+++ /dev/null
-/*
- * Copyright © 2009 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.
- */
-
-#ifndef AO_FLIGHT_TEST
-#include "ao.h"
-#endif
-
-/* Main flight thread. */
-
-__pdata enum ao_flight_state ao_flight_state; /* current flight state */
-__pdata uint16_t ao_flight_tick; /* time of last data */
-__pdata uint16_t ao_flight_prev_tick; /* time of previous data */
-__pdata int16_t ao_flight_accel; /* filtered acceleration */
-__pdata int16_t ao_flight_pres; /* filtered pressure */
-__pdata int16_t ao_ground_pres; /* startup pressure */
-__pdata int16_t ao_ground_accel; /* startup acceleration */
-__pdata int16_t ao_min_pres; /* minimum recorded pressure */
-__pdata uint16_t ao_launch_tick; /* time of launch detect */
-__pdata int16_t ao_main_pres; /* pressure to eject main */
-
-/*
- * track min/max data over a long interval to detect
- * resting
- */
-__pdata uint16_t ao_interval_end;
-__pdata int16_t ao_interval_cur_min_accel;
-__pdata int16_t ao_interval_cur_max_accel;
-__pdata int16_t ao_interval_cur_min_pres;
-__pdata int16_t ao_interval_cur_max_pres;
-__pdata int16_t ao_interval_min_accel;
-__pdata int16_t ao_interval_max_accel;
-__pdata int16_t ao_interval_min_pres;
-__pdata int16_t ao_interval_max_pres;
-
-__data uint8_t ao_flight_adc;
-__pdata int16_t ao_raw_accel, ao_raw_accel_prev, ao_raw_pres;
-
-/* Accelerometer calibration
- *
- * We're sampling the accelerometer through a resistor divider which
- * consists of 5k and 10k resistors. This multiplies the values by 2/3.
- * That goes into the cc1111 A/D converter, which is running at 11 bits
- * of precision with the bits in the MSB of the 16 bit value. Only positive
- * values are used, so values should range from 0-32752 for 0-3.3V. The
- * specs say we should see 40mV/g (uncalibrated), multiply by 2/3 for what
- * the A/D converter sees (26.67 mV/g). We should see 32752/3300 counts/mV,
- * for a final computation of:
- *
- * 26.67 mV/g * 32767/3300 counts/mV = 264.8 counts/g
- *
- * Zero g was measured at 16000 (we would expect 16384).
- * Note that this value is only require to tell if the
- * rocket is standing upright. Once that is determined,
- * the value of the accelerometer is averaged for 100 samples
- * to find the resting accelerometer value, which is used
- * for all further flight computations
- */
-
-#define GRAVITY 9.80665
-/* convert m/s to velocity count */
-#define VEL_MPS_TO_COUNT(mps) ((int32_t) (((mps) / GRAVITY) * ACCEL_G * 100))
-
-#define ACCEL_G 265
-#define ACCEL_ZERO_G 16000
-#define ACCEL_NOSE_UP (ACCEL_G * 2 /3)
-#define ACCEL_BOOST ACCEL_G * 2
-#define ACCEL_INT_LAND (ACCEL_G / 10)
-#define ACCEL_VEL_LAND VEL_MPS_TO_COUNT(10)
-#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
- *
- * We directly sample the barometer. The specs say:
- *
- * Pressure range: 15-115 kPa
- * Voltage at 115kPa: 2.82
- * Output scale: 27mV/kPa
- *
- * If we want to detect launch with the barometer, we need
- * a large enough bump to not be fooled by noise. At typical
- * launch elevations (0-2000m), a 200Pa pressure change cooresponds
- * to about a 20m elevation change. This is 5.4mV, or about 3LSB.
