Sharif Digital Repository

There are many applications for micro aerial vehicles (MAV) and in nature they are flying as birds and insects. It can be said that a MAV that can mimic flying capabilities of birds and insects can be used as a solution for flying in low Reynolds number regimes. It seems that Flapping Wing MAVs have better performance than fixed and rotary wings MAV in low Reynolds number regimes. So far there haven’t been many theories and methods introduced for controlling flapping wing MAVs and many researches failed to provide a convenient way for designing an effective controller. On the other hand, models presented in literature for aerodynamics, dynamics and kinematics of flapping wing are not... 

In this thesis, the theory of robust control is applied to design a controller for the longitudinal dynamics of a tail-sitter jet engine unmanned aerial vehicle. The engine thrust deflection is considered as the input controller of the system. The aircraft dynamical model is developed based on the assumption of no aerodynamic loads in low speed flight associated with the hovering condition. The controller is primarily designed using both classical and modern control techniques. Then and synthesis approaches are applied to design the robust controller. The results obtained from different approaches are compared. It is shown that the robust controller techniques are more stable and robust... 

In this thesis, the theory of robust control is applied to design a controller for hover flight of a tail-sitter unmanned aerial vehicle with 2 ducted-fan propulsion. The control surface deflection (in propeller slipstream) is considered as the input controller of the system. The aircraft dynamical model is developed based on the assumption of no aerodynamic loads on other parts of uav in low speed flight associated with the hovering condition. The controller is primarily designed using both classical and modern control techniques. Then H ∞ and µ synthesis approaches are applied to design the robust controller. The results obtained from different approaches are compared. It is shown that... 

Ducted fan vertical take-off and landing (VTOL) aerial vehicles have drawn many attentions in the world because of their capability to offer high power to weight ratio for a certain vehicle diameter relative to open rotors or helicopters. However, due to inherent uncertainties in dynamics and inefficient and poor quality responses, significant control challenges are still unsolved and exciting fields for research. In the current study, a nonlinear dynamic model is proposed for the controller design purpose. This model is validated against simulation by performing several standard scenarios. An adaptive control method, named model reference (MRAC), is utilized to design a perfect controller... 

In this research work, modeling, simulation, and controller design for a single-blade aerial vehicle or monocopter are carried out. The combined Momentum and Blade-Element theory is used to calculate the aerodynamic forces and moments. The Newton-Euler approach is employes for the development of the six degrees of freedom equations of motion of the monocopter. The obtained mathematical model is then implemented and solved on computer using MATLAB Simulink environment. A periodic behavior of the states is observed which is compatible with reality. Also, sensitivity studies are carried out in order to better understand how different initial conditions affect the behavior of the monocopter. The... 

The subject of this study is design of a linear quadratic Gaussian controller based on identification of dynamic behavior of unmanned model helicopter “Raptor” in its hover flight. To achieve this end, first, the helicopter linear transfer functions are identified with frequency response method by applying specific inputs to the model of Raptor in the X-Plane software and receiving system outputs via Simulink. Next, using the identified dynamic model of the helicopter, an optimum linear controller is designed for hover flight. As an optimum linear controller needs all the state variables, a Kalman filter is utilized to estimate them, using outputs of various sonsors such as GPS and gyro.... 

This project deals with the design, fabrication and control of a tilting-rotor quadrotor. This type of UAV can have high maneuverability in all 6 degrees of freedom (3D attitude and 3D position). The rotor axes can be tilted independently to produce desired force and torque vectors. This capability resolves limitations of the classic quadrotors and provides independent control of orientation and position. To control this UAV, we have proposed a control scheme relating the desired trajectory to the required forces and torques. Then a PID controller for the simultaneous control of position and attitude is designed. This controller is tested in a simulation and the results show that the control...