2 * Copyright © 2011 Keith Packard <keithp@keithp.com>
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.
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.
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.
18 #ifndef AO_FLIGHT_TEST
24 #include <ao_quaternion.h>
28 * Current sensor values
32 #define PRES_TYPE int32_t
33 #define ALT_TYPE int32_t
34 #define ACCEL_TYPE int16_t
37 __pdata uint16_t ao_sample_tick; /* time of last data */
38 __pdata pres_t ao_sample_pres;
39 __pdata alt_t ao_sample_alt;
40 __pdata alt_t ao_sample_height;
42 __pdata accel_t ao_sample_accel;
45 __pdata accel_t ao_sample_accel_along;
46 __pdata accel_t ao_sample_accel_across;
47 __pdata accel_t ao_sample_accel_through;
48 __pdata gyro_t ao_sample_roll;
49 __pdata gyro_t ao_sample_pitch;
50 __pdata gyro_t ao_sample_yaw;
51 __pdata angle_t ao_sample_orient;
54 __data uint8_t ao_sample_data;
57 * Sensor calibration values
60 __pdata pres_t ao_ground_pres; /* startup pressure */
61 __pdata alt_t ao_ground_height; /* MSL of ao_ground_pres */
64 __pdata accel_t ao_ground_accel; /* startup acceleration */
65 __pdata accel_t ao_accel_2g; /* factory accel calibration */
66 __pdata int32_t ao_accel_scale; /* sensor to m/s² conversion */
70 __pdata accel_t ao_ground_accel_along;
71 __pdata accel_t ao_ground_accel_across;
72 __pdata accel_t ao_ground_accel_through;
73 __pdata gyro_t ao_ground_pitch;
74 __pdata gyro_t ao_ground_yaw;
75 __pdata gyro_t ao_ground_roll;
78 static __pdata uint8_t ao_preflight; /* in preflight mode */
80 static __pdata uint16_t nsamples;
81 __pdata int32_t ao_sample_pres_sum;
83 __pdata int32_t ao_sample_accel_sum;
86 __pdata int32_t ao_sample_accel_along_sum;
87 __pdata int32_t ao_sample_accel_across_sum;
88 __pdata int32_t ao_sample_accel_through_sum;
89 __pdata int32_t ao_sample_pitch_sum;
90 __pdata int32_t ao_sample_yaw_sum;
91 __pdata int32_t ao_sample_roll_sum;
92 static struct ao_quaternion ao_rotation;
93 static struct ao_quaternion ao_pad_orientation;
97 ao_sample_preflight_add(void)
100 ao_sample_accel_sum += ao_sample_accel;
102 ao_sample_pres_sum += ao_sample_pres;
104 ao_sample_accel_along_sum += ao_sample_accel_along;
105 ao_sample_accel_across_sum += ao_sample_accel_across;
106 ao_sample_accel_through_sum += ao_sample_accel_through;
107 ao_sample_pitch_sum += ao_sample_pitch;
108 ao_sample_yaw_sum += ao_sample_yaw;
109 ao_sample_roll_sum += ao_sample_roll;
115 ao_sample_preflight_set(void)
118 ao_ground_accel = ao_sample_accel_sum >> 9;
119 ao_sample_accel_sum = 0;
121 ao_ground_pres = ao_sample_pres_sum >> 9;
122 ao_ground_height = pres_to_altitude(ao_ground_pres);
123 ao_sample_pres_sum = 0;
125 ao_ground_accel_along = ao_sample_accel_along_sum >> 9;
126 ao_ground_accel_across = ao_sample_accel_across_sum >> 9;
127 ao_ground_accel_through = ao_sample_accel_through_sum >> 9;
128 ao_ground_pitch = ao_sample_pitch_sum >> 9;
129 ao_ground_yaw = ao_sample_yaw_sum >> 9;
130 ao_ground_roll = ao_sample_roll_sum >> 9;
131 ao_sample_accel_along_sum = 0;
132 ao_sample_accel_across_sum = 0;
133 ao_sample_accel_through_sum = 0;
134 ao_sample_pitch_sum = 0;
135 ao_sample_yaw_sum = 0;
136 ao_sample_roll_sum = 0;
137 ao_sample_orient = 0;
139 /* No rotation yet */
140 ao_quaternion_init_zero_rotation(&ao_rotation);
142 /* Take the pad IMU acceleration values and compute our current direction
144 ao_quaternion_init_vector(&ao_pad_orientation,
145 ao_ground_accel_across - ao_config.accel_zero_across,
146 ao_ground_accel_through - ao_config.accel_zero_through,
147 -ao_ground_accel_along - ao_config.accel_zero_along);
149 ao_quaternion_normalize(&ao_pad_orientation,
150 &ao_pad_orientation);
158 ao_sample_rotate(void)
160 #ifdef AO_FLIGHT_TEST
161 float dt = (ao_sample_tick - ao_sample_prev_tick) / 100.0;
163 static const float dt = 1/100.0;
165 float x = ao_mpu6000_gyro(ao_sample_pitch - ao_ground_pitch) * dt;
166 float y = ao_mpu6000_gyro(ao_sample_yaw - ao_ground_yaw) * dt;
167 float z = ao_mpu6000_gyro(ao_sample_roll - ao_ground_roll) * dt;
172 struct ao_quaternion rot;
173 struct ao_quaternion point;
175 /* The amount of rotation is just the length of the vector. Now,
176 * here's the trick -- assume that the rotation amount is small. In this case,
177 * sin(x) ≃ x, so we can just make this the sin.
