Functions for quaternion operations. More...

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <signal.h>
#include <curses.h>
#include <string.h>
#include <time.h>
#include <math.h>
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_vector.h>
#include <gsl/gsl_blas.h>
#include <gsl/gsl_eigen.h>
#include <vector>

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Functions
void	quat_multiply (gsl_vector M1, gsl_vector M2, gsl_vector *ans0)
	Multiply quaternions.
void	quat_rotate (gsl_vector quat1, gsl_vector vect, gsl_vector *ans1)
	Rotate vector by quaternion.
void	quat_invert (gsl_vector *quat)
void	free_acc (double accl, double quat)
	Subtract gravitational acceleration from accl readings.
void	rodrigues_to_quat (gsl_vector quat_rod, gsl_vector quat)
	Convert quaterion in rodrigues formulation to normal quaternion.
void	get_quaternion_avg (vector< vector< double > > quat_datas, gsl_vector *quat_avg)
	Get the average quaternion.

Detailed Description

Functions for quaternion operations.

Function Documentation

void free_acc	(	double *	accl,
		double *	quat
	)

Subtract gravitational acceleration from accl readings.

Parameters:

[in,out]	accl	Acceleration vector. The gravity-free component is stored back
[in]	quat	Quaternion describing orientation of acclerometer w.r.t earth fixed system

References quat_rotate().

Referenced by load_accl_data().

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void get_quaternion_avg	(	vector< vector< double > >	quat_datas,
		gsl_vector *	quat_avg
	)

Get the average quaternion.

Since quaternions are not regular vectors, but rather representations of orientation, an average quaternion cannot just be obtained by taking a weighted mean. This function implements the work done by paper by F. Landis Merkley (DOI: 10.2514/1.28949) to calculate the average quaternion

void quat_invert ( gsl_vector * quat )

Referenced by main().

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void quat_multiply	(	gsl_vector *	M1,
		gsl_vector *	M2,
		gsl_vector *	ans0
	)

Multiply quaternions.

Referenced by accl_mario_orient(), main(), and quat_rotate().

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void quat_rotate	(	gsl_vector *	quat1,
		gsl_vector *	vect,
		gsl_vector *	ans1
	)

Rotate vector by quaternion.

References quat_multiply().

Referenced by free_acc().

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void rodrigues_to_quat	(	gsl_vector *	quat_rod,
		gsl_vector *	quat
	)

Convert quaterion in rodrigues formulation to normal quaternion.