Sharif Digital Repository

Cancer is refer to a class of diseases that create as the result of abnormal growth of cells and invasion of them to normal cells of human body, and annually cause the considerable percentage of death in the world. Because cancer can be considered as a complex system, various models presented to modeling and simulation of the behavior of it, using of different methods such as cellular automata, agent-based, game theory and other methods. Multi-agent simulation models as a special kind of agent-based models, is a method that used to simulate some real-world phenomena that usually contains many different components and interact using different and complex ways. Since the cells are located in... 

Recent developments in space industry and the great tendency for definition of efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of the multiple satellite control methods is the subject of the present project. In this project, the governing equations of motion of satellite formation flight are developed. Based on this development, it is shown that the satellite linear equations of motion like many other linear system presentations, can not sufficiently model the real system. Therefore, some of the most famous uncertainties in space dynamics such as semimajor axis and eccentricity... 

The goal of this project is the development of a control algorithm for a flock of non-holonomic aerial agents. For this purpose,the swarm architecture having some unique features such as robustness, flexibility, and scalability is utilized. Swarm is defined as a group of simple agents having local interactions between themselves and the environmentwhich shows an unpredictable emergent behavior.Behavior based control which is inspired from the animal behaviors is employed to control the swarm of mobile agents. Accordingly, the necessary behaviors which are distance adjustment, velocity agreement, and virtual leader tracking together with a fuzzy coordinator are designed. In this study, in... 

This thesis represents the obstacle avoidance of a fixed-wing small aircraft using optical flow information of cameras mounted on the aircraft. The thesis consists of two main sections. In section one, the ideal optical flow has been simulated based on the camera model, complete six DOF of flight equations, and the geometry of the environment. An analytical formula has been derived to relate the obstacle detection distance to the maneuverability of the aircraft. Having the obstacle detection distance, the control and navigation algorithms have been developed to achieve a collision-free flight for the aircraft in urban canyons and junctions. The effect of some parameters such as approach... 

In this thesis, maneuverability enhancement of a given twin engine fighter aircraft with integrated thrust-vector and conventional aerodynamic control surfaces havebeen studied. For this purpose a nonlinear 6DOF simulation program base on a near exact mathematical model has been prepared for the aircraft, and then a thrust vectoring system for producing moments about three body axes, like that used in F/A-18, has been added to the simulation. The control method that is employed to control the aircraft in simulation environment is based on Nonlinear Dynamic Inversion (NDI). Finally the Velocity Vector Roll (VVR) maneuver has been considered as an example tostudymaneuverability enhacement. It... 

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... 

One of the key technologies in the future space missions is the formation flight of small satellites. Currently, widespread research in this field is being carried out and remarkable developments have been achieved. In the mentioned laboratory researches, satellite navigation is performed by conventional sensors like infrared and ultrasonic. Both of these sensors are of active type and energy consuming. Also, use of the ultrasonic sensors is impractical in space missions (due to vacuum condition). Therefore, as an alternative for space missions, visual sensors are good candidates. The main goal of this research is to present a method for the relative navigation in proximity operations in an... 

In this research work, several guidance laws have been utilized and validated, considering the contraints on the missslie seeker angle and maximum acceleration, in order to simultaneously intercept the so-called Close-in Weapon System (CIWS) by multiple missiles. First of all, the existing guidance laws for salvo-attack are reveiwed. Then, a simulation program has been developed and validated for the misslie and CIWS as a five and two degrees of freedom systems, respectively. Optimization of the system is then carried out by the method of Particle Swarm Optimization, considering the given constraints. In the next step, for the improvement of the optimized guidance law, paramertic study has... 

In this project an algorithm is designed for automatic landing of unmanned helicopter on a pad moving with six degrees of freedom. The designed controller is based on state dependent riccati equations (SDRE).by developing nonlinear mathematical model of helicopter and then converting this model to state dependent coefficient (SDC) form. A nonlinear compensator is added to controller to compensate effect of some nonlinear terms of model that are not able to translate and then state dependent riccati equations are solved.
The relative pose-estimation of landing pad is based on vision. Corner detection algorithm is used to identify and detect features by processing of image taken from... 

Modeling and simulation are widely used as essential tools to predict and analyze complex systems in various scientific and engineering fields. For an aerospace system such as aircraft, mathematical models are useful used to carry out such tasks as dynamic analysis, autopilot development and combination of flight control laws, hazardous behaviors prediction, the controller design and validation, the study of the handling qualities, or the implementing simulators used for training pilots and many other tasks. In general, the aircraft flight dynamics is a nonlinear and coupled system whose dynamic modeling, in addition to pilot control inputs, depends on flight conditions (i.e., Mach and... 

In this study, the possibility of detecting known and unknown anomalies in a micro jet engine is evaluated. the proposed method is neural network and clustering analysis. The process consists of two main parts, first part is experimental abnormal behavior simulation and second part is validation of proposed detection method. In the first part a micro jet engine (Olympuse HP) were used and we created pre-designed errors in engine normal behavior to record significant changes in its performance. Recorded outputs consist of six different variables: RPM, Exhaust gas temperature, Throttle command, Fuel pump voltage, Thrust and Fuel weight. In the second part, for analyzing data, we used... 

