The Inertial object provides a representation for the mass and inertia matrix of a body B. The components of the inertia matrix are expressed in what we call the "inertial" frame Bi of the body, i.e. the frame in which these inertia components are measured. The inertial frame Bi must be located at the center of mass of the body, but not necessarily aligned with the body’s frame. In addition, this class allows users to specify a frame F for these inertial properties by specifying the pose X_FBi of the inertial frame Bi in the inertial object frame F. More...
#include <ignition/math/Inertial.hh>
Public Member Functions  
Inertial ()  
Default Constructor. More...  
Inertial (const MassMatrix3< T > &_massMatrix, const Pose3< T > &_pose)  
Constructs an inertial object from the mass matrix for a body B, about its center of mass Bcm, and expressed in a frame that we’ll call the "inertial" frame Bi, i.e. the frame in which the components of the mass matrix are specified (see this class’s documentation for details). The pose object specifies the pose X_FBi of the inertial frame Bi in the frame F of this inertial object (see class’s documentation). More...  
Inertial (const Inertial< T > &_inertial)  
Copy constructor. More...  
virtual  ~Inertial () 
Destructor. More...  
const MassMatrix3< T > &  MassMatrix () const 
Get the mass and inertia matrix. More...  
Matrix3< T >  MOI () const 
Get the moment of inertia matrix computer about the body's center of mass and expressed in this Inertial object’s frame F. More...  
Matrix3< T >  Moi () const 
Get the moment of inertia matrix computer about the body's center of mass and expressed in this Inertial object’s frame F. More...  
bool  operator!= (const Inertial< T > &_inertial) const 
Inequality test operator. More...  
const Inertial< T >  operator+ (const Inertial< T > &_inertial) const 
Adds inertial properties to current object. The mass, center of mass location, and inertia matrix are updated as long as the total mass is positive. More...  
Inertial< T > &  operator+= (const Inertial< T > &_inertial) 
Adds inertial properties to current object. The mass, center of mass location, and inertia matrix are updated as long as the total mass is positive. More...  
Inertial &  operator= (const Inertial< T > &_inertial) 
Equal operator. More...  
bool  operator== (const Inertial< T > &_inertial) const 
Equality comparison operator. More...  
const Pose3< T > &  Pose () const 
Get the pose of the center of mass reference frame. More...  
bool  SetInertialRotation (const Quaternion< T > &_q) 
Set the inertial pose rotation without affecting the MOI in the base coordinate frame. More...  
bool  SetMassMatrix (const MassMatrix3< T > &_m, const T _tolerance=IGN_MASSMATRIX3_DEFAULT_TOLERANCE< T >) 
Set the mass and inertia matrix. More...  
bool  SetMassMatrixRotation (const Quaternion< T > &_q, const T _tol=1e6) 
Set the MassMatrix rotation (eigenvectors of inertia matrix) without affecting the MOI in the base coordinate frame. Note that symmetries in inertia matrix may prevent the output of MassMatrix3::PrincipalAxesOffset to match this function's input _q, but it is guaranteed that the MOI in the base frame will not change. A negative value of _tol (such as 1e6) can be passed to ensure that diagonal values are always sorted. More...  
bool  SetPose (const Pose3< T > &_pose) 
Set the pose of the center of mass reference frame. More...  
Detailed Description
template<typename T>
class ignition::math::Inertial< T >
The Inertial object provides a representation for the mass and inertia matrix of a body B. The components of the inertia matrix are expressed in what we call the "inertial" frame Bi of the body, i.e. the frame in which these inertia components are measured. The inertial frame Bi must be located at the center of mass of the body, but not necessarily aligned with the body’s frame. In addition, this class allows users to specify a frame F for these inertial properties by specifying the pose X_FBi of the inertial frame Bi in the inertial object frame F.
For information about the X_FBi notation, see http://drake.mit.edu/doxygen_cxx/group__multibody__spatial__pose.html
Constructor & Destructor Documentation
◆ Inertial() [1/3]

inline 
Default Constructor.
◆ Inertial() [2/3]

inline 
Constructs an inertial object from the mass matrix for a body B, about its center of mass Bcm, and expressed in a frame that we’ll call the "inertial" frame Bi, i.e. the frame in which the components of the mass matrix are specified (see this class’s documentation for details). The pose object specifies the pose X_FBi of the inertial frame Bi in the frame F of this inertial object (see class’s documentation).
 Parameters

[in] _massMatrix Mass and inertia matrix. [in] _pose Pose of center of mass reference frame.
◆ Inertial() [3/3]
Copy constructor.
 Parameters

