292 lines
7.1 KiB
C
292 lines
7.1 KiB
C
#include "imuread.h"
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static int rawcount=OVERSAMPLE_RATIO;
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static AccelSensor_t accel;
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static MagSensor_t mag;
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static GyroSensor_t gyro;
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void raw_data_reset(void)
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{
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rawcount = OVERSAMPLE_RATIO;
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fusion_init();
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memset(&magcal, 0, sizeof(magcal));
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magcal.V[2] = 80.0f; // initial guess
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magcal.invW[0][0] = 1.0f;
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magcal.invW[1][1] = 1.0f;
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magcal.invW[2][2] = 1.0f;
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magcal.FitError = 100.0f;
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magcal.FitErrorAge = 100.0f;
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magcal.B = 50.0f;
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}
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static int choose_discard_magcal(void)
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{
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int32_t rawx, rawy, rawz;
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int32_t dx, dy, dz;
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float x, y, z;
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uint64_t distsq, minsum=0xFFFFFFFFFFFFFFFF;
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static int runcount=0;
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int i, j, minindex=0;
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Point_t point;
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float gaps, field, error, errormax;
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// When enough data is collected (gaps error is low), assume we
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// have a pretty good coverage and the field stregth is known.
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gaps = quality_surface_gap_error();
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if (gaps < 25.0f) {
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// occasionally look for points farthest from average field strength
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// always rate limit assumption-based data purging, but allow the
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// rate to increase as the angular coverage improves.
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if (gaps < 1.0f) gaps = 1.0f;
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if (++runcount > (int)(gaps * 10.0f)) {
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j = MAGBUFFSIZE;
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errormax = 0.0f;
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for (i=0; i < MAGBUFFSIZE; i++) {
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rawx = magcal.BpFast[0][i];
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rawy = magcal.BpFast[1][i];
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rawz = magcal.BpFast[2][i];
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apply_calibration(rawx, rawy, rawz, &point);
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x = point.x;
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y = point.y;
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z = point.z;
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field = sqrtf(x * x + y * y + z * z);
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// if magcal.B is bad, things could go horribly wrong
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error = fabsf(field - magcal.B);
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if (error > errormax) {
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errormax = error;
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j = i;
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}
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}
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runcount = 0;
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if (j < MAGBUFFSIZE) {
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//printf("worst error at %d\n", j);
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return j;
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}
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}
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} else {
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runcount = 0;
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}
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// When solid info isn't availabe, find 2 points closest to each other,
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// and randomly discard one. When we don't have good coverage, this
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// approach tends to add points into previously unmeasured areas while
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// discarding info from areas with highly redundant info.
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for (i=0; i < MAGBUFFSIZE; i++) {
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for (j=i+1; j < MAGBUFFSIZE; j++) {
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dx = magcal.BpFast[0][i] - magcal.BpFast[0][j];
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dy = magcal.BpFast[1][i] - magcal.BpFast[1][j];
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dz = magcal.BpFast[2][i] - magcal.BpFast[2][j];
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distsq = (int64_t)dx * (int64_t)dx;
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distsq += (int64_t)dy * (int64_t)dy;
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distsq += (int64_t)dz * (int64_t)dz;
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if (distsq < minsum) {
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minsum = distsq;
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minindex = (random() & 1) ? i : j;
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}
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}
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}
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return minindex;
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}
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static void add_magcal_data(const int16_t *data)
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{
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int i;
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// first look for an unused caldata slot
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for (i=0; i < MAGBUFFSIZE; i++) {
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if (!magcal.valid[i]) break;
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}
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// If the buffer is full, we must choose which old data to discard.
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// We must choose wisely! Throwing away the wrong data could prevent
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// collecting enough data distributed across the entire 3D angular
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// range, preventing a decent cal from ever happening at all. Making
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// any assumption about good vs bad data is particularly risky,
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// because being wrong could cause an unstable feedback loop where
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// bad data leads to wrong decisions which leads to even worse data.
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// But if done well, purging bad data has massive potential to
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// improve results. The trick is telling the good from the bad while
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// still in the process of learning what's good...
