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betaflight/src/imu.c
timecop@gmail.com 1dea2b3b3b integrated tommie's eeprom sanity check. much less chances of new firmware screwing up due to old config version.
fixed pwm init for airplane mode mistakenly deleting motors from the mix. flyingwing should really work now.
removed led debug from althold


git-svn-id: https://afrodevices.googlecode.com/svn/trunk/baseflight@223 7c89a4a9-59b9-e629-4cfe-3a2d53b20e61
2012-09-21 04:12:17 +00:00

370 lines
12 KiB
C
Executable file

#include "board.h"
#include "mw.h"
int16_t gyroADC[3], accADC[3], accSmooth[3], magADC[3];
float accLPFVel[3];
int16_t acc_25deg = 0;
int32_t BaroAlt;
int16_t sonarAlt; //to think about the unit
int32_t EstAlt; // in cm
int16_t BaroPID = 0;
int32_t AltHold;
int16_t errorAltitudeI = 0;
float magneticDeclination = 0.0f; // calculated at startup from config
float accVelScale;
// **************
// gyro+acc IMU
// **************
int16_t gyroData[3] = { 0, 0, 0 };
int16_t gyroZero[3] = { 0, 0, 0 };
int16_t angle[2] = { 0, 0 }; // absolute angle inclination in multiple of 0.1 degree 180 deg = 1800
static void getEstimatedAttitude(void);
void imuInit(void)
{
acc_25deg = acc_1G * 0.423f;
accVelScale = 9.80665f / acc_1G / 10000.0f;
#ifdef MAG
// if mag sensor is enabled, use it
if (sensors(SENSOR_MAG))
Mag_init();
#endif
}
void computeIMU(void)
{
uint32_t axis;
static int16_t gyroADCprevious[3] = { 0, 0, 0 };
int16_t gyroADCp[3];
int16_t gyroADCinter[3];
static uint32_t timeInterleave = 0;
static int16_t gyroYawSmooth = 0;
#define GYRO_INTERLEAVE
if (sensors(SENSOR_ACC)) {
ACC_getADC();
getEstimatedAttitude();
}
Gyro_getADC();
for (axis = 0; axis < 3; axis++) {
#ifdef GYRO_INTERLEAVE
gyroADCp[axis] = gyroADC[axis];
#else
gyroData[axis] = gyroADC[axis];
#endif
if (!sensors(SENSOR_ACC))
accADC[axis] = 0;
}
timeInterleave = micros();
annexCode();
#ifdef GYRO_INTERLEAVE
if ((micros() - timeInterleave) > 650) {
annex650_overrun_count++;
} else {
while ((micros() - timeInterleave) < 650); // empirical, interleaving delay between 2 consecutive reads
}
Gyro_getADC();
for (axis = 0; axis < 3; axis++) {
gyroADCinter[axis] = gyroADC[axis] + gyroADCp[axis];
// empirical, we take a weighted value of the current and the previous values
gyroData[axis] = (gyroADCinter[axis] + gyroADCprevious[axis]) / 3;
gyroADCprevious[axis] = gyroADCinter[axis] / 2;
if (!sensors(SENSOR_ACC))
accADC[axis] = 0;
}
#endif
if (feature(FEATURE_GYRO_SMOOTHING)) {
static uint8_t Smoothing[3] = { 0, 0, 0 };
static int16_t gyroSmooth[3] = { 0, 0, 0 };
if (Smoothing[0] == 0) {
// initialize
Smoothing[ROLL] = (cfg.gyro_smoothing_factor >> 16) & 0xff;
Smoothing[PITCH] = (cfg.gyro_smoothing_factor >> 8) & 0xff;
Smoothing[YAW] = (cfg.gyro_smoothing_factor) & 0xff;
}
for (axis = 0; axis < 3; axis++) {
gyroData[axis] = (int16_t)(((int32_t)((int32_t)gyroSmooth[axis] * (Smoothing[axis] - 1)) + gyroData[axis] + 1 ) / Smoothing[axis]);
gyroSmooth[axis] = gyroData[axis];
}
} else if (cfg.mixerConfiguration == MULTITYPE_TRI) {
gyroData[YAW] = (gyroYawSmooth * 2 + gyroData[YAW]) / 3;
gyroYawSmooth = gyroData[YAW];
}
}
// **************************************************
// Simplified IMU based on "Complementary Filter"
// Inspired by http://starlino.com/imu_guide.html
//
// adapted by ziss_dm : http://www.multiwii.com/forum/viewtopic.php?f=8&t=198
//
// The following ideas was used in this project:
// 1) Rotation matrix: http://en.wikipedia.org/wiki/Rotation_matrix
// 2) Small-angle approximation: http://en.wikipedia.org/wiki/Small-angle_approximation
// 3) C. Hastings approximation for atan2()
// 4) Optimization tricks: http://www.hackersdelight.org/
//
// Currently Magnetometer uses separate CF which is used only
// for heading approximation.
