New Madgwick filter library
This commit is contained in:
parent
fb4e197439
commit
50df1cf9d2
@ -1,47 +1,51 @@
|
||||
//=====================================================================================================
|
||||
//=============================================================================================
|
||||
// MadgwickAHRS.c
|
||||
//=====================================================================================================
|
||||
//=============================================================================================
|
||||
//
|
||||
// Implementation of Madgwick's IMU and AHRS algorithms.
|
||||
// See: http://www.x-io.co.uk/node/8#open_source_ahrs_and_imu_algorithms
|
||||
// See: http://www.x-io.co.uk/open-source-imu-and-ahrs-algorithms/
|
||||
//
|
||||
// From the x-io website "Open-source resources available on this website are
|
||||
// provided under the GNU General Public Licence unless an alternative licence
|
||||
// is provided in source."
|
||||
//
|
||||
// Date Author Notes
|
||||
// 29/09/2011 SOH Madgwick Initial release
|
||||
// 02/10/2011 SOH Madgwick Optimised for reduced CPU load
|
||||
// 19/02/2012 SOH Madgwick Magnetometer measurement is normalised
|
||||
//
|
||||
//=====================================================================================================
|
||||
//=============================================================================================
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
//-------------------------------------------------------------------------------------------
|
||||
// Header files
|
||||
|
||||
#include "MadgwickAHRS.h"
|
||||
#include <math.h>
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
//-------------------------------------------------------------------------------------------
|
||||
// Definitions
|
||||
|
||||
#define sampleFreq 512.0f // sample frequency in Hz
|
||||
#define sampleFreqDef 512.0f // sample frequency in Hz
|
||||
#define betaDef 0.1f // 2 * proportional gain
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
// Variable definitions
|
||||
|
||||
volatile float beta = betaDef; // 2 * proportional gain (Kp)
|
||||
volatile float q0 = 1.0f, q1 = 0.0f, q2 = 0.0f, q3 = 0.0f; // quaternion of sensor frame relative to auxiliary frame
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
// Function declarations
|
||||
|
||||
float invSqrt(float x);
|
||||
|
||||
//====================================================================================================
|
||||
//============================================================================================
|
||||
// Functions
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
//-------------------------------------------------------------------------------------------
|
||||
// AHRS algorithm update
|
||||
|
||||
void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz) {
|
||||
Madgwick::Madgwick() {
|
||||
beta = betaDef;
|
||||
q0 = 1.0f;
|
||||
q1 = 0.0f;
|
||||
q2 = 0.0f;
|
||||
q3 = 0.0f;
|
||||
invSampleFreq = 1.0f / sampleFreqDef;
|
||||
anglesComputed = 0;
|
||||
}
|
||||
|
||||
void Madgwick::update(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz) {
|
||||
float recipNorm;
|
||||
float s0, s1, s2, s3;
|
||||
float qDot1, qDot2, qDot3, qDot4;
|
||||
@ -50,10 +54,15 @@ void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float
|
||||
|
||||
// Use IMU algorithm if magnetometer measurement invalid (avoids NaN in magnetometer normalisation)
|
||||
if((mx == 0.0f) && (my == 0.0f) && (mz == 0.0f)) {
|
||||
MadgwickAHRSupdateIMU(gx, gy, gz, ax, ay, az);
|
||||
updateIMU(gx, gy, gz, ax, ay, az);
|
||||
return;
|
||||
}
|
||||
|
||||
// Convert gyroscope degrees/sec to radians/sec
|
||||
gx *= 0.0174533f;
|
||||
gy *= 0.0174533f;
|
||||
gz *= 0.0174533f;
|
||||
|
||||
// Rate of change of quaternion from gyroscope
|
||||
qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
|
||||
qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
|
||||
@ -100,7 +109,7 @@ void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float
|
||||
// Reference direction of Earth's magnetic field
|
||||
hx = mx * q0q0 - _2q0my * q3 + _2q0mz * q2 + mx * q1q1 + _2q1 * my * q2 + _2q1 * mz * q3 - mx * q2q2 - mx * q3q3;
|
||||
hy = _2q0mx * q3 + my * q0q0 - _2q0mz * q1 + _2q1mx * q2 - my * q1q1 + my * q2q2 + _2q2 * mz * q3 - my * q3q3;
|
||||
_2bx = sqrt(hx * hx + hy * hy);
|
||||
_2bx = sqrtf(hx * hx + hy * hy);
|