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if (i >= MAGBUFFSIZE) {
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i = choose_discard_magcal();
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if (i < 0 || i >= MAGBUFFSIZE) {
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i = random() % MAGBUFFSIZE;
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}
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}
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// add it to the cal buffer
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magcal.BpFast[0][i] = data[6];
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magcal.BpFast[1][i] = data[7];
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magcal.BpFast[2][i] = data[8];
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magcal.valid[i] = 1;
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}
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void cal1_data(const float *data)
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{
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#if 0
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int i;
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printf("got cal1_data:\n");
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for (i=0; i<10; i++) {
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printf(" %.5f\n", data[i]);
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}
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#endif
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}
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void cal2_data(const float *data)
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{
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#if 0
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int i;
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printf("got cal2_data:\n");
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for (i=0; i<9; i++) {
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printf(" %.5f\n", data[i]);
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}
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#endif
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}
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void raw_data(const int16_t *data)
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{
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static int force_orientation_counter=0;
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float x, y, z, ratio, magdiff;
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Point_t point;
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add_magcal_data(data);
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x = magcal.V[0];
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y = magcal.V[1];
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z = magcal.V[2];
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if (MagCal_Run()) {
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x -= magcal.V[0];
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y -= magcal.V[1];
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z -= magcal.V[2];
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magdiff = sqrtf(x * x + y * y + z * z);
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//printf("magdiff = %.2f\n", magdiff);
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if (magdiff > 0.8f) {
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fusion_init();
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rawcount = OVERSAMPLE_RATIO;
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force_orientation_counter = 240;
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}
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}
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if (force_orientation_counter > 0) {
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if (--force_orientation_counter == 0) {
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//printf("delayed forcible orientation reset\n");
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fusion_init();
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rawcount = OVERSAMPLE_RATIO;
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}
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}
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if (rawcount >= OVERSAMPLE_RATIO) {
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memset(&accel, 0, sizeof(accel));
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memset(&mag, 0, sizeof(mag));
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memset(&gyro, 0, sizeof(gyro));
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rawcount = 0;
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}
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x = (float)data[0] * G_PER_COUNT;
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y = (float)data[1] * G_PER_COUNT;
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z = (float)data[2] * G_PER_COUNT;
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accel.GpFast[0] = x;
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accel.GpFast[1] = y;
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accel.GpFast[2] = y;
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accel.Gp[0] += x;
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accel.Gp[1] += y;
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accel.Gp[2] += y;
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x = (float)data[3] * DEG_PER_SEC_PER_COUNT;
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y = (float)data[4] * DEG_PER_SEC_PER_COUNT;
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z = (float)data[5] * DEG_PER_SEC_PER_COUNT;
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gyro.Yp[0] += x;
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gyro.Yp[1] += y;
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gyro.Yp[2] += z;
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gyro.YpFast[rawcount][0] = x;
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gyro.YpFast[rawcount][1] = y;
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gyro.YpFast[rawcount][2] = z;
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apply_calibration(data[6], data[7], data[8], &point);
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mag.BcFast[0] = point.x;
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mag.BcFast[1] = point.y;
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mag.BcFast[2] = point.z;
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mag.Bc[0] += point.x;
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mag.Bc[1] += point.y;
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mag.Bc[2] += point.z;
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rawcount++;
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if (rawcount >= OVERSAMPLE_RATIO) {
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ratio = 1.0f / (float)OVERSAMPLE_RATIO;
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accel.Gp[0] *= ratio;
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accel.Gp[1] *= ratio;
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accel.Gp[2] *= ratio;
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gyro.Yp[0] *= ratio;
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gyro.Yp[1] *= ratio;
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gyro.Yp[2] *= ratio;
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mag.Bc[0] *= ratio;
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mag.Bc[1] *= ratio;
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mag.Bc[2] *= ratio;
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fusion_update(&accel, &mag, &gyro, &magcal);
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fusion_read(¤t_orientation);
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}
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}
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static uint16_t crc16(uint16_t crc, uint8_t data)
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{
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unsigned int i;
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crc ^= data;
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for (i = 0; i < 8; ++i) {
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if (crc & 1) {
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crc = (crc >> 1) ^ 0xA001;
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} else {
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crc = (crc >> 1);
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}
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}
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return crc;
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}
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static uint8_t * copy_lsb_first(uint8_t *dst, float f)
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{
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union {
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float f;
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uint32_t n;
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} data;
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data.f = f;
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*dst++ = data.n;
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*dst++ = data.n >> 8;
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*dst++ = data.n >> 16;
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*dst++ = data.n >> 24;
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return dst;
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}
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int send_calibration(void)
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{
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uint8_t *p, buf[68];
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uint16_t crc;
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int i;
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p = buf;
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*p++ = 117; // 2 byte signature
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*p++ = 84;
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for (i=0; i < 3; i++) {
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p = copy_lsb_first(p, 0.0f); // accelerometer offsets
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}
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for (i=0; i < 3; i++) {
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p = copy_lsb_first(p, 0.0f); // gyroscope offsets
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}
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for (i=0; i < 3; i++) {
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p = copy_lsb_first(p, magcal.V[i]); // 12 bytes offset/hardiron
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}
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p = copy_lsb_first(p, magcal.B); // field strength
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p = copy_lsb_first(p, magcal.invW[0][0]); //10
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p = copy_lsb_first(p, magcal.invW[1][1]); //11
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p = copy_lsb_first(p, magcal.invW[2][2]); //12
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p = copy_lsb_first(p, magcal.invW[0][1]); //13
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p = copy_lsb_first(p, magcal.invW[0][2]); //14
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p = copy_lsb_first(p, magcal.invW[1][2]); //15
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crc = 0xFFFF;
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for (i=0; i < 66; i++) {
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crc = crc16(crc, buf[i]);
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}
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*p++ = crc; // 2 byte crc check
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*p++ = crc >> 8;
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return write_serial_data(buf, 68);
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}
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