altos: Add kalman filters for baro-only boards

This adds a baro-only kalman filter to track the state of the rocket,
and then uses it to control flight events instead of the existing
ad-hoc mechanisms.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/ao_flight.c b/src/ao_flight.c
index 8e370c4fa16d7d1eb86bbff1e99ae266feceebbd..e8130baab3070d54cb40a05adc88554508ff6b44 100644 (file)
--- a/src/ao_flight.c
+++ b/src/ao_flight.c
@@ -31,6 +31,10 @@
 #error Please define HAS_USB
 #endif
 
+#ifndef USE_KALMAN
+#error Please define USE_KALMAN
+#endif
+
 /* Main flight thread. */
 
 __pdata enum ao_flight_state   ao_flight_state;        /* current flight state */
@@ -150,6 +154,62 @@ __pdata int16_t ao_old_vel_tick;
 __xdata int32_t ao_raw_accel_sum;
 #endif
 
+#if USE_KALMAN
+__pdata int16_t                        ao_ground_height;
+__pdata int32_t                        ao_k_max_height;
+__pdata int32_t                        ao_k_height;
+__pdata int32_t                        ao_k_speed;
+__pdata int32_t                        ao_k_accel;
+
+#define to_fix16(x) ((int16_t) ((x) * 65536.0 + 0.5))
+#define to_fix32(x) ((int32_t) ((x) * 65536.0 + 0.5))
+
+#define from_fix(x)    ((x) >> 16)
+
+#define AO_K0_100      to_fix16(0.05680323)
+#define AO_K1_100      to_fix16(0.16608182)
+#define AO_K2_100      to_fix16(0.24279580)
+
+#define AO_K_STEP_100          to_fix16(0.01)
+#define AO_K_STEP_2_2_100      to_fix16(0.00005)
+
+#define AO_K0_10       to_fix16(0.23772023)
+#define AO_K1_10       to_fix16(0.32214149)
+#define AO_K2_10       to_fix16(0.21827159)
+
+#define AO_K_STEP_10           to_fix16(0.1)
+#define AO_K_STEP_2_2_10       to_fix16(0.005)
+
+static void
+ao_kalman_baro(void)
+{
+       int16_t err = ((ao_pres_to_altitude(ao_raw_pres) - ao_ground_height))
+               - (int16_t) (ao_k_height >> 16);
+
+#ifdef AO_FLIGHT_TEST
+       if (ao_flight_tick - ao_flight_prev_tick > 5) {
+               ao_k_height += ((ao_k_speed >> 16) * AO_K_STEP_10 +
+                               (ao_k_accel >> 16) * AO_K_STEP_2_2_10);
+               ao_k_speed += (ao_k_accel >> 16) * AO_K_STEP_10;
+
+               /* correct */
+               ao_k_height += (int32_t) AO_K0_10 * err;
+               ao_k_speed += (int32_t) AO_K1_10 * err;
+               ao_k_accel += (int32_t) AO_K2_10 * err;
+               return;
+       }
+#endif
+       ao_k_height += ((ao_k_speed >> 16) * AO_K_STEP_100 +
+                       (ao_k_accel >> 16) * AO_K_STEP_2_2_100);
+       ao_k_speed += (ao_k_accel >> 16) * AO_K_STEP_100;
+
+       /* correct */
+       ao_k_height += (int32_t) AO_K0_100 * err;
+       ao_k_speed += (int32_t) AO_K1_100 * err;
+       ao_k_accel += (int32_t) AO_K2_100 * err;
+}
+#endif
+
 __xdata int32_t ao_raw_pres_sum;
 
 /* Landing is detected by getting constant readings from both pressure and accelerometer
@@ -296,6 +356,10 @@ ao_flight(void)
                                ao_flight_vel += (int32_t) ao_vel_change * (int32_t) ticks;
 #endif
 
+#if USE_KALMAN
+                       if (ao_flight_state > ao_flight_idle)
+                               ao_kalman_baro();
+#endif
                        ao_flight_adc = ao_adc_ring_next(ao_flight_adc);
                }
 
