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