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kalman added

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This commit is contained in:
Edward V. Emelianov
2026-03-23 12:10:20 +03:00
parent 8698dfa016
commit 9e7c732afd
7 changed files with 270 additions and 92 deletions
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1
PID.c
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@@ -149,6 +149,7 @@ static double getspeed(const coordval_t *tagpos, PIDController_t *pid, axisdata_
// TODO: we can point somehow that we are at target or introduce new axis state
}else DBG("Current abs error: %g", fe);
break;
case AXIS_GONNASTOP:
case AXIS_STOPPED: // start pointing to target; will change speed next time
DBG("AXIS STOPPED!!!! --> Slewing");
axis->state = AXIS_SLEWING;

169
kalman.c Normal file
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@@ -0,0 +1,169 @@
/*
* This file is part of the libsidservo project.
* Copyright 2026 Edward V. Emelianov <edward.emelianoff@gmail.com>.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <math.h>
#include "kalman.h"
void kalman3_init(Kalman3 *kf, double dt, double enc_var){
kf->dt = dt;
kf->x[0] = 0;
kf->x[1] = 0;
kf->x[2] = 0;
for(int i=0;i<3;i++)
for(int j=0;j<3;j++)
kf->P[i][j] = 0;
kf->P[0][0] = 1;
kf->P[1][1] = 1;
kf->P[2][2] = 1;
// process noise
kf->Q[0][0] = 1e-6;
kf->Q[1][1] = 1e-4;
kf->Q[2][2] = 1e-3;
kf->R = enc_var; // encoder noise variance
}
void kalman3_set_jerk_noise(Kalman3 *kf, double sigma_j){
double dt = kf->dt;
double dt2 = dt*dt;
double dt3 = dt2*dt;
double dt4 = dt3*dt;
double dt5 = dt4*dt;
double q = sigma_j * sigma_j;
kf->Q[0][0] = q * dt5 / 20.0;
kf->Q[0][1] = q * dt4 / 8.0;
kf->Q[0][2] = q * dt3 / 6.0;
kf->Q[1][0] = q * dt4 / 8.0;
kf->Q[1][1] = q * dt3 / 3.0;
kf->Q[1][2] = q * dt2 / 2.0;
kf->Q[2][0] = q * dt3 / 6.0;
kf->Q[2][1] = q * dt2 / 2.0;
kf->Q[2][2] = q * dt;
}
void kalman3_predict(Kalman3 *kf){
double dt = kf->dt;
double dt2 = 0.5 * dt * dt;
double theta = kf->x[0];
double omega = kf->x[1];
double alpha = kf->x[2];
// state prediction
kf->x[0] = theta + omega*dt + alpha*dt2;
kf->x[1] = omega + alpha*dt;
kf->x[2] = alpha;
// transition matrix
double F[3][3] =
{
{1, dt, dt2},
{0, 1, dt},
{0, 0, 1}
};
// P = FPF^T + Q
double FP[3][3];
for(int i=0;i<3;i++)
for(int j=0;j<3;j++){
FP[i][j] =
F[i][0]*kf->P[0][j] +
F[i][1]*kf->P[1][j] +
F[i][2]*kf->P[2][j];
}
double Pnew[3][3];
for(int i=0;i<3;i++)
for(int j=0;j<3;j++){
Pnew[i][j] =
FP[i][0]*F[j][0] +
FP[i][1]*F[j][1] +
FP[i][2]*F[j][2] +
kf->Q[i][j];
}
for(int i=0;i<3;i++)
for(int j=0;j<3;j++)
kf->P[i][j] = Pnew[i][j];
}
void kalman3_update(Kalman3 *kf, double z){
// innovation
double y = z - kf->x[0];
// S = HPH^T + R
double S = kf->P[0][0] + kf->R;
// Kalman gain
double K[3];
K[0] = kf->P[0][0] / S;
K[1] = kf->P[1][0] / S;
K[2] = kf->P[2][0] / S;
// state update
kf->x[0] += K[0] * y;
kf->x[1] += K[1] * y;
kf->x[2] += K[2] * y;
// covariance update
double P00 = kf->P[0][0];
double P01 = kf->P[0][1];
double P02 = kf->P[0][2];
double P10 = kf->P[1][0];
double P11 = kf->P[1][1];
double P12 = kf->P[1][2];
double P20 = kf->P[2][0];
double P21 = kf->P[2][1];
double P22 = kf->P[2][2];
kf->P[0][0] = P00 - K[0]*P00;
kf->P[0][1] = P01 - K[0]*P01;
kf->P[0][2] = P02 - K[0]*P02;
kf->P[1][0] = P10 - K[1]*P00;
kf->P[1][1] = P11 - K[1]*P01;
kf->P[1][2] = P12 - K[1]*P02;
kf->P[2][0] = P20 - K[2]*P00;
kf->P[2][1] = P21 - K[2]*P01;
kf->P[2][2] = P22 - K[2]*P02;
}
// estimation of the R
double encoder_noise(int counts){
double d = 2.0*M_PI / counts;
return d*d / 12.0;
}

