221 lines
8.0 KiB
C

/*
* This file is part of the moving_model project.
* Copyright 2025 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/>.
*/
// simplest trapezioidal ramp
#include <math.h>
#include <strings.h>
#include "main.h"
#include "ramp.h"
static double coord_tolerance = COORD_TOLERANCE_DEFAULT;
static movestate_t state = ST_STOP;
static moveparam_t Min, Max;
typedef enum{
STAGE_ACCEL, // start from zero speed and accelerate to Max speed
STAGE_MAXSPEED, // go with target speed
STAGE_DECEL, // go from target speed to zero
STAGE_STOPPED, // stop
STAGE_AMOUNT
} movingstage_t;
static movingstage_t movingstage = STAGE_STOPPED;
static double Times[STAGE_AMOUNT] = {0}; // time when each stage starts
static moveparam_t Params[STAGE_AMOUNT] = {0}; // starting parameters for each stage
static moveparam_t curparams = {0}; // current coordinate/speed/acceleration
static int initlims(limits_t *lim){
if(!lim) return FALSE;
Min = lim->min;
Max = lim->max;
return TRUE;
}
static void emstop(double _U_ t){
curparams.accel = 0.;
curparams.speed = 0.;
bzero(Times, sizeof(Times));
bzero(Params, sizeof(Params));
state = ST_STOP;
movingstage = STAGE_STOPPED;
}
static void stop(double t){
if(state == ST_STOP || movingstage == STAGE_STOPPED) return;
movingstage = STAGE_DECEL;
state = ST_MOVE;
Times[STAGE_DECEL] = t;
Params[STAGE_DECEL].speed = curparams.speed;
if(curparams.speed > 0.) Params[STAGE_DECEL].accel = -Max.accel;
else Params[STAGE_DECEL].accel = Max.accel;
Params[STAGE_DECEL].coord = curparams.coord;
// speed: v=v2+a2(t-t2), v2 and a2 have different signs; t3: v3=0 -> t3=t2-v2/a2
Times[STAGE_STOPPED] = t - curparams.speed / Params[STAGE_DECEL].accel;
// coordinate: x=x2+v2(t-t2)+a2(t-t2)^2/2 -> x3=x2+v2(t3-t2)+a2(t3-t2)^2/2
double dt = Times[STAGE_STOPPED] - t;
Params[STAGE_STOPPED].coord = curparams.coord + curparams.speed * dt +
Params[STAGE_DECEL].accel * dt * dt / 2.;
}
/**
* @brief calc - moving calculation
* @param x - using max speed (>0!!!) and coordinate
* @param t - current time value
* @return FALSE if can't move with given parameters
*/
static int calc(moveparam_t *x, double t){
if(!x) return FALSE;
if(x->coord < Min.coord || x->coord > Max.coord) return FALSE;
if(x->speed < Min.speed || x->speed > Max.speed) return FALSE;
double Dx = fabs(x->coord - curparams.coord); // full distance
double sign = (x->coord > curparams.coord) ? 1. : -1.; // sign of target accelerations and speeds
// we have two variants: with or without stage with constant speed
double dt23 = x->speed / Max.accel; // time of deceleration stage for given speed
double dx23 = x->speed * dt23 / 2.; // distance on dec stage (abs)
DBG("Dx=%g, sign=%g, dt23=%g, dx23=%g", Dx, sign, dt23, dx23);
double setspeed = x->speed; // new max speed (we can change it if need)
double dt01, dx01; // we'll fill them depending on starting conditions
Times[0] = t;
Params[0].speed = curparams.speed;
Params[0].coord = curparams.coord;
double curspeed = fabs(curparams.speed);
double dt0s = curspeed / Max.accel; // time of stopping phase
double dx0s = curspeed * dt0s / 2.; // distance
DBG("dt0s=%g, dx0s=%g", dt0s, dx0s);
if(dx0s > Dx){
DBG("distance too short");
return FALSE;
}
if(fabs(Dx - dx0s) < coord_tolerance){ // just stop and we'll be on target
DBG("Distance good to just stop");
stop(t);
return TRUE;
