Sharif Digital Repository

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... 

The final target of this research is to design an appropriate intelligent control strategy for energy management purposes in a well designed parallel hybrid electric vehicle. In the first step, the conventional “Samand” vehicle has been simulated using real data for vehicle parameters and power train components, has been simulated. Using experimental results, simulation results are validated. In the second step due to the primarily defined parallel electric assist control strategy (PEACS) for the hybrid electric vehicle and performance requirements, components such as engine, electric machine and battery pack were selected and sized. In the final step a Fuzzy Logic Controller (FLC) has been... 

In this study, chapter 1 is dedicated to GEO satellites. In chapter 2, slosh dynamics of fluid and its governing dynamical equations are investigated due to the importance of this phenomena in geostationary transfer orbit. In chapter 3, dynamics of satellite orbit and satellite attitude are investigated and governing equations are derived by considering these effects: orbital noise (e.g. shape of earth, gravitation of sun and moon), moment noise (e.g. slosh dynamics of fuel and oxidizer, and liquid apogee motor misalignment). Following the third chapter, some simulations are carried out before the implementation of controllers. In chapter 4, a PID controller and a classical fuzzy controller... 

The purpose of this project is to use adaptive model predictive and fuzzy controllers to control the pH in a proper location and right amount as well as applying optimal dose of electrical current to prevent the destruction of healthy tissue during treatment. Comsol software has been used to simulate the electrochemical treatment of liver cancer. Since the Comsol software does not have the ability to solve the tumor model in spherical coordinates, the modeling/simulation was performed in cylindrical ordinates. In this study, only the reactions of oxygen and chlorine production in the anode were considered. The predictive control used in this study is GPC type and fmincon algorithm is used... 

Quantum interference and coherence are responsible for a novel set of physical phenomena, where Electromagnetically Induced Transparency is one of the most important of them. Each of these phenomena can make a new possibility for modifying the optical properties of a coherently prepared medium. Fast controllability of optical properties in one hand and flexibility of this control process in the other hand, are important factors that attract interests into coherent control of light .Coherent control of optical properties of the medium can be used in designing some advanced and challenging devices including All-Optical Switches. In this work , in a consistent picture, using a step by step... 

One of the most important processes in the manufacture of mechanical parts in the industry is the machining process. High-speed milling is growing in aerospace, automotive, and many other industries due to advantages such as high material removal rates and better surface finish. However, the instability caused by self-excited vibration (chatter) is not only one of the main limitations for the productivity and quality of the workpiece but also reduces the life of machines and tools. In this research, after introducing the matter of milling flexible parts, the basic concepts of machining are first described, and common terms in machining are explained. Then, a review of past research has been... 

The aerial vehicle capable of vertical takeoff and landing (VTOL), have created an interest in the community of researchers and admirers of Unmanned Aerial Vehicles. Among the existing UAV's, those with the capability of vertical takeoff and landing are prominent due to their higher maneuverability and hover capability. Quadrotors mostly have been considered as a flying robot for save and rescue operations in dangerous and unreachable places in addition to its military application. In cross shape of Quadrotor platform on each edge is appointed an electric motor with light rotors that usually are controled by considering motor rates as their only inputs. This thesis aims, to simulate and... 

Magnetic levitation is an appropriate solution for noncontact 3D manipulation. Workspace of the previously proposed maglev systems is confined to a relatively small cube, which severely limits the application of this technology. In addition, most of the previously given mechanisms require the design and application of a subsystem in order to unify their magnetic field. In this paper, a moving magnet is proposed which results in a horizontally extendable workspace; moreover, the field unifying section is not needed since one electromagnet only is used. Further, details of the mechanism and finite element based design procedure of the magnet are presented. Dynamic equations of the system... 

The Active Learning Method is in fact an adaptive recursive algorithm which embodies a Multi Input and a Single Output (MISO) system as in a fuzzy combination of several Single Input systems and Single Output systems (SISO), and by utilizing a fuzzy technique of Ink Drop Spread tries to explore and extract input to output transfer function behavior in the system of a single-input to a single-output. Although in simulation state, the speed of this model is set at a much higher speed in comparison to other presented models, still is slower than the processing speed of human brain. In regards to hardware implementation, also there remain the fundamental implementation challenges through more... 

The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetric,Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling.The satellite orbit, position, attitude angles and interior orientation parameters have to be adjusted in the geometrical model to achieve optimal accuracy with the use of a minimum number of Ground Control Points (GCPs). In order to obtain high resolution and definition imaging for many applications including surveillance, target tracking, and... 

