Sharif Digital Repository

Disturbance rejection is one of the most important criteria that should be considered when designing control systems. The problem has been widely investigated and studied when the parameters of disturbance signal is known. However, there are still ongoing researches in the field when the parameters of disturbance signals are uncertain and/or varying with time. In some applications the disturbance signal can be modelled by special dynamics, e.g., step type disturbances with unknown magnitude, sinusoidal disturbances with unknown magnitude and frequency, and damped sinusoidal disturbances with unknown magnitude, frequency and damping factor. In such cases, an adaptive scheme for estimating the... 

This thesis deals with identification of Errors-In-Variable(EIV) models with Compensated Prediction Error Method (CPEM). In EIV model structure, noise affects both on input and output data. We introduce a method to identify linear and discrete EIV models where the conventional PEM in classical identification, has been used in. Using PEM on EIV models leads to a biased estimation. Therefore, the reason of incorrect estimationobtained from PEM in the presence of input noise is investigated and the importance of consideringthe input noise is explained. Then by introducing two modifications, we try to compensate the deficiencies caused due to the presence of input noise. First, some changes are... 

The set of human arm, forearm, and wrist has the ability of performing very miscellaneous movements which has led to human inspiration for designing sorts of robots for various tasks. The aim of the present study is the design and simulation of a robot, similar to the human hand and arm. In the beginning, a shape-adaptive 2 DOF under-actuated mechanism which is actuated by one motor, is selected as the second and third phalanges of the human finger. Also the first phalanx of the finger moves independently by another motor. By adding a ratchet to the second joint of the finger, with the help of only two actuators, the feasibility of exerting isotropic force to the object in three phalanges... 

Microbial fuel cell is one of the new technologies in the field of power generation from the organic energy resource. The fuel cell system in a process similar to chemical fuel cell generate electrical energy through oxidation of organic composition by uses of electrogenic microorganisms as biocatalyst. In this study the main object is providing a comprehensive mathematical model for the fuel cell system in micro-liter size. To achieve this purpose, we start to investigate properties of fuel cell system in this size. And according to the geometry of system we choose chemotactic equation for estimating hydrodynamic behavior of microorganism and using combination of conductive base and... 

Attaining accurate information about satellite attitude is one of the most important requirements in space missions in order to improve the accuracy of the satellite control and mission objectives. Many different sensors such as sun sensor, star sensor, horizon sensor, etc. are used to estimate spacecraft’s attitude. Attitude estimation using temperature sensors is a topic that has recently been addressed by some related researchers because, they need less power and budget to operate in comparison with the other sensors.Accuracy and heat model performance improvement is the main purpose of this project. To achieve a more accurate perspective of space thermal model, and the way heat transfers... 

Because of lower energy consumption and lower capital cost, divided wall columns attracted wide attention. The main challenge of these units is their controllability. In this thesis dynamic simulation and control of a divided wall column is investigated and an adaptive model predictive controller has been used for control purpose. For dynamic simulation the Aspen Dynamics software and for applying control strategy the MATLAB software have been utilized. The model used for model predictive controller has been obtained by using open loop responses of the system. The main advantage of presented work over the existing ones is using the input-output transfer function of the system model instead... 

Because of importance of knowing angular velocity in a lot of engineering problems, Rate gyroscopes is widely used in different engineering fields. Among all kinds of gyroscopes, proof mems MEMS gyroscopes are mostly used because of their low cost and light weight. Improvement of the accuracy of the MEMS gyroscopes and their based inertial navigation systems is intended in this thesis considering some undesirable conditions on the gyro and trying to solve the gyro’s equations in that conditions. Existing linear or angular acceleration on the structure that the gyro is installed on is one of these undesirable conditions; Quadrature error in the gyroscope is the other one. In this thesis, the... 

Proper operation of a permanent magnet synchronous motor (PMSM) requires rotor position information. Commonly a rotor position sensor, such as optical encoder or resolver, is used for this purpose. These sensors add cost, weight and degrade reliability of the drive system. Using position and speed sensors for control of PMSM’s in home appliances is not cost effective. In this thesis, a novel method for predicting position of the rotor and winding inductance of the permanent magnet synchronous machine has been presented. In this method, machine anisotropy is utilized for rotor position estimation purposes like what in the high frequency injection techniques. Each leg of the PWM inverter... 

Given many computing errors in current systems, a method appears necessary for predicting the nuclear parameter quickly and accurately. In this thesis, a neural network was used to predict safety in a nuclear power plant in order to develop an operating aid tool for preventive measures.First, some studies were conducted on appropriate feature selection for training neural networks. Some case studies have also been carried out on parameter prediction through soft computing in a power plant. In the next section, an expert judgment was taken into account to select DNBR (Departure from Nucleate Boiling Ratio) as a criterion for safety evaluation in the exploitation of a nuclear power plant (PWR)... 

Nowadays, using sparsity of signals has been utilized in diverse applications in signal processing community. Two important applications of signal sparsity are sparse source separation and sparse signal representation. These two problems are joined with a Sparse Component Analysis (SCA) framework. In SCA, the problem is divided into two subproblems which are matrix estimation and sparse vector estimation. In this thesis, a MAP-based algorithm is suggested for sparse vector estimation with a Bernoulli-Gaussian distribution for sparse vector elements. To reduce the complexity, an iterative Bayesian algoritm is used in which an steepest-ascent is utilized for maximization. A complete... 