||||
_2bz = -_2q0mx * q2 + _2q0my * q1 + mz * q0q0 + _2q1mx * q3 - mz * q1q1 + _2q2 * my * q3 - mz * q2q2 + mz * q3q3;
|
||||
_4bx = 2.0f * _2bx;
|
||||
_4bz = 2.0f * _2bz;
|
||||
@ -124,10 +133,10 @@ void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float
|
||||
}
|
||||
|
||||
// Integrate rate of change of quaternion to yield quaternion
|
||||
q0 += qDot1 * (1.0f / sampleFreq);
|
||||
q1 += qDot2 * (1.0f / sampleFreq);
|
||||
q2 += qDot3 * (1.0f / sampleFreq);
|
||||
q3 += qDot4 * (1.0f / sampleFreq);
|
||||
q0 += qDot1 * invSampleFreq;
|
||||
q1 += qDot2 * invSampleFreq;
|
||||
q2 += qDot3 * invSampleFreq;
|
||||
q3 += qDot4 * invSampleFreq;
|
||||
|
||||
// Normalise quaternion
|
||||
recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
|
||||
@ -135,17 +144,23 @@ void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float
|
||||
q1 *= recipNorm;
|
||||
q2 *= recipNorm;
|
||||
q3 *= recipNorm;
|
||||
anglesComputed = 0;
|
||||
}
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
//-------------------------------------------------------------------------------------------
|
||||
// IMU algorithm update
|
||||
|
||||
void MadgwickAHRSupdateIMU(float gx, float gy, float gz, float ax, float ay, float az) {
|
||||
void Madgwick::updateIMU(float gx, float gy, float gz, float ax, float ay, float az) {
|
||||
float recipNorm;
|
||||
float s0, s1, s2, s3;
|
||||
float qDot1, qDot2, qDot3, qDot4;
|
||||
float _2q0, _2q1, _2q2, _2q3, _4q0, _4q1, _4q2 ,_8q1, _8q2, q0q0, q1q1, q2q2, q3q3;
|
||||
|
||||
// Convert gyroscope degrees/sec to radians/sec
|
||||
gx *= 0.0174533f;
|
||||
gy *= 0.0174533f;
|
||||
gz *= 0.0174533f;
|
||||
|
||||
// Rate of change of quaternion from gyroscope
|
||||
qDot1 = 0.5f * (-q1 * gx - q2 * gy - q3 * gz);
|
||||
qDot2 = 0.5f * (q0 * gx + q2 * gz - q3 * gy);
|
||||
@ -195,10 +210,10 @@ void MadgwickAHRSupdateIMU(float gx, float gy, float gz, float ax, float ay, flo
|
||||
}
|
||||
|
||||
// Integrate rate of change of quaternion to yield quaternion
|
||||
q0 += qDot1 * (1.0f / sampleFreq);
|
||||
q1 += qDot2 * (1.0f / sampleFreq);
|
||||
q2 += qDot3 * (1.0f / sampleFreq);
|
||||
q3 += qDot4 * (1.0f / sampleFreq);
|
||||
q0 += qDot1 * invSampleFreq;
|
||||
q1 += qDot2 * invSampleFreq;
|
||||
q2 += qDot3 * invSampleFreq;
|
||||
q3 += qDot4 * invSampleFreq;
|
||||
|
||||
// Normalise quaternion
|
||||
recipNorm = invSqrt(q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3);
|
||||
@ -206,27 +221,30 @@ void MadgwickAHRSupdateIMU(float gx, float gy, float gz, float ax, float ay, flo
|
||||
q1 *= recipNorm;
|
||||
q2 *= recipNorm;
|
||||
q3 *= recipNorm;
|
||||
anglesComputed = 0;
|
||||
}
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
//-------------------------------------------------------------------------------------------
|
||||
// Fast inverse square-root
|
||||
// See: http://en.wikipedia.org/wiki/Fast_inverse_square_root
|
||||
|
||||
float invSqrt(float x) {
|
||||
float Madgwick::invSqrt(float x) {
|
||||
float halfx = 0.5f * x;
|
||||
float y = x;
|
||||
long i = *(long*)&y;
|
||||
i = 0x5f3759df - (i>>1);
|
||||
y = *(float*)&i;
|
||||
y = y * (1.5f - (halfx * y * y));
|
||||
y = y * (1.5f - (halfx * y * y));
|
||||
return y;
|
||||
}
|
||||
|
||||
float getPitch()
|
||||
{
|
||||
return asinf(-2.0f * (q1*q3 - q0*q2));
|
||||
}
|
||||
//-------------------------------------------------------------------------------------------
|
||||
|
||||
//====================================================================================================
|
||||
// END OF CODE
|
||||
//====================================================================================================
|
||||
void Madgwick::computeAngles()
|
||||
{
|
||||
roll = atan2f(q0*q1 + q2*q3, 0.5f - q1*q1 - q2*q2);
|
||||
pitch = asinf(-2.0f * (q1*q3 - q0*q2));
|
||||
yaw = atan2f(q1*q2 + q0*q3, 0.5f - q2*q2 - q3*q3);
|
||||
anglesComputed = 1;
|
||||
}
|
||||
@ -1,32 +1,71 @@
|
||||
//=====================================================================================================
|
||||
//=============================================================================================
|
||||
// MadgwickAHRS.h
|
||||
//=====================================================================================================
|
||||
//=============================================================================================
|
||||
//
|
||||
// Implementation of Madgwick's IMU and AHRS algorithms.