- * As all of our calculations are done in 16 bits, we'll actually see a change
- * of 16 times this though
- *
- * 27 mV/kPa * 32767 / 3300 counts/mV = 268.1 counts/kPa
- */
-
-#define BARO_kPa 268
-#define BARO_LAUNCH (BARO_kPa / 5) /* .2kPa, or about 20m */
-#define BARO_APOGEE (BARO_kPa / 10) /* .1kPa, or about 10m */
-#define BARO_COAST (BARO_kPa * 5) /* 5kpa, or about 500m */
-#define BARO_MAIN (BARO_kPa) /* 1kPa, or about 100m */
-#define BARO_INT_LAND (BARO_kPa / 20) /* .05kPa, or about 5m */
-#define BARO_LAND (BARO_kPa * 10) /* 10kPa or about 1000m */
-
-/* We also have a clock, which can be used to sanity check things in
- * case of other failures
- */
-
-#define BOOST_TICKS_MAX AO_SEC_TO_TICKS(15)
-
-/* This value is scaled in a weird way. It's a running total of accelerometer
- * readings minus the ground accelerometer reading. That means it measures
- * velocity, and quite accurately too. As it gets updated 100 times a second,
- * it's scaled by 100
- */
-__pdata int32_t ao_flight_vel;
-__pdata int32_t ao_min_vel;
-__pdata int32_t ao_old_vel;
-__pdata int16_t ao_old_vel_tick;
-__xdata int32_t ao_raw_accel_sum, ao_raw_pres_sum;
-
-/* Landing is detected by getting constant readings from both pressure and accelerometer
- * for a fairly long time (AO_INTERVAL_TICKS)
- */
-#define AO_INTERVAL_TICKS AO_SEC_TO_TICKS(20)
-
-#define abs(a) ((a) < 0 ? -(a) : (a))
-
-void
-ao_flight(void)
-{
- __pdata static uint16_t nsamples = 0;
-
- ao_flight_adc = ao_adc_head;
- ao_raw_accel_prev = 0;
- ao_raw_accel = 0;
- ao_raw_pres = 0;
- ao_flight_tick = 0;
- for (;;) {
- ao_sleep(&ao_adc_ring);
- while (ao_flight_adc != ao_adc_head) {
- __pdata uint8_t ticks;
- __pdata int16_t ao_vel_change;
- ao_flight_prev_tick = ao_flight_tick;
-
- /* Capture a sample */
- ao_raw_accel = ao_adc_ring[ao_flight_adc].accel;
- ao_raw_pres = ao_adc_ring[ao_flight_adc].pres;
- ao_flight_tick = ao_adc_ring[ao_flight_adc].tick;
-
- ao_flight_accel -= ao_flight_accel >> 4;
- ao_flight_accel += ao_raw_accel >> 4;
- ao_flight_pres -= ao_flight_pres >> 4;
- ao_flight_pres += ao_raw_pres >> 4;
- /* Update velocity
- *
- * The accelerometer is mounted so that
- * acceleration yields negative values
- * while deceleration yields positive values,
- * so subtract instead of add.
