lejos.hardware.motor

Class JavaMotorRegulator

java.lang.Object

lejos.hardware.motor.JavaMotorRegulator

All Implemented Interfaces:

MotorRegulator

public class JavaMotorRegulator
extends java.lang.Object
implements MotorRegulator

Java based regulator regulate velocity; also stop motor at desired rotation angle. This class uses a very simple movement model based on simple linear acceleration. This model is used to generate ideal target positions which are then used to generate error terms between the actual and target position this error term is then used to drive a PID style motor controller to regulate the power supplied to the motor. If new command are issued while a move is in progress, the new command is blended with the current one to provide smooth movement. If the requested speed is not possible then the controller will simply drop move cycles until the motor catches up with the ideal position. If too many consecutive dropped moves are required then the motor is viewed to have stalled and the move is terminated. Once the motor stops, the final position is held using the same PID control mechanism (with slightly different parameters), as that used for movement. TODO: Should we add synchronization to this?

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	JavaMotorRegulator.Controller This class provides a single thread that drives all of the motor regulation process.

Field Summary

Fields

Modifier and Type	Field and Description
protected static JavaMotorRegulator.Controller	cont
int	power
protected int	stallLimit
protected int	stallTime
protected TachoMotorPort	tachoPort

Fields inherited from interface lejos.hardware.motor.MotorRegulator

NO_LIMIT

Constructor Summary

Constructors

Constructor and Description
JavaMotorRegulator(TachoMotorPort p)

Method Summary

Modifier and Type	Method and Description
void	addListener(RegulatedMotor motor, RegulatedMotorListener listener) Add a motor listener.
void	adjustAcceleration(int newAcc) The target acceleration has been changed.
void	adjustSpeed(float newSpeed) The target speed has been changed.
void	endSynchronization(boolean b) Complete a set of synchronized motor operations.
float	getCurrentVelocity() Return the current velocity (in degrees/second) that the motor is currently running at.
int	getLimitAngle() Return the angle that this Motor is rotating to.
float	getPosition() return the regulations models current position.
int	getTachoCount() Get the current hardware tachometer reading for the motor,
boolean	isMoving() Return true if the motor is currently active
boolean	isStalled() Return true if the motor is currently stalled.
void	newMove(float speed, int acceleration, int limit, boolean hold, boolean waitComplete) Initiate a new move and optionally wait for it to complete.
RegulatedMotorListener	removeListener()
protected void	reset() Reset the tachometer readings
void	resetTachoCount() Reset the tachometer base value, after this call the tachometer will return zero for the current position.
void	setControlParamaters(int typ, float moveP, float moveI, float moveD, float holdP, float holdI, float holdD, int offset) Set the motion control parameters used by the regulator.
void	setStallThreshold(int error, int time) Set the stall detection parameters.
void	startSynchronization() Begin a set of synchronized motor operations
void	synchronizeWith(MotorRegulator[] rl) Specify a set of motors that should be kept in synchronization with this one.
protected void	updateState(int velocity, boolean hold, boolean stalled) Update the internal state of the motor.
void	waitComplete() Wait until the current movement operation is complete (this can include the motor stalling).

Methods inherited from class java.lang.Object

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

Field Detail

power

public int power

stallLimit

protected int stallLimit

stallTime

protected int stallTime

tachoPort

protected TachoMotorPort tachoPort

cont

protected static final JavaMotorRegulator.Controller cont

Constructor Detail

JavaMotorRegulator

public JavaMotorRegulator(TachoMotorPort p)

Method Detail

getTachoCount

public int getTachoCount()

Description copied from interface: MotorRegulator

Get the current hardware tachometer reading for the motor,

Specified by:

getTachoCount in interface MotorRegulator

Returns:

hardware reading

resetTachoCount

public void resetTachoCount()

Description copied from interface: MotorRegulator

Reset the tachometer base value, after this call the tachometer will return zero for the current position. Note that any in progress movements will be aborted.

