shoe_mcu/hal/hal_mahonyAHRS.c

//=============================================================================================
// MahonyAHRS.c
//=============================================================================================
//
// Madgwick's implementation of Mayhony's AHRS algorithm.
// 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
//
// Algorithm paper:
// http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4608934&url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D4608934
//
//=============================================================================================

//-------------------------------------------------------------------------------------------
// Header files

#include "hal_mahonyAHRS.h"
#include <math.h>
#include "system.h"
#include "ble_comm.h"
#include "hal_ble_client.h"

//-------------------------------------------------------------------------------------------
// Definitions

#define twoKpDef        (200.0f * 0.5f)        // 2 * proportional gain
#define twoKiDef        (0.0f * 1.0f)        // 2 * integral gain


//float Mahony_GetRoll(void) {return P->roll;}
//float Mahony_GetPitch(void) {return P->pitch;}
//float Mahony_GetYaw(void) {return P->yaw;}
//void Mahony_GetAccN(float* accn){accn[0] = P->accN[1];	accn[1] = P->accN[2]; accn[2] = P->accN[3];}

void Mahony_send_ANO(uint8_t fun,uint8_t* p,int len)
{
		uint8_t buf[256];
		int L=0;
		uint8_t ver = 0;
	 
		buf[L] = 0xAA; ver += buf[L++];
		buf[L] = 0x05; ver += buf[L++];
		buf[L] = 0xAF; ver += buf[L++];
		buf[L] = fun;  ver += buf[L++];
		buf[L] = len;  ver += buf[L++];
		for(int i=0;i<len;i++){
						buf[L] = p[i]; ver += buf[L++];
		}
		buf[L++] = ver;
		send_bytes_client(buf,L);
	
}

static void quaternProd(float* ab, float* a, float* b)
{
	ab[0] = a[0] * b[0] - a[1] * b[1] - a[2] * b[2] - a[3] * b[3];
	ab[1] = a[0] * b[1] + a[1] * b[0] + a[2] * b[3] - a[3] * b[2];
	ab[2] = a[0] * b[2] - a[1] * b[3] + a[2] * b[0] + a[3] * b[1];
	ab[3] = a[0] * b[3] + a[1] * b[2] - a[2] * b[1] + a[3] * b[0];
}

static void quaternConj(float* a)
{
	a[1] = -a[1];
	a[2] = -a[2];
	a[3] = -a[3];
}

float Mahony_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;
}

void Mahony_update(MahonyAHRS_t *P,float gx, float gy, float gz, float ax, float ay, float az, float mx, float my, float mz)
{
	float recipNorm;
	float q0q0, q0q1, q0q2, q0q3, q1q1, q1q2, q1q3, q2q2, q2q3, q3q3;
	float hx, hy, bx, bz;
	float halfvx, halfvy, halfvz, halfwx, halfwy, halfwz;
	float halfex, halfey, halfez;
	float qa, qb, qc;
	
	//因为下面算法会改变原始值，所以先保存一份
	P->accN[0] = 0.0f;
	P->accN[1] = ax;
	P->accN[2] = ay;
	P->accN[3] = az;

	// Compute feedback only if accelerometer measurement valid
	// (avoids NaN in accelerometer normalisation)
	if(!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) {

		// Normalise accelerometer measurement
		recipNorm = Mahony_invSqrt(ax * ax + ay * ay + az * az);
		ax *= recipNorm;
		ay *= recipNorm;
		az *= recipNorm;

		// Normalise magnetometer measurement
		recipNorm = Mahony_invSqrt(mx * mx + my * my + mz * mz);
		mx *= recipNorm;
		my *= recipNorm;
		mz *= recipNorm;

		// Auxiliary variables to avoid repeated arithmetic
		q0q0 = P->q0 * P->q0;
		q0q1 = P->q0 * P->q1;
		q0q2 = P->q0 * P->q2;
		q0q3 = P->q0 * P->q3;
		q1q1 = P->q1 * P->q1;
		q1q2 = P->q1 * P->q2;
		q1q3 = P->q1 * P->q3;
		q2q2 = P->q2 * P->q2;
		q2q3 = P->q2 * P->q3;
		q3q3 = P->q3 * P->q3;

		// Reference direction of Earth's magnetic field
		hx = 2.0f * (mx * (0.5f - q2q2 - q3q3) + my * (q1q2 - q0q3) + mz * (q1q3 + q0q2));
		hy = 2.0f * (mx * (q1q2 + q0q3) + my * (0.5f - q1q1 - q3q3) + mz * (q2q3 - q0q1));
		bx = sqrtf(hx * hx + hy * hy);
		bz = 2.0f * (mx * (q1q3 - q0q2) + my * (q2q3 + q0q1) + mz * (0.5f - q1q1 - q2q2));

