Module com.marginallyclever.ro3

Package com.marginallyclever.ro3.node.nodes.pose.poses

Class Limb

java.lang.Object

com.marginallyclever.ro3.node.Node

com.marginallyclever.ro3.node.nodes.pose.Pose

com.marginallyclever.ro3.node.nodes.pose.poses.Limb

All Implemented Interfaces:

PoseChangeListener, EventListener

public class Limb
extends Pose

Limb is a linear chain of bones driven by joints powered by muscles. Limb is designed to handle six joints or less.

• Bones are represented by Poses.
• Joints are represented by HingeJoints.
• Muscles are represented by Motors.
• The end of the chain - at the wrist - is a Pose called the end effector.
• The target is a Pose that the end effector is trying to reach at a given linear velocity.

Limbs perform both Forward Kinematics and Inverse kinematics. In earlier versions of the app the concerns were separated, but this made it difficult to tell who was in charge and led to cyclic, jittery behavior.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	ACTION_ARRIVED_AT_GOAL
static final double	DEFAULT_GOAL_MARGIN_OF_ERROR
static final double	DEFAULT_LINEAR_VELOCITY
static final int	MAX_JOINTS
static final String	PROPERTY_POSE_CHANGED

Fields inherited from class com.marginallyclever.ro3.node.Node

ICON

Constructor Summary

Constructors

Constructor	Description
Limb()
Limb(String name)

Method Summary

Modifier and Type	Method	Description
void	addActionListener(ActionListener listener)
void	addPropertyChangeListener(PropertyChangeListener listener)
void	fromJSON(org.json.JSONObject from)	Deserialize this node and its children from a JSON object and its children.
double[]	getAllJointAngles()
void	getComponents(List<JPanel> list)	Build a Swing Component that represents this Node.
double	getDistanceToTarget()
NodePath<Pose>	getEndEffector()
double	getGoalMarginOfError()
Icon	getIcon()	Set a custom icon for this node.
boolean	getIsAtGoal()
Motor	getJoint(int index)	Get the motor at the given index.
double	getLinearVelocity()
List<NodePath<Motor>>	getMotors()
int	getNumJoints()
NodePath<Pose>	getTarget()
void	moveTargetToEndEffector()	Move the target to the end effector's current pose, stopping all motion of the arm (because it is now at the target).
boolean	readyToSolve()
void	removeActionListener(ActionListener listener)
void	removePropertyChangeListener(PropertyChangeListener listener)
static void	scaleVectorToMagnitude(double[] vector, double maxLen)	Make sure the given vector's length does not exceed linearVelocity.
void	setAllJointAngles(double[] values)	Set all joint angles at once while respecting the joint range limits.
void	setAllJointAnglesUnsafe(double[] values)	Set all joint angles at once without respecting the joint range limits.
void	setAllJointVelocities(double @NotNull [] values)
void	setEndEffector(Pose pose)
void	setGoalMarginOfError(double goalMarginOfError)
void	setIsAtGoal(boolean isAtGoal)
void	setJoint(int index, Motor newValue)	Get the motor at the given index.
void	setLinearVelocity(double linearVelocity)	Set the linear velocity of the end effector in cm/s.
void	setMotorAngle(Motor motor, double angle)	Move a motor to a specific angle and notify listeners that the pose has changed.
void	setTarget(Pose target)	Set the target to move towards.
org.json.JSONObject	toJSON()	Serialize this node and its children to a JSON object and its children.
void	update(double dt)	Called every frame.

Methods inherited from class com.marginallyclever.ro3.node.nodes.pose.Pose

addPoseChangeListener, getLocal, getParentPose, getPosition, getRotationEuler, getRotationIndex, getWorld, onPoseChange, removePoseChangeListener, setLocal, setPosition, setRotationEuler, setRotationIndex, setWorld

Methods inherited from class com.marginallyclever.ro3.node.Node

addAttachListener, addChild, addChild, addDetachListener, addReadyListener, addRenameListener, findByPath, findChild, findChild, findFirstChild, findFirstSibling, findNodeByID, findParent, findParent, getAbsolutePath, getChildren, getName, getParent, getRootNode, getUniqueID, hasChild, hasParent, isNameUsedBySibling, removeAttachListener, removeChild, removeDetachListener, removeReadyListener, removeRenameListener, setName, witnessProtection

Methods inherited from class java.lang.Object

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

Field Details

MAX_JOINTS

public static final int MAX_JOINTS

See Also:

• Constant Field Values

DEFAULT_LINEAR_VELOCITY

public static final double DEFAULT_LINEAR_VELOCITY

See Also:

• Constant Field Values

DEFAULT_GOAL_MARGIN_OF_ERROR

public static final double DEFAULT_GOAL_MARGIN_OF_ERROR

See Also:

