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Developing the Design Methods for Adaptive Fractional Order PID Controllers
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor)
Abstract
The PID controller has been used for a long history in control engineering and is acceptable for many real applications due to its simplicity in architecture. Hence, in many real industrial applications, the PID controller is still widely used even though lots of new control techniques have been proposed. In recent years, by developing fractional calculus in control applications, using fractional order PID controller —which is simply called — was proposed by Podlubny. Up to now, several methods of tuning fractional order PID controller has been established for time invariant systems, but dynamics of real systems are mostly time varying. Because of this fact, using adaptive control and...
Modeling and Control of Quadcopter UAV with Tilting Arms
, M.Sc. Thesis Sharif University of Technology ; Nejat, Hossein (Supervisor) ; Alasty, Aria (Supervisor)
Abstract
Quadcopters are a bunch of vertical takeoff and landing UAVs and generally consist of four symmetric arms, each possessing a rotor-blade at the end. Quadcopters are able to retain their state and position by performing static maneuverability. Conventional quadcopters have less actuators (four engines) than their DOF (six degrees of freedom in the space). Thus, it is impossible to control all DOF of the system independently. Nevertheless, one can make a solution to this problem by increasing the number of actuators, so that each rotor-blade can also rotate about the corresponding arm. Such a quadcopter is so called a “tilt-rotor quadcopter”. The aim of this work is to model a tilt-rotor...
Modelling and Electromechanical Control of Variable Speed wind Turbine in Order to Gain Maximum Wind Power
, M.Sc. Thesis Sharif University of Technology ; Moradi, Hamed (Supervisor)
Abstract
In this research, the main purpose of the controller design is in the second region of operation of a wind turbine, which involves absorbing the maximum energy from the wind. WindPACT 1.5MW turbine has been investigated and the power coefficient of this turbine has been obtained using WT-PERF and FAST softwares. Simulations show that the results of both methods are well matched. Then, using ANFIS, a method for estimating the wind speed is derived from the data obtained by FAST. Inputs to the ANFIS system are the turbine aerodynamic power, rotor speed and blade pitch angle while the output of ANFIS system is the estimated wind speed. The maximum power coefficient of the wind turbine occurs...
Fuzzy Control of Percutaneous Needle Using Ultrasound Imaging-Based
Trajectory Planning
,
M.Sc. Thesis
Sharif University of Technology
;
Jahed, Mehran
(Supervisor)
Abstract
Subcutaneous needle insertion is one of the key methods of limited invasive surgery in medical diagnosis and treatment. However, errors in needle targeting can reduce the effectiveness of such efforts. One of the main factors of errors is due to the human guidance of the needle, which many researches have approached in recent years, and among the suggested solutions is the use of automatic or semi-automatic assist systems. Considering the treatment of prostate cancer by brachytherapy method, this research has developed a semi-automatic physician assistance system using navigation based on the potential field method and ultrasound images of the needle location, and sliding mode fuzzy...
Designing a Multi-Model Sliding Mode Controller for a Magnetic Levitation System
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohammad (Supervisor)
Abstract
In this project a complete simulator for a two-winding, 25cm air gap Maglev system by considering the pratical constaritns, position and velocity observer and the current sensor dynamics was derived. In order to control the ball in any desired position a twisting sliding mode controller was designed as the basic controller in the rest of project. The designed controller can not transfer the ball in far trajectory. In first step we modify that to reach a better performance by changing the value of current, passing through the coils in steady state. In the second step, the far trajectories are divided to a finite number of sub-trajectory such that the ball can pass these sub-trajectory by...
Chaos Control in Continuous Time Systems Using Delayed Phase Space Constructed by Takens’ Embedding Theory
, M.Sc. Thesis Sharif University of Technology ; Salarieh, Hassan (Supervisor)
Abstract
This research has dedicated to study the control of chaos when the system dynamics is unknown and there are some limitations on measuring states. There are many chaotic systems with these features occurring in many biological, economical and mechanical systems. The usual chaos control methods do not have the ability to present a systematic control method for these kinds of systems. To fulfill these strict conditions we have employed Takens embedding theory which guarantees the preservation of topological characteristics of the chaotic attractor under an embedding named "Takens transformation". Takens transformation just needs time series of one of the measurable states. This transformation...
Design and Implementation of a Real Time Controller for a 6 DOF Manipulator
, M.Sc. Thesis Sharif University of Technology ; Meghdari, Ali (Supervisor)
Abstract
In recent decades, the usage of robots in industrial applications increased dramatically. One group of robots are manipulators which they are used in production lines for moving parts, cutting, welding, …. In these applications, different control methods are used to control the end effector of manipulators precisely. From one aspect, control methods are divided to two parts: A) The methods that do not need to equation of motion of robot, such as proportional-integral-derivative method. B) The methods that are designed based on equation of motion of robot. To use these methods, first the equation of motion of manipulator should be calculated according to its structure. These equations are...
