diff options
Diffstat (limited to 'src/kernel/ao_sample.c')
| -rw-r--r-- | src/kernel/ao_sample.c | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/src/kernel/ao_sample.c b/src/kernel/ao_sample.c new file mode 100644 index 00000000..34658951 --- /dev/null +++ b/src/kernel/ao_sample.c @@ -0,0 +1,372 @@ +/* + * Copyright © 2011 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" +#include <ao_data.h> +#endif + +#if HAS_GYRO +#include <ao_quaternion.h> +#endif + +/* + * Current sensor values + */ + +#ifndef PRES_TYPE +#define PRES_TYPE int32_t +#define ALT_TYPE int32_t +#define ACCEL_TYPE int16_t +#endif + +__pdata uint16_t ao_sample_tick; /* time of last data */ +__pdata pres_t ao_sample_pres; +__pdata alt_t ao_sample_alt; +__pdata alt_t ao_sample_height; +#if HAS_ACCEL +__pdata accel_t ao_sample_accel; +#endif +#if HAS_GYRO +__pdata accel_t ao_sample_accel_along; +__pdata accel_t ao_sample_accel_across; +__pdata accel_t ao_sample_accel_through; +__pdata gyro_t ao_sample_roll; +__pdata gyro_t ao_sample_pitch; +__pdata gyro_t ao_sample_yaw; +__pdata angle_t ao_sample_orient; +#endif + +__data uint8_t ao_sample_data; + +/* + * Sensor calibration values + */ + +__pdata pres_t ao_ground_pres; /* startup pressure */ +__pdata alt_t ao_ground_height; /* MSL of ao_ground_pres */ + +#if HAS_ACCEL +__pdata accel_t ao_ground_accel; /* startup acceleration */ +__pdata accel_t ao_accel_2g; /* factory accel calibration */ +__pdata int32_t ao_accel_scale; /* sensor to m/s² conversion */ +#endif + +#if HAS_GYRO +__pdata accel_t ao_ground_accel_along; +__pdata accel_t ao_ground_accel_across; +__pdata accel_t ao_ground_accel_through; +__pdata int32_t ao_ground_pitch; +__pdata int32_t ao_ground_yaw; +__pdata int32_t ao_ground_roll; +#endif + +static __pdata uint8_t ao_preflight; /* in preflight mode */ + +static __pdata uint16_t nsamples; +__pdata int32_t ao_sample_pres_sum; +#if HAS_ACCEL +__pdata int32_t ao_sample_accel_sum; +#endif +#if HAS_GYRO +__pdata int32_t ao_sample_accel_along_sum; +__pdata int32_t ao_sample_accel_across_sum; +__pdata int32_t ao_sample_accel_through_sum; +__pdata int32_t ao_sample_pitch_sum; +__pdata int32_t ao_sample_yaw_sum; +__pdata int32_t ao_sample_roll_sum; +static struct ao_quaternion ao_rotation; +#endif + +#if HAS_FLIGHT_DEBUG +extern uint8_t ao_orient_test; +#endif + +static void +ao_sample_preflight_add(void) +{ +#if HAS_ACCEL + ao_sample_accel_sum += ao_sample_accel; +#endif + ao_sample_pres_sum += ao_sample_pres; +#if HAS_GYRO + ao_sample_accel_along_sum += ao_sample_accel_along; + ao_sample_accel_across_sum += ao_sample_accel_across; + ao_sample_accel_through_sum += ao_sample_accel_through; + ao_sample_pitch_sum += ao_sample_pitch; + ao_sample_yaw_sum += ao_sample_yaw; + ao_sample_roll_sum += ao_sample_roll; +#endif + ++nsamples; +} + +static void +ao_sample_preflight_set(void) +{ +#if HAS_ACCEL + ao_ground_accel = ao_sample_accel_sum >> 9; + ao_sample_accel_sum = 0; +#endif + ao_ground_pres = ao_sample_pres_sum >> 9; + ao_ground_height = pres_to_altitude(ao_ground_pres); + ao_sample_pres_sum = 0; +#if HAS_GYRO + ao_ground_accel_along = ao_sample_accel_along_sum >> 9; + ao_ground_accel_across = ao_sample_accel_across_sum >> 9; + ao_ground_accel_through = ao_sample_accel_through_sum >> 9; + ao_ground_pitch = ao_sample_pitch_sum; + ao_ground_yaw = ao_sample_yaw_sum; + ao_ground_roll = ao_sample_roll_sum; + ao_sample_accel_along_sum = 0; + ao_sample_accel_across_sum = 0; + ao_sample_accel_through_sum = 0; + ao_sample_pitch_sum = 0; + ao_sample_yaw_sum = 0; + ao_sample_roll_sum = 0; + ao_sample_orient = 0; + + struct ao_quaternion orient; + + /* Take the pad IMU acceleration values and compute our current direction + */ + + ao_quaternion_init_vector(&orient, + (ao_ground_accel_across - ao_config.accel_zero_across), + (ao_ground_accel_through - ao_config.accel_zero_through), + (ao_ground_accel_along - ao_config.accel_zero_along)); + + ao_quaternion_normalize(&orient, + &orient); + + /* Here's up */ + + struct ao_quaternion up = { .r = 0, .x = 0, .y = 0, .z = 1 }; + + if (ao_config.pad_orientation != AO_PAD_ORIENTATION_ANTENNA_UP) + up.z = -1; + + /* Compute rotation to get from up to our current orientation, set + * that as the current rotation vector + */ + ao_quaternion_vectors_to_rotation(&ao_rotation, &up, &orient); +#if HAS_FLIGHT_DEBUG + if (ao_orient_test) + printf("\n\treset\n"); +#endif +#endif + nsamples = 0; +} + +#if HAS_GYRO + +#define TIME_DIV 200.0f + +static void +ao_sample_rotate(void) +{ +#ifdef AO_FLIGHT_TEST + float dt = (ao_sample_tick - ao_sample_prev_tick) / TIME_DIV; +#else + static const float dt = 1/TIME_DIV; +#endif + float x = ao_mpu6000_gyro((float) ((ao_sample_pitch << 9) - ao_ground_pitch) / 512.0f) * dt; + float y = ao_mpu6000_gyro((float) ((ao_sample_yaw << 9) - ao_ground_yaw) / 512.0f) * dt; + float z = ao_mpu6000_gyro((float) ((ao_sample_roll << 9) - ao_ground_roll) / 512.0f) * dt; + struct ao_quaternion rot; + + ao_quaternion_init_half_euler(&rot, x, y, z); + ao_quaternion_multiply(&ao_rotation, &rot, &ao_rotation); + + /* And normalize to make sure it remains a unit vector */ + ao_quaternion_normalize(&ao_rotation, &ao_rotation); + + /* Compute pitch angle from vertical by taking the pad + * orientation vector and rotating it by the current total + * rotation value. That will be a unit vector pointing along + * the airframe axis. The Z value will be the cosine of the + * change in the angle from vertical since boost. + * + * rot = ao_rotation * vertical * ao_rotation° + * rot = ao_rotation * (0,0,0,1) * ao_rotation° + * = ((a.z, a.y, -a.x, a.r) * (a.r, -a.x, -a.y, -a.z)) .z + * + * = (-a.z * -a.z) + (a.y * -a.y) - (-a.x * -a.x) + (a.r * a.r) + * = a.z² - a.y² - a.x² + a.r² + * + * rot = ao_rotation * (0, 0, 0, -1) * ao_rotation° + * = ((-a.z, -a.y, a.x, -a.r) * (a.r, -a.x, -a.y, -a.z)) .z + * + * = (a.z * -a.z) + (-a.y * -a.y) - (a.x * -a.x) + (-a.r * a.r) + * = -a.z² + a.y² + a.x² - a.r² + */ + + float rotz; + rotz = ao_rotation.z * ao_rotation.z - ao_rotation.y * ao_rotation.y - ao_rotation.x * ao_rotation.x + ao_rotation.r * ao_rotation.r; + + ao_sample_orient = acosf(rotz) * (float) (180.0/M_PI); + +#if HAS_FLIGHT_DEBUG + if (ao_orient_test) { + printf ("rot %d %d %d orient %d \r", + (int) (x * 1000), + (int) (y * 1000), + (int) (z * 1000), + ao_sample_orient); + } +#endif + +} +#endif + +static void +ao_sample_preflight(void) +{ + /* startup state: + * + * Collect 512 samples of