ziggi/stm32uav
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

added original Mahony alg for comparation; impr IMU calbration

Browse Source
This commit is contained in:
Oleg Borodin
2022-09-07 03:13:22 +02:00
parent 9a973c054d
commit f85bc21e21
3 changed files with 171 additions and 76 deletions
Download Patch File Download Diff File Expand all files Collapse all files
mculoop/main.c
+125 -45
View File
@@ -60,7 +60,7 @@ static void usart_setup(void) {
usart_enable(USART1);
}
const uint32_t systic_freq = 50 * 1000;
const uint32_t systic_freq = 100 * 1000;
static void systick_setup(void) {
g_sys_tick_counter = 0;
@@ -114,7 +114,100 @@ double invSqrt(double x) {
return 1.0f / sqrt(x);
}
void ahrs_update(double dt, quaternion_t* q, mpu_value_t* m) {
volatile float twoKp = (2.0f * 0.5f); // 2 * proportional gain (Kp)
volatile float twoKi = (2.0f * 0.0f); // 2 * integral gain (Ki)
volatile float integralFBx = 0.0f;
volatile float integralFBy = 0.0f;
volatile float integralFBz = 0.0f;
void quaternion_update_mahony(double dt, quaternion_t* q, mpu_value_t* m) {
double q0 = q->w;
double q1 = q->x;
double q2 = q->y;
double q3 = q->z; // quaternion of sensor frame relative to auxiliary frame
double gx = m->gx;
double gy = m->gy;
double gz = m->gz;
double ax = m->ax;
double ay = m->ay;
double az = m->az;
double recipNorm;
double halfvx, halfvy, halfvz;
double halfex, halfey, halfez;
double qa, qb, qc;
// 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 = invSqrt(ax*ax + ay*ay + az*az);
ax *= recipNorm;
ay *= recipNorm;
az *= recipNorm;
// Estimated direction of gravity and vector perpendicular to magnetic flux
halfvx = q1*q3 - q0*q2;
halfvy = q0*q1 + q2*q3;
halfvz = q0*q0 - 0.5f + q3*q3;
// Error is sum of cross product between estimated and measured direction of gravity
halfex = (ay*halfvz - az*halfvy);
halfey = (az*halfvx - ax*halfvz);
halfez = (ax*halfvy - ay*halfvx);
// Compute and apply integral feedback if enabled
if(twoKi > 0.0f) {
integralFBx += twoKi*halfex*dt; // integral error scaled by Ki
integralFBy += twoKi*halfey*dt;
integralFBz += twoKi*halfez*dt;
gx += integralFBx; // apply integral feedback
gy += integralFBy;
gz += integralFBz;
}
else {
integralFBx = 0.0f; // prevent integral windup
integralFBy = 0.0f;
integralFBz = 0.0f;
}
// Apply proportional feedback
gx += twoKp*halfex;
gy += twoKp*halfey;
gz += twoKp*halfez;
}
// Integrate rate of change of quaternion
gx *= (0.5f*dt); // pre-multiply common factors
gy *= (0.5f*dt);
gz *= (0.5f*dt);
qa = q0;
qb = q1;
qc = q2;
q0 += (-qb*gx - qc*gy - q3*gz);
q1 += ( qa*gx + qc*gz - q3*gy);
q2 += ( qa*gy - qb*gz + q3*gx);
q3 += ( qa*gz + qb*gy - qc*gx);
// Normalise quaternion
recipNorm = invSqrt(q0*q0 + q1*q1 + q2*q2 + q3*q3);
q0 *= recipNorm;
q1 *= recipNorm;
q2 *= recipNorm;
q3 *= recipNorm;
q->w = q0;
q->x = q1;
q->y = q2;
q->z = q3;
}
void quaternion_update(double dt, quaternion_t* q, mpu_value_t* m) {
double q0 = q->w;
double q1 = q->x;
@@ -133,16 +226,15 @@ void ahrs_update(double dt, quaternion_t* q, mpu_value_t* m) {
double recipNorm;
double s0, s1, s2, s3;
double qDot1, qDot2, qDot3, qDot4;
double _2q0, _2q1, _2q2, _2q3, _4q0, _4q1, _4q2, _8q1, _8q2, q0q0, q1q1, q2q2, q3q3;
// 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);
qDot3 = 0.5f * ( q0*gy - q1*gz + q3*gx);
qDot4 = 0.5f * ( q0*gz + q1*gy - q2*gx);
qDot1 = 0.5 * (-q1*gx - q2*gy - q3*gz);
qDot2 = 0.5 * ( q0*gx + q2*gz - q3*gy);
qDot3 = 0.5 * ( q0*gy - q1*gz + q3*gx);
qDot4 = 0.5 * ( q0*gz + q1*gy - q2*gx);
// Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
if (!((ax == 0.0f) && (ay == 0.0f) && (az == 0.0f))) {
if (!((ax == 0.0) && (ay == 0.0) && (az == 0.0))) {
// Normalise accelerometer measurement
recipNorm = invSqrt(ax*ax + ay*ay + az*az);
@@ -150,28 +242,14 @@ void ahrs_update(double dt, quaternion_t* q, mpu_value_t* m) {
ay *= recipNorm;
az *= recipNorm;
// Auxiliary variables to avoid repeated arithmetic
_2q0 = 2.0f * q0;
_2q1 = 2.0f * q1;
_2q2 = 2.0f * q2;
_2q3 = 2.0f * q3;
_4q0 = 4.0f * q0;
_4q1 = 4.0f * q1;
_4q2 = 4.0f * q2;
_8q1 = 8.0f * q1;
_8q2 = 8.0f * q2;
q0q0 = q0 * q0;
q1q1 = q1 * q1;
q2q2 = q2 * q2;
q3q3 = q3 * q3;
// Gradient decent algorithm corrective step
s0 = _4q0*q2q2 + _2q2*ax + _4q0*q1q1 - _2q1*ay;
s1 = _4q1*q3q3 - _2q3*ax + 4.0f*q0q0*q1 - _2q0*ay - _4q1 + _8q1*q1q1 + _8q1*q2q2 + _4q1*az;
s2 = 4.0f*q0q0*q2 + _2q0*ax + _4q2*q3q3 - _2q3*ay - _4q2 + _8q2*q1q1 + _8q2*q2q2 + _4q2*az;
s3 = 4.0f*q1q1*q3 - _2q1*ax + 4.0f*q2q2*q3 - _2q2*ay;
s0 = 4.0*q0*q2*q2 + 2.0*q2*ax + 4.0*q0*q1*q1 - 2.0*q1*ay;
s1 = 4.0*q1*q3*q3 - 2.0*q3*ax + 4.0*q0*q0*q1 - 2.0*q0*ay - 4.0*q1 + 8.0*q1*q1*q1 + 8.0*q1*q2*q2 + 4.0*q1*az;
s2 = 4.0*q0*q0*q2 + 2.0*q0*ax + 4.0*q2*q3*q3 - 2.0*q3*ay - 4.0*q2 + 8.0*q2*q1*q1 + 8.0*q2*q2*q2 + 4.0*q2*az;
s3 = 4.0*q1*q1*q3 - 2.0*q1*ax + 4.0*q2*q2*q3 - 2.0*q2*ay;
recipNorm = invSqrt(s0*s0 + s1*s1 + s2*s2 + s3*s3); // normalise step magnitude
// Normalise step magnitude
recipNorm = invSqrt(s0*s0 + s1*s1 + s2*s2 + s3*s3);
s0 *= recipNorm;
s1 *= recipNorm;
s2 *= recipNorm;
@@ -203,6 +281,7 @@ void ahrs_update(double dt, quaternion_t* q, mpu_value_t* m) {
q->z = q3;
}
double radian2degrees(double radians) {
return radians * (180.0f / M_PI);
}
@@ -245,12 +324,12 @@ angle_t quaternion2xyz(quaternion_t* q) {
double t0 = (x + z)*(x - z); // x^2-z^2
double t1 = (w + y)*(w - y); // w^2-y^2
double xx = 0.5f * (t0 + t1); // 1/2 x of x'
double xx = 0.5 * (t0 + t1); // 1/2 x of x'
double xy = x*y + w*z; // 1/2 y of x'
double xz = w*y - x*z; // 1/2 z of x'
double t = xx*xx + xy*xy; // cos(theta)^2
double yz = 2.0f * (y*z + w*x); // z of y'
double yz = 2.0 * (y*z + w*x); // z of y'
a.z = atan2(xy, xx); // yaw (psi)
a.y = atan(xz /sqrt(t)); // pitch (theta)
@@ -263,6 +342,13 @@ angle_t quaternion2xyz(quaternion_t* q) {
return a;
}
void angle_norm(angle_t* a) {
double n = sqrt(a->x*a->x + a->y*a->y + a->z*a->z);
a->x *= n;
a->y *= n;
a->z *= n;
}
int main(void) {
@@ -273,35 +359,29 @@ int main(void) {
i2c_setup();
systick_setup();
printf("==== start ====\r\n");
mpu_t mpu;
printf("==== mpu initialize ====\r\n");
mpu_setup(&mpu, I2C1, 0x68);
_delay(10);
_delay(100);
mpu_calibrate(&mpu, 20000);
printf("==== mpu ====\r\n");
printf("==== mpu started ====\r\n");
mpu_value_t mval;
uint32_t prev_ts = 0, last_ts = 0;
quaternion_t q;
quaternion_init(&q);
int i = 0;
uint32_t prev_ts = 0;
uint32_t last_ts = 0;
printf("==== main loop ====\r\n");
while (true) {
mpu_read(&mpu, &mval);
gpio_toggle(GPIOB, GPIO6);
//if ((i % 350) == 0) {
// printf("gx=%8.4f gy=%8.4f gz=%8.4f ax=%8.4f ay=%8.4f az=%8.4f \r\n", mval.gx, mval.gy, mval.gz, mval.ax, mval.ay, mval.az);
//}
i++;
last_ts = g_sys_tick_counter;
float dt = (float)(last_ts - prev_ts) / (float)systic_freq;
double dt = (float)(last_ts - prev_ts) / (float)systic_freq;
prev_ts = last_ts;
ahrs_update(dt, &q, &mval);
quaternion_update(dt, &q, &mval);
angle_t a = quaternion2xyz(&q);
angle_degress(&a);