[in] _inertial Inertial element to copy
◆ ~Inertial()

inlinevirtual 
Destructor.
Member Function Documentation
◆ MassMatrix()

inline 
Get the mass and inertia matrix.
 Returns
 The mass matrix about the body’s center of mass and expressed in the inertial frame Bi as defined by this class’s documentation
Referenced by Inertial< T >::operator+=(), Inertial< T >::operator=(), Inertial< T >::operator==(), and Inertial< T >::SetMassMatrixRotation().
◆ MOI()

inline 
Get the moment of inertia matrix computer about the body's center of mass and expressed in this Inertial object’s frame F.
 Returns
 The inertia matrix computed about the body’s center of mass and expressed in this Inertial object’s frame F, as defined in this class’s documentation.
 Deprecated:
 See Matrix3<T> Moi() const
References Inertial< T >::Moi().
◆ Moi()

inline 
Get the moment of inertia matrix computer about the body's center of mass and expressed in this Inertial object’s frame F.
 Returns
 The inertia matrix computed about the body’s center of mass and expressed in this Inertial object’s frame F, as defined in this class’s documentation.
Referenced by Inertial< T >::MOI(), Inertial< T >::operator+=(), and Inertial< T >::SetInertialRotation().
◆ operator!=()

inline 
Inequality test operator.
 Parameters

[in] _inertial Inertial<T> to test
 Returns
 True if not equal (using the default tolerance of 1e6)
◆ operator+()
Adds inertial properties to current object. The mass, center of mass location, and inertia matrix are updated as long as the total mass is positive.
 Parameters

[in] _inertial Inertial to add.
 Returns
 Sum of inertials as new object.
◆ operator+=()
Adds inertial properties to current object. The mass, center of mass location, and inertia matrix are updated as long as the total mass is positive.
 Parameters

[in] _inertial Inertial to add.
 Returns
 Reference to this object.
References Inertial< T >::MassMatrix(), Inertial< T >::Moi(), Inertial< T >::Pose(), std::pow(), Vector3< T >::X(), Vector3< T >::Y(), and Vector3< T >::Z().
◆ operator=()
Equal operator.
 Parameters

[in] _inertial Inertial to copy.
 Returns
 Reference to this object.
References Inertial< T >::MassMatrix(), and Inertial< T >::Pose().
◆ operator==()

inline 
Equality comparison operator.
 Parameters

[in] _inertial Inertial to copy.
 Returns
 true if each component is equal within a default tolerance, false otherwise
References Inertial< T >::MassMatrix(), and Inertial< T >::Pose().
◆ Pose()

inline 
Get the pose of the center of mass reference frame.
 Returns
 The pose of the inertial frame Bi in the frame F of this Inertial object as defined by this class’s documentation.
Referenced by Inertial< T >::operator+=(), Inertial< T >::operator=(), and Inertial< T >::operator==().
◆ SetInertialRotation()

inline 
Set the inertial pose rotation without affecting the MOI in the base coordinate frame.
 Parameters

[in] _q New rotation for inertial pose.
 Returns
 True if the MassMatrix3 is valid.
References Inertial< T >::Moi().
◆ SetMassMatrix()

inline 
Set the mass and inertia matrix.
 Parameters

[in] _m New MassMatrix3 object. [in] _tolerance Tolerance is passed to MassMatrix3::IsValid and is the amount of error to accept when checking whether the MassMatrix3 _m is valid. Refer to MassMatrix3::Epsilon for detailed description of _tolerance.
 Returns
 True if the MassMatrix3 is valid.
◆ SetMassMatrixRotation()

inline 
Set the MassMatrix rotation (eigenvectors of inertia matrix) without affecting the MOI in the base coordinate frame. Note that symmetries in inertia matrix may prevent the output of MassMatrix3::PrincipalAxesOffset to match this function's input _q, but it is guaranteed that the MOI in the base frame will not change. A negative value of _tol (such as 1e6) can be passed to ensure that diagonal values are always sorted.
 Parameters

[in] _q New rotation. [in] _tol Relative tolerance given by absolute value of _tol. This is passed to the MassMatrix3 PrincipalMoments and PrincipalAxesOffset functions.
 Returns
 True if the MassMatrix3 is valid.
References Quaternion< T >::Inverse(), Inertial< T >::MassMatrix(), and Matrix3< T >::Transposed().
◆ SetPose()

inline 
Set the pose of the center of mass reference frame.
 Parameters

[in] _pose New pose.
 Returns
 True if the MassMatrix3 is valid.
The documentation for this class was generated from the following file: