User:Jouvencel

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Revision as of 00:32, 8 August 2013 by Jouvencel (talk | contribs) (→‎Control command based of quaternions)
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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

Fiche1.jpg

  • Control structure

Fiche2.jpg

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

Fiche3.jpg

  • Feedforward part

Fiche4.jpg

  • Feedback part


Fiche5.jpg


  • 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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