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412 lines
14 KiB
C
Executable file
412 lines
14 KiB
C
Executable file
#include "board.h"
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#include "mw.h"
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int16_t gyroADC[3], accADC[3], accSmooth[3], magADC[3];
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int32_t accSum[3];
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uint32_t accTimeSum = 0; // keep track for integration of acc
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int accSumCount = 0;
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int16_t accZ_25deg = 0;
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int32_t baroPressure = 0;
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int32_t baroTemperature = 0;
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uint32_t baroPressureSum = 0;
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int32_t BaroAlt = 0;
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int32_t sonarAlt; // to think about the unit
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int32_t EstAlt; // in cm
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int32_t BaroPID = 0;
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int32_t AltHold;
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int32_t errorAltitudeI = 0;
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int32_t vario = 0; // variometer in cm/s
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int16_t throttleAngleCorrection = 0; // correction of throttle in lateral wind,
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float magneticDeclination = 0.0f; // calculated at startup from config
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float accVelScale;
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// **************
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// gyro+acc IMU
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// **************
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int16_t gyroData[3] = { 0, 0, 0 };
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int16_t gyroZero[3] = { 0, 0, 0 };
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int16_t angle[2] = { 0, 0 }; // absolute angle inclination in multiple of 0.1 degree 180 deg = 1800
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float anglerad[2] = { 0.0f, 0.0f }; // absolute angle inclination in radians
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static void getEstimatedAttitude(void);
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void imuInit(void)
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{
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accZ_25deg = acc_1G * cosf(RAD * 25.0f);
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accVelScale = 9.80665f / acc_1G / 10000.0f;
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#ifdef MAG
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// if mag sensor is enabled, use it
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if (sensors(SENSOR_MAG))
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Mag_init();
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#endif
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}
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void computeIMU(void)
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{
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uint32_t axis;
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static int16_t gyroYawSmooth = 0;
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Gyro_getADC();
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if (sensors(SENSOR_ACC)) {
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ACC_getADC();
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getEstimatedAttitude();
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} else {
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accADC[X] = 0;
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accADC[Y] = 0;
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accADC[Z] = 0;
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}
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if (feature(FEATURE_GYRO_SMOOTHING)) {
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static uint8_t Smoothing[3] = { 0, 0, 0 };
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static int16_t gyroSmooth[3] = { 0, 0, 0 };
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if (Smoothing[0] == 0) {
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// initialize
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Smoothing[ROLL] = (mcfg.gyro_smoothing_factor >> 16) & 0xff;
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Smoothing[PITCH] = (mcfg.gyro_smoothing_factor >> 8) & 0xff;
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Smoothing[YAW] = (mcfg.gyro_smoothing_factor) & 0xff;
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}
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for (axis = 0; axis < 3; axis++) {
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gyroData[axis] = (int16_t)(((int32_t)((int32_t)gyroSmooth[axis] * (Smoothing[axis] - 1)) + gyroADC[axis] + 1) / Smoothing[axis]);
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gyroSmooth[axis] = gyroData[axis];
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}
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} else if (mcfg.mixerConfiguration == MULTITYPE_TRI) {
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gyroData[YAW] = (gyroYawSmooth * 2 + gyroADC[YAW]) / 3;
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gyroYawSmooth = gyroData[YAW];
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gyroData[ROLL] = gyroADC[ROLL];
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gyroData[PITCH] = gyroADC[PITCH];
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} else {
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for (axis = 0; axis < 3; axis++)
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gyroData[axis] = gyroADC[axis];
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}
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}
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// **************************************************
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// Simplified IMU based on "Complementary Filter"
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// Inspired by http://starlino.com/imu_guide.html
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//
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// adapted by ziss_dm : http://www.multiwii.com/forum/viewtopic.php?f=8&t=198
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//
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// The following ideas was used in this project:
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// 1) Rotation matrix: http://en.wikipedia.org/wiki/Rotation_matrix
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//
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// Currently Magnetometer uses separate CF which is used only
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// for heading approximation.