34
kalman.h Normal file
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@@ -0,0 +1,34 @@
/*
* This file is part of the libsidservo project.
* Copyright 2026 Edward V. Emelianov <edward.emelianoff@gmail.com>.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
typedef struct{
double x[3]; // [theta, omega, alpha]
double P[3][3]; // covariance
double Q[3][3]; // process noise
double R; // measurement noise
double dt;
} Kalman3;
double encoder_noise(int counts);
void kalman3_update(Kalman3 *kf, double z);
void kalman3_predict(Kalman3 *kf);
void kalman3_set_jerk_noise(Kalman3 *kf, double sigma_j);
void kalman3_init(Kalman3 *kf, double dt, double enc_var);

2
libsidservo.files
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@@ -13,12 +13,14 @@ examples/dumpswing.c
examples/goto.c
examples/scmd_traectory.c
examples/simpleconv.h
kalman.c
main.c
sidservo.h
serial.c
examples/CMakeLists.txt
examples/traectories.c
examples/traectories.h
kalman.h
main.h
movingmodel.c
movingmodel.h

126
serial.c
View File

@@ -31,6 +31,7 @@
#include <sys/stat.h>
#include <unistd.h>
#include "kalman.h"
#include "main.h"
#include "movingmodel.h"
#include "serial.h"
@@ -141,77 +142,6 @@ static void parse_encbuf(uint8_t databuf[ENC_DATALEN], struct timespec *t){
//DBG("time = %zd+%zd/1e6, X=%g deg, Y=%g deg", tv->tv_sec, tv->tv_usec, mountdata.encposition.X*180./M_PI, mountdata.encposition.Y*180./M_PI);
}
#if 0
/**
* @brief getencval - get uint64_t data from encoder
* @param fd - encoder fd
* @param val - value read
* @param t - measurement time
* @return amount of data read or 0 if problem
*/
static int getencval(int fd, double *val, struct timespec *t){
if(fd < 0){
DBG("Encoder fd < 0!");
return FALSE;
}
char buf[128];
int got = 0, Lmax = 127;
double t0 = timefromstart();
//DBG("start: %.6g", t0);
do{
fd_set rfds;
FD_ZERO(&rfds);
FD_SET(fd, &rfds);
struct timeval tv = encRtmout;
int retval = select(fd + 1, &rfds, NULL, NULL, &tv);
if(!retval){
//DBG("select()==0 - timeout, %.6g", timefromstart());
break;
}
if(retval < 0){
if(errno == EINTR){
DBG("EINTR");
continue;
}
DBG("select() < 0");
return 0;
}
if(FD_ISSET(fd, &rfds)){
ssize_t l = read(fd, &buf[got], Lmax);
if(l < 1){
DBG("read() < 0");
return 0; // disconnected ??
}
got += l; Lmax -= l;
buf[got] = 0;
} else continue;
if(buf[got-1] == '\n') break; // got EOL as last symbol
}while(Lmax && timefromstart() - t0 < Conf.EncoderReqInterval / 5.);
if(got == 0){
//DBG("No data from encoder, tfs=%.6g", timefromstart());
return 0;
}
char *estr = strrchr(buf, '\n');
if(!estr){
DBG("No EOL");
return 0;
}
*estr = 0;
char *bgn = strrchr(buf, '\n');
if(bgn) ++bgn;
else bgn = buf;
char *eptr;
long data = strtol(bgn, &eptr, 10);
if(eptr != estr){
DBG("NAN");
return 0; // wrong number
}
if(val) *val = (double) data;
if(t){ if(!curtime(t)){ DBG("Can't get time"); return 0; }}
return got;
}
#endif
// try to read 1 byte from encoder; return -1 if nothing to read or -2 if device seems to be disconnected
static int getencbyte(){
if(encfd[0] < 0) return -1;
