Sharif Digital Repository

Chemotherapy is a proven and effective systematic approach to treat various types of cancers. Despite its advantages, chemotherapy would kill healthy as well as cancer cells. To overcome this problem, different controlling strategies are implemented. This study aims to provide a medicine drug delivery schedule for chemotherapy (by designing a proper controlling system) based on the verifiable mathematical models. First, the dynamic model is analysed and stability points are reviewed. The selected model has five state variables and two inputs. In this study, the focus is on dynamic model analysis and obtaining an effective and appropriate treatment pattern by designing a proper controller. To... 

Environmental issues and energy crisis have led the world attention to the renewable energies; especially wind power, since they have low cost and high reliability. One of the most challenging areas of studying for wind power is to increase the capacity of wind turbines. As a result, over the years, wind turbines have got progressively larger. Vibration is one of the problems that reduces the life and efficiency of wind turbines; and the growing size of the blades has worsen this problem due to the importance of nonlinear effects in large scale wind turbines. Researchers have been constantly working on this issue in order to make the wind turbines more efficient. In this research, a... 

Wind turbines have been the subject of many researches in recent decades. Optimization and continuous improvement of these systems play a decisive role in the development and exploitation of wind farms. Wind turbines can be studied from several aspects such as structure, dynamics, aerodynamics, electricity and control. In this research, robust power control of the wind turbine has been studied with emphasis on accurate 2 DOF mechanical and aerodynamic modeling. Aerodynamic coefficients of the turbine have been calculated using the numerical methods and the effect of this numerical modeling has been studied in comparison with the analytical methods on the turbine power control. Several new... 

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... 

Best cancer treatment is the one which reduces the tumor density in minimum time and side effects, considering the input limitations. In this paper, tracking controller and robust controllers are designed to achieve the mentioned objectives, simultaneously. An ODE-based mathematical model of the human body under chemovirotherapy is selected, which includes the uninfected and infected tumor cells, free viruses, immune cells, and a chemotherapeutic drug. For tracking purposes, a servo controller based on the entire eigenstructure assignment (EESA) approach is applied to the model, continuously and discretely. For robust purposes H-infinity and D-K iteration approaches are implemented and... 

Today, cancer mortality is one of the most important problems, even considering the scientific advances that offer more effective solutions to treat some diseases, providing a way to prevent and treat this disease is one of the most important issues that engineers have considered. This is achieved by designing a controller to minimize the size of the cancer tumor population, increase healthy cells, optimize treatment time, and drug dose.To achieve this goal, pharmacokinetic, pharmacodynamic, tumor growth, and healthy cell growth models, and mathematical models for subsystems that affect tumor growth, such as the angiogenic system, have been studied to develop a single mathematical model. In... 

Power transmission lines, which are responsible for the distribution and transmission of electrical energy from the power plant to the consumer areas, due to their characteristics such as long length and flexibility with low structural damping, face environmental irritations, especially the galloping phenomenon, causing many damages annually. In this study, it has been attempted to reduce the vibrations of power transmission lines by designing a robust active control and by using intermediate actuators in such a way that the failures of these lines can be prevented. For this purpose, linear modeling of the system and designing the controller using the pole replacement method have been done.... 

The power control of horizontal axis wind turbines can affect significantly the vibration loads and fatigue life of the tower and the blades. In this thesis, we are going to consider both the power control and vibration load mitigation of the tower fore-aft vibration. For this purpose, at first, we developed a fully coupled model of the NREL 5MW turbine. This model considers the full aeroelastic behavior of the blades and tower and is validated by experiment results, comparing the time history data with the FAST (Fatigue, Aerodynamics, Structures, and Turbulence ) code which is developed by NREL (National Renewable Energy Lab in the United States). In the next, to estimate EWV, a novel... 

Nowadays electricity power has a key role in developing various aspects of the world. The great importance of fossil fuel power plants come from their large contribution in electricity power generation. Among the different fossil fuel power generation technologies, supercritical power plants have great advantages. They are an advanced power generation technology with high plant efficiency, high coal utilization and low emission. Their complexity and existing many unavoidable uncertainty sources in their dynamic such as changes of ambient temperature, climate condition and wear of components make their control challenging. To overcome mentioned problems and achieving a good performance, a... 

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 purpose of this project is to model a rotating beam with variable properties of the cross section and also to present an active control method for suppressing the undesired vibrations due to external loading. The beam is modeled as a cantilever Euler-Bernoulli beam with nonuniform physical and geometrical properties. For a practical example, the characteristics of a wind turbine blade was used to solve the problem. The analyzed blade in this study is NREL 5-MW wind turbine blade. But the method can be extended to be used for other blades as well . First the natural frequencies and modeshapes were computed by MATLAB. Then by applying pole placement method, a control strategy was designed... 