//
// Modified: 19/04/2011 by ziss_dm
// Version: V1.1
//
// code size deduction and tmp vector intermediate step for vector rotation computation: October 2011 by Alex
// **************************************************
//****** advanced users settings *******************
/* Set the Low Pass Filter factor for Magnetometer */
/* Increasing this value would reduce Magnetometer noise (not visible in GUI), but would increase Magnetometer lag time*/
/* Comment this if you do not want filter at all.*/
/* Default WMC value: n/a*/
//#define MG_LPF_FACTOR 4
/* Set the Gyro Weight for Gyro/Magnetometer complementary filter */
/* Increasing this value would reduce and delay Magnetometer influence on the output of the filter*/
/* Default WMC value: n/a*/
#define GYR_CMPFM_FACTOR 200.0f
//****** end of advanced users settings *************
#define INV_GYR_CMPF_FACTOR (1.0f / ((float)cfg.gyro_cmpf_factor + 1.0f))
#define INV_GYR_CMPFM_FACTOR (1.0f / (GYR_CMPFM_FACTOR + 1.0f))
#define GYRO_SCALE ((1998 * M_PI)/((32767.0f / 4.0f ) * 180.0f * 1000000.0f)) // 32767 / 16.4lsb/dps for MPU3000
// #define GYRO_SCALE ((2380 * M_PI)/((32767.0f / 4.0f ) * 180.0f * 1000000.0f)) //should be 2279.44 but 2380 gives better result (ITG-3200)
// +-2000/sec deg scale
//#define GYRO_SCALE ((200.0f * PI)/((32768.0f / 5.0f / 4.0f ) * 180.0f * 1000000.0f) * 1.5f)
// +- 200/sec deg scale
// 1.5 is emperical, not sure what it means
// should be in rad/sec
typedef struct fp_vector {
float X;
float Y;
float Z;
} t_fp_vector_def;
typedef union {
float A[3];
t_fp_vector_def V;
} t_fp_vector;
t_fp_vector EstG;
// Rotate Estimated vector(s) with small angle approximation, according to the gyro data
void rotateV(struct fp_vector *v, float *delta)
{
struct fp_vector v_tmp = *v;
v->Z -= delta[ROLL] * v_tmp.X + delta[PITCH] * v_tmp.Y;
v->X += delta[ROLL] * v_tmp.Z - delta[YAW] * v_tmp.Y;
v->Y += delta[PITCH] * v_tmp.Z + delta[YAW] * v_tmp.X;
}
static int16_t _atan2f(float y, float x)
{
// no need for aidsy inaccurate shortcuts on a proper platform
return (int16_t)(atan2f(y, x) * (180.0f / M_PI * 10.0f));
}
static void getEstimatedAttitude(void)
{
uint32_t axis;
int32_t accMag = 0;
static t_fp_vector EstM;
#if defined(MG_LPF_FACTOR)
static int16_t mgSmooth[3];
#endif
static float accLPF[3];
static uint32_t previousT;
uint32_t currentT = micros();
float scale, deltaGyroAngle[3];
scale = (currentT - previousT) * GYRO_SCALE;
previousT = currentT;
// Initialization
for (axis = 0; axis < 3; axis++) {
deltaGyroAngle[axis] = gyroADC[axis] * scale;
if (cfg.acc_lpf_factor > 0) {
accLPF[axis] = accLPF[axis] * (1.0f - (1.0f / cfg.acc_lpf_factor)) + accADC[axis] * (1.0f / cfg.acc_lpf_factor);
accSmooth[axis] = accLPF[axis];
} else {
accSmooth[axis] = accADC[axis];
}
accLPFVel[axis] = accLPFVel[axis] * (1.0f - (1.0f / cfg.acc_lpf_for_velocity)) + accADC[axis] * (1.0f / cfg.acc_lpf_for_velocity);
accMag += (int32_t)accSmooth[axis] * accSmooth[axis];
if (sensors(SENSOR_MAG)) {
#if defined(MG_LPF_FACTOR)
mgSmooth[axis] = (mgSmooth[axis] * (MG_LPF_FACTOR - 1) + magADC[axis]) / MG_LPF_FACTOR; // LPF for Magnetometer values
#define MAG_VALUE mgSmooth[axis]
#else
#define MAG_VALUE magADC[axis]
#endif
}
}
accMag = accMag * 100 / ((int32_t)acc_1G * acc_1G);
rotateV(&EstG.V, deltaGyroAngle);
if (sensors(SENSOR_MAG))
rotateV(&EstM.V, deltaGyroAngle);
if (abs(accSmooth[ROLL]) < acc_25deg && abs(accSmooth[PITCH]) < acc_25deg && accSmooth[YAW] > 0)
f.SMALL_ANGLES_25 = 1;
else
f.SMALL_ANGLES_25 = 0;
// Apply complimentary filter (Gyro drift correction)
// If accel magnitude >1.4G or <0.6G and ACC vector outside of the limit range => we neutralize the effect of accelerometers in the angle estimation.