@@ -333,6 +397,9 @@ ao_flight(void)
                        ao_ground_pres = ao_raw_pres_sum >> 9;
                        ao_min_pres = ao_ground_pres;
                        ao_config_get();
+#if USE_KALMAN
+                       ao_ground_height = ao_pres_to_altitude(ao_ground_pres);
+#endif
                        ao_main_pres = ao_altitude_to_pres(ao_pres_to_altitude(ao_ground_pres) + ao_config.main_deploy);
 #if HAS_ACCEL
                        ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g;
@@ -369,7 +436,6 @@ ao_flight(void)
                        {
                                /* Set pad mode - we can fly! */
                                ao_flight_state = ao_flight_pad;
-
 #if HAS_USB
                                /* Disable the USB controller in flight mode
                                 * to save power
@@ -421,14 +487,20 @@ ao_flight(void)
                         * the barometer, but we use both to make sure this
                         * transition is detected
                         */
+#if USE_KALMAN
+                       if ((ao_k_accel > to_fix32(20) &&
+                            ao_k_speed > to_fix32(5)) ||
+                           ao_k_height > to_fix32(20))
+#else
                        if (
 #if HAS_ACCEL
                                (ao_flight_accel < ao_ground_accel - ACCEL_BOOST &&
                                 ao_flight_vel > ACCEL_VEL_BOOST) ||
 #endif
                            ao_flight_pres < ao_ground_pres - BARO_LAUNCH)
+#endif
                        {
-#if HAS_ACCEL
+#if HAS_ACCEL || USE_KALMAN
                                ao_flight_state = ao_flight_boost;
 #else
                                ao_flight_state = ao_flight_coast;
@@ -454,7 +526,7 @@ ao_flight(void)
                                break;
                        }
                        break;
-#if HAS_ACCEL
+#if HAS_ACCEL || USE_KALMAN
                case ao_flight_boost:
 
                        /* boost to fast:
@@ -467,8 +539,13 @@ ao_flight(void)
                         * deceleration, or by waiting until the maximum burn duration
                         * (15 seconds) has past.
                         */
+#if USE_KALMAN
+                       if ((ao_k_accel < to_fix32(-10) && ao_k_height > to_fix32(100)) ||
+                           (int16_t) (ao_flight_tick - ao_launch_tick) > BOOST_TICKS_MAX)
+#else
                        if (ao_flight_accel > ao_ground_accel + ACCEL_COAST ||
                            (int16_t) (ao_flight_tick - ao_launch_tick) > BOOST_TICKS_MAX)
+#endif
                        {
                                ao_flight_state = ao_flight_fast;
                                ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
@@ -492,20 +569,34 @@ ao_flight(void)
                         * how big a pressure change the mach transition
                         * generates would be useful here.
                         */
+#if USE_KALMAN
+                       if (ao_k_speed < to_fix32(200) ||
+                           ao_k_height < ao_k_max_height - to_fix32(500))
+#else
                        if (ao_flight_vel < ACCEL_VEL_MACH ||
                            ao_flight_pres > ao_min_pres + BARO_COAST)
+#endif
                        {
+#if HAS_ACCEL
                                /* set min velocity to current velocity for
                                 * apogee detect
                                 */
                                ao_min_vel = abs(ao_flight_vel);
+#endif
                                ao_flight_state = ao_flight_coast;
                                ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
                        }
                        break;
-#endif
+#endif /* HAS_ACCEL */
                case ao_flight_coast:
 
+#if USE_KALMAN
+                       /* apogee detect: coast to drogue deploy:
+                        *
+                        * speed: < 0
+                        */
+                       if (ao_k_speed < 0)
+#else
                        /* apogee detect: coast to drogue deploy:
                         *
                         * barometer: fall at least 10m
@@ -517,6 +608,7 @@ ao_flight(void)
                         * we'll trust to a single sensor for this test
                         */
                        if (ao_flight_pres > ao_min_pres + BARO_APOGEE)
+#endif
                        {
                                /* ignite the drogue charge */
                                ao_ignite(ao_igniter_drogue);
@@ -569,7 +661,11 @@ ao_flight(void)
                         * at that point. Perhaps also use the drogue sense lines
                         * to notice continutity?
                         */
+#if USE_KALMAN
+                       if (from_fix(ao_k_height) < ao_config.main_deploy)
+#else
                        if (ao_flight_pres >= ao_main_pres)
+#endif
                        {
                                ao_ignite(ao_igniter_main);
                                ao_flight_state = ao_flight_main;

diff --git a/src/ao_flight_test.c b/src/ao_flight_test.c
index a635803f41b226b2bc988a65b229aaab60520883..1616764451be187b0a3e1c407509a000e5fe0034 100644 (file)
--- a/src/ao_flight_test.c
+++ b/src/ao_flight_test.c
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <getopt.h>
 
 #define AO_HERTZ       100
 
@@ -62,6 +63,7 @@ enum ao_flight_state {
 
 struct ao_adc ao_adc_ring[AO_ADC_RING];
 uint8_t ao_adc_head;
+int    ao_summary = 0;
 
 #define ao_led_on(l)
 #define ao_led_off(l)
@@ -79,10 +81,13 @@ enum ao_igniter {
        ao_igniter_main = 1
 };
 
