__pdata gyro_t ao_sample_roll;
__pdata gyro_t ao_sample_pitch;
__pdata gyro_t ao_sample_yaw;
-__pdata angle_t ao_orient;
+__pdata angle_t ao_sample_orient;
#endif
__data uint8_t ao_sample_data;
__pdata accel_t ao_ground_accel_along;
__pdata accel_t ao_ground_accel_across;
__pdata accel_t ao_ground_accel_through;
-__pdata gyro_t ao_ground_pitch;
-__pdata gyro_t ao_ground_yaw;
-__pdata gyro_t ao_ground_roll;
+__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 */
__pdata int32_t ao_sample_yaw_sum;
__pdata int32_t ao_sample_roll_sum;
static struct ao_quaternion ao_rotation;
-static struct ao_quaternion ao_pad_orientation;
#endif
static void
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 >> 9;
- ao_ground_yaw = ao_sample_yaw_sum >> 9;
- ao_ground_roll = ao_sample_roll_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_orient = 0;
+ ao_sample_orient = 0;
- /* No rotation yet */
- ao_quaternion_init_zero_rotation(&ao_rotation);
+ struct ao_quaternion orient;
/* Take the pad IMU acceleration values and compute our current direction
*/
- ao_quaternion_init_vector(&ao_pad_orientation,
- 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(&ao_pad_orientation,
- &ao_pad_orientation);
-
+
+ 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);
#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) / 100.0;
+ float dt = (ao_sample_tick - ao_sample_prev_tick) / TIME_DIV;
#else
- static const float dt = 1/100.0;
+ static const float dt = 1/TIME_DIV;
#endif
- float x = ao_mpu6000_gyro(ao_sample_pitch - ao_ground_pitch) * dt;
- float y = ao_mpu6000_gyro(ao_sample_yaw - ao_ground_yaw) * dt;
- float z = ao_mpu6000_gyro(ao_sample_roll - ao_ground_roll) * dt;
-
- float n_2, n;
- float s, c;
-
+ 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;
- struct ao_quaternion point;
- /* The amount of rotation is just the length of the vector. Now,
- * here's the trick -- assume that the rotation amount is small. In this case,
- * sin(x) ≃ x, so we can just make this the sin.
- */
-
- n_2 = x*x + y*y + z*z;
- n = sqrtf(n_2);
- s = n / 2;
- if (s > 1)
- s = 1;
- c = sqrtf(1 - s*s);
-
- /* Make unit vector */
- if (n > 0) {
- x /= n;
- y /= n;
- z /= n;
- }
-
- /* Now compute the unified rotation quaternion */
-
- ao_quaternion_init_rotation(&rot,
- x, y, z,
- s, c);
-
- /* Integrate with the previous rotation amount */
- ao_quaternion_multiply(&ao_rotation, &ao_rotation, &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);
* 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
+ * 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
*/
- ao_quaternion_rotate(&point, &ao_pad_orientation, &ao_rotation);
+ 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_orient = acosf(point.z) * (float) (180.0/M_PI);
+ ao_sample_orient = acosf(rotz) * (float) (180.0/M_PI);
}
#endif
ao_sample_pitch = 0;
ao_sample_yaw = 0;
ao_sample_roll = 0;
- ao_orient = 0;
+ ao_sample_orient = 0;
#endif
ao_sample_data = ao_data_head;
ao_preflight = TRUE;
projects / fw / altos / blobdiff