Today, SAR radars are one of the most practical tools for controlling and monitoring surface targets, and so far, several methods have been proposed to create a profile image of the reflection coefficient of surface targets in these Radars. The main problem in these methods is the ability to simultaneously create a reflection coefficient profile image for stationary and moving targets. To create a profile image of the reflection coefficient of moving targets, first it is necessary to detect and estimate its kinetic parameters.This thesis presents a method for detecting and estimating Ground moving targets parameters using Keystone transfer conversion and also presents a method for creating... 

operation of a nuclear power plant. Therefore, constant monitoring of the reactor core with reliable methods is important. To monitor the reactor heart, it is necessary to estimate and calculate some parameters, with high speed and accuracy, such as power distribution inside the heart, reactivity feedback coefficients, PPF, DNBR, etc. Analytical methods are often used to calculate these parameters, which in case of failure of the sensors, the calculations will be practically disrupted, and the method used in this research can solve these problems by losing a small amount of accuracy.In this study using real data of Bushehr nuclear power plant (BNPP) and by soft computing methods and... 

Due to the importance of recognizing the underwater and the existence of danger to human life in this environment, the use of AUVs has greatly expanded. To build and use these vehicles, we need to model dynamic behavior, and control these systems. The nonlinear dynamics of the AUV makes it difficult to use common linear controllers. On the other hand, the coefficients used in dynamic equations have uncertainty and changes, and as a result, dynamic analysis may be probably un-accurate. If the controller is designed, the controller must be self-tuning and robust to be able to withstand changes and uncertainty. Adaptive control is an approach for controlling such systems. The main idea in... 

Nowadays, application of AUVs in marine missions is a crucial research field. To reach a fully automated underwater vehicle, it should suitably be designed, controlled, navigated and its fault is detected immediately. An Identified model of AUV is usable for all of these goals. Thus, in this project, parameters of an appropriate dynamic model of AUV is estimated using augmented state space method and TUKF.By investigating possibility of parameter estimation of 6-DOF model and sub models in different cases, a scenario for estimation of cruise, steering and diving sub model parameters of AUV, using output of DVL and Gyroscope is proposed. Furthermore, planar misalignment between DVL and IMU,... 

In the early days of implementing state estimation in power systems, only the steady-state and quasi-steady-state models of the system were considered for formulating the state estimation problem, accordingly called, Static State Estimation (SSE). However, after a few decades, with the growing diversity of power system components and complexity of its dynamic phenomena, uncertainty in the power system has dramatically increased. Consequently, the need for situational awareness of the dynamic states of the system (such as rotor angle and speed of the generators) is felt more than ever. In addition, occurrence of the catastrophic blackouts in the world owing to deficiency in dynamic monitoring... 

The goal of controlling robot manipulators is to perform the mission intended for its end effector. Model-based control is a solution that can achieve the control goal with high speed and accuracy in the presence or absence of environmental obstacles by using the knowledge of the robot model. In this thesis, the Armtin 5 robot model parameters were identified in two steps. In the first step, the gravity and friction parameters and in the second step, the dynamic parameters were estimated. In the estimation of gravity and friction parameters, the non-linear behavior of friction causes the estimated parameters to be accompanied by a large amount of error. Estimation of the parameters was... 

Ground-Source Heat Pumps (GSHPs) are efficient means of space heating and cooling. However, owing to their high installation costs, their development in societies has not grown as it should. Therefore, it is crucial to have a meticulous design of these systems. The first step in designing GSHPs is determining the ground and grout thermal properties. Thermal Response Tests (TRTs) are developed for this purpose. The previous methods of estimating the unknown thermal properties are either computationally inefficient or yield inaccurate estimates for the ground volumetric heat capacity, to which the mean fluid temperature has the slightest sensitivity among all thermal properties. Among previous... 

The development of theoretical models in recent years emphasizes more and more the importance of intermediate goods in determining the welfare benefit of countries from international trade. In addition, due to the increase in computing power as well as the extent of international data, the experimental part has become an integral part of the research of this branch. In Ahmadi's thesis (1394), a multi-industry and multi-country general equilibrium model is presented by dividing the industries into two intermediate and consumption sectors based on the Caliendo and Parro (2014) model. In this model, a relationship has been obtained in terms of the basic parameters of the countries' industries,... 

A random vector with binary components that are independent of each other is referred to as a Bernoulli random vector. A Bernoulli Mixture Model (BMM) is a combination of a finite number of Bernoulli models, where each sample is generated randomly according to one of these models. The important challenge is to estimate the parameters of a Bernoulli Mixture Model or to cluster samples based on their source models. This problem has applications in bioinformatics, image recognition, text classification, social networks, and more. For example, in bioinformatics, it pertains to clustering ethnic groups based on genetic data. Many studies have introduced algorithms for solving this problem without... 

Different models describing the procedure of epidemics are complicated and involving numerous factors. Some of these models that used a stochastic network for modelling epidemics had been successful in statistical prediction of spreading epidemics. However, in many cases there is no direct way to determine parameters of these models. In this thesis it has been desired to estimate those parameters based on historical data of epidemics To estimate structural parameters, concerning epidemic network, two independent inference have been studied. In the first inference, the probability of disease transmission from one person to another is estimated.
In the second, using Bayesian inference,...