• Constant Field Values

ACTION_ARRIVED_AT_GOAL

public static final String ACTION_ARRIVED_AT_GOAL

See Also:

• Constant Field Values

PROPERTY_POSE_CHANGED

public static final String PROPERTY_POSE_CHANGED

See Also:

• Constant Field Values

Constructor Details

Limb

public Limb()

Limb

public Limb(String name)

Method Details

getEndEffector

public NodePath<Pose> getEndEffector()

Returns:

the end effector pose or null if not set.

setEndEffector

public void setEndEffector(Pose pose)

getMotors

public List<NodePath<Motor>> getMotors()

getNumJoints

public int getNumJoints()

getJoint

public Motor getJoint(int index)

Get the motor at the given index.

Parameters:

index - the index of the motor to get.

Returns:

the motor at the given index.

Throws:

IndexOutOfBoundsException - if the index is out of range.

getAllJointAngles

public double[] getAllJointAngles()

setJoint

public void setJoint(int index,
 Motor newValue)

Get the motor at the given index.

Parameters:

index - the index of the motor to get.

newValue - the new motor to set.

Throws:

IndexOutOfBoundsException - if the index is out of range.

setAllJointAngles

public void setAllJointAngles(double[] values)

Set all joint angles at once while respecting the joint range limits. Then notify listeners that the pose has changed.

Parameters:

values - the angles to set each joint to.

setAllJointAnglesUnsafe

public void setAllJointAnglesUnsafe(double[] values)

Set all joint angles at once without respecting the joint range limits.

Parameters:

values - the angles to set each joint to.

setAllJointVelocities

public void setAllJointVelocities(double @NotNull [] values)

toJSON

public org.json.JSONObject toJSON()

Description copied from class: Node

Serialize this node and its children to a JSON object and its children. Classes that override this method should call super.toJSON() first, then add to the object returned.

Overrides:

toJSON in class Pose

Returns:

the JSON object.

fromJSON

public void fromJSON(org.json.JSONObject from)

Description copied from class: Node

Deserialize this node and its children from a JSON object and its children. Classes that override this method should call super.fromJSON(). When they do it will trigger the creation of child nodes. The child nodes will then call their own fromJSON() methods.

Overrides:

fromJSON in class Pose

Parameters:

from - the JSON object to read from.

getComponents

public void getComponents(List<JPanel> list)

Description copied from class: Pose

Build a Swing Component that represents this Node.

Overrides:

getComponents in class Pose

Parameters:

list - the list to add components to.

getIcon

public Icon getIcon()

Description copied from class: Node

Set a custom icon for this node.

Overrides:

getIcon in class Pose

Returns:

the icon, or null if none.

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener listener)

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener listener)

setMotorAngle

public void setMotorAngle(Motor motor,
 double angle)

Move a motor to a specific angle and notify listeners that the pose has changed.

Parameters:

motor - the motor to move

angle - the angle to move the motor to

getTarget

public NodePath<Pose> getTarget()

setTarget

public void setTarget(Pose target)

Set the target to move towards. target must be in the same node tree as this instance.

Parameters:

target - the target to move towards

update

public void update(double dt)

Description copied from class: Node

Called every frame.

Overrides:

update in class Node

Parameters:

dt - the time since the last frame.

readyToSolve

public boolean readyToSolve()

Returns:

true if the solver has a limb, an end effector, and a target. Does not guarantee that a solution exists.

scaleVectorToMagnitude

public static void scaleVectorToMagnitude(double[] vector,
 double maxLen)

Make sure the given vector's length does not exceed linearVelocity. This means as the limb approaches the target the velocity will slow down.

Store the results in the original array.

Parameters:

vector - the vector to cap

maxLen - the max length of the vector.

moveTargetToEndEffector

public void moveTargetToEndEffector()

Move the target to the end effector's current pose, stopping all motion of the arm (because it is now at the target).

getLinearVelocity

public double getLinearVelocity()

setLinearVelocity

public void setLinearVelocity(double linearVelocity)

Set the linear velocity of the end effector in cm/s.

Parameters:

linearVelocity - must be >= 0

getDistanceToTarget

public double getDistanceToTarget()

Returns:

the distance to the target that is a combination of linear and angular distances.

getGoalMarginOfError

public double getGoalMarginOfError()

Returns:

the distance to the target that is a combination of linear and angular distances.

setGoalMarginOfError

public void setGoalMarginOfError(double goalMarginOfError)

Parameters:

goalMarginOfError - the distance to the target that is a combination of linear and angular distances.

addActionListener

public void addActionListener(ActionListener listener)

removeActionListener

public void removeActionListener(ActionListener listener)

setIsAtGoal

public void setIsAtGoal(boolean isAtGoal)

getIsAtGoal

public boolean getIsAtGoal()