Sharif Digital Repository

Topic that is investigated in this article include identify and localization a number of aerial target penetrating into a protected by area by a swarm of UAVs is fixed wing. UAVs do not have any prior notice of positioning targets. In addition, it is assumed that lacks any radiation exploitable targets and thus use UAVs for Targets Detection from an active radar system. Obviously this article focus on developing a guidance algorithm UAVs to this particular issue and also as the targets participatory is localization algorithm. In addition, extraction type and performance characteristics radar system required and also performance characteristics of the class of UAVs, which is suitable to... 

In this project, a method for cooperative search and localization of RF ground moving targets by a group of UAVs is developed. It should be noted that UAVs are just equipped with GPS and directional sensors. Since there is fuel constraint for UAVs, they take fuel from a tanker whenever they require. Moreover, searching method enables the UAVs to see different parts of the desired area with almost uniform distribution. In addition, the proposed approach enables the UAVs to perform a local search with the aim of finding the targets having lost their signal during localization mode. Finally, based upon a fueling decision function the UAVs take turn, approach to the fuel tanker, and start... 

Nowdays much of the organic solid waste and wastewater is buried using centralized and traditional methods. This leads to many problems, including groundwater pollution, methane emissions into the atmosphere and rapid transmission of disease. In order to avoid these problems, using a decentralized approach can be a good solution. In this study, recovery of organic waste and wastewater of residential buildings using anaerobic digester as a decentralized way, have been examined. Using experiments, the optimum mass ratio of organic solid waste and wastewater is obtained as 80% and 20% respectively. Biogas production model is developed using mass balance and Balance of electrons in redox... 

The purpose of this paper is to design an integrated controller and observer (ICO) for a nonlinear system using genetic programming. ICO is a function that constructs control command directly from the measured state variables of the system. It means that, this function should imitate the behavior of the observer and controller and control the system with acceptable performance in different initial conditions, at the presence of disturbances and system uncertainties. The complexity of this design method, is not related to the complexity of the plant, in fact, the complexity in plant just effects at run time, but the design procedure does not change. So, if exact model of plant exist, using... 

In this research a novel intelligent back-stepping control method is developed. This method is robust to sensor noise and external disturbances. In addition, the controller is robust under model uncertainty. This controller does not need precise knowledge of system parameters. This method is based on three methods of: back-stepping control, least squares estimation and a fuzzy compensator. This controller is used to control quadrotor stand witch is like an inverse pendulum. In quadrotor stand modeling, the inverse pendulum effect is considered too, witch is one of the innovations of the research. By doing various simulations, the validity of controller is tested. Also the performance of the... 

In this study, a multiple model wind estimator is proposed to detect the wind type and to estimate the wind components as well as the states of a fixed-wing UAV without any direct measurement of the air data. Then, the identified wind model and the estimated states are compensated in the heuristic nonlinear model predictive controller during landing phase. For this purpose, a static multiple model approach is taken, comprised of four independent extended Kalman filters, each one is estimating the wind based on one of the four wind models including a constant wind, a “1-cosine” model, a wind shear and a microburst.Moreover, a new heuristic multiple model filter, called Multiple Model Extended... 

In this Thesis, an unmanned multicopter with a new structure is modeled and a nonlinear controller is designed for it to track the trajectories precisely. The multicopter in this thesis, has six propellers with a hybrid propulsion system (a combination of fuel and electric propulsion system) that has the ability to carry more payload and maintain more flight duration compared to electric multicopters. In the beginning, the performance characteristics and technical specifications of the hexacopter are presented. For modeling, first the equations of six degrees of freedom movement of the hexacopter are derived by the Newton-Euler method. In the next step, the forces and torques applied to the... 

The problem that we will solve in this thesis is the automatic landing using model predictive control. Due to the large growth in the use of fixed wing UAVs and the challenges faced by these type of UAVs with respect to other types of UAVs, in this project, the automatic landing of a UAV will be studied in the presence of variable uncertainties with time that will be considered in the modeling. The airplan is assumed to have inertial sensors, gps, speedometer and altimeter. The innovation of the thesis is that until now, Adaptive Model Predictive Control has not been used to control the fixed wing UAV landing. One of the weaknesses in Model Predictive Control is the loss of performance in... 

The aim of the present thesis is to develop a novel heuristic filter by utilizing Firefly Optimization Algorithm for state estimation of nonlinear, non-Gaussian systems. The proposed filter formulates the estimation problem as a dynamic, stochastic one. The swarm intelligence of the fireflies enables the filter to find and track the best estimation. To estimate the states of a system, the model of the system is required. Hence, an 8-DoF quadrotor with slung payload system, as a case study, is modeled by the tensor method. In this case, as a highly nonlinear system, in order not to rely on extra sensors for monitoring swing-angle, the estimation of payload states is needed. In this regard,... 