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//
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// **************************************************
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#define INV_GYR_CMPF_FACTOR (1.0f / ((float)mcfg.gyro_cmpf_factor + 1.0f))
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#define INV_GYR_CMPFM_FACTOR (1.0f / ((float)mcfg.gyro_cmpfm_factor + 1.0f))
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typedef struct fp_vector {
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float X;
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float Y;
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float Z;
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} t_fp_vector_def;
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typedef union {
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float A[3];
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t_fp_vector_def V;
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} t_fp_vector;
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t_fp_vector EstG;
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// Normalize a vector
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void normalizeV(struct fp_vector *src, struct fp_vector *dest)
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{
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float length;
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length = sqrtf(src->X * src->X + src->Y * src->Y + src->Z * src->Z);
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if (length != 0) {
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dest->X = src->X / length;
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dest->Y = src->Y / length;
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dest->Z = src->Z / length;
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}
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}
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// Rotate Estimated vector(s) with small angle approximation, according to the gyro data
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void rotateV(struct fp_vector *v, float *delta)
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{
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struct fp_vector v_tmp = *v;
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// This does a "proper" matrix rotation using gyro deltas without small-angle approximation
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float mat[3][3];
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float cosx, sinx, cosy, siny, cosz, sinz;
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float coszcosx, coszcosy, sinzcosx, coszsinx, sinzsinx;
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cosx = cosf(delta[ROLL]);
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sinx = sinf(delta[ROLL]);
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cosy = cosf(delta[PITCH]);
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siny = sinf(delta[PITCH]);
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cosz = cosf(delta[YAW]);
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sinz = sinf(delta[YAW]);
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coszcosx = cosz * cosx;
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coszcosy = cosz * cosy;
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sinzcosx = sinz * cosx;
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coszsinx = sinx * cosz;
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sinzsinx = sinx * sinz;
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mat[0][0] = coszcosy;
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mat[0][1] = -cosy * sinz;
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mat[0][2] = siny;
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mat[1][0] = sinzcosx + (coszsinx * siny);
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mat[1][1] = coszcosx - (sinzsinx * siny);
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mat[1][2] = -sinx * cosy;
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mat[2][0] = (sinzsinx) - (coszcosx * siny);
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mat[2][1] = (coszsinx) + (sinzcosx * siny);
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mat[2][2] = cosy * cosx;
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v->X = v_tmp.X * mat[0][0] + v_tmp.Y * mat[1][0] + v_tmp.Z * mat[2][0];
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v->Y = v_tmp.X * mat[0][1] + v_tmp.Y * mat[1][1] + v_tmp.Z * mat[2][1];
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v->Z = v_tmp.X * mat[0][2] + v_tmp.Y * mat[1][2] + v_tmp.Z * mat[2][2];
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}
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int32_t applyDeadband(int32_t value, int32_t deadband)
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{
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if (abs(value) < deadband) {
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value = 0;
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} else if (value > 0) {
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value -= deadband;
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} else if (value < 0) {
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value += deadband;
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}
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return value;
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}
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#define F_CUT_ACCZ 20.0f
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static const float fc_acc = 0.5f / (M_PI * F_CUT_ACCZ);
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// rotate acc into Earth frame and calculate acceleration in it
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void acc_calc(uint32_t deltaT)
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{
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static int32_t accZoffset = 0;
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static float accz_smooth;
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float rpy[3];
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t_fp_vector accel_ned;
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// the accel values have to be rotated into the earth frame
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rpy[0] = -(float)anglerad[ROLL];
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rpy[1] = -(float)anglerad[PITCH];
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rpy[2] = -(float)heading * RAD;
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accel_ned.V.X = accSmooth[0];
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accel_ned.V.Y = accSmooth[1];
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accel_ned.V.Z = accSmooth[2];
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rotateV(&accel_ned.V, rpy);
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if (cfg.acc_unarmedcal == 1) {
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if (!f.ARMED) {
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accZoffset -= accZoffset / 64;
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accZoffset += accel_ned.V.Z;
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}
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accel_ned.V.Z -= accZoffset / 64; // compensate for gravitation on z-axis
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} else
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accel_ned.V.Z -= acc_1G;
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accz_smooth = accz_smooth + (deltaT / (fc_acc + deltaT)) * (accel_ned.V.Z - accz_smooth); // low pass filter