180 n_2 = x*x + y*y + z*z;
187 /* Make unit vector */
194 /* Now compute the unified rotation quaternion */
196 ao_quaternion_init_rotation(&rot,
200 /* Integrate with the previous rotation amount */
201 ao_quaternion_multiply(&ao_rotation, &ao_rotation, &rot);
203 /* And normalize to make sure it remains a unit vector */
204 ao_quaternion_normalize(&ao_rotation, &ao_rotation);
206 /* Compute pitch angle from vertical by taking the pad
207 * orientation vector and rotating it by the current total
208 * rotation value. That will be a unit vector pointing along
209 * the airframe axis. The Z value will be the cosine of the
210 * change in the angle from vertical since boost
213 ao_quaternion_rotate(&point, &ao_pad_orientation, &ao_rotation);
215 ao_sample_orient = acosf(rotz) * (float) (180.0/M_PI);
220 ao_sample_preflight(void)
224 * Collect 512 samples of acceleration and pressure
225 * data and average them to find the resting values
227 if (nsamples < 512) {
228 ao_sample_preflight_add();
231 ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g;
232 ao_accel_scale = to_fix32(GRAVITY * 2 * 16) / ao_accel_2g;
234 ao_sample_preflight_set();
235 ao_preflight = FALSE;
240 * While in pad mode, constantly update the ground state by
241 * re-averaging the data. This tracks changes in orientation, which
242 * might be caused by adjustments to the rocket on the pad and
243 * pressure, which might be caused by changes in the weather.
247 ao_sample_preflight_update(void)
250 ao_sample_preflight_add();
251 else if (nsamples < 1024)
254 ao_sample_preflight_set();
259 static int32_t p_filt;
260 static int32_t y_filt;
262 static gyro_t inline ao_gyro(void) {
263 gyro_t p = ao_sample_pitch - ao_ground_pitch;
264 gyro_t y = ao_sample_yaw - ao_ground_yaw;
266 p_filt = p_filt - (p_filt >> 6) + p;
267 y_filt = y_filt - (y_filt >> 6) + y;
271 return ao_sqrt(p*p + y*y);
279 ao_wakeup(DATA_TO_XDATA(&ao_sample_data));
280 ao_sleep((void *) DATA_TO_XDATA(&ao_data_head));
281 while (ao_sample_data != ao_data_head) {
282 __xdata struct ao_data *ao_data;
284 /* Capture a sample */
285 ao_data = (struct ao_data *) &ao_data_ring[ao_sample_data];
286 ao_sample_tick = ao_data->tick;
289 ao_data_pres_cook(ao_data);
290 ao_sample_pres = ao_data_pres(ao_data);
291 ao_sample_alt = pres_to_altitude(ao_sample_pres);
292 ao_sample_height = ao_sample_alt - ao_ground_height;
296 ao_sample_accel = ao_data_accel_cook(ao_data);
297 if (ao_config.pad_orientation != AO_PAD_ORIENTATION_ANTENNA_UP)
298 ao_sample_accel = ao_data_accel_invert(ao_sample_accel);
299 ao_data_set_accel(ao_data, ao_sample_accel);
302 ao_sample_accel_along = ao_data_along(ao_data);
303 ao_sample_accel_across = ao_data_across(ao_data);
304 ao_sample_accel_through = ao_data_through(ao_data);
305 ao_sample_pitch = ao_data_pitch(ao_data);
306 ao_sample_yaw = ao_data_yaw(ao_data);
307 ao_sample_roll = ao_data_roll(ao_data);
311 ao_sample_preflight();
313 if (ao_flight_state < ao_flight_boost)
314 ao_sample_preflight_update();
320 #ifdef AO_FLIGHT_TEST
321 ao_sample_prev_tick = ao_sample_tick;
323 ao_sample_data = ao_data_ring_next(ao_sample_data);
325 return !ao_preflight;
333 ao_sample_pres_sum = 0;
336 ao_sample_accel_sum = 0;
340 ao_sample_accel_along_sum = 0;
341 ao_sample_accel_across_sum = 0;
342 ao_sample_accel_through_sum = 0;
343 ao_sample_accel_along = 0;
344 ao_sample_accel_across = 0;
345 ao_sample_accel_through = 0;
346 ao_sample_pitch_sum = 0;
347 ao_sample_yaw_sum = 0;
348 ao_sample_roll_sum = 0;
352 ao_sample_orient = 0;
354 ao_sample_data = ao_data_head;