In control systems, actuators are subjected to faults during operation. In the present work, a controller for nonlinear systems under several restrictions and in the presence of actuator failure has been proposed. The controller is designed for large-scale multi-input multi-output (MIMO) uncertain nonlinear systems subject to unmodeled dynamics, unknown state dependent control gain functions, unknown state time varying delay, unknown subsystems interactions, unknown external disturbances and input nonlinearity. The backlash has been assumed for input nonlinearity. No restriction has been considered regarding the number of actuator failure. The backstepping technique has been applied for... 

Polymer membrane fuel cell is a rich source of renewable energy. Two problems of short life and low reliability in fuel cells are the main problems of this system. The difference in partial pressure of hydrogen and oxygen causes serious damage to the fuel cell and inefficiency of the electricity production capacity. On the other hand, the life and optimal performance of the fuel cell depends on the moisture content of the membrane because the membrane needs sufficient moisture to pass ions. Transparent fuel cells can be used to study the water in the fuel cell. With direct imaging of this type of fuel cells, the phenomenon of water creation in the fuel cell can be studied with the help of... 

Controlling four legged robots is a complex challenge. The previous works in this field can be divided into two main categories, Analytic method and intelligence method. The analytic method is based on extracting the motion equations of the robot, but in most cases these equations are so complicated, and their implementation is difficult. Another method is intelligence method, which is based on learning algorithms. Despite the improvements in walking robots field, still their walking quality is far from human and animal walking. Researchers believe that this advantage is the result of the learning ability in animals and human. Therefore in this paper the human learning ability is used to... 

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... 

There are lots of researches performed to investigate human being learning and try to model it. But, in case of huge complexity of its structure and function, almost none of so-far learning algorithms can model human learning process and, indeed, performance of human brain in real problems is much more than these algorithms. Moreover, in many cases, human is not aware or informed about internal structure or mathematical model of the present system he is working on; a child learning to walk has no information about his neuromuscular system and his brain slowly learns how to convey his little body by choosing the proper timing of muscle contractions. One of the accomplished researches in order... 

This project is intended to introduce a semi-active control for suspension systems of passenger cars wherein, in addition to usual dampers, the damper using Magnetorheological (MR) fluid instead of ordinary oil is used. In order to model the suspension system, a mass-spring model with eight degree-of-freedoms without considering the effect of car velocity is developed. A semi-active vibration control is presented to reduce the amplitude of automotive vibration caused by the alteration of road profile. In order to design a suitable control mechanism, first, an optimal control algorithm, Linear Quadratic Regulator (LQR) and Linear Quadratic Gaussian (LQG), are used to control the system;... 

Gyrover is a kind of robot which can move with only one single wheel. In this robot, all the mechanical and electronics’ systems are placed in the wheel of robot. So the wheel of robot is the boundary which separates the inner equipment of gyrover with outside environment. In this robot, only one wheel is used for moving, so the amount of friction of movement in gyrover robot is less in comparison with two and more wheeled vehicles. Because of this gyrover can move to more domains. Gyrover robot can move both on land and water. Gyrover robot is not intrinsically stable which means that it cannot stand on ground. So for stability of gyrover another dynamic system should be used. The best... 

In this paper, controlling the cutting force of an end-milling process using a supervisory fuzzy controller has been investigated. The proposed control consists of an ordinary fuzzy controller and a fuzzy supervisor. In a machining process, there are several parameters which do not contribute to the force control system directly. Therefore an ordinary fuzzy force controller is suitable when these parameter have only small amount of variations. Since in practice this assumption is not valid, then a supervisory fuzzy controller has been added to the system. The designed fuzzy supervisor, inspects the dynamic behavior of the cutting force, estimates a pre-defined ‘sensitivity’ parameter and... 

Dynamic positioning system is a controller system used to maintain the position and heading of a vessel with no use of anchors, jack ups but only using the propellers installed on the vessel. A vessel has six degrees of freedom, including three rotations and three transfer. In dynamic positioning systems, the vessel is controlled only on the horizontal plane such that its position and heading are controlled according to predetermined values. To achieve this, position and heading of the vessel is determined and the controller system computes the direction and required power of each propeller. Preliminary systems utilized PID controllers. As the control science has advanced, model based... 

In recent years، one of the most popular and wide areas of research have been focused on Unmanned Aerial Vehicles (UAVs). Among them، Quadrotor which has the capability of Vertical Take-off and Landing (VTOL)، hovering، great agility and maneuverability، simple structure، light weight and reasonable size has particular importance. In the industry، we always deal with plants which there are no precise information about their dynamic model، or their model is too complex to identify. So designing controllers with less dependency to system model and no need to exact knowledge of the system is absolutely vital. The arrangement of motors in a Quadrotor provides six Degree Of Freedoms (DOF) for...