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   1 /*
   2  * Copyright © 2009 Keith Packard <keithp@keithp.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; version 2 of the License.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  16  */
  17
  18 #ifndef AO_FLIGHT_TEST
  19 #include "ao.h"
  20 #endif
  21
  22 #ifndef HAS_ACCEL
  23 #error Please define HAS_ACCEL
  24 #endif
  25
  26 #ifndef HAS_GPS
  27 #error Please define HAS_GPS
  28 #endif
  29
  30 #ifndef HAS_USB
  31 #error Please define HAS_USB
  32 #endif
  33
  34 /* Main flight thread. */
  35
  36 __pdata enum ao_flight_state    ao_flight_state;        /* current flight state */
  37 __pdata uint16_t                ao_launch_tick;         /* time of launch detect */
  38
  39 /*
  40  * track min/max data over a long interval to detect
  41  * resting
  42  */
  43 __pdata uint16_t                ao_interval_end;
  44 __pdata int16_t                 ao_interval_min_height;
  45 __pdata int16_t                 ao_interval_max_height;
  46
  47 __xdata uint8_t                 ao_flight_force_idle;
  48
  49 /* We also have a clock, which can be used to sanity check things in
  50  * case of other failures
  51  */
  52
  53 #define BOOST_TICKS_MAX AO_SEC_TO_TICKS(15)
  54
  55 /* Landing is detected by getting constant readings from both pressure and accelerometer
  56  * for a fairly long time (AO_INTERVAL_TICKS)
  57  */
  58 #define AO_INTERVAL_TICKS       AO_SEC_TO_TICKS(5)
  59
  60 #define abs(a)  ((a) < 0 ? -(a) : (a))
  61
  62 void
  63 ao_flight(void)
  64 {
  65         ao_sample_init();
  66         ao_flight_state = ao_flight_startup;
  67         for (;;) {
  68
  69                 /*
  70                  * Process ADC samples, just looping
  71                  * until the sensors are calibrated.
  72                  */
  73                 if (!ao_sample())
  74                         continue;
  75
  76                 switch (ao_flight_state) {
  77                 case ao_flight_startup:
  78
  79                         /* Check to see what mode we should go to.
  80                          *  - Invalid mode if accel cal appears to be out
  81                          *  - pad mode if we're upright,
  82                          *  - idle mode otherwise
  83                          */
  84 #if HAS_ACCEL
  85                         if (ao_config.accel_plus_g == 0 ||
  86                             ao_config.accel_minus_g == 0 ||
  87                             ao_ground_accel < ao_config.accel_plus_g - ACCEL_NOSE_UP ||
  88                             ao_ground_accel > ao_config.accel_minus_g + ACCEL_NOSE_UP)
  89                         {
  90                                 /* Detected an accel value outside -1.5g to 1.5g
  91                                  * (or uncalibrated values), so we go into invalid mode
  92                                  */
  93                                 ao_flight_state = ao_flight_invalid;
  94
  95                         } else
  96 #endif
  97                                 if (!ao_flight_force_idle
  98 #if HAS_ACCEL
  99                                     && ao_ground_accel < ao_config.accel_plus_g + ACCEL_NOSE_UP
 100 #endif
 101                                         )
 102                         {
 103                                 /* Set pad mode - we can fly! */
 104                                 ao_flight_state = ao_flight_pad;
 105 #if HAS_USB
 106                                 /* Disable the USB controller in flight mode
 107                                  * to save power
 108                                  */
 109                                 ao_usb_disable();
 110 #endif
 111
 112                                 /* Disable packet mode in pad state */
 113                                 ao_packet_slave_stop();
 114
 115                                 /* Turn on telemetry system */
 116                                 ao_rdf_set(1);
 117                                 ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_PAD);
 118
 119                                 /* signal successful initialization by turning off the LED */
 120                                 ao_led_off(AO_LED_RED);
 121                         } else {
 122                                 /* Set idle mode */
 123                                 ao_flight_state = ao_flight_idle;
 124
 125                                 /* signal successful initialization by turning off the LED */
 126                                 ao_led_off(AO_LED_RED);
 127                         }
 128                         /* wakeup threads due to state change */
 129                         ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 130
 131                         break;
 132                 case ao_flight_pad:
 133
 134                         /* pad to boost:
 135                          *
 136                          * barometer: > 20m vertical motion
 137                          *             OR
 138                          * accelerometer: > 2g AND velocity > 5m/s
 139                          *
 140                          * The accelerometer should always detect motion before
 141                          * the barometer, but we use both to make sure this
 142                          * transition is detected. If the device
 143                          * doesn't have an accelerometer, then ignore the
 144                          * speed and acceleration as they are quite noisy
 145                          * on the pad.
 146                          */
 147                         if (ao_height > AO_M_TO_HEIGHT(20)
 148 #if HAS_ACCEL
 149                             || (ao_accel > AO_MSS_TO_ACCEL(20) &&
 150                                 ao_speed > AO_MS_TO_SPEED(5))
 151 #endif
 152                                 )
 153                         {
 154                                 ao_flight_state = ao_flight_boost;
 155                                 ao_launch_tick = ao_sample_tick;
 156
 157                                 /* start logging data */
 158                                 ao_log_start();
 159
 160                                 /* Increase telemetry rate */
 161                                 ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_FLIGHT);
 162
 163                                 /* disable RDF beacon */
 164                                 ao_rdf_set(0);
 165
 166 #if HAS_GPS
 167                                 /* Record current GPS position by waking up GPS log tasks */
 168                                 ao_wakeup(&ao_gps_data);
 169                                 ao_wakeup(&ao_gps_tracking_data);
 170 #endif
 171
 172                                 ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 173                                 break;
 174                         }
 175                         break;
 176                 case ao_flight_boost:
 177
 178                         /* boost to fast:
 179                          *
 180                          * accelerometer: start to fall at > 1/4 G
 181                          *              OR
 182                          * time: boost for more than 15 seconds
 183                          *
 184                          * Detects motor burn out by the switch from acceleration to
 185                          * deceleration, or by waiting until the maximum burn duration
 186                          * (15 seconds) has past.
