artisynth.core.mechmodels

Class YPRStiffnessUtils

java.lang.Object

artisynth.core.mechmodels.YPRStiffnessUtils

public class YPRStiffnessUtils
extends java.lang.Object

Methods to support the computation of stiffness matrices where the orientation derivatives for Frames are represented with respect to yaw-pitch-roll instead of angular displacement. The latter have the advantage of being symmetric if they arise solely from conservative forces.

Constructor Summary

Constructors

Constructor and Description
YPRStiffnessUtils()

Method Summary

Modifier and Type	Method and Description
static void	convertActiveForcesToYPR(VectorNd fr, VectorNd f0, MechModel mech) Converts a system force vector to one that uses yaw-pitch-roll displacements.
static void	convertActiveVelocitiesFromYPR(VectorNd vr, VectorNd v0, MechModel mech) Converts a system velocity vector from one that uses yaw-pitch-roll displacements.
static void	convertStiffnessToYPR(SparseBlockMatrix K, VectorNd f, java.util.ArrayList<DynamicComponent> comps) Converts, in place, a stiffness matrix K and a (optional) force vector f from an angular displacement formulation to one using yaw-pitch-roll displacements.

Methods inherited from class java.lang.Object

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

Constructor Detail

YPRStiffnessUtils

public YPRStiffnessUtils()

Method Detail

convertActiveForcesToYPR

public static void convertActiveForcesToYPR(VectorNd fr,
                                            VectorNd f0,
                                            MechModel mech)

Converts a system force vector to one that uses yaw-pitch-roll displacements.

Parameters:

fr - converted force vector

f0 - original force vector (can be the same as fr)

mech - MechModel associated with the system

convertActiveVelocitiesFromYPR

public static void convertActiveVelocitiesFromYPR(VectorNd vr,
                                                  VectorNd v0,
                                                  MechModel mech)

Converts a system velocity vector from one that uses yaw-pitch-roll displacements.

Parameters:

vr - converted velocities

v0 - original velocites (can be the same as vr)

mech - MechModel associated with the system

convertStiffnessToYPR

public static void convertStiffnessToYPR(SparseBlockMatrix K,
                                         VectorNd f,
                                         java.util.ArrayList<DynamicComponent> comps)

Converts, in place, a stiffness matrix K and a (optional) force vector f from an angular displacement formulation to one using yaw-pitch-roll displacements. If f is not null, it supplies the forces used for the conversion. Otherwise, these force are obtained directly from the components.

Parameters:

K - matrix to convert

f - if not null, force vector to convert

comps - dynamic components associated with each matrix block entry