+struct ao_adc ao_adc_static;
+
 void
 ao_ignite(enum ao_igniter igniter)
 {
-       printf ("ignite %s\n", igniter == ao_igniter_drogue ? "drogue" : "main");
+       printf ("ignite %s at %7.2f\n", igniter == ao_igniter_drogue ? "drogue" : "main",
+               (double) ao_adc_static.tick / 100.0);
 }
 
 struct ao_task {
@@ -99,8 +104,6 @@ struct ao_task {
 
 #define AO_FLIGHT_TEST
 
-struct ao_adc ao_adc_static;
-
 FILE *emulator_in;
 
 void
@@ -140,20 +143,37 @@ struct ao_config ao_config;
 #ifndef HAS_ACCEL
 #define HAS_ACCEL 1
 #define HAS_ACCEL_REF 0
+#define USE_KALMAN 0
+#else
+#define USE_KALMAN 1
 #endif
 
 #include "ao_flight.c"
 
+#define to_double(f)   ((f) / 65536.0)
+
 void
 ao_insert(void)
 {
        ao_adc_ring[ao_adc_head] = ao_adc_static;
        ao_adc_head = ao_adc_ring_next(ao_adc_head);
+       if (ao_summary)
+               return;
        if (ao_flight_state != ao_flight_startup) {
+#if USE_KALMAN
+               printf("time %7.2f accel %d pres %d k_height %8.2f k_speed %8.5f k_accel %8.5f\n",
+                      (double) ao_adc_static.tick / 100,
+                      ao_adc_static.accel,
+                      ao_adc_static.pres,
+                      to_double(ao_k_height),
+                      to_double(ao_k_speed),
+                      to_double(ao_k_accel));
+#else
                printf("time %g accel %d pres %d\n",
                       (double) ao_adc_static.tick / 100,
                       ao_adc_static.accel,
                       ao_adc_static.pres);
+#endif
        }
 }
 
@@ -269,6 +289,8 @@ ao_dump_state(void)
 {
        if (ao_flight_state == ao_flight_startup)
                return;
+       if (ao_summary)
+               return;
 #if HAS_ACCEL
        printf ("\t\t\t\t\t%s accel %g vel %g alt %d main %d\n",
                ao_state_names[ao_flight_state],
@@ -286,14 +308,44 @@ ao_dump_state(void)
                exit(0);
 }
 
+static const struct option options[] = {
+       { .name = "summary", .has_arg = 0, .val = 's' },
+       { 0, 0, 0, 0},
+};
+
+void run_flight_fixed(char *name, FILE *f, int summary)
+{
+       emulator_in = f;
+       ao_summary = summary;
+       ao_flight_init();
+       ao_flight();
+}
+
 int
 main (int argc, char **argv)
 {
-       emulator_in = fopen (argv[1], "r");
-       if (!emulator_in) {
-               perror(argv[1]);
-               exit(1);
+       int     summary = 0;
+       int     c;
+       int     i;
+
+       while ((c = getopt_long(argc, argv, "s", options, NULL)) != -1) {
+               switch (c) {
+               case 's':
+                       summary = 1;
+                       break;
+               }
        }
-       ao_flight_init();
-       ao_flight();
+
+       if (optind == argc)
+               run_flight_fixed("<stdin>", stdin, summary);
+       else
+               for (i = optind; i < argc; i++) {
+                       FILE    *f = fopen(argv[i], "r");
+                       if (!f) {
+                               perror(argv[i]);
+                               continue;
+                       }
+                       run_flight_fixed(argv[i], f, summary);
+                       fclose(f);
+               }
 }

diff --git a/src/ao_pins.h b/src/ao_pins.h
index 0de3997001950c94bb60d45ee49d01e8462a5711..353b5fd52559cb712923acfb1229973341c1cf68 100644 (file)
--- a/src/ao_pins.h
+++ b/src/ao_pins.h
@@ -27,6 +27,7 @@
        #define HAS_ADC                 1
        #define HAS_EEPROM              1
        #define HAS_DBG                 1
+       #define USE_KALMAN              0
        #define DBG_ON_P1               1
        #define DBG_ON_P0               0
        #define IGNITE_ON_P2            1
@@ -50,6 +51,7 @@
        #define HAS_ADC                 1
        #define HAS_EEPROM              1
        #define HAS_DBG                 1
+       #define USE_KALMAN              0
        #define DBG_ON_P1               1
        #define DBG_ON_P0               0
        #define IGNITE_ON_P2            1
@@ -98,6 +100,7 @@
        #define HAS_ADC                 1
        #define HAS_EEPROM              1
        #define HAS_DBG                 0
+       #define USE_KALMAN              1
        #define IGNITE_ON_P2            0
        #define IGNITE_ON_P0            1
        #define PACKET_HAS_MASTER       0
@@ -118,6 +121,7 @@
        #define HAS_SERIAL_1            1
        #define HAS_ADC                 1
        #define HAS_DBG                 0
+       #define USE_KALMAN              0
        #define HAS_EEPROM              1
        #define DBG_ON_P1               0
        #define DBG_ON_P0               1