clockwerk::DCM Class Reference

Class defining a direction cosine matrix inherited from Matrix. More...

#include <DCM.h>

Inheritance diagram for clockwerk::DCM:

Public Member Functions
	DCM ()
	Default constructor generates DCM as an identity matrix.
	DCM (const floating_point(&initial)[3][3])
	DCM (const DCM &initial)
	DCM (const std::array< std::array< floating_point, 3 >, 3 > &initial)
	~DCM ()
int16	inverse (DCM &result) const
	Function to return the inverse of the matrix.
DCM	inverse () const
void	rate (const CartesianVector< 3 > &omega_f1_f2__f1, Matrix< 3, 3 > &dcmdot_f1_f2)
	Function to calculate the rate of change in the current representation based on the omega vector.
int16	toEuler321 (Euler321 &euler_f1_f2) const
	Function to convert current attitude to 321 Euler sequence.
Euler321	toEuler321 ()
int16	toQuaternion (Quaternion &q_f1_f2) const
	Overloaded functions to convert current attitude to quaternion.
Quaternion	toQuaternion ()
int16	toMRP (MRP &mrp_f1_f2) const
	Overloaded functions to convert current attitude to MRP.
MRP	toMRP ()
Public Member Functions inherited from clockwerk::Matrix< 3, 3 >
	Matrix ()
	Default constructor to initialize a matrix to all zeroes for ease of use.
	~Matrix ()
int16	str (char *output, size_t size) const
	Function to dump information on matrix.
int16	fromStr (const char *val)
	Set value of matrix from string in same format as str().
int16	set (uint32 row, uint32 col, const floating_point &value)
	Function to set a single value in the matrix.
int16	get (uint32 row, uint32 col, floating_point &result) const
	Function to get a single value in the matrix.
void	setFromArray (const floating_point *start_ptr, bool column_major=false)
	Function to set the values of the matrix row-wise.
void	getAsArray (floating_point *start_ptr, bool column_major=false) const
	Function to get the values of the matrix row-wise.
void	getCopy (Matrix< R, C > &result) const
	Function to get a copy of the matrix.
Matrix< R, C > &	operator= (const Matrix< R, C > &other)
	Equals operator overload for matrix.
floating_point *	operator[] (uint32 idx)
	Function to return a matrix row or vector value.
std::pair< uint32, uint32 >	size () const
	Function to get the size of the matrix.
void	max (floating_point &result, std::pair< uint32, uint32 > &index) const
	Function to return the maximum value in the matrix.
void	min (floating_point &result, std::pair< uint32, uint32 > &index) const
	Function to return the minimum value in the matrix.
int16	det (floating_point &result) const
	Function to return the determinant of the matrix.
int16	chol (Matrix< R, C > &retval) const
	Take the cholesky decomposition of this matrix.
int16	inverse (Matrix< R, C > &result) const
	Function to return the inverse of the matrix.
int16	pseudoinverse (Matrix< C, R > &result) const
void	transpose (Matrix< C, R > &result) const
	Function to return the transpose of the matrix.
int16	trace (floating_point &result) const
	Function to return the trace of the matrix.
void	setToZeros ()
	Function to set all elements of the matrix to zero.
int16	identity ()
	Function to set matrix to identity, if it is a square matrix.
int16	eye ()

Additional Inherited Members
Public Attributes inherited from clockwerk::Matrix< 3, 3 >
std::array< std::array< floating_point, C >, R >	values
Protected Member Functions inherited from clockwerk::Matrix< 3, 3 >
int16	_checkLookupBoundaries (uint32 start_r, uint32 end_r, uint32 start_c, uint32 end_c) const
int16	_LUPDecompose (floating_point *A[R], uint32 P[R+1]) const
	Function to take a 2-d matrix represented by A and decompose it into LU form.

Detailed Description

Class defining a direction cosine matrix inherited from Matrix.