		// Estimated direction of gravity and magnetic field
		halfvx = q1q3 - q0q2;
		halfvy = q0q1 + q2q3;
		halfvz = q0q0 - 0.5f + q3q3;
		halfwx = bx * (0.5f - q2q2 - q3q3) + bz * (q1q3 - q0q2);
		halfwy = bx * (q1q2 - q0q3) + bz * (q0q1 + q2q3);
		halfwz = bx * (q0q2 + q1q3) + bz * (0.5f - q1q1 - q2q2);

		// Error is sum of cross product between estimated direction
		// and measured direction of field vectors
		halfex = (ay * halfvz - az * halfvy) + (my * halfwz - mz * halfwy);
		halfey = (az * halfvx - ax * halfvz) + (mz * halfwx - mx * halfwz);
		halfez = (ax * halfvy - ay * halfvx) + (mx * halfwy - my * halfwx);

		// Compute and apply integral feedback if enabled
		if(P->twoKi > 0.0f) {
			// integral error scaled by Ki
			P->integralFBx += P->twoKi * halfex * P->invSampleFreq;
			P->integralFBy += P->twoKi * halfey * P->invSampleFreq;
			P->integralFBz += P->twoKi * halfez * P->invSampleFreq;
			gx += P->integralFBx;        // apply integral feedback
			gy += P->integralFBy;
			gz += P->integralFBz;
		} else {
			P->integralFBx = 0.0f;        // prevent integral windup
			P->integralFBy = 0.0f;
			P->integralFBz = 0.0f;
		}

		// Apply proportional feedback
		gx += P->twoKp * halfex;
		gy += P->twoKp * halfey;
		gz += P->twoKp * halfez;
//		SEGGER_RTT_printf(0,"P->twoKp %d\n",(int)(P->twoKp*100));
	}

	// Integrate rate of change of quaternion
	gx *= (0.5f * P->invSampleFreq);                // pre-multiply common factors
	gy *= (0.5f * P->invSampleFreq);
	gz *= (0.5f * P->invSampleFreq);
	qa = P->q0;
	qb = P->q1;
	qc = P->q2;
	P->q0 += (-qb * gx - qc * gy - P->q3 * gz);
	P->q1 += (qa * gx + qc * gz - P->q3 * gy);
	P->q2 += (qa * gy - qb * gz + P->q3 * gx);
	P->q3 += (qa * gz + qb * gy - qc * gx);

	// Normalise quaternion
	recipNorm = Mahony_invSqrt(P->q0 * P->q0 + P->q1 * P->q1 + P->q2 * P->q2 + P->q3 * P->q3);
	P->q0 *= recipNorm;
	P->q1 *= recipNorm;
	P->q2 *= recipNorm;
	P->q3 *= recipNorm;
	
	//计算三个角度
	P->roll = atan2f(P->q0*P->q1 + P->q2*P->q3, 0.5f - P->q1*P->q1 - P->q2*P->q2) * 57.29578f;;
	P->pitch = asinf(-2.0f * (P->q1*P->q3 - P->q0*P->q2)) * 57.29578f;;
	P->yaw = atan2f(P->q1*P->q2 + P->q0*P->q3, 0.5f - P->q2*P->q2 - P->q3*P->q3) * 57.29578f;;
	
	//坐标系转换
	P->q[0] = P->q0;
	P->q[1] = P->q1;
	P->q[2] = P->q2;
	P->q[3] = P->q3;
	
	
	float tmp_vector2[4];
	
	quaternProd(tmp_vector2, P->q, P->accN);
	quaternConj(P->q);
	quaternProd(P->accN, tmp_vector2, P->q);
	P->accN[3] = P->accN[3] - 1.0f;//去重力
}

void Mahony_SetKp(MahonyAHRS_t *P,float twoKp1)
{
	P->twoKp = twoKp1;        // 2 * integral gain (Ki
}

void Mahony_Init(MahonyAHRS_t *P,float sampleFrequency)
{
	P->twoKi = twoKiDef;        // 2 * integral gain (Ki)
	P->twoKp = twoKpDef;
	P->q0 = 1.0f;
	P->q1 = 0.0f;
	P->q2 = 0.0f;
	P->q3 = 0.0f;
	P->integralFBx = 0.0f;
	P->integralFBy = 0.0f;
	P->integralFBz = 0.0f;
	P->invSampleFreq = 1.0f / sampleFrequency;
}


//============================================================================================
// END OF CODE
//============================================================================================