Control of Experimental Swarm Robots for Identification, Imaging & 3D Modeling Purposes
, M.Sc. Thesis Sharif University of Technology ; Alasty, Aria (Supervisor)
Abstract
The aim of this project is decentralized control of a group of robots (swarm robots); such that the aggregation maneuver, leader following, Identification and imaging the target, will be performed so good as to make a three-dimensional model of the target from these images. Swarm robots consist of a number of similar and limited features robots which interaction in a group of robots, will lead to special features for the group. Any agent of group decides what to do only with its local information from the environment. Swarm robots are more applicable for the jobs in which a distributed perception from the environments needed, for example space exploration and military operations.In this...
Design and Make a Prototype of a Gantry Crane and Controller for Suspense Load
, M.Sc. Thesis Sharif University of Technology ; Saadat Foumani, Mahmood (Supervisor)
Abstract
Swaying is an unfavorable phenomenon in moving suspended loads. So, cranes are usually equipped by anti-sway controllers. In this thesis, various controllers have been applied to a prototype of gantry crane system with various control inputs, and their competency has been assessed. First, a 2-DOF model has been introduced. This model contains a trolley and double pendulum with variable length attached to it. Then, it has verified by two approaches: first is comparing with simplified equations of model with flexible cable; and second is comparing with behavior of simulated system by Visual Nastran software. Next, a SISO linear controller has been designed for container cranes and applied to...
Modeling and Sliding Mode Control of a Roll-Pitch Seeker
, M.Sc. Thesis Sharif University of Technology ; Nobahari, Hadi (Supervisor) ; Pourtakdoust, Hossein (Supervisor) ; Mohammad Karimi, Hamed (Co-Supervisor)
Abstract
The purpose of this thesis is sliding mode control of a roll-pitch seeker by considering the zenith pass problem. This problem takes place when the target appears in front of the seeker’s head. First, the mathematical model of the roll and pitch frames is obtained by the Newton-Euler equations of motion. Then, a MIMO sliding mode controller is designed. The performance of the controller is investigated in the presence of model uncertainties and seeker disturbances. The results indicate that the designed controller is robust enough and provides a suitable performance in the stabilization, tracking and guidance loops.
Completion of Electromagnetic System and Design of Robust Controller to Control the Movement of Micro-robots in Three-Dimensional Space
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Today, the need to access very small environments is felt in various medical, industrial, biological and military fields. Due to their small size, microrobots have the ability to perform tasks that would be very difficult to do on a larger scale, but this ability of microrobots makes feeding and controlling them challenging. There are several methods for providing power and control of microrobots, which include their internal or external stimulation, among which the magnetic stimulation method is used in this research, which does not cause damage to body tissues.In this thesis, an electromagnetic system with nine cylindrical coils is used to control the three-dimensional movement of magnetic...
Modeling, Simulation, and Sliding Mode Control Analysis of SQ15-06N Robot
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Amir Ali Akbar (Supervisor) ; Selk Ghafari, Ali (Supervisor)
Abstract
In this thesis, kinematic, dynamic modeling and simulation, and control of SQ15-06N industrial robot have been presented. This robot is mostly used in the painting industry. Studying the robot requires familiarity with the robot programming and the hardware used in the robot. In this research, robot characteristics such as repeatability, load carrying capacity and accessibility have been investigated. The principles of industrial robot programming and robot programming language have been studied. The use of simulation software is common due to cost savings, reduced time, no need for robots and controllers, and the ability to test programs in a virtual environment. For this purpose, the...
Decentralized and Scalable Control of Multi-Agent Systems for Obstacle Avoidance and Changing Formation
, M.Sc. Thesis Sharif University of Technology ; Sayyaadi, Hassan (Supervisor)
Abstract
Coordinate motion is a considerable phenomenon in biology and very powerful tool for leading and controlling a group of robots. In recent years, robotic becomes a helpful technology for acompilishing in works which is impossiple for human, such as working in toxic environments. In this project, we introduce coordinate motion problems which are applicable in multi-agent systems, and we also present suitable control algorithms for solving this problem. In other word, we use potential field method to model coordinate motion. We propose a three-cycle robot as an agent, such that it has two nonholonomic constraints. Designing an algorithm for solving coordinate motion problems, we propose these...