This file defines a simple DCM attitude representation for cartesian coordinate systems. It is largely the same as the base matrix class, with the following exceptions:

• Set to be square, 3x3 (that's where it will primarily be used)
• Default constructor is identity matrix, rather than zeroes
• Inverse is set to account for orthogonal matrix
• Functions defined to convert to other attitude
• Function defined to calculate rate of change as a function of omega

Naming conventions

• All naming conventions and equations are per Analytical Mechanics of Space Systems by Schaub and Junkins
• The omega vector is sometimes denoted by w and assumed frame consistent with the attitude representation. For example, if a DCM represents the relative orientation between two frames [BN] the omega vector is assumed to be w_(B/N)
• The naming convention for all vectors is: variablename_obj1_obj2__frameN (note the double underscore preceding frame) and reads back as: "variable variablename representing the relationship between obj1 and obj2 represented in frameN"
• Unless otherwise noted angles are in RADIANS NOTE: All attitude representations, including DCMs, are assumed to represent a three dimensional, cartesian coordinate system because that is what they are used, and in many cases defined, for.

Constructor & Destructor Documentation

DCM() [1/4]

clockwerk::DCM::DCM ( )

inline

Default constructor generates DCM as an identity matrix.

DCM() [2/4]

clockwerk::DCM::DCM ( const floating_point(&) initial[3][3] )

inline

Constructor for Matrix class with initialization. Initializes matrix to values passed in via array

DCM() [3/4]

clockwerk::DCM::DCM ( const DCM & initial )

inline

Copy constructor for Matrix class. Copies data from matrix object to the current instance

DCM() [4/4]

clockwerk::DCM::DCM ( const std::array< std::array< floating_point, 3 >, 3 > & initial )

inline

Constructor for Matrix class with initialization. Initializes matrix to values passed in via array

~DCM()

clockwerk::DCM::~DCM ( )

inline

Destructor – doesn't do anything because we don't dynamically allocate

Member Function Documentation

inverse() [1/2]

DCM clockwerk::DCM::inverse ( ) const

inline

inverse() [2/2]

int16 clockwerk::DCM::inverse

(

DCM &

result

)

const

Function to return the inverse of the matrix.

Parameters

result

PBR return of matrix inverse

Returns

Integer value corresponding to error codes in clockwerkerrrors.h

Note

Overloaded for value return

rate()

void clockwerk::DCM::rate	(	const CartesianVector< 3 > &	omega_f1_f2__f1,
		Matrix< 3, 3 > &	dcmdot_f1_f2 )

Function to calculate the rate of change in the current representation based on the omega vector.

---

Dynamics and kinematics functions

Parameters

omega_f1_f2__f1	Angular velocity vector for the attitude representation - omega of frame 1 wrt frame 2 expressed in frame 1
dcmdot_f1_f2	Rate of change in the current DCM

toEuler321() [1/2]

Euler321 clockwerk::DCM::toEuler321

(

)

toEuler321() [2/2]

int16 clockwerk::DCM::toEuler321

(

Euler321 &

euler_f1_f2

)

const

Function to convert current attitude to 321 Euler sequence.

---

Conversions to other attitude representations

Parameters

PBR	return of 321 Euler sequence in PBR case

Returns

Integer error code corresponding to errors in clockwerkerrors.h

Note

Cannot overload for return by value because conversion isn't guaranteed

toMRP() [1/2]

MRP clockwerk::DCM::toMRP

(

)

toMRP() [2/2]

int16 clockwerk::DCM::toMRP

(

MRP &

mrp_f1_f2

)

const

Overloaded functions to convert current attitude to MRP.

Parameters

PBR	return of MRP in PBR case

Returns

MRP in return by value case

toQuaternion() [1/2]

Quaternion clockwerk::DCM::toQuaternion

(

)

toQuaternion() [2/2]

int16 clockwerk::DCM::toQuaternion

(

Quaternion &

q_f1_f2

)

const

Overloaded functions to convert current attitude to quaternion.

Parameters

PBR	return of quaternion in PBR case

Returns

Quaternion in return by value case

---

The documentation for this class was generated from the following files:

• /Users/mickey/Documents/Projects/warptwin/warpos/clockwerk/src/dynamics/DCM.h
• /Users/mickey/Documents/Projects/warptwin/warpos/clockwerk/src/dynamics/DCM.cpp