User:Jouvencel
Control command based of quaternions
Files :
- stabilization_attitude_quat_int.c (.h)
- stabilization_attitude_ref_quat_int.c (.h)
- quat_setpoint_int.c (.h)
- Position in the autopilot structure
- Control structure
note : () number of decimals for integer calculus
- Comments
- "stab_att_sp_quat (15)" attitude to reach
- "stab_att_ref_accel(12)", "stab_att_ref_rate(16)","stab_att_ref_quat(15)" references défined by two order model
- stabilization_cmd[X] (X=ROLL, PITCH, YAW) commands défined by a feedforward part and feedback part, feedback part is based on PID
- quaternions define the orientation of rotorcraft,
- the error between the quat_sp and the quat_ref is computed by a quaternion product,
- the dot_quaternion is computed by the formula
- The second order model :
-- Integrates accelerate to obtain "stab_att_ref_rate" by the Euler method
-- Integrates rate to obtain "stab_att_ref_quat" by the Euler method
-- The Euler method uses dt. Here dt is implicite and equal 1/512 or ,
-- Determines the stab_att_ref_accel(12) by a second order with and . and are defined in airframe.xml.
- The second order
- Feedforward part
- Feedback part
- Comments
With the assumption of small variations so and so on for pitch and yaw, terms of second order are ignored :
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