updates the state of the arm.

Overrides:

updateX in class LinearSystemSim<N2,N1,N1>

Parameters:

currentXhat - The current state estimate.

u - The system inputs (voltage).

dtSeconds - The time difference between controller updates.

Returns:

The new state.