 187                          */
 188                         if ((ao_accel < AO_MSS_TO_ACCEL(-2.5) && ao_height > AO_M_TO_HEIGHT(100)) ||
 189                             (int16_t) (ao_sample_tick - ao_launch_tick) > BOOST_TICKS_MAX)
 190                         {
 191 #if HAS_ACCEL
 192                                 ao_flight_state = ao_flight_fast;
 193 #else
 194                                 ao_flight_state = ao_flight_coast;
 195 #endif
 196                                 ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 197                                 break;
 198                         }
 199                         break;
 200 #if HAS_ACCEL
 201                 case ao_flight_fast:
 202                         /*
 203                          * This is essentially the same as coast,
 204                          * but the barometer is being ignored as
 205                          * it may be unreliable.
 206                          */
 207                         if (ao_speed < AO_MS_TO_SPEED(AO_MAX_BARO_SPEED))
 208                         {
 209                                 ao_flight_state = ao_flight_coast;
 210                                 ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 211                                 break;
 212                         }
 213                         break;
 214 #endif
 215                 case ao_flight_coast:
 216
 217                         /* apogee detect: coast to drogue deploy:
 218                          *
 219                          * speed: < 0
 220                          *
 221                          * Also make sure the model altitude is tracking
 222                          * the measured altitude reasonably closely; otherwise
 223                          * we're probably transsonic.
 224                          */
 225                         if (ao_speed < 0
 226 #if !HAS_ACCEL
 227                             && (ao_sample_alt >= AO_MAX_BARO_HEIGHT || ao_error_h_sq_avg < 100)
 228 #endif
 229                                 )
 230                         {
 231                                 /* ignite the drogue charge */
 232                                 ao_ignite(ao_igniter_drogue);
 233
 234                                 /* slow down the telemetry system */
 235                                 ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_RECOVER);
 236
 237                                 /* Turn the RDF beacon back on */
 238                                 ao_rdf_set(1);
 239
 240                                 /*
 241                                  * Start recording min/max height
 242                                  * to figure out when the rocket has landed
 243                                  */
 244
 245                                 /* initialize interval values */
 246                                 ao_interval_end = ao_sample_tick + AO_INTERVAL_TICKS;
 247
 248                                 ao_interval_min_height = ao_interval_max_height = ao_height;
 249
 250                                 /* and enter drogue state */
 251                                 ao_flight_state = ao_flight_drogue;
 252                                 ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 253                         }
 254
 255                         break;
 256                 case ao_flight_drogue:
 257
 258                         /* drogue to main deploy:
 259                          *
 260                          * barometer: reach main deploy altitude
 261                          *
 262                          * Would like to use the accelerometer for this test, but
 263                          * the orientation of the flight computer is unknown after
 264                          * drogue deploy, so we ignore it. Could also detect
 265                          * high descent rate using the pressure sensor to
 266                          * recognize drogue deploy failure and eject the main
 267                          * at that point. Perhaps also use the drogue sense lines
 268                          * to notice continutity?
 269                          */
 270                         if (ao_height <= ao_config.main_deploy)
 271                         {
 272                                 ao_ignite(ao_igniter_main);
 273                                 ao_flight_state = ao_flight_main;
 274                                 ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 275                         }
 276
 277                         /* fall through... */
 278                 case ao_flight_main:
 279
 280                         /* drogue/main to land:
 281                          *
 282                          * barometer: altitude stable and within 1000m of the launch altitude
 283                          */
 284
 285                         if (ao_height < ao_interval_min_height)
 286                                 ao_interval_min_height = ao_height;
 287                         if (ao_height > ao_interval_max_height)
 288                                 ao_interval_max_height = ao_height;
 289
 290                         if ((int16_t) (ao_sample_tick - ao_interval_end) >= 0) {
 291                                 if (ao_height < AO_M_TO_HEIGHT(1000) &&
 292                                     ao_interval_max_height - ao_interval_min_height < AO_M_TO_HEIGHT(5))
 293                                 {
 294                                         ao_flight_state = ao_flight_landed;
 295
 296                                         /* turn off the ADC capture */
 297                                         ao_timer_set_adc_interval(0);
 298
 299                                         ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
 300                                 }
 301                                 ao_interval_min_height = ao_interval_max_height = ao_height;
 302                                 ao_interval_end = ao_sample_tick + AO_INTERVAL_TICKS;
 303                         }
 304                         break;
 305                 case ao_flight_landed:
 306                         break;
 307                 }
 308         }
 309 }
 310
 311 static __xdata struct ao_task   flight_task;
 312
 313 void
 314 ao_flight_init(void)
 315 {
 316         ao_flight_state = ao_flight_startup;
 317         ao_add_task(&flight_task, ao_flight, "flight");
 318 }