Specified by:

resetTachoCount in interface MotorRegulator

isMoving

public boolean isMoving()

Description copied from interface: MotorRegulator

Return true if the motor is currently active

Specified by:

isMoving in interface MotorRegulator

Returns:

True if the motor is moving.

getCurrentVelocity

public float getCurrentVelocity()

Description copied from interface: MotorRegulator

Return the current velocity (in degrees/second) that the motor is currently running at. Note that this value may be supplied from the internal control model not from actually measuring the rotation speed. If the regulator is functioning correctly this will closely match the actual velocity

Specified by:

getCurrentVelocity in interface MotorRegulator

Returns:

velocity

setStallThreshold

public void setStallThreshold(int error,
                              int time)

Description copied from interface: MotorRegulator

Set the stall detection parameters. The motor will be declared as stalled if the error in the motor position exceeds the specified value for longer than the given time.

Specified by:

setStallThreshold in interface MotorRegulator

updateState

protected void updateState(int velocity,
                           boolean hold,
                           boolean stalled)

Update the internal state of the motor.

Parameters:

velocity -

hold -

stalled -

addListener

public void addListener(RegulatedMotor motor,
                        RegulatedMotorListener listener)

Description copied from interface: MotorRegulator

Add a motor listener. Move operations will be reported to this object.

Specified by:

addListener in interface MotorRegulator

removeListener

public RegulatedMotorListener removeListener()

Specified by:

removeListener in interface MotorRegulator

setControlParamaters

public void setControlParamaters(int typ,
                                 float moveP,
                                 float moveI,
                                 float moveD,
                                 float holdP,
                                 float holdI,
                                 float holdD,
                                 int offset)

Description copied from interface: MotorRegulator

Set the motion control parameters used by the regulator.

Specified by:

setControlParamaters in interface MotorRegulator

Parameters:

typ - The type of motor

moveP - The Proportional control value used while moving

moveI - The integral control parameter used while moving

moveD - The differential control parameter used while moving

holdP - The Proportional control value used while holding position

holdI - The integral control value used while holding position

holdD - The differential control value used while holding position

offset - Motor PWM offset value range 0-10000.

waitComplete

public void waitComplete()

Description copied from interface: MotorRegulator

Wait until the current movement operation is complete (this can include the motor stalling).

Specified by:

waitComplete in interface MotorRegulator

getLimitAngle

public int getLimitAngle()

Description copied from interface: MotorRegulator

Return the angle that this Motor is rotating to.

Specified by:

getLimitAngle in interface MotorRegulator

Returns:

angle in degrees

isStalled

public boolean isStalled()

Description copied from interface: MotorRegulator

Return true if the motor is currently stalled.

Specified by:

isStalled in interface MotorRegulator

Returns:

true if the motor is stalled, else false

reset

protected void reset()

Reset the tachometer readings

getPosition

public float getPosition()

return the regulations models current position. Ensure that the motor is active if needed.

Specified by:

getPosition in interface MotorRegulator

Returns:

the models current position

newMove

public void newMove(float speed,
                    int acceleration,
                    int limit,
                    boolean hold,
                    boolean waitComplete)

Initiate a new move and optionally wait for it to complete. If some other move is currently executing then ensure that this move is terminated correctly and then start the new move operation.

Specified by:

newMove in interface MotorRegulator

Parameters:

speed -

acceleration -

limit -

hold -

waitComplete -

adjustSpeed

public void adjustSpeed(float newSpeed)

The target speed has been changed. Reflect this change in the regulator.

Specified by:

adjustSpeed in interface MotorRegulator

Parameters:

newSpeed - new target speed.

adjustAcceleration

public void adjustAcceleration(int newAcc)

The target acceleration has been changed. Updated the regulator.

Specified by:

adjustAcceleration in interface MotorRegulator

Parameters:

newAcc -

startSynchronization

public void startSynchronization()

Description copied from interface: MotorRegulator

Begin a set of synchronized motor operations

Specified by:

startSynchronization in interface MotorRegulator

endSynchronization

public void endSynchronization(boolean b)

Description copied from interface: MotorRegulator

Complete a set of synchronized motor operations.

Specified by:

endSynchronization in interface MotorRegulator

synchronizeWith

public void synchronizeWith(MotorRegulator[] rl)

Description copied from interface: MotorRegulator

Specify a set of motors that should be kept in synchronization with this one. The synchronization mechanism simply ensures that operations between a startSynchronization call and an endSynchronization call will all be executed at the same time (when the endSynchronization method is called). This is all that is needed to ensure that motors will operate in a synchronized fashion. The start/end methods can also be used to ensure that reads of the motor state will also be consistent.

Specified by:

synchronizeWith in interface MotorRegulator

Parameters:

rl - an array of motors to synchronize with.