quaternion_filter.h File Reference

Quaternion second order filter. More...

#include "std.h"
#include "math/pprz_algebra_float.h"

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Data Structures
struct	QuatSecondOrderLowPass
	Quaternion second order filter model (float) More...

Typedefs
typedef struct QuatSecondOrderLowPass	QuatButterworthLowPass
	Second order Butterworth low pass filter.

Functions
static void	init_quat_second_order_low_pass (struct QuatSecondOrderLowPass *filter, const float omega, const float damp, const float sample_time, const struct FloatQuat q0)
	Init second order quaternion low pass filter.
static void	reset_quat_second_order_low_pass (struct QuatSecondOrderLowPass *filter, const struct FloatQuat q0)
	Reset the second order quaternion low-pass filter to a specific value.
static struct FloatQuat	update_quat_second_order_low_pass (struct QuatSecondOrderLowPass *filter, const struct FloatQuat q)
	Update second order quaterion low pass filter state with a new value.
static struct FloatQuat	get_quat_second_order_low_pass (const struct QuatSecondOrderLowPass *filter)
	Get current value of the second order quaterion low pass filter.
static void	init_quat_butterworth_low_pass (QuatButterworthLowPass *filter, const float omega, const float sample_time, const struct FloatQuat q0)
	Init a second order quaternion Butterworth filter.
static struct FloatQuat	update_quat_butterworth_low_pass (QuatButterworthLowPass *filter, const struct FloatQuat quat)
	Update second order quaternion Butterworth low pass filter state with a new value.
static void	reset_quat_butterworth_low_pass (QuatButterworthLowPass *filter, const struct FloatQuat quat)
	Reset a quaternion Butterworth low-pass filter to a specific value.
static struct FloatQuat	get_quat_butterworth_low_pass (const QuatButterworthLowPass *filter)
	Get current value of the second order quaternion Butterworth low pass filter.

Detailed Description

Quaternion second order filter.

Definition in file quaternion_filter.h.

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Data Structure Documentation

QuatSecondOrderLowPass

struct QuatSecondOrderLowPass

Quaternion second order filter model (float)

Definition at line 34 of file quaternion_filter.h.

Collaboration diagram for QuatSecondOrderLowPass:

Data Fields
struct FloatRates	accel
float	dt
struct FloatQuat	quat
struct FloatRates	rate
float	two_omega2
float	two_zeta_omega

Typedef Documentation

QuatButterworthLowPass

typedef struct QuatSecondOrderLowPass QuatButterworthLowPass

Second order Butterworth low pass filter.

Definition at line 132 of file quaternion_filter.h.

Function Documentation

get_quat_butterworth_low_pass()

static struct FloatQuat get_quat_butterworth_low_pass ( const QuatButterworthLowPass *  filter )

inlinestatic

Get current value of the second order quaternion Butterworth low pass filter.

Parameters

filter

second order quaternion Butterworth low pass filter structure

Returns

current orientation of the filter

Definition at line 184 of file quaternion_filter.h.

References get_quat_second_order_low_pass().

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get_quat_second_order_low_pass()

static struct FloatQuat get_quat_second_order_low_pass ( const struct QuatSecondOrderLowPass *  filter )

inlinestatic

Get current value of the second order quaterion low pass filter.

Parameters

filter

filter structure

Returns

current orientation of the filter

Definition at line 123 of file quaternion_filter.h.

Referenced by get_quat_butterworth_low_pass().

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init_quat_butterworth_low_pass()

static void init_quat_butterworth_low_pass ( QuatButterworthLowPass *  filter, const float  omega, const float  sample_time, const struct FloatQuat  q0  )

inlinestatic

Init a second order quaternion Butterworth filter.

based on the generic second order filter with zeta = 0.7071 = 1/sqrt(2)

Parameters

filter	second order quaternion Butterworth low pass filter structure
omega	cutoff frequency of the second order low pass filter
sample_time	sampling period of the signal
q0	initial orientation of the filter

Definition at line 144 of file quaternion_filter.h.

References foo, and init_quat_second_order_low_pass().

Referenced by guidance_indi_enter(), and guidance_indi_init().

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init_quat_second_order_low_pass()

static void init_quat_second_order_low_pass ( struct QuatSecondOrderLowPass *  filter, const float  omega, const float  damp, const float  sample_time, const struct FloatQuat  q0  )

inlinestatic

Init second order quaternion low pass filter.

Parameters

filter	second order low pass filter structure
omega	cutoff frequency of the second order low pass filter
damp	damping coefficient of the second order low pass filter
sample_time	sampling period of the signal
q0	initial orientation of the filter

Definition at line 52 of file quaternion_filter.h.

References QuatSecondOrderLowPass::accel, QuatSecondOrderLowPass::dt, FLOAT_RATES_ZERO, foo, QuatSecondOrderLowPass::quat, QuatSecondOrderLowPass::rate, QuatSecondOrderLowPass::two_omega2, and QuatSecondOrderLowPass::two_zeta_omega.

Referenced by init_quat_butterworth_low_pass().

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reset_quat_butterworth_low_pass()

static void reset_quat_butterworth_low_pass ( QuatButterworthLowPass *  filter, const struct FloatQuat  quat  )

inlinestatic

Reset a quaternion Butterworth low-pass filter to a specific value.

Parameters

[out]	filter	QuatButterworth2LowPass filter instance to reset.
[in]	quat	Value to reset the filter to.

Definition at line 172 of file quaternion_filter.h.

References reset_quat_second_order_low_pass().

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reset_quat_second_order_low_pass()

static void reset_quat_second_order_low_pass ( struct QuatSecondOrderLowPass *  filter, const struct FloatQuat  q0  )

inlinestatic

Reset the second order quaternion low-pass filter to a specific value.

Parameters

filter	filter structure
q0	quaternion to reset the filter to

Definition at line 72 of file quaternion_filter.h.

References QuatSecondOrderLowPass::accel, FLOAT_RATES_ZERO, foo, QuatSecondOrderLowPass::quat, and QuatSecondOrderLowPass::rate.

Referenced by reset_quat_butterworth_low_pass().

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update_quat_butterworth_low_pass()

static struct FloatQuat update_quat_butterworth_low_pass ( QuatButterworthLowPass *  filter, const struct FloatQuat  quat  )

inlinestatic

Update second order quaternion Butterworth low pass filter state with a new value.

Parameters

filter	second order quaternion Butterworth low pass filter structure
q	new input orientation of the filter

Returns

new filtered quaternion

Definition at line 159 of file quaternion_filter.h.

References update_quat_second_order_low_pass().

Referenced by guidance_indi_propagate_filters(), and guidance_indi_propagate_filters().

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update_quat_second_order_low_pass()

static struct FloatQuat update_quat_second_order_low_pass ( struct QuatSecondOrderLowPass *  filter, const struct FloatQuat  q  )

inlinestatic

Update second order quaterion low pass filter state with a new value.

Parameters

filter	filter structure
q	quaternion input value of the filter

Returns

new filtered quaternion

Definition at line 87 of file quaternion_filter.h.

References float_quat_derivative(), float_quat_inv_comp(), float_quat_normalize(), float_quat_wrap_shortest(), foo, QUAT_ADD, QUAT_SMUL, FloatQuat::qx, FloatQuat::qy, FloatQuat::qz, RATES_ADD, and RATES_SMUL.

Referenced by update_quat_butterworth_low_pass().

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