Package edu.wpi.first.math.geometry

Class Twist3d

java.lang.Object

edu.wpi.first.math.geometry.Twist3d

All Implemented Interfaces:

ProtobufSerializable, StructSerializable, WPISerializable

public class Twist3d
extends Object
implements ProtobufSerializable, StructSerializable

A change in distance along a 3D arc since the last pose update. We can use ideas from differential calculus to create new Pose3d objects from a Twist3d and vice versa.

A Twist can be used to represent a difference between two poses.

Field Summary

Fields

Modifier and Type	Field	Description
double	dx	Linear "dx" component.
double	dy	Linear "dy" component.
double	dz	Linear "dz" component.
static final Twist3dProto	proto	Twist3d protobuf for serialization.
double	rx	Rotation vector x component (radians).
double	ry	Rotation vector y component (radians).
double	rz	Rotation vector z component (radians).
static final Twist3dStruct	struct	Twist3d struct for serialization.

Constructor Summary

Constructors

Constructor	Description
Twist3d()	Default constructor.
Twist3d(double dx, double dy, double dz, double rx, double ry, double rz)	Constructs a Twist3d with the given values.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)	Checks equality between this Twist3d and another object.
Transform3d	exp()	Obtain a new Transform3d from a (constant curvature) velocity.
int	hashCode()
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Details

dx

public double dx

Linear "dx" component.

dy

public double dy

Linear "dy" component.

dz

public double dz

Linear "dz" component.

rx

public double rx

Rotation vector x component (radians).

ry

public double ry

Rotation vector y component (radians).

rz

public double rz

Rotation vector z component (radians).

proto

public static final Twist3dProto proto

Twist3d protobuf for serialization.

struct

public static final Twist3dStruct struct

Twist3d struct for serialization.

Constructor Details

Twist3d

public Twist3d()

Default constructor.

Twist3d

public Twist3d(double dx,
 double dy,
 double dz,
 double rx,
 double ry,
 double rz)

Constructs a Twist3d with the given values.

Parameters:

dx - Change in x direction relative to robot.

dy - Change in y direction relative to robot.

dz - Change in z direction relative to robot.

rx - Rotation vector x component.

ry - Rotation vector y component.

rz - Rotation vector z component.

Method Details

exp

public Transform3d exp()

Obtain a new Transform3d from a (constant curvature) velocity.

See Controls Engineering in the FIRST Robotics Competition section 10.2 "Pose exponential" for a derivation.

The twist is a change in pose in the robot's coordinate frame since the previous pose update. When the user runs exp() on the twist, the user will receive the pose delta.

"Exp" represents the pose exponential, which is solving a differential equation moving the pose forward in time.

Returns:

The pose delta of the robot.

toString

public String toString()

Overrides:

toString in class Object

equals

public boolean equals(Object obj)

Checks equality between this Twist3d and another object.

Overrides:

equals in class Object

Parameters:

obj - The other object.

Returns:

Whether the two objects are equal or not.

hashCode

public int hashCode()

Overrides:

hashCode in class Object