lejos.localization
Class TachoLocalizer

java.lang.Object
  lejos.navigation.SimpleNavigator
      lejos.localization.TachoLocalizer

All Implemented Interfaces:

Localizer, Navigator

public abstract class TachoLocalizer
extends SimpleNavigator
implements Localizer

An abstract extension to TachoNavigator that uses a map and a set of particles to implement the Monte Carlo Localization algorithm to estimate the pose of the robot as it moves about. Note that the navigator uses its own local coordinates relative to the robot's starting position, whereas the estimated pose is in global coordinates, as used by the map. This class must be extended and the takeReadings method implemented. Note that only travel and rotate methods update the particle set.

Author:

Lawrie Griffiths

Field Summary

protected float	angle
protected float	distance
protected Map	map
protected Move	mv
protected int	numParticles
protected int	numReadings
protected ParticleSet	particles
protected float	projection
protected RangeReadings	readings

Constructor Summary

TachoLocalizer(Map map, int numParticles, int numReadings, float wheelDiameter, float trackWidth, Motor leftMotor, Motor rightMotor, float projection, boolean reverse)

Method Summary

Pose	getEstimatedPose() Get the estimated position and angle of the robot.
Map	getMap() Get the map
ParticleSet	getParticles() Get the particle set
float	getProjection() Get the forward projection of the robot
RangeReadings	getReadings() Return readings
int	numParticles() Get the number of particles
void	rotate(float angle, boolean immediateReturn) Rotates the NXT robot a specific number of degrees in a direction (+ or -).
abstract void	takeReadings() Take a set of readings to the nearest map features
void	travel(float distance, boolean immediateReturn) Moves the NXT robot a specific distance.
void	updatePosition() Update the robot position and apply it to all the particles.

Methods inherited from class lejos.navigation.SimpleNavigator

angleTo, backward, distanceTo, forward, getAngle, getPilot, getX, getY, goTo, goTo, isMoving, rotate, rotateLeft, rotateRight, rotateTo, rotateTo, setMoveSpeed, setPosition, setSpeed, setTurnSpeed, stop, travel, turn, turn, turn

Methods inherited from class java.lang.Object

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

Methods inherited from interface lejos.navigation.Navigator

angleTo, backward, distanceTo, forward, getAngle, getX, getY, goTo, goTo, isMoving, rotate, rotateLeft, rotateRight, rotateTo, rotateTo, setMoveSpeed, setPosition, setTurnSpeed, stop, travel

Field Detail

readings

protected RangeReadings readings

projection

protected float projection

map

protected Map map

numParticles

protected int numParticles

particles

protected ParticleSet particles

angle

protected float angle

distance

protected float distance

mv

protected Move mv

numReadings

protected int numReadings

Constructor Detail

TachoLocalizer

public TachoLocalizer(Map map,
                      int numParticles,
                      int numReadings,
                      float wheelDiameter,
                      float trackWidth,
                      Motor leftMotor,
                      Motor rightMotor,
                      float projection,
                      boolean reverse)

Method Detail

takeReadings

public abstract void takeReadings()

Description copied from interface: Localizer

Take a set of readings to the nearest map features

Specified by:

takeReadings in interface Localizer

rotate

public void rotate(float angle,
                   boolean immediateReturn)

Description copied from class: SimpleNavigator

Rotates the NXT robot a specific number of degrees in a direction (+ or -). If immediateReturn is true, method returns immidiately and your code MUST call updatePostion() when the robot has stopped. Otherwise, the robot position is lost. If false, the robot position is updated automatically.

Specified by:

rotate in interface Navigator

Overrides:

rotate in class SimpleNavigator

Parameters:

angle - Angle to rotate in degrees. A positive value rotates left, a negative value right.

immediateReturn - iff true, the method returns immediately, in which case the programmer
is responsible for calling updatePosition() before the robot moves again.

travel

public void travel(float distance,
                   boolean immediateReturn)

Description copied from class: SimpleNavigator

Moves the NXT robot a specific distance. A positive value moves it forwards and a negative value moves it backwards. If immediateReturnis true, method returns immidiately and your code MUST call updatePostion() when the robot has stopped. Otherwise, the robot position is lost.

Specified by:

travel in interface Navigator

Overrides:

travel in class SimpleNavigator

Parameters:

distance - The positive or negative distance to move the robot, same units as _wheelDiameter

immediateReturn - iff true, the method returns immediately, in which case the programmer
is responsible for calling updatePosition() before the robot moves again.

updatePosition

public void updatePosition()

Update the robot position and apply it to all the particles. Note that only travel and rotate methods update the particle set.

Specified by:

updatePosition in interface Navigator

Overrides:

updatePosition in class SimpleNavigator

getProjection

public float getProjection()

Get the forward projection of the robot

Returns:

the distance from the range sensor to the front of the robot

numParticles

public int numParticles()

Get the number of particles

Returns:

the number of particles

getParticles

public ParticleSet getParticles()

Get the particle set

Returns:

the particle set

getMap

public Map getMap()

Get the map

Returns:

the map

getEstimatedPose

public Pose getEstimatedPose()

Get the estimated position and angle of the robot.

Specified by:

getEstimatedPose in interface Localizer

Returns:

the estimated pose

getReadings

public RangeReadings getReadings()

Return readings

Returns:

the range readings