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Optimal Combination of Aerodynamic and Reaction Jet Control in a Vertical Launch Vehicle

Khosravi Samani, Mahdi | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41723 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Nobahari, Hadi; Kashefi, Saeid
  7. Abstract:
  8. In this research, the design of control system has been studied for a special flying vehicle at whole of flight time. This flying vehicle is vertically launched and few time after launch its attitude changes to the desired attitude by a reaction jet control system, then the acceleration commands are tracked when the aerodynamic is activated. Design process includes attitude control system design in launch phase and aerodynamic control system design. Because of the existence of nonlinear and multi-variable dynamics in the flying vehicle and the presence of uncertainty and disturbance, combination of nonlinear, robust and adaptive methods are used in controller design process. Design of attitude controller is performed based on the feedback linearization technique. The robustness of the controller is guaranteed by the Liapunov function and extended state observer techniques. Aerodynamic control is also accomplished by two methods. In the first method, the angular rate loop is controlled by feedback linearization technique. Then an estimator is used for adaptation. In the second method, feedback linearization technique is used to control the lateral acceleration directly and again an estimator is used for adaptation purpose. Moreover, the roll angle is controlled by two techniques, sliding mode control and uncertainty and disturbance estimation. Also, the nonlinear liunberger observer is used for observation of unmeasurable states. Design process is performed in the manner satisfies the systematic requirement. Finally, the well-known multi-objective real-coded memetic algorithm is utilized to concurrently optimize the design variables of the overall control system. The designed control system is evaluated in each part using a variable mass 6DOF flight simulation based on the full nonlinear equations of motion that shows superior performance
  9. Keywords:
  10. Aerodynamic Control ; Estimators ; Optimization ; Sliding Mode Control ; Feedback Linearization ; Reaction Jet Attitude Control ; Extended State Observer

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