Accelerometer-based velocity values are invalid after apogee

[fw/altos] / ao_flight.c

diff --git a/ao_flight.c b/ao_flight.c
index 91953975203c830fa76814e1cd02fb35fc33a68b..0b47bfa51a8a50adcaef8a9d1c1cdc3319872437 100644 (file)
--- a/ao_flight.c
+++ b/ao_flight.c
@@ -83,6 +83,7 @@ __pdata int16_t ao_raw_accel, ao_raw_accel_prev, ao_raw_pres;
 #define ACCEL_VEL_MACH VEL_MPS_TO_COUNT(200)
 #define ACCEL_VEL_APOGEE       VEL_MPS_TO_COUNT(2)
 #define ACCEL_VEL_MAIN VEL_MPS_TO_COUNT(100)
+#define ACCEL_VEL_BOOST        VEL_MPS_TO_COUNT(5)
 
 /*
  * Barometer calibration
@@ -242,7 +243,7 @@ ao_flight(void)
 
                        /* pad to boost:
                         *
-                        * accelerometer: > 2g
+                        * accelerometer: > 2g AND velocity > 5m/s
                         *             OR
                         * barometer: > 20m vertical motion
                         *
@@ -250,7 +251,8 @@ ao_flight(void)
                         * the barometer, but we use both to make sure this
                         * transition is detected
                         */
-                       if (ao_flight_accel < ao_ground_accel - ACCEL_BOOST ||
+                       if ((ao_flight_accel < ao_ground_accel - ACCEL_BOOST &&
+                            ao_flight_vel > ACCEL_VEL_BOOST) ||
                            ao_flight_pres < ao_ground_pres - BARO_LAUNCH)
                        {
                                ao_flight_state = ao_flight_boost;
@@ -347,39 +349,45 @@ ao_flight(void)
                                /* Enable RDF beacon */
                                ao_rdf_set(1);
 
+                               /*
+                                * Start recording min/max accel and pres for a while
+                                * to figure out when the rocket has landed
+                                */
+                               /* Set the 'last' limits to max range to prevent
+                                * early resting detection
+                                */
+                               ao_interval_min_accel = 0;
+                               ao_interval_max_accel = 0x7fff;
+                               ao_interval_min_pres = 0;
+                               ao_interval_max_pres = 0x7fff;
+
+                               /* initialize interval values */
+                               ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
+
+                               ao_interval_cur_min_pres = ao_interval_cur_max_pres = ao_flight_pres;
+                               ao_interval_cur_min_accel = ao_interval_cur_max_accel = ao_flight_accel;
+
+                               /* and enter drogue state */
                                ao_flight_state = ao_flight_drogue;
                                ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
                        }
-                       /*
-                        * Start recording min/max accel and pres for a while
-                        * to figure out when the rocket has landed
-                        */
-                       /* Set the 'last' limits to max range to prevent
-                        * early resting detection
-                        */
-                       ao_interval_min_accel = 0;
-                       ao_interval_max_accel = 0x7fff;
-                       ao_interval_min_pres = 0;
-                       ao_interval_max_pres = 0x7fff;
-
-                       /* initialize interval values */
-                       ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
-
-                       ao_interval_cur_min_pres = ao_interval_cur_max_pres = ao_flight_pres;
-                       ao_interval_cur_min_accel = ao_interval_cur_max_accel = ao_flight_accel;
 
                        break;
                case ao_flight_drogue:
 
                        /* drogue to main deploy:
                         *
-                        * accelerometer: abs(velocity) > 100m/s (in case the drogue failed)
-                        *               OR
                         * barometer: reach main deploy altitude
+                        *
+                        * Would like to use the accelerometer for this test, but
+                        * the orientation of the flight computer is unknown after
+                        * drogue deploy, so we ignore it. Could also detect
+                        * high descent rate using the pressure sensor to
+                        * recognize drogue deploy failure and eject the main
+                        * at that point. Perhaps also use the drogue sense lines
+                        * to notice continutity?
                         */
-                       if (ao_flight_vel < -ACCEL_VEL_MAIN ||
-                           ao_flight_vel > ACCEL_VEL_MAIN ||
-                           ao_flight_pres >= ao_main_pres)
+                       if (ao_flight_pres >= ao_main_pres)
                        {
                                ao_ignite(ao_igniter_main);
                                ao_flight_state = ao_flight_main;
@@ -391,8 +399,8 @@ ao_flight(void)
 
                        /* drogue/main to land:
                         *
-                        * accelerometer: value stable and velocity less than 10m/s
-                        *                           OR
+                        * accelerometer: value stable
+                        *                           AND
                         * barometer: altitude stable and within 1000m of the launch altitude
                         */
 
@@ -415,10 +423,9 @@ ao_flight(void)
                                ao_interval_cur_min_accel = ao_interval_cur_max_accel = ao_flight_accel;
                        }
 
-                       if ((abs(ao_flight_vel) < ACCEL_VEL_LAND &&
-                            (uint16_t) (ao_interval_max_accel - ao_interval_min_accel) < (uint16_t) ACCEL_INT_LAND) ||
-                           (ao_flight_pres > ao_ground_pres - BARO_LAND &&
-                            (uint16_t) (ao_interval_max_pres - ao_interval_min_pres) < (uint16_t) BARO_INT_LAND))
+                       if ((uint16_t) (ao_interval_max_accel - ao_interval_min_accel) < (uint16_t) ACCEL_INT_LAND &&
+                           ao_flight_pres > ao_ground_pres - BARO_LAND &&
+                           (uint16_t) (ao_interval_max_pres - ao_interval_min_pres) < (uint16_t) BARO_INT_LAND)
                        {
                                ao_flight_state = ao_flight_landed;