Vibrations in HAWT reduce their efficiency and increase maintenance costs. In this paper, the blade edgewise vibrations are reduced by using several actuators in different parts of the wind turbine blade and optimization of the number and locations of actuators. The wind turbine blade dynamic behavior is investigated by using dynamic modeling. The actuators are trusses that are located inside each blade and apply control force to different parts of the blade. Active control force is applied to reduce edgewise vibrations. The designed controller is applied and simulated on NREL 5MW wind turbine. By applying the controller, the edgewise vibrations of wind turbine blades are significantly... 

The main goal of controlling overhead crane systems is to safely transfer the load to its desired position with maximum speed and accuracy, as well as to minimize or eliminate load oscillations. The overhead crane system is considered as an underactuated mechanical system in which the number of control inputs (actuators) is less than the number of degrees of freedom. In addition, overhead crane systems are generally associated with parametric or unmodeled uncertainties. Also, in these systems, external disturbances such as wind have a destructive effect on the system's performance. In addition, if the overhead crane has the hoisting mechanism and the length of the rope changes as the trolley... 

Nowadays, economical extraction of oil and gas, and their products is an important issue for many countries. Up to now, vertical wells have been used for oil extraction but some wells exist that they cannot be reached by using vertical drilling; for example the wells under a sea. Therefore, this makes the governments and scientists determined to find a new way to reach them. Horizontal drilling is one of the new ways to reach such worthy wells. In this project, dynamics of the horizontal drill string is studied. Then, according to the forces that affect the dynamics of drilling, its vibration is analyzed. After finding the boundary conditions and normal modes of the system with using mode... 

Self-excitation vibration or chatter in the milling process is one of the most critical factors in reducing the tool life and surface smoothness. With the change of tool speed or depth of cut, bifurcation phenomena occur at some points (bifurcation points) such that the system behaviour becomes unstable and the chatter is observed. In this study, using nonlinear modelling for cutting forces, two main methods for active control of this process are proposed. The first is an intelligent control based on emotional learning, which is a model-free strategy. In this method, the critic generates a signal (stress signal) using error and its derivative. The purpose of this controller is to reduce the... 

Nowadays, due to the increasing use of Air Handling Units (AHU) in buildings, reducing energy consumption and improving the performance of these devices is one of the most important goals of researchers in the field of heating, ventilation and air conditioning (HVAC) technology. The purpose of this project is to design an optimal control system in different parts of the Air Handling Unit in order to provide standard ambient and breathing conditions for the people. Therefore, the mathematical model of the multi-zone space and the equipment of the Air Handling Unit are studied as separate subsystems based on the laws of thermodynamics and heat transfer. The obtained equations provide a... 

Optimizing the energy consumption of air conditioning systems has gained great importance in recent years. In addition, maintaining thermal comfort and air quality in buildings is important. The multi-evaporator air conditioning system, which is a direct expansion system, shows the complex and distributed structure of air conditioning systems due to the thermal connection between zones and its large scale. The modeling of these systems is associated with uncertainties. Therefore, designing a suitable control structure for multi-zone systems is very important to achieve optimal energy consumption and maintain comfort conditions in the presence of uncertainty. Model predictive control has been... 

Renewable energies and their various types have been recognized as sustainable solutions to address the challenges arising from increasing energy consumption and environmental issues. The use of wind energy as one of the renewable energy sources has particular advantages, considering it as one of the most sustainable energy sources. One of the key factors in wind turbine development is the diversity and multiplicity in their structural designs. Therefore, the design of wind turbine structures with characteristics such as suitable strength, high energy efficiency, optimal cost, and high reliability is of great importance. By employing various sciences such as vibrations and optimization in... 

Nowadays, horizontal drill string is a powerful tool for drilling in the oil and gas industry and an efficient method for constructing underground tunnels in cities. Despite its many uses, this method is exclusive to limited countries and is considered among the most advanced methods for drilling. One of the most important problems in the field of horizontal drilling is the existence of destructive axial, torsional and lateral vibrations. If these vibrations are not controlled, they can cause irreparable damage to the plant and drilling well. Among the introduced vibrations, axial and torsional vibrations have a very dominant effect on the drilling process, so the purpose of this research is... 

With the advent of new technologies in everyday human life, issues related to the use of vehicles have become crucial subjects of investigation. In this context, vibrations transmitted from the vehicle to the human body, especially in terms of long-term health effects, have garnered special attention and significance. The main objective of this research is to develop a control system for the active control of vibrations transmitted to the human body. To achieve this goal, a 5-DOF model of the human body has been employed as the study system. Considering the uncertainties in the parameters and dynamics of this model, H∞ and µ-synthesis methods have been utilized for robust control design. The...