It is well known that data centres consume high amounts of energy, which has become a major concern in the field of cloud computing. Therefore, energy consumption could be reduced by using intelligent mechanisms work to adapt the set of network components to the total traffic volume. SDN is an efficient way to do so because it has many benefits over traditional approaches, such as centralised management, low capex, flexibility, scalability and virtualisation of network functions. In our work will we use the heuristic energy-aware routing (HEAR) model, which is composed of the proposed heuristic algorithm and the energy-aware routing algorithm. This work identifies the unused links and... 

This research presents three new guidance laws for trajectory tracking of an unmanned aerial vehicle in the presence of wind disturbances. The first method is a linear combination of line-of-sight and velocity-pursuit guidance laws, the parameters of which are tuned using a fuzzy system in an online manner. The second method is an adaptive optimal guidance law based on the differential game theory. The third method (main method) is a model predictive guidance law based on the differential game theory. In the main method, linear point mass equations of motion are used to predict the future path of the vehicle. Also, the linear model predictive control is used to achieve an optimal analytical... 

Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic... 

In this thesis a guidance algorithm is developed to control middle phase landing of a quadrotor on a moving platform. Middle phase guidance is consisted of approaching time, speed, and angle constraints. In the first step proportional guidance algorithms was studied. Then a six-freedom model of a quadrotor dynamic was developed. At the next step an appropriate guidance algorithm was developed to control a quadrotor for the mentioned constraints. Finally, the parameters of the algorithm were optimized by numerical methods. Monte-Carlo method used to validate this method. For this reason, 850 numerical simulations with random initial and final conditions were performed and the statistics... 

Thread connections are widely used in tubular downhole equipment. Connections are usually weaker than tubulars and their failure will result in very high cost. Thread connections of downhole equipment are divided into two groups: standard connections and premium connections. Standard connections, despite being widely used, have limitations and will loose their efficiency in complex loadings. According to the mentioned limitations, premium connections have been proposed according to the existing need related to improving the strength of the structure, proper sealing and resistance to galling. One of the most obvious applications of premium connections is in downhole tubulars that are... 

The purpose of this thesis is to design and implement a controller for a Ducted-Fan in the landing and take-off phase using a linear quadratic tuning method based on differential game theory. This is a control method with a robust control approach and tries to see all the disturbances and unmodulated dynamics in the form of the second actor and produce a control command according to the worst behavior of the second actor. For this purpose, 6 DOF Ducted-Fan have been modeled. then The proposed controller is designed for a linearized model around the hover point. In the next step, the performance of the proposed controller is compared with the SlidingMode Controller. Also, the parameters of... 

Nowadays, the use of vehicles is inevitable for all people including pregnant females. Vehicle vibrations during passing road bumps and holes is one of the pregnant females’ concerns. The aim of the present study is to develop a biomechanical model of a Uterus and Fetus Set (UFS) to evaluate its response to the inferior excitation, caused by the vehicle passing over speed bumps. The most important innovation of this research is "Analysis of the effect of vehicle speed and speed bumps characteristics on the risk of injury to the fetus." "Modeling the pregnant uterus complex separately from other abdominal organs", "Biomechanical modeling based on CT scan data from a real subject", "Providing... 

Spinning vehicles are a large category of aerospace vehicles including shoulder launched missiles, intelligent anti-armor projectiles, guided rockets and some of re-entry vehicles, anti tank missiles and satellites. This thesis presents the problems of guidance and control in a spinning vehicle with a single plane of On-Off control surface. The missile uses this single surface to control both yaw and pitch channels. The actuator used in this missile is a discrete On-Off type which makes the missile behavior nonlinear. Using describing function technique, a linear model of the spinning missile dynamics in the presence of an On-Off actuator is derived and a classic controller is designed... 

In this thesis an algorithm has been implemented for automatic landing of a quadrotor under the ground effect. In this regard the six degrees of freedom equations of motion using the Newton-Euler method has been designed. Then, the ground effect has been modeled by inspiring from the similar available models in the literature. The proposed models and proportional-integral-derivative attitude control loops have been simulated in MATLAB/Simulink environment. Also, two control strategies, a classical proportional-integral-derivative controller and a sliding mode controller have been utilized for height control loop.Since sliding mode controller requires all state variables to generate control...