@@ -385,7 +315,7 @@ static int getdata(buf_t *buf, long *out){
if(!buf || buf->len < 1 || buf->len > (XYBUFSZ+1)){
return FALSE;
}
DBG("got data");
// DBG("got data");
// read record between last '\n' and previous (or start of string)
char *last = &buf->buf[buf->len - 1];
//DBG("buf: _%s_", buf->buf);
@@ -433,6 +363,18 @@ static void *encoderthread2(void _U_ *u){
asknext(encfd[0]); asknext(encfd[1]);
t0[0] = t0[1] = tstart = timefromstart();
int errctr = 0;
// init Kalman for both axes
Kalman3 kf[2];
double dt = Conf.EncoderReqInterval; // 1ms encoders step
double sigma_jx = 1e-6, sigma_jy = 1e-6; // "jerk" sigma
double xnoice = encoder_noise(X_ENC_STEPSPERREV);
double ynoice = encoder_noise(Y_ENC_STEPSPERREV);
kalman3_init(&kf[0], dt, xnoice);
kalman3_init(&kf[1], dt, ynoice);
kalman3_set_jerk_noise(&kf[0], sigma_jx);
kalman3_set_jerk_noise(&kf[1], sigma_jy);
do{ // main cycle
if(poll(pfds, 2, 0) < 0){
DBG("poll()");
@@ -450,25 +392,37 @@ static void *encoderthread2(void _U_ *u){
double curt = timefromstart();
if(getdata(&strbuf[i], &msrlast[i])) mtlast[i] = curt;
if(curt - t0[i] >= Conf.EncoderReqInterval){ // get last records
DBG("last rec %d, curt=%g, t0=%g, mtlast=%g", i, curt, t0[i], mtlast[i]);
//DBG("last rec %d, curt=%g, t0=%g, mtlast=%g", i, curt, t0[i], mtlast[i]);
if(curt - mtlast[i] < 1.5*Conf.EncoderReqInterval){
DBG("time OK");
//DBG("time OK");
pthread_mutex_lock(&datamutex);
double pos = (double)msrlast[i];
//DBG("pos[%d]=%g", i, pos);
;;
//DBG("Got med: %g", pos);
if(i == 0){
mountdata.encXposition.val = Xenc2rad(pos);
pos = Xenc2rad(pos);
// Kalman filtering
kalman3_predict(&kf[i]);
kalman3_update(&kf[i], pos);
DBG("Got pos=%g, kalman: angle=%g, vel=%g, acc=%g",
pos, kf[i].x[0], kf[i].x[1], kf[i].x[2]);
mountdata.encXposition.val = kf[i].x[0];
curtime(&mountdata.encXposition.t);
/*DBG("msrlast=%ld, Xpos.val=%g, t=%zd; XEzero=%d, SPR=%g",
msrlast[i], mountdata.encXposition.val, mountdata.encXposition.t.tv_sec,
X_ENC_ZERO, X_ENC_STEPSPERREV);*/
getXspeed();
//getXspeed();
mountdata.encXspeed.val = kf[i].x[1];
mountdata.encXspeed.t = mountdata.encXposition.t;
}else{
mountdata.encYposition.val = Yenc2rad(pos);
pos = Yenc2rad(pos);
kalman3_predict(&kf[i]);
kalman3_update(&kf[i], pos);
DBG("Got pos=%g, kalman: angle=%g, vel=%g, acc=%g",
pos, kf[i].x[0], kf[i].x[1], kf[i].x[2]);
mountdata.encYposition.val = kf[i].x[0];
curtime(&mountdata.encYposition.t);
getYspeed();
//getYspeed();
mountdata.encYspeed.val = kf[i].x[1];
mountdata.encYspeed.t = mountdata.encYposition.t;
}
pthread_mutex_unlock(&datamutex);
}
@@ -860,11 +814,17 @@ static int bincmd(uint8_t *cmd, int len){
}else{
goto rtn;
}
data_t d;
SSstat ans;
data_t d, in;
d.buf = cmd;
d.len = d.maxlen = len;
ret = wr(&d, NULL, 0);
in.buf = (uint8_t*)&ans; in.maxlen = sizeof(SSstat);
ret = wr(&d, &in, 0);
DBG("%s", ret ? "SUCCESS" : "FAIL");
if(ret){
DBG("ANS: Xmot/Ymot: %d/%d, Ylast/Ylast: %d/%d",
ans.Xmot, ans.Ymot, ans.XLast, ans.YLast);
}
rtn:
pthread_mutex_unlock(&mntmutex);
return ret;