|
||||
// See: http://www.x-io.co.uk/node/8#open_source_ahrs_and_imu_algorithms
|
||||
// See: http://www.x-io.co.uk/open-source-imu-and-ahrs-algorithms/
|
||||
//
|
||||
// From the x-io website "Open-source resources available on this website are
|
||||
// provided under the GNU General Public Licence unless an alternative licence
|
||||
// is provided in source."
|
||||
//
|
||||
// Date Author Notes
|
||||
// 29/09/2011 SOH Madgwick Initial release
|
||||
// 02/10/2011 SOH Madgwick Optimised for reduced CPU load
|
||||
//
|
||||
//=====================================================================================================
|
||||
//=============================================================================================
|
||||
#ifndef MadgwickAHRS_h
|
||||
#define MadgwickAHRS_h
|
||||
#include <math.h>
|
||||
|
||||
//----------------------------------------------------------------------------------------------------
|
||||
//--------------------------------------------------------------------------------------------
|
||||
// Variable declaration
|
||||
class Madgwick{
|
||||
private:
|
||||
static float invSqrt(float x);
|
||||
float beta; // algorithm gain
|
||||
float q0;
|
||||
float q1;
|
||||
float q2;
|
||||
float q3; // quaternion of sensor frame relative to auxiliary frame
|
||||
float invSampleFreq;
|
||||
float roll;
|
||||
float pitch;
|
||||
float yaw;
|
||||
char anglesComputed;
|
||||
void computeAngles();
|
||||
|
||||
extern volatile float beta; // algorithm gain
|
||||
extern volatile float q0, q1, q2, q3; // quaternion of sensor frame relative to auxiliary frame
|
||||
|
||||
//---------------------------------------------------------------------------------------------------
|
||||
//-------------------------------------------------------------------------------------------
|
||||
// Function declarations
|
||||
public:
|
||||
Madgwick(void);
|
||||
void begin(float sampleFrequency) { invSampleFreq = 1.0f / sampleFrequency; }
|
||||
void update(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz);
|
||||
void updateIMU(float gx, float gy, float gz, float ax, float ay, float az);
|
||||
|
||||
void MadgwickAHRSupdate(float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz);
|
||||
void MadgwickAHRSupdateIMU(float gx, float gy, float gz, float ax, float ay, float az);
|
||||
|
||||
float getPitch();
|
||||
float getRoll() {
|
||||
if (!anglesComputed) computeAngles();
|
||||
return roll * 57.29578f;
|
||||
}
|
||||
float getPitch() {
|
||||
if (!anglesComputed) computeAngles();
|
||||
return pitch * 57.29578f;
|
||||
}
|
||||
float getYaw() {
|
||||
if (!anglesComputed) computeAngles();
|
||||
return yaw * 57.29578f + 180.0f;
|
||||
}
|
||||
float getRollRadians() {
|
||||
if (!anglesComputed) computeAngles();
|
||||
return roll;
|
||||
}
|
||||
float getPitchRadians() {
|
||||
if (!anglesComputed) computeAngles();
|
||||
return pitch;
|
||||
}
|
||||
float getYawRadians() {
|
||||
if (!anglesComputed) computeAngles();
|
||||
return yaw;
|
||||
}
|
||||
};
|
||||
#endif
|
||||
//=====================================================================================================
|
||||
// End of file
|
||||
//=====================================================================================================
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user