// To do that, we just skip filter, as EstV already rotated by Gyro
if ((36 < accMag && accMag < 196) || f.SMALL_ANGLES_25) {
for (axis = 0; axis < 3; axis++)
EstG.A[axis] = (EstG.A[axis] * (float)cfg.gyro_cmpf_factor + accSmooth[axis]) * INV_GYR_CMPF_FACTOR;
}
if (sensors(SENSOR_MAG)) {
for (axis = 0; axis < 3; axis++)
EstM.A[axis] = (EstM.A[axis] * GYR_CMPFM_FACTOR + MAG_VALUE) * INV_GYR_CMPFM_FACTOR;
}
// Attitude of the estimated vector
angle[ROLL] = _atan2f(EstG.V.X, EstG.V.Z);
angle[PITCH] = _atan2f(EstG.V.Y, EstG.V.Z);
#ifdef MAG
if (sensors(SENSOR_MAG)) {
// Attitude of the cross product vector GxM
heading = _atan2f(EstG.V.X * EstM.V.Z - EstG.V.Z * EstM.V.X, EstG.V.Z * EstM.V.Y - EstG.V.Y * EstM.V.Z);
heading = heading + magneticDeclination;
heading = heading / 10;
if (heading > 180)
heading = heading - 360;
else if (heading < -180)
heading = heading + 360;
}
#endif
}
#ifdef BARO
#define UPDATE_INTERVAL 25000 // 40hz update rate (20hz LPF on acc)
#define INIT_DELAY 4000000 // 4 sec initialization delay
int16_t applyDeadband16(int16_t value, int16_t deadband)
{
if (abs(value) < deadband) {
value = 0;
} else if (value > 0) {
value -= deadband;
} else if (value < 0) {
value += deadband;
}
return value;
}
float applyDeadbandFloat(float value, int16_t deadband)
{
if (abs(value) < deadband) {
value = 0;
} else if (value > 0) {
value -= deadband;
} else if (value < 0) {
value += deadband;
}
return value;
}
float InvSqrt(float x)
{
union {
int32_t i;
float f;
} conv;
conv.f = x;
conv.i = 0x5f3759df - (conv.i >> 1);
return 0.5f * conv.f * (3.0f - x * conv.f * conv.f);
}
int32_t isq(int32_t x)
{
return x * x;
}
void getEstimatedAltitude(void)
{
static uint32_t deadLine = INIT_DELAY;
static int16_t baroHistTab[BARO_TAB_SIZE_MAX];
static int8_t baroHistIdx;
static int32_t baroHigh;
uint32_t dTime;
int16_t error;
float invG;
int16_t accZ;
static float vel = 0.0f;
static int32_t lastBaroAlt;
float baroVel;
if ((int32_t)(currentTime - deadLine) < UPDATE_INTERVAL)
return;
dTime = currentTime - deadLine;
deadLine = currentTime;
// **** Alt. Set Point stabilization PID ****
baroHistTab[baroHistIdx] = BaroAlt / 10;
baroHigh += baroHistTab[baroHistIdx];
baroHigh -= baroHistTab[(baroHistIdx + 1) % cfg.baro_tab_size];
baroHistIdx++;
if (baroHistIdx == cfg.baro_tab_size)
baroHistIdx = 0;
EstAlt = EstAlt * cfg.baro_noise_lpf + (baroHigh * 10.0f / (cfg.baro_tab_size - 1)) * (1.0f - cfg.baro_noise_lpf); // additional LPF to reduce baro noise
// P
error = constrain(AltHold - EstAlt, -300, 300);
error = applyDeadband16(error, 10); // remove small P parametr to reduce noise near zero position
BaroPID = constrain((cfg.P8[PIDALT] * error / 100), -150, +150);
// I
errorAltitudeI += error * cfg.I8[PIDALT] / 50;
errorAltitudeI = constrain(errorAltitudeI, -30000, 30000);
BaroPID += (errorAltitudeI / 500); // I in range +/-60
// projection of ACC vector to global Z, with 1G subtructed
// Math: accZ = A * G / |G| - 1G
invG = InvSqrt(isq(EstG.V.X) + isq(EstG.V.Y) + isq(EstG.V.Z));
accZ = (accLPFVel[ROLL] * EstG.V.X + accLPFVel[PITCH] * EstG.V.Y + accLPFVel[YAW] * EstG.V.Z) * invG - acc_1G;
accZ = applyDeadband16(accZ, acc_1G / cfg.accz_deadband);
debug[0] = accZ;
// Integrator - velocity, cm/sec
vel += accZ * accVelScale * dTime;
baroVel = (EstAlt - lastBaroAlt) / (dTime / 1000000.0f);
baroVel = constrain(baroVel, -300, 300); // constrain baro velocity +/- 300cm/s
baroVel = applyDeadbandFloat(baroVel, 10); // to reduce noise near zero
lastBaroAlt = EstAlt;
debug[1] = baroVel;
// apply Complimentary Filter to keep near zero caluculated velocity based on baro velocity
vel = vel * cfg.baro_cf + baroVel * (1.0f - cfg.baro_cf);
// vel = constrain(vel, -300, 300); // constrain velocity +/- 300cm/s
debug[2] = vel;
// debug[3] = applyDeadbandFloat(vel, 5);
// D
BaroPID -= constrain(cfg.D8[PIDALT] * applyDeadbandFloat(vel, 5) / 20, -150, 150);
debug[3] = BaroPID;
}
#endif /* BARO */