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simscape.multibody.SphericalSpringDamper class

Package: simscape.multibody
Superclasses: simscape.multibody.JointForceLaw

Construct spherical spring-damper force law

Description

Use an object of the simscape.multibody.SphericalSpringDamper class to construct a spherical spring-damper force law. You can use the force law to apply a pure torque to a simscape.multibody.SphericalPrimitive object.

The spherical spring-damper force law is a vector force law. The deviation between the current and equilibrium position is expressed as

Rrel=Re1R,

where:

SymbolDescription
RrelRelative rotation, specified as a vector.
ReEquilibrium position of a spherical primitive, specified as a vector.
RCurrent position of the spherical primitive, specified as a vector that represents a 3-D rotation from the follower to the base frame of the primitive.

The relative rotation can be parameterized by a natural angle-axis pair. The angle, θ, is a scalar angle in the range of [0,180] degree, and the axis, u, is a unit vector along the axis. Therefore, the torque is expressed as

T=ksθukdω,

where:

SymbolDescription
TApplied torque, specified as a vector.
ksSpring stiffness
kdDamping coefficient
uNatural axis of the rotation, specified as a vector. For more information about the natural axis, see naturalAxis method.
θNatural angle of the rotation. For more information about the natural angle, see naturalAngle method.
ωSpherical primitive 3-D angular velocity, specified as a vector.

Class Attributes

Sealed
true
ConstructOnLoad
true
RestrictsSubclassing
true

For information on class attributes, see Class Attributes.

Creation

Description

ssd = simscape.multibody.SphericalSpringDamper constructs a spherical spring-damper force law with default values.

Properties

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Equilibrium position of the spherical spring, specified as an object of a subclass of the simscape.multibody.Rotation class. The torque is zero when the primitive position is at the equilibrium position.

Example: simscape.multibody.AlignedAxesRotation(simscape.multibody.Axis.PosX, simscape.multibody.Axis.NegZ,simscape.multibody.Axis.NegY,simscape.multibody.Axis.PosY)

Attributes:

GetAccess
public
SetAccess
public
NonCopyable
true

Stiffness of the spherical spring, specified as a simscape.Value object that represents a scalar with a unit of torque/angle. The scalar is a measure of how hard the spring pushes the primitive position toward the equilibrium position and must be nonnegative.

Example: simscape.Value(5,"N*m/deg")

Attributes:

GetAccess
public
SetAccess
public
NonCopyable
true

Damping coefficient of the spherical damper, specified as a simscape.Value object that represents a scalar with a unit of torque/angular velocity. The scalar is a measure of how hard the damper resists the motion of a primitive and must be nonnegative.

Example: simscape.Value(10,"N*m/(deg/s))

Attributes:

GetAccess
public
SetAccess
public
NonCopyable
true

Version History

Introduced in R2022a