altos: Rename ao_orient to ao_sample_orient

[fw/altos] / src / core / ao_sample.c

diff --git a/src/core/ao_sample.c b/src/core/ao_sample.c
index dec44f9fa0910aa422ce8e7771c75001aba3fb94..47c5ea2e3660d15d0dcb4d526c1136653bb729e5 100644 (file)
--- a/src/core/ao_sample.c
+++ b/src/core/ao_sample.c
@@ -20,6 +20,10 @@
 #include <ao_data.h>
 #endif
 
+#if HAS_GYRO
+#include <ao_quaternion.h>
+#endif
+
 /*
  * Current sensor values
  */
@@ -44,8 +48,7 @@ __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_angle;
-__pdata angle_t                ao_sample_roll_angle;
+__pdata angle_t                ao_sample_orient;
 #endif
 
 __data uint8_t         ao_sample_data;
@@ -86,6 +89,8 @@ __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;
+static struct ao_quaternion ao_pad_orientation;
 #endif
 
 static void
@@ -129,11 +134,88 @@ ao_sample_preflight_set(void)
        ao_sample_pitch_sum = 0;
        ao_sample_yaw_sum = 0;
        ao_sample_roll_sum = 0;
-       ao_sample_angle = 0;
+       ao_sample_orient = 0;
+
+       /* No rotation yet */
+       ao_quaternion_init_zero_rotation(&ao_rotation);
+
+       /* 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);
+                                 
 #endif 
        nsamples = 0;
 }
 
+#if HAS_GYRO
+static void
+ao_sample_rotate(void)
+{
+#ifdef AO_FLIGHT_TEST
+       float   dt = (ao_sample_tick - ao_sample_prev_tick) / 100.0;
+#else
+       static const float dt = 1/100.0;
+#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;
+       
+       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);
+
+       /* 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
+        */
+
+       ao_quaternion_rotate(&point, &ao_pad_orientation, &ao_rotation);
+
+       ao_sample_orient = acosf(rotz) * (float) (180.0/M_PI);
+}
+#endif
+
 static void
 ao_sample_preflight(void)
 {
@@ -232,9 +314,12 @@ ao_sample(void)
                                ao_sample_preflight_update();
                        ao_kalman();
 #if HAS_GYRO
-                       /* do quaternion stuff here... */
+                       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;
@@ -264,7 +349,7 @@ ao_sample_init(void)
        ao_sample_pitch = 0;
        ao_sample_yaw = 0;
        ao_sample_roll = 0;
-       ao_sample_angle = 0;
+       ao_sample_orient = 0;
 #endif
        ao_sample_data = ao_data_head;
        ao_preflight = TRUE;