Class CoordinateConstraint

Class CoordinateConstraint#

Inheritance Relationships#

Base Type#

Class Documentation#

class CoordinateConstraint : public Karana::Dynamics::BilateralConstraintBase#

Class for coordinate constraints.

This constraint requires that the ratio of the Q coordinates for a pair of subhinges be related via a specific scale ratio.

See the Coordinate constraints section for more discussion on coordinate constraints.

Public Functions

CoordinateConstraint(std::string_view name, kc::ks_ptr<Multibody> mb, kc::ks_ptr<PhysicalSubhinge> osh, kc::ks_ptr<PhysicalSubhinge> psh)#

Constructor.

Parameters:
virtual size_t nResiduals() const override#

Return the number of dofs allowed by the constraint.

Returns:

the number of dofs allowed by the constraint

inline void setScaleRatio(double scale_ratio)#

Set the Q(pshg)/Q(oshg) coordinate scale ratio.

Parameters:

scale_ratio – The scale ratio

inline double getScaleRatio() const#

Return the Q(pshg)/Q(oshg) coordinate scale ratio.

Returns:

The scale ratio

inline kc::ks_ptr<PhysicalSubhinge> osubhinge() const#

Return the first subhinge for this coordinate constraint.

Returns:

The first subhinge.

inline kc::ks_ptr<PhysicalSubhinge> psubhinge() const#

Return the second subhinge for this coordinate constraint.

Returns:

The second subhinge.

virtual bool isReady() const override#

Checks is the params for the object have been initialized.

Returns:

True if the params have set up.

virtual km::Vec velError() const override#

Return the current U constraint velocity error.

Returns:

the velocity error

virtual km::Vec accelError() const override#

Return the current Udot constraint acceleration error.

Returns:

the acceleration error

virtual km::Vec poseError() const override#

Return the current Q constraint coordinate error.

Returns:

the coordinate error

Public Static Functions

static const kc::ks_ptr<CoordinateConstraint> create(std::string_view name, kc::ks_ptr<Multibody> mb, kc::ks_ptr<PhysicalSubhinge> osh, kc::ks_ptr<PhysicalSubhinge> psh)#

Factory method for creating a CoordinateConstraint instance.

Parameters:
Returns:

a CoordinateConstraint instance

Protected Functions

virtual km::Vec _poseResidual() const override#

Return the nResiduals() size pose residual term for the constraint.

Used for computing the Baumgarte error control term for TA dynamics

Returns:

The pose residual error

virtual km::Vec _velResidual() const override#

Return the nResiduals() size velocity residual term for the constraint.

Used for computing the Baumgarte error control term for TA dynamics

Returns:

The velocity residual error

virtual km::Vec _accelResidual() const override#

Return the 1-d size accel residual term for the constraint.

Used for computing the acceleration kinematics and the lambda (Lagrange multiplier) terms for the TA dynamics correction step

Returns:

The acceleration residual error

void _lambdaToConstraintGenForces(const km::Vec &lambda) const#

Convert the lambda Lagrange multiplier term for the coordinate constraint into constraint generalized forces at its subhinges.

Parameters:

lambda – the Lagrange multiplier value

void _discard(kc::ks_ptr<kc::Base> &base) override#

Protected Attributes

kc::ks_ptr<PhysicalSubhinge> _oshg = nullptr#

the source of 1-dof subhinges pair whose coordinates are being constrained

kc::ks_ptr<PhysicalSubhinge> _pshg = nullptr#

the target of the 1-dof subhinges pair whose coordinates are being constrained

double _scale_ratio = km::notReadyNaN#

U(pshg)/U(pshg) coordinate scale ratio

Contents