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/*
* Copyright © 2014 Keith Packard <keithp@keithp.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; version 2 of the License.
*
* 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, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include "ao-fakeflight.h"
char *state_name[] = {
[state_ascent] = "ascent",
[state_drogue] = "drogue",
[state_main] = "main",
[state_landed] = "landed",
};
struct rocket o5778 = {
.models = {
[state_ascent] = {
.cd = 0.5,
.diameter = .100
},
[state_drogue] = {
.cd = 1.3,
.diameter = .300
},
[state_main] = {
.cd = 1.3,
.diameter = 1.0
},
},
.empty_mass = 15.0,
.main_deploy = 250,
.motors = {
[0] = {
.fuel_mass = 18.021,
.average_thrust = 5778.0,
.burn_time = 8.52,
.delay = 0.0,
},
[1] = {
.fuel_mass = 18.021,
.average_thrust = 5778.0,
.burn_time = 0, /* 17.04 */
.delay = 18.0,
},
},
};
struct rocket n5778 = {
.models = {
[state_ascent] = {
.cd = 0.5,
.diameter = .100
},
[state_drogue] = {
.cd = 1.3,
.diameter = .300
},
[state_main] = {
.cd = 1.3,
.diameter = 1.0
},
},
.empty_mass = 15.0,
.main_deploy = 250,
.motors = {
[0] = {
.fuel_mass = 9.0105,
.average_thrust = 5778.0,
.burn_time = 4.26,
.delay = 0.0,
},
},
};
/*
* Move the flight one tick forward
*/
void
step(struct flight *f, struct rocket *r)
{
double drag = rocket_drag(f, r);
double thrust = rocket_thrust(f, r);
double gravity = rocket_gravity(f, r);
double mass = rocket_mass(f, r);
double accel;
/* This is our acceleration relative to the earth */
accel = (drag + thrust - gravity) / mass;
/* Because the accelerometer is also affected by gravity, it
* only measures *other* forces applied to the rocket
*/
f->accel = (drag + thrust) / mass;
f->altitude += f->speed * STEP + 0.5 * (accel * STEP) * (accel * STEP);
f->speed += accel * STEP;
f->time += STEP;
}
void
init(struct flight *f, struct rocket *r)
{
double gravity = rocket_gravity(f, r);
/* The pad is pushing up on the rocket to counter
* gravity, so the accelerometer, which only measures
* forces other than gravity, sees only this
*/
f->accel = gravity / rocket_mass(f, r);
f->speed = 0;
f->altitude = 0;
f->time += STEP;
}
void
fly(FILE *file, struct rocket *r)
{
struct flight f = {
.time = -1,
.altitude = 0,
.speed = 0,
.accel = 0,
.state = state_ascent,
};
double max_speed = 0;
double max_alt = 0;
double max_accel = 0;
ao_show_header(file, r);
while (f.time < 0) {
init(&f, r);
ao_log(file, &f, r);
}
while (f.altitude >= 0) {
step(&f, r);
switch (f.state) {
case state_ascent:
if (f.speed >= 0)
break;
f.state = state_drogue;
/* fall through */
case state_drogue:
if (f.altitude > o5778.main_deploy)
break;
f.state = state_main;
/* fall through */
case state_main:
break;
}
ao_log(file, &f, r);
max_speed = fmax(max_speed, f.speed);
max_accel = fmax(max_accel, f.accel);
max_alt = fmax(max_alt, f.altitude);
}
fprintf(stderr, "max alt %9.1f speed %9.1f accel %9.1f\n",
max_alt, max_speed, max_accel);
}
int
main(int argc, char **argv)
{
fly(stdout, &o5778);
// fly(stdout, &n5778);
return 0;
}
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