- */
- ticks = ao_flight_tick - ao_flight_prev_tick;
- ao_vel_change = (((ao_raw_accel >> 1) + (ao_raw_accel_prev >> 1)) - ao_ground_accel);
- ao_raw_accel_prev = ao_raw_accel;
-
- /* one is a common interval */
- if (ticks == 1)
- ao_flight_vel -= (int32_t) ao_vel_change;
- else
- ao_flight_vel -= (int32_t) ao_vel_change * (int32_t) ticks;
-
- ao_flight_adc = ao_adc_ring_next(ao_flight_adc);
- }
-
- if (ao_flight_pres < ao_min_pres)
- ao_min_pres = ao_flight_pres;
- if (ao_flight_vel >= 0) {
- if (ao_flight_vel < ao_min_vel)
- ao_min_vel = ao_flight_vel;
- } else {
- if (-ao_flight_vel < ao_min_vel)
- ao_min_vel = -ao_flight_vel;
- }
-
- switch (ao_flight_state) {
- case ao_flight_startup:
-
- /* startup state:
- *
- * Collect 1000 samples of acceleration and pressure
- * data and average them to find the resting values
- */
- if (nsamples < 1000) {
- ao_raw_accel_sum += ao_raw_accel;
- ao_raw_pres_sum += ao_raw_pres;
- ++nsamples;
- continue;
- }
- ao_ground_accel = (ao_raw_accel_sum / nsamples);
- ao_ground_pres = (ao_raw_pres_sum / nsamples);
- ao_min_pres = ao_ground_pres;
- ao_config_get();
- ao_main_pres = ao_altitude_to_pres(ao_pres_to_altitude(ao_ground_pres) + ao_config.main_deploy);
- ao_flight_vel = 0;
- ao_min_vel = 0;
- ao_old_vel = ao_flight_vel;
- ao_old_vel_tick = ao_flight_tick;
-
- /* Go to launchpad state if the nose is pointing up */
- ao_config_get();
- if (ao_flight_accel < ao_config.accel_zero_g - ACCEL_NOSE_UP) {
-
- /* Disable the USB controller in flight mode
- * to save power
- */
- ao_usb_disable();
-
- /* Turn on telemetry system
- */
- ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_PAD);
-
- ao_flight_state = ao_flight_launchpad;
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- } else {
- ao_flight_state = ao_flight_idle;
-
- /* Turn on the Green LED in idle mode
- */
- ao_led_on(AO_LED_GREEN);
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- }
- /* signal successful initialization by turning off the LED */
- ao_led_off(AO_LED_RED);
- break;
- case ao_flight_launchpad:
-
- /* Trim velocity
- *
- * Once a second, remove any velocity from
- * a second ago
- */
- if ((int16_t) (ao_flight_tick - ao_old_vel_tick) >= AO_SEC_TO_TICKS(1)) {
- ao_old_vel_tick = ao_flight_tick;
- ao_flight_vel -= ao_old_vel;
- ao_old_vel = ao_flight_vel;
- }
- /* pad to boost:
- *
- * accelerometer: > 2g AND velocity > 5m/s
- * OR
- * barometer: > 20m vertical motion
- *
- * The accelerometer should always detect motion before
- * the barometer, but we use both to make sure this
- * transition is detected
- */
- 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;
- ao_launch_tick = ao_flight_tick;
-
- /* start logging data */
- ao_log_start();
-
- /* Increase telemetry rate */
- ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_FLIGHT);
-
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- break;
- }
- break;
- case ao_flight_boost:
-
- /* boost to coast:
- *
- * accelerometer: start to fall at > 1/4 G
- * OR
- * time: boost for more than 15 seconds
- *
- * Detects motor burn out by the switch from acceleration to
- * deceleration, or by waiting until the maximum burn duration
- * (15 seconds) has past.
- */
- if (ao_flight_accel > ao_ground_accel + (ACCEL_G >> 2) ||
- (int16_t) (ao_flight_tick - ao_launch_tick) > BOOST_TICKS_MAX)
- {
- ao_flight_state = ao_flight_coast;
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- break;
- }
- break;
- case ao_flight_coast:
-
- /* coast to apogee detect:
- *
- * accelerometer: integrated velocity < 200 m/s
- * OR
- * barometer: fall at least 500m from max altitude
- *
- * This extra state is required to avoid mis-detecting
- * apogee due to mach transitions.
- *
- * XXX this is essentially a single-detector test
- * as the 500m altitude change would likely result
- * in a loss of the rocket. More data on precisely
- * how big a pressure change the mach transition
- * generates would be useful here.