1
sidservo.h
View File

@@ -137,6 +137,7 @@ typedef struct{
typedef enum{
AXIS_STOPPED, // stop
AXIS_GONNASTOP, // stop command run
AXIS_SLEWING, // go to target with maximal speed
AXIS_POINTING, // axis is in pointing zone, use PID
AXIS_GUIDING, // near target

25
ssii.c
View File

@@ -45,27 +45,35 @@ uint16_t SScalcChecksum(uint8_t *buf, int len){
}
// Next three functions runs under locked mountdata_t mutex and shouldn't call locked it again!!
static void chkstopstat(int32_t *prev, int32_t cur, int *nstopped, axis_status_t *stat){
static axis_status_t chkstopstat(int32_t *prev, int32_t cur, int *nstopped, axis_status_t stat){
if(*prev == INT32_MAX){
*stat = AXIS_STOPPED;
stat = AXIS_STOPPED;
DBG("START");
}else if(*stat != AXIS_STOPPED){
if(*prev == cur && ++(*nstopped) > MOTOR_STOPPED_CNT){
*stat = AXIS_STOPPED;
}else if(stat == AXIS_GONNASTOP){ // check stop
if(*prev == cur){
if(++(*nstopped) > MOTOR_STOPPED_CNT){
stat = AXIS_STOPPED;
DBG("AXIS stopped");
}
}else *nstopped = 0;
}else if(*prev != cur){
DBG("AXIS moving");
*nstopped = 0;
}
*prev = cur;
return stat;
}
// check for stopped/pointing states
static void ChkStopped(const SSstat *s, mountdata_t *m){
static int32_t Xmot_prev = INT32_MAX, Ymot_prev = INT32_MAX; // previous coordinates
static int Xnstopped = 0, Ynstopped = 0; // counters to get STOPPED state
chkstopstat(&Xmot_prev, s->Xmot, &Xnstopped, &m->Xstate);
chkstopstat(&Ymot_prev, s->Ymot, &Ynstopped, &m->Ystate);
axis_status_t Xstat, Ystat;
Xstat = chkstopstat(&Xmot_prev, s->Xmot, &Xnstopped, m->Xstate);
Ystat = chkstopstat(&Ymot_prev, s->Ymot, &Ynstopped, m->Ystate);
if(Xstat != m->Xstate || Ystat != m->Ystate){
DBG("Status changed");
setStat(Xstat, Ystat);
}
}
/**
@@ -170,14 +178,17 @@ int SSsetterI(const char *cmd, int32_t ival){
}
int SSstop(int emerg){
FNAME();
int i = 0;
const char *cmdx = (emerg) ? CMD_EMSTOPX : CMD_STOPX;
const char *cmdy = (emerg) ? CMD_EMSTOPY : CMD_STOPY;
setStat(AXIS_GONNASTOP, AXIS_GONNASTOP);
for(; i < 10; ++i){
if(!SStextcmd(cmdx, NULL)) continue;
if(SStextcmd(cmdy, NULL)) break;
}
if(i == 10) return FALSE;
DBG("Stopped");
return TRUE;
}