void stabilization_attitude_ref_update(void) {
/* integrate reference attitude */
#if STABILIZATION_ATTITUDE_REF_QUAT_INFINITESIMAL_STEP
struct FloatQuat qdot;
FLOAT_QUAT_DERIVATIVE(qdot, stab_att_ref_rate, stab_att_ref_quat);
QUAT_SMUL(qdot, qdot, DT_UPDATE);
QUAT_ADD(stab_att_ref_quat, qdot);
#else // use finite step (involves trig)
struct FloatQuat delta_q;
FLOAT_QUAT_DIFFERENTIAL(delta_q, stab_att_ref_rate, DT_UPDATE);
/* compose new ref_quat by quaternion multiplication of delta rotation and current ref_quat */
struct FloatQuat new_ref_quat;
FLOAT_QUAT_COMP(new_ref_quat, delta_q, stab_att_ref_quat);
QUAT_COPY(stab_att_ref_quat, new_ref_quat);
#endif
FLOAT_QUAT_NORMALIZE(stab_att_ref_quat);
/* integrate reference rotational speeds */
struct FloatRates delta_rate;
RATES_SMUL(delta_rate, stab_att_ref_accel, DT_UPDATE);
RATES_ADD(stab_att_ref_rate, delta_rate);
/* compute reference angular accelerations */
struct FloatQuat err;
/* compute reference attitude error */
FLOAT_QUAT_INV_COMP(err, stab_att_sp_quat, stab_att_ref_quat);
/* wrap it in the shortest direction */
FLOAT_QUAT_WRAP_SHORTEST(err);
/* propagate the 2nd order linear model */
stab_att_ref_accel.p = -2.*stab_att_ref_model[ref_idx].zeta.p*stab_att_ref_model[ref_idx].omega.p*stab_att_ref_rate.p
- stab_att_ref_model[ref_idx].omega.p*stab_att_ref_model[ref_idx].omega.p*err.qx;
stab_att_ref_accel.q = -2.*stab_att_ref_model[ref_idx].zeta.q*stab_att_ref_model[ref_idx].omega.q*stab_att_ref_rate.q
- stab_att_ref_model[ref_idx].omega.q*stab_att_ref_model[ref_idx].omega.q*err.qy;
stab_att_ref_accel.r = -2.*stab_att_ref_model[ref_idx].zeta.r*stab_att_ref_model[ref_idx].omega.r*stab_att_ref_rate.r
- stab_att_ref_model[ref_idx].omega.r*stab_att_ref_model[ref_idx].omega.r*err.qz;
/* saturate acceleration */
const struct FloatRates MIN_ACCEL = { -REF_ACCEL_MAX_P, -REF_ACCEL_MAX_Q, -REF_ACCEL_MAX_R };
const struct FloatRates MAX_ACCEL = { REF_ACCEL_MAX_P, REF_ACCEL_MAX_Q, REF_ACCEL_MAX_R };
RATES_BOUND_BOX(stab_att_ref_accel, MIN_ACCEL, MAX_ACCEL);
/* saturate angular speed and trim accel accordingly */
SATURATE_SPEED_TRIM_ACCEL();
/* compute ref_euler */
FLOAT_EULERS_OF_QUAT(stab_att_ref_euler, stab_att_ref_quat);
}
void stabilization_attitude_ref_update() {
/* integrate reference attitude */
struct FloatQuat qdot;
FLOAT_QUAT_DERIVATIVE(qdot, stab_att_ref_rate, stab_att_ref_quat);
QUAT_SMUL(qdot, qdot, DT_UPDATE);
QUAT_ADD(stab_att_ref_quat, qdot);
FLOAT_QUAT_NORMALIZE(stab_att_ref_quat);
/* integrate reference rotational speeds */
struct FloatRates delta_rate;
RATES_SMUL(delta_rate, stab_att_ref_accel, DT_UPDATE);
RATES_ADD(stab_att_ref_rate, delta_rate);
/* compute reference angular accelerations */
struct FloatQuat err;
/* compute reference attitude error */
FLOAT_QUAT_INV_COMP(err, stab_att_sp_quat, stab_att_ref_quat);
/* wrap it in the shortest direction */
FLOAT_QUAT_WRAP_SHORTEST(err);
/* propagate the 2nd order linear model */
stab_att_ref_accel.p = -2.*stab_att_ref_model[ref_idx].zeta.p*stab_att_ref_model[ref_idx].omega.p*stab_att_ref_rate.p
- stab_att_ref_model[ref_idx].omega.p*stab_att_ref_model[ref_idx].omega.p*err.qx;
stab_att_ref_accel.q = -2.*stab_att_ref_model[ref_idx].zeta.q*stab_att_ref_model[ref_idx].omega.q*stab_att_ref_rate.q
- stab_att_ref_model[ref_idx].omega.q*stab_att_ref_model[ref_idx].omega.q*err.qy;
stab_att_ref_accel.r = -2.*stab_att_ref_model[ref_idx].zeta.r*stab_att_ref_model[ref_idx].omega.r*stab_att_ref_rate.r
- stab_att_ref_model[ref_idx].omega.r*stab_att_ref_model[ref_idx].omega.r*err.qz;
/* saturate acceleration */
const struct FloatRates MIN_ACCEL = { -REF_ACCEL_MAX_P, -REF_ACCEL_MAX_Q, -REF_ACCEL_MAX_R };
const struct FloatRates MAX_ACCEL = { REF_ACCEL_MAX_P, REF_ACCEL_MAX_Q, REF_ACCEL_MAX_R };
RATES_BOUND_BOX(stab_att_ref_accel, MIN_ACCEL, MAX_ACCEL);
/* compute ref_euler */
FLOAT_EULERS_OF_QUAT(stab_att_ref_euler, stab_att_ref_quat);
}
