m5::imu::ComplementaryFilter Class Reference

Angle-based first-order complementary filter. More...

#include <complementary.hpp>

Inheritance diagram for m5::imu::ComplementaryFilter:

Public Member Functions
virtual void	reset () override
	Reset the internal attitude estimate (and any filter state) to identity.
virtual void	update (const float dt, const float accel[3], const float gyro[3], const float *mag) override
	Fuse one IMU sample into the attitude estimate.
virtual void	quaternion (float &w, float &x, float &y, float &z) const override
	Current fused attitude.
bool	writeAlpha (const float alpha)
	Set the complementary blend factor.
float	readAlpha () const
	Current complementary blend factor.

Detailed Description

Angle-based first-order complementary filter.

Blends the gyro-integrated angle with a reference angle independently for roll, pitch and yaw: angle = alpha * (angle + gyro * dt) + (1 - alpha) * angle_ref. Roll/pitch reference angles come from the accelerometer; the yaw reference comes from a tilt-compensated magnetometer heading when a magnetometer sample is supplied (pure gyro integration otherwise). See filter_base.hpp for the unit and coordinate convention this filter assumes.

Member Function Documentation

quaternion()

void m5::imu::ComplementaryFilter::quaternion ( float & w, float & x, float & y, float & z ) const

overridevirtual

Current fused attitude.

Parameters

[out]	w	Quaternion scalar part
[out]	x	Quaternion vector part X
[out]	y	Quaternion vector part Y
[out]	z	Quaternion vector part Z

Implements m5::imu::AhrsFilterBase.

reset()

void m5::imu::ComplementaryFilter::reset ( )

overridevirtual

Reset the internal attitude estimate (and any filter state) to identity.

Implements m5::imu::AhrsFilterBase.

update()

void m5::imu::ComplementaryFilter::update ( const float dt, const float accel[3], const float gyro[3], const float * mag )

overridevirtual

Fuse one IMU sample into the attitude estimate.

Parameters

dt	Time elapsed since the previous update(), in seconds
accel	Accelerometer reading (G), body frame, X/Y/Z
gyro	Gyroscope reading (dps), body frame, X/Y/Z
mag	Magnetometer reading (uT), body frame, X/Y/Z; pass nullptr for 6-axis (accel+gyro only) operation

Implements m5::imu::AhrsFilterBase.

writeAlpha()

bool m5::imu::ComplementaryFilter::writeAlpha

(

const float

alpha

)

Set the complementary blend factor.

Parameters

alpha

Weight given to the gyro-integrated angle, must be in the open interval (0, 1)

Returns

False (and keeps the previous value) if alpha is out of range