Class HingeBase

Class HingeBase#

Nested Relationships#

Nested Types#

Inheritance Relationships#

Derived Types#

Class Documentation#

class HingeBase#

Represents the base class for articulation hinges.

This is the abstract base class for hinge containers for PhysicalHinge and CompoundHinge classes that define articulation for bodies. See Connecting bodies via hinges section for more discussion on hinges.

Subclassed by Karana::Dynamics::CompoundHinge, Karana::Dynamics::FramePairHinge

Public Functions

inline HingeBase(HingeType htype)#

Constructs a HingeBase.

Parameters:

htype – the hinge type

virtual std::string_view typeString(bool brief) const noexcept = 0#

Returns the type string of the HingeBase.

Parameters:

brief – if true, return the short form of the class type name, else the full type name

Returns:

The type string.

inline virtual ~HingeBase()#

HingeBase destructor.

virtual std::string_view name() const = 0#

Return the name of the hinge instance.

Returns:

the hinge name

kc::ks_ptr<SubhingeBase> subhinge(size_t index) const#

Return the SubhingeBase subhinge instance at the specified index.

Parameters:

index – the subhinge index

Returns:

the subhinge object

inline size_t nSubhinges() const#

Return the number of subhinges in the hinge.

Returns:

the number of subhinges

size_t nU() const#

Return the total nU dofs from all the subhinges.

Returns:

the total number of U coordinates across the subhinges

inline HingeType hingeType() const#

Return the HingeType hinge type for this hinge.

Returns:

The hinge type used by this body.

inline const kc::ks_ptr<CoordData> &coordData() const#

Return the CoordData for the hinge’s list of subhinges.

Returns:

the CoordData for the subhinges

inline const kc::RegistryList<SubhingeBase> &subhinges() const#

Return the list of SubhingeBase subhinges.

Returns:

the list of subhinges

virtual km::Mat pframeCoordMapMatrix() const = 0#

The overall pframe coordinate map matrix for the hinge.

Return the overall 6xnU() coord map matrix for the hinge in the pframe frame from all of its subhinges. Note that the matrix will be configuration dependent when there are multiple subhinges. This method is specialized by PhysicalHinge and CompoundHinge hinges.

Returns:

the coordinate map matrix

km::Mat pframeCoordMapMatrixOrthoComplement() const#

Return the orthogonal complement for the pframeCoordMapMatrix() matrix.

Compute the orthogonal complement (OC) of the pframe coord map matrix computed by pframeCoordMapMatrix(). The product of this OC with the pframe coord map matrix is zero.

Returns:

the orthogonal complement matrix

km::Mat oframeCoordMapMatrixOrthoComplement() const#

Return the orthogonal complement for the oframe coordinate map matrix.

Compute the orthogonal complement (OC) of the pframe coord map matrix. The product of the OC with the oframe coord map matrix is zero.

Returns:

the orthogonal complement matrix

km::Vec pframeCoordMapSingularValues() const#

Return list of singular values for the hinge’s pframe coord map matrix.

This method is handy for monitoring potential loss in rank for hinges such as ujoint and gimbal hinges. For full rank, there should be nu() singular values.

Returns:

Array of singular values.

Public Static Functions

static std::vector<SubhingeType> getSubhingeTypes(HingeType htype)#

Return the list of SubhingeBase::SubhingeType subhinge types for a known hinge type.

A hinge is a container for a list of subhinges. This method returns the list of subhinge types for a known hinge type.

Parameters:

htype – the hinge type

Returns:

list of subhinge types

static std::string hingeTypeString(HingeType htype)#

Helper method to return the string name for a HingeType hinge type.

Parameters:

htype – the hinge type

Returns:

the hinge type as a string

static HingeParams getHookeHingeParams(const km::UnitQuaternion &ij_q)#

Helper method to compute the onode, pnode transform and axis params for a HingeType::HOOKE hinge.

For a HingeType::HOOKE joint, an outboard body’s frame’s Y-axis is constrained to remain perpendicular to an inboard body frame’s X-axis, and the pair of frames to remain co-located.

Parameters:

ij_q – the inboard to outboard frames relative orientation unit quaternion

Returns:

struct with the hinge onode, pnode and axis parameter values

static HingeParams getInlineHingeParams()#

Helper method to compute the onode, pnode transform and axis params for an HingeType::INLINE hinge.

For an HingeType::INLINE joint, an outboard body frame is constrained to translate only along an inboard body frame’s Z-axis

Returns:

struct with the hinge onode, pnode and axis parameter values

static HingeParams getInplaneHingeParams()#

Helper method to compute the onode, pnode transform and axis params for an HingeType::INPLANE hinge.

For an HingeType::INPLANE joint, an outboard body frame is constrained to translate only within the inboard frame’s XY-plane

Returns:

struct with the hinge onode, pnode and axis parameter values

static HingeParams getPerpendicularHingeParams(const km::UnitQuaternion &ij_q)#

Helper method to compute the onode, pnode transform and axis params for a HingeType::PERPENDICULAR hinge.

For a HingeType::PERPENDICULAR joint, an outboard body frame’s Z-axis is constrained to remain perpendicular to an inboard body frame’s Z-axis

Parameters:

ij_q – the inboard to outboard frames relative orientation unit quaternion

Returns:

struct with the hinge onode, pnode and axis parameter values

static HingeParams getParallelHingeParams()#

Helper method to compute the onode, pnode transform and axis params for a HingeType::PARALLEL hinge.

For a HingeType::PARALLEL joint, an outboard body frame’s Z-axis is constrained to remain parallel to an inboard body frame’s Z-axis. It is assumed that the outboard frame’s Z-axis is parallel to the inboard frame’s Z-axis to begin with.

Returns:

struct with the hinge onode, pnode and axis parameter values

Protected Functions

inline virtual km::Mat oframeCoordMapMatrix() const#

The coordinate map matrix across all subhinges in the onode frame.

Returns:

the coordinate map matrix

Protected Attributes

kc::RegistryList<SubhingeBase> _subhinges_list#

ordered list of subhinges

HingeType _hinge_type#

the hinge type

std::vector<SubhingeType> _subhinge_types#

the list of subhinge types for the hinge

kc::ks_ptr<CoordData> _hinge_coord_data = nullptr#

the CoordData for the hinge’s subhinge coordinates

struct HingeParams#

Struct with hinge parameters for the HingeType::HOOKE, HingeType::INLINE etc hinge types defined by motion constraints between a pair of frames on the inboard and outboard bodies.

Public Members

km::UnitQuaternion i_to_onode_q = km::UnitQuaternion(0, 0, 0, 1)#

onode orientation with respect to the inboard frame

km::UnitQuaternion j_to_pnode_q = km::UnitQuaternion(0, 0, 0, 1)#

onode orientation with respect to the outboard frame

km::Mat axes#

3xm matrix with columns defining the 1-dof subhinge axes

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