Robust Multivariable Control of Electro-mechanical System in Horizontal Wind Turbines under Off-design Conditions
, M.Sc. Thesis Sharif University of Technology ; Vosughi Vahdat, Bijan (Supervisor) ; Moradi, Hamed (Supervisor)
Abstract
Advanced control techniques are required to achieve a cost-effective and reliable use of the wind power generation. The wind turbines are generally controlled based on two control objectives: the turbine protection and the generation of acceptable power for the utility grid. These objectives are achieved if the control inputs are applied based on appropriate control logics. In this work, a nonlinear multivariable model of the wind turbine with a DFIG generator is considered. The rotor speed and the d-axis rotor current (as the control outputs) are controlled via manipulation of the two generator voltages (as the control inputs) in low wind velocity condition. For high wind velocity, the...
Robust Control of Spacecraft Rendezvous in Halo Orbits in the Three Body Problem
, M.Sc. Thesis Sharif University of Technology ; Pourtakdoust, Hossein (Supervisor)
Abstract
The problem of spacecraft rendezvous on periodic orbits around the L_1Lagrange point of the Earth-Moon system is investigated. For this purpose, the nonlinear relative equations of motion are drived within the contex of the Circular Restricted Three Body (CRTB) problem. Subsequently, several types of rendezvous missionas well as control teqniques are considered for analysis and simulation. Application of different control approaches allows for partial verification as well as comparison of results achieved with various teqniques. The considered control approaches include optimal closed loop Linear Quadratic Regulator (LQR), nonlinear Feedback Linearazation (FL) as well as the nonlinear...
A Robust Controller Approach for Configuration Selection for an Urban Transportation Electric Vertical Takeoff and Landing Aircraft (EVTOL)
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor)
Abstract
This thesis addresses the problem of configuration selection for an urban air mobility EVTOL aircraft utilizing a robust controller approach.First of all, to arrive at a final configuration, different feasible concepts for an urban transportation EVTOL aircraft have been proposed and studied during several brainstorming sessions. As a result, five potentially viable configurations have been selected for further investigation and analysis. These preliminary designs have been nominated utilizing the method of decision matrices and considering the design team and control system designer’s selection criteria. Finally, a tilt-rotor tandem-wing configuration has been selected to go through the...
Design and Control of a Robotic Arm and Hand with Simulation on Performance
, M.Sc. Thesis Sharif University of Technology ; Zohour, Hassan (Supervisor)
Abstract
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...
Fractional Order Sliding Mode Controller (FOSMC) Design for Attitude Control of a Satellite with Coupled Rigid–Flexible Structures Using Fractional Order Transfer Function
, M.Sc. Thesis Sharif University of Technology ; Fathi Jegarkandi, Mohsen (Supervisor)
Abstract
With the development of fractional order calculus and more accurately modeling of physical phenomena, the problem of controlling these systems, by considering the uncertainties in the system, will become necessary and inevitable. In this thesis, the fractional order transfer function model of a satellite with Coupled rigid-flexible structures is used as the reference work of the research. To control this dynamical system, sliding mode control method, which is one of the robust control methods, has been used. It is clear that it is not possible to directly design a sliding mode controller for a transfer function. For this reason, a fractional order pseudo-state space model is first obtained...
Impedance Control of Flexible Base Moving Manipulators
, Ph.D. Dissertation Sharif University of Technology ; Vossoughi, Gholamreza (Supervisor)
Abstract
In this paper, the general research of impedance control is addressed for a robotic manipulator with a moving flexible base. Impedance control imposes a relation between force and displacement at the contact point with the environment. The concept of impedance control of flexible base moving manipulators (FBMM) is rather new and is being considered. The dynamic of manipulator is decomposed into slow and fast dynamics using singular perturbation method. New sliding mode impedance control method (SMIC), using an element on the end effector is proposed for high precision impedance control of FBMM. The sliding mode impedance control method as a robust impedance control law is derived for the...
Localization and Control of a Magnetic Device in the Presence of an External Field with Application in Stomach Capsule Endoscopy
, M.Sc. Thesis Sharif University of Technology ; Vosoughi, Gholamreza (Supervisor) ; Moradi, Hamed (Supervisor) ; Nejat Pishkenari, Hossein (Co-Supervisor)
Abstract
Capsule endoscopy is a minimally invasive diagnostic technology for gastrointestinal diseases providing images from the human’s digestion system. Developing a robust and real-time localization algorithm to determine the orientation and position of the endoscopic capsule is a crucial step toward medical diagnostics. In this thesis, we propose a novel model-aided real-time localization approach to estimate the position and orientation of a magnetic endoscopic capsule swimming inside the stomach. In the proposed method, the governing equations of the motion of an ellipsoidal capsule inside the fluid, considering different hydrodynamics interactions, are derived. Then, based on the dynamic...