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// apply Deadband to reduce integration drift and vibration influence
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accel_ned.V.Z = applyDeadband(lrintf(accz_smooth), cfg.accz_deadband);
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accel_ned.V.X = applyDeadband(lrintf(accel_ned.V.X), cfg.accxy_deadband);
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accel_ned.V.Y = applyDeadband(lrintf(accel_ned.V.Y), cfg.accxy_deadband);
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// sum up Values for later integration to get velocity and distance
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accTimeSum += deltaT;
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accSumCount++;
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accSum[X] += lrintf(accel_ned.V.X);
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accSum[Y] += lrintf(accel_ned.V.Y);
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accSum[Z] += lrintf(accel_ned.V.Z);
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}
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void accSum_reset(void)
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{
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accSum[0] = 0;
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accSum[1] = 0;
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accSum[2] = 0;
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accSumCount = 0;
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accTimeSum = 0;
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}
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// baseflight calculation by Luggi09 originates from arducopter
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static int16_t calculateHeading(t_fp_vector *vec)
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{
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int16_t head;
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float cosineRoll = cosf(anglerad[ROLL]);
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float sineRoll = sinf(anglerad[ROLL]);
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float cosinePitch = cosf(anglerad[PITCH]);
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float sinePitch = sinf(anglerad[PITCH]);
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float Xh = vec->A[X] * cosinePitch + vec->A[Y] * sineRoll * sinePitch + vec->A[Z] * sinePitch * cosineRoll;
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float Yh = vec->A[Y] * cosineRoll - vec->A[Z] * sineRoll;
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float hd = (atan2f(Yh, Xh) * 1800.0f / M_PI + magneticDeclination) / 10.0f;
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head = lrintf(hd);
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if (head < 0)
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head += 360;
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return head;
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}
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static void getEstimatedAttitude(void)
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{
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uint32_t axis;
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int32_t accMag = 0;
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static t_fp_vector EstM;
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static t_fp_vector EstN = { .A = { 1000.0f, 0.0f, 0.0f } };
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static float accLPF[3];
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static uint32_t previousT;
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uint32_t currentT = micros();
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uint32_t deltaT;
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float scale, deltaGyroAngle[3];
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deltaT = currentT - previousT;
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scale = deltaT * gyro.scale;
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previousT = currentT;
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// Initialization
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for (axis = 0; axis < 3; axis++) {
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deltaGyroAngle[axis] = gyroADC[axis] * scale;
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if (cfg.acc_lpf_factor > 0) {
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accLPF[axis] = accLPF[axis] * (1.0f - (1.0f / cfg.acc_lpf_factor)) + accADC[axis] * (1.0f / cfg.acc_lpf_factor);
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accSmooth[axis] = accLPF[axis];
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} else {
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accSmooth[axis] = accADC[axis];
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}
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accMag += (int32_t)accSmooth[axis] * accSmooth[axis];
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}
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accMag = accMag * 100 / ((int32_t)acc_1G * acc_1G);
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rotateV(&EstG.V, deltaGyroAngle);
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if (sensors(SENSOR_MAG))
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rotateV(&EstM.V, deltaGyroAngle);
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else
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rotateV(&EstN.V, deltaGyroAngle);
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// Apply complimentary filter (Gyro drift correction)
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// If accel magnitude >1.15G or <0.85G and ACC vector outside of the limit range => we neutralize the effect of accelerometers in the angle estimation.
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// To do that, we just skip filter, as EstV already rotated by Gyro
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if (72 < (uint16_t)accMag && (uint16_t)accMag < 133) {
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for (axis = 0; axis < 3; axis++)
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EstG.A[axis] = (EstG.A[axis] * (float)mcfg.gyro_cmpf_factor + accSmooth[axis]) * INV_GYR_CMPF_FACTOR;
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}
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if (sensors(SENSOR_MAG)) {
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for (axis = 0; axis < 3; axis++)
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EstM.A[axis] = (EstM.A[axis] * (float)mcfg.gyro_cmpfm_factor + magADC[axis]) * INV_GYR_CMPFM_FACTOR;
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}
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if (EstG.A[Z] > accZ_25deg)
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f.SMALL_ANGLES_25 = 1;
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else
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f.SMALL_ANGLES_25 = 0;
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// Attitude of the estimated vector
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anglerad[ROLL] = atan2f(EstG.V.Y, EstG.V.Z);
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anglerad[PITCH] = atan2f(-EstG.V.X, sqrtf(EstG.V.Y * EstG.V.Y + EstG.V.Z * EstG.V.Z));
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angle[ROLL] = lrintf(anglerad[ROLL] * (1800.0f / M_PI));
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angle[PITCH] = lrintf(anglerad[PITCH] * (1800.0f / M_PI));