}
if(curparams.speed * sign < 0. || state == ST_STOP){ // we should change speed sign
// after stop we will have full profile
double dxs3 = Dx - dx0s;
double newspeed = sqrt(Max.accel * dxs3);
if(newspeed < setspeed) setspeed = newspeed; // we can't reach user speed
DBG("dxs3=%g, setspeed=%g", dxs3, setspeed);
dt01 = fabs(sign*setspeed - curparams.speed) / Max.accel;
Params[0].accel = sign * Max.accel;
if(state == ST_STOP) dx01 = setspeed * dt01 / 2.;
else dx01 = dt01 * (dt01 / 2. * Max.accel - curspeed);
DBG("dx01=%g, dt01=%g", dx01, dt01);
}else{ // increase or decrease speed without stopping phase
dt01 = fabs(sign*setspeed - curparams.speed) / Max.accel;
double a = sign * Max.accel;
if(sign * curparams.speed < 0.){DBG("change direction"); a = -a;}
else if(curspeed > setspeed){ DBG("lower speed @ this direction"); a = -a;}
//double a = (curspeed > setspeed) ? -Max.accel : Max.accel;
dx01 = curspeed * dt01 + a * dt01 * dt01 / 2.;
DBG("dt01=%g, a=%g, dx01=%g", dt01, a, dx01);
if(dx01 + dx23 > Dx){ // calculate max speed
setspeed = sqrt(Max.accel * Dx - curspeed * curspeed / 2.);
if(setspeed < curspeed){
setspeed = curparams.speed;
dt01 = 0.; dx01 = 0.;
Params[0].accel = 0.;
}else{
Params[0].accel = a;
dt01 = fabs(setspeed - curspeed) / Max.accel;
dx01 = curspeed * dt01 + Max.accel * dt01 * dt01 / 2.;
}
}else Params[0].accel = a;
}
if(setspeed < Min.speed){
DBG("New speed should be too small");
return FALSE;
}
moveparam_t *p = &Params[STAGE_MAXSPEED];
p->accel = 0.; p->speed = sign * setspeed;
p->coord = curparams.coord + dx01 * sign;
Times[STAGE_MAXSPEED] = Times[0] + dt01;
dt23 = setspeed / Max.accel;
dx23 = setspeed * dt23 / 2.;
// calculate dx12 and dt12
double dx12 = Dx - dx01 - dx23;
if(dx12 < -coord_tolerance){
DBG("Oops, WTF dx12=%g?", dx12);
return FALSE;
}
double dt12 = dx12 / setspeed;
p = &Params[STAGE_DECEL];
p->accel = -sign * Max.accel;
p->speed = sign * setspeed;
p->coord = Params[STAGE_MAXSPEED].coord + sign * dx12;
Times[STAGE_DECEL] = Times[STAGE_MAXSPEED] + dt12;
p = &Params[STAGE_STOPPED];
p->accel = 0.; p->speed = 0.; p->coord = x->coord;
Times[STAGE_STOPPED] = Times[STAGE_DECEL] + dt23;
for(int i = 0; i < 4; ++i)
DBG("%d: t=%g, coord=%g, speed=%g, accel=%g", i,
Times[i], Params[i].coord, Params[i].speed, Params[i].accel);
state = ST_MOVE;
movingstage = STAGE_ACCEL;
return TRUE;
}
static movestate_t proc(moveparam_t *next, double t){
if(state == ST_STOP) goto ret;
for(movingstage_t s = STAGE_STOPPED; s >= 0; --s){
if(Times[s] <= t){ // check time for current stage
movingstage = s;
break;
}
}
if(movingstage == STAGE_STOPPED){
curparams.coord = Params[STAGE_STOPPED].coord;
emstop(t);
goto ret;
}
// calculate current parameters
double dt = t - Times[movingstage];
double a = Params[movingstage].accel;
double v0 = Params[movingstage].speed;
double x0 = Params[movingstage].coord;
curparams.accel = a;
curparams.speed = v0 + a * dt;
curparams.coord = x0 + v0 * dt + a * dt * dt / 2.;
ret:
if(next) *next = curparams;
return state;
}
static movestate_t getst(moveparam_t *cur){
if(cur) *cur = curparams;
return state;
}
static double gettstop(){
return Times[STAGE_STOPPED];
}
movemodel_t trapez = {
.init_limits = initlims,
.stop = stop,
.emergency_stop = emstop,
.get_state = getst,
.calculate = calc,
.proc_move = proc,
.stoppenanotime = gettstop,
};