One of the most important technologies in space missions is capability of moving satellites together with a predefined structure (virtual structure). This structure can reconfigure itself to any desired space mission and it is known as reconfiguration maneuver, in this maneuver all of the satellites have to follow needed virtual structure from any initial configuration to any desired second composition. In available virtual structure methods, there are a lot of limitations in maneuver because of algorithm constraints, in this project we try to extend available algorithm in virtual structure method and reach an algorithm which can start from any initial condition and complete the maneuver in... 

Quadrotors are one of the most popular unmanned aerial vehicle (UAVs) that has been subject of extensive research in recent years. One of the most important applications of these aerial vehicles is transporting a cable-suspended payload from one point to another. The major challenge in modeling of this system is dynamic coupling which exist between all components of the system i.e. payload, cable and quadrotor. The purpose of this research is mathematical modeling and dynamic analysis of the system in presence of this dynamic coupling and considering the effects of cable's flexibility. In this regard, it is assumed that the payload has variable mass. In this thesis, in the first step, by... 

Using unmanned aerial vehicles in aerial payload carrying leads many changes requiring significant study and research. In recent years, there has been considerable maturation in Micro Aerial Vehicles (MAV) developement especially quadcopters. In addition to the endurance restriction, considerations on volume and weight that can be carried, and safety issues are also obstacles to the development of unmanned aerial payload carrying in urban environments. One of the ways to make a quadcopter more agile while carrying a load is to hang the cargo from the quadcopter via a cable. In this way, it is possible that quadcopters carry the cargo in a cooperative way, which if properly arranged,... 

In this research work, the concept of an unmanned aerial firefighting system with water thrusters has been studied. This system consists of a platform head, a waterhose and a ground pump. The concept is briefly to pump water through the hose and then fall it down on fire from the platform. This conceptual system may have many other applications. The other applications have also been addressed in the introduction section. This platform can be considered as an unmanned aerial vehicle whose lift and control forces is provided by water thrusters. The conceptual study has been carried out based on three subjects of preliminary sizing, system dynamic modeling and controller design for platform... 

In this research, the aerial load transportation in the urban environment by cooperative quadrotors is investigated. This system requires two sub-systems: path planning and control. The path planning subsystem designs the payload's path and at the same time determines the shape of the flight formation of agents in order to be able to carry the payload. The design of the path-formation is done in the presence of constraints such as the collision avoidance with obstacles, inter-collision avoidance to each other, the collision avoidance of the slung load with the obstacles and the minimum and maximum allowable cables' forces. Therefore, the shape of the formation flight is determined... 

This thesis addresses the topic of cooperative search by a group of unmanned aerial vehicles (UAVs) in a bounded region, while encountering obstacles and searching for moving targets. A review of relevant research on cooperative search for finding one or multiple targets is presented. Then, a general description of the logic of cooperative search, which is based on optimal routing by minimizing a cost function, is explained. In this context, three maps called the uncertainty map, target presence probability map, and target map are introduced. Two phases of search and tracking are defined for the UAVs, and the criteria for achieving each phase are presented. In the search phase, each UAV... 

One of the considerable issues in fullereneresearch is low yield of endohedral fullerene production.In this project, synthesis and optimization of endohedral metallofullereneproduction was undertaken byarc reactor applying vertical graphite electrodes, using vaporizing composite lanthanum-oxide-graphite-dopped rod. Increasing the efficiency of endohedral fullerrene production in sootwas followed applyingcarbide formation in electrode which was studied by X-ray diffraction(XRD), thermogravimetric analysis(TGA) and infrared (IR) spectroscopy. In addition, as a simple and fast method, the liquid column chromatography was applied in separation and purification of fullerenes as well as endohedral... 

In the present research, two series of N2O2- and N4O2-naphthadiaza-crown macrocyclic ligands with different macroring size, 15-21 memberd (L1-L7) were synthesized using direct method. The products were characterized by applying 1H and 13C NMR, IR spectroscopy, mass spectrometry and elemental analysis and in some cases by X-ray crystallography. Firstly, to study on emission properties of naphthadiaza-crown macrocyclic ligands as a fluorophore, we employed different amines as fluorescence quencher. It was observed that the quenching effects of 3o aliphatic amines like triethylamine were more pronounce than other group of amines. Also, the quenching constants for interactions of macrocyclic... 

The trailing edge brakes are the conventional controller mechanisms for autonomous precision delivery parafoil systems. Asymetric braking creates differential drag on the left and right sides of canopy leading to generation of turn rate, whereas symmetric deflection changes the aangle of attack which in turn affects airspeed and limit the glide slope. In the current work , in addition to the conventional controller , the canopy is considered to have the ability of changing its longitudinal and lateral incidence angles. This can be achieved by changing the length of sidelong suspension lines.Unlike brakes, the lateral incidence angle creates heavily coupling in lateral dynamics.The results...