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if (sensors(SENSOR_MAG))
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heading = calculateHeading(&EstM);
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else
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heading = calculateHeading(&EstN);
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acc_calc(deltaT); // rotate acc vector into earth frame
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if (cfg.throttle_angle_correction) {
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int cosZ = EstG.V.Z / (acc_1G * 100.0f);
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throttleAngleCorrection = cfg.throttle_angle_correction * constrain(100 - cosZ, 0, 100) / 8;
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}
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}
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#ifdef BARO
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#define UPDATE_INTERVAL 25000 // 40hz update rate (20hz LPF on acc)
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int getEstimatedAltitude(void)
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{
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static uint32_t previousT;
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uint32_t currentT = micros();
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uint32_t dTime;
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int32_t error;
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int32_t baroVel;
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int32_t vel_tmp;
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int32_t BaroAlt_tmp;
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float dt;
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float vel_acc;
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static float vel = 0.0f;
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static float accAlt = 0.0f;
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static int32_t lastBaroAlt;
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static int32_t baroGroundAltitude = 0;
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static int32_t baroGroundPressure = 0;
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dTime = currentT - previousT;
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if (dTime < UPDATE_INTERVAL)
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return 0;
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previousT = currentT;
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if (calibratingB > 0) {
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baroGroundPressure -= baroGroundPressure / 8;
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baroGroundPressure += baroPressureSum / (cfg.baro_tab_size - 1);
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baroGroundAltitude = (1.0f - powf((baroGroundPressure / 8) / 101325.0f, 0.190295f)) * 4433000.0f;
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vel = 0;
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accAlt = 0;
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calibratingB--;
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}
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// calculates height from ground via baro readings
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// see: https://github.com/diydrones/ardupilot/blob/master/libraries/AP_Baro/AP_Baro.cpp#L140
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BaroAlt_tmp = lrintf((1.0f - powf((float)(baroPressureSum / (cfg.baro_tab_size - 1)) / 101325.0f, 0.190295f)) * 4433000.0f); // in cm
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BaroAlt_tmp -= baroGroundAltitude;
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BaroAlt = lrintf((float)BaroAlt * cfg.baro_noise_lpf + (float)BaroAlt_tmp * (1.0f - cfg.baro_noise_lpf)); // additional LPF to reduce baro noise
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dt = accTimeSum * 1e-6f; // delta acc reading time in seconds
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// Integrator - velocity, cm/sec
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vel_acc = (float)accSum[2] * accVelScale * (float)accTimeSum / (float)accSumCount;
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// Integrator - Altitude in cm
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accAlt += (vel_acc * 0.5f) * dt + vel * dt; // integrate velocity to get distance (x= a/2 * t^2)
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accAlt = accAlt * cfg.baro_cf_alt + (float) BaroAlt *(1.0f - cfg.baro_cf_alt); // complementary filter for Altitude estimation (baro & acc)
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EstAlt = accAlt;
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vel += vel_acc;
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#if 0
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debug[0] = accSum[2] / accSumCount; // acceleration
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debug[1] = vel; // velocity
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debug[2] = accAlt; // height
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#endif
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accSum_reset();
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//P
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error = constrain(AltHold - EstAlt, -300, 300);
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error = applyDeadband(error, 10); // remove small P parametr to reduce noise near zero position
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BaroPID = constrain((cfg.P8[PIDALT] * error / 128), -200, +200);
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//I
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errorAltitudeI += cfg.I8[PIDALT] * error / 64;
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errorAltitudeI = constrain(errorAltitudeI, -50000, 50000);
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BaroPID += errorAltitudeI / 512; // I in range +/-100
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baroVel = (BaroAlt - lastBaroAlt) * 1000000.0f / dTime;
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lastBaroAlt = BaroAlt;
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baroVel = constrain(baroVel, -300, 300); // constrain baro velocity +/- 300cm/s
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baroVel = applyDeadband(baroVel, 10); // to reduce noise near zero
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// apply Complimentary Filter to keep the calculated velocity based on baro velocity (i.e. near real velocity).
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// By using CF it's possible to correct the drift of integrated accZ (velocity) without loosing the phase, i.e without delay
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vel = vel * cfg.baro_cf_vel + baroVel * (1 - cfg.baro_cf_vel);
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vel = constrain(vel, -1000, 1000); // limit max velocity to +/- 10m/s (36km/h)
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// D
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vel_tmp = lrintf(vel);
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vel_tmp = applyDeadband(vel_tmp, 5);
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vario = vel_tmp;
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BaroPID -= constrain(cfg.D8[PIDALT] * vel_tmp / 16, -150, 150);
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return 1;
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}
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#endif /* BARO */
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