acceleration and pressure + * data and average them to find the resting values + */ + if (nsamples < 512) { + ao_sample_preflight_add(); + } else { +#if HAS_ACCEL + ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g; + ao_accel_scale = to_fix32(GRAVITY * 2 * 16) / ao_accel_2g; +#endif + ao_sample_preflight_set(); + ao_preflight = FALSE; + } +} + +/* + * While in pad mode, constantly update the ground state by + * re-averaging the data. This tracks changes in orientation, which + * might be caused by adjustments to the rocket on the pad and + * pressure, which might be caused by changes in the weather. + */ + +static void +ao_sample_preflight_update(void) +{ + if (nsamples < 512) + ao_sample_preflight_add(); + else if (nsamples < 1024) + ++nsamples; + else + ao_sample_preflight_set(); +} + +#if 0 +#if HAS_GYRO +static int32_t p_filt; +static int32_t y_filt; + +static gyro_t inline ao_gyro(void) { + gyro_t p = ao_sample_pitch - ao_ground_pitch; + gyro_t y = ao_sample_yaw - ao_ground_yaw; + + p_filt = p_filt - (p_filt >> 6) + p; + y_filt = y_filt - (y_filt >> 6) + y; + + p = p_filt >> 6; + y = y_filt >> 6; + return ao_sqrt(p*p + y*y); +} +#endif +#endif + +uint8_t +ao_sample(void) +{ + ao_wakeup(DATA_TO_XDATA(&ao_sample_data)); + ao_sleep((void *) DATA_TO_XDATA(&ao_data_head)); + while (ao_sample_data != ao_data_head) { + __xdata struct ao_data *ao_data; + + /* Capture a sample */ + ao_data = (struct ao_data *) &ao_data_ring[ao_sample_data]; + ao_sample_tick = ao_data->tick; + +#if HAS_BARO + ao_data_pres_cook(ao_data); + ao_sample_pres = ao_data_pres(ao_data); + ao_sample_alt = pres_to_altitude(ao_sample_pres); + ao_sample_height = ao_sample_alt - ao_ground_height; +#endif + +#if HAS_ACCEL + ao_sample_accel = ao_data_accel_cook(ao_data); + if (ao_config.pad_orientation != AO_PAD_ORIENTATION_ANTENNA_UP) + ao_sample_accel = ao_data_accel_invert(ao_sample_accel); + ao_data_set_accel(ao_data, ao_sample_accel); +#endif +#if HAS_GYRO + ao_sample_accel_along = ao_data_along(ao_data); + ao_sample_accel_across = ao_data_across(ao_data); + ao_sample_accel_through = ao_data_through(ao_data); + ao_sample_pitch = ao_data_pitch(ao_data); + ao_sample_yaw = ao_data_yaw(ao_data); + ao_sample_roll = ao_data_roll(ao_data); +#endif + + if (ao_preflight) + ao_sample_preflight(); + else { + if (ao_flight_state < ao_flight_boost) + ao_sample_preflight_update(); + ao_kalman(); +#if HAS_GYRO + ao_sample_rotate(); +#endif + } +#ifdef AO_FLIGHT_TEST + ao_sample_prev_tick = ao_sample_tick; +#endif + ao_sample_data = ao_data_ring_next(ao_sample_data); + } + return !ao_preflight; +} + +void +ao_sample_init(void) +{ + ao_config_get(); + nsamples = 0; + ao_sample_pres_sum = 0; + ao_sample_pres = 0; +#if HAS_ACCEL + ao_sample_accel_sum = 0; + ao_sample_accel = 0; +#endif +#if HAS_GYRO + ao_sample_accel_along_sum = 0; + ao_sample_accel_across_sum = 0; + ao_sample_accel_through_sum = 0; + ao_sample_accel_along = 0; + ao_sample_accel_across = 0; + ao_sample_accel_through = 0; + ao_sample_pitch_sum = 0; + ao_sample_yaw_sum = 0; + ao_sample_roll_sum = 0; + ao_sample_pitch = 0; + ao_sample_yaw = 0; + ao_sample_roll = 0; + ao_sample_orient = 0; +#endif + ao_sample_data = ao_data_head; + ao_preflight = TRUE; +} |