- */
- if (ao_flight_vel < ACCEL_VEL_MACH ||
- ao_flight_pres > ao_min_pres + BARO_COAST)
- {
- /* set min velocity to current velocity for
- * apogee detect
- */
- ao_min_vel = abs(ao_flight_vel);
- ao_flight_state = ao_flight_apogee;
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- }
- break;
- case ao_flight_apogee:
-
- /* apogee detect to drogue deploy:
- *
- * accelerometer: abs(velocity) > min_velocity + 2m/s
- * OR
- * barometer: fall at least 10m
- *
- * If the barometer saturates because the flight
- * goes over its measuring range (about 53k'),
- * requiring a 10m fall will avoid prematurely
- * detecting apogee; the accelerometer will take
- * over in that case and the integrated velocity
- * measurement should suffice to find apogee
- */
- if (/* abs(ao_flight_vel) > ao_min_vel + ACCEL_VEL_APOGEE || */
- ao_flight_pres > ao_min_pres + BARO_APOGEE)
- {
- /* ignite the drogue charge */
- ao_ignite(ao_igniter_drogue);
-
- /* slow down the telemetry system */
- ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_RECOVER);
-
- /* slow down the ADC sample rate */
- ao_timer_set_adc_interval(10);
-
- /*
- * 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));
- }
-
- break;
- case ao_flight_drogue:
-
- /* drogue to main deploy:
- *
- * 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_pres >= ao_main_pres)
- {
- ao_ignite(ao_igniter_main);
- ao_flight_state = ao_flight_main;
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- }
-
- /* fall through... */
- case ao_flight_main:
-
- /* drogue/main to land:
- *
- * accelerometer: value stable
- * AND
- * barometer: altitude stable and within 1000m of the launch altitude
- */
-
- if (ao_flight_pres < ao_interval_cur_min_pres)
- ao_interval_cur_min_pres = ao_flight_pres;
- if (ao_flight_pres > ao_interval_cur_max_pres)
- ao_interval_cur_max_pres = ao_flight_pres;
- if (ao_flight_accel < ao_interval_cur_min_accel)
- ao_interval_cur_min_accel = ao_flight_accel;
- if (ao_flight_accel > ao_interval_cur_max_accel)
- ao_interval_cur_max_accel = ao_flight_accel;
-
- if ((int16_t) (ao_flight_tick - ao_interval_end) >= 0) {
- ao_interval_max_pres = ao_interval_cur_max_pres;
- ao_interval_min_pres = ao_interval_cur_min_pres;
- ao_interval_max_accel = ao_interval_cur_max_accel;
- ao_interval_min_accel = ao_interval_cur_min_accel;
- 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;
- }
-
- 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;
-
- /* turn off the ADC capture */
- ao_timer_set_adc_interval(0);
-
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
- }
- break;
- case ao_flight_landed:
- break;
- }
- }
-}
-
-#define AO_ACCEL_COUNT_TO_MSS(count) ((count) / 27)
-#define AO_VEL_COUNT_TO_MS(count) ((int16_t) ((count) / 2700))
-
-static void
-ao_flight_status(void)
-{
- printf("STATE: %7s accel: %d speed: %d altitude: %d main: %d\n",
- ao_state_names[ao_flight_state],
- AO_ACCEL_COUNT_TO_MSS(ACCEL_ZERO_G - ao_flight_accel),
- AO_VEL_COUNT_TO_MS(ao_flight_vel),
- ao_pres_to_altitude(ao_flight_pres),
- ao_pres_to_altitude(ao_main_pres));
-}
-
-static __xdata struct ao_task flight_task;
-
-__code struct ao_cmds ao_flight_cmds[] = {
- { 'f', ao_flight_status, "f Display current flight state" },
- { 0, ao_flight_status, NULL }
-};
-
-void
-ao_flight_init(void)
-{
- ao_flight_state = ao_flight_startup;
- ao_interval_min_accel = 0;
- ao_interval_max_accel = 0x7fff;
- ao_interval_min_pres = 0;
- ao_interval_max_pres = 0x7fff;
- ao_interval_end = AO_INTERVAL_TICKS;
-
- ao_add_task(&flight_task, ao_flight, "flight");
- ao_cmd_register(&ao_flight_cmds[0]);
-}
projects / fw / altos / blobdiff