Sharif Digital Repository

Polyethylene terephthalate (PET) is known as the most important polyester in the world. This polymer is the raw material for synthetic fibers, films and plastic objects and widely used in textiles and food industry. In this project transesterification and polycondensation reactors of a semi-batch process with dimethyl terephthalate/ethylene glycol feedare simulated. First simulations areperformed for reactors in the laboratory scale.Then the reactors are scaled up to industrial scale in order to produce 100 tons per year of PET product. The optimal temperature trajectory for the fisrt reactor is obtained based on a performance index. This performance index includes the reaction time and... 

One of the reducing and controlling tools of high speed crafts is intelligent interceptor. Interceptor is a small blade that is originally installed vertically in stern. This blade creates a high pressure area under hull of the craft and produces lift force and a moment to the bow. The amount of lift force and moment can be changed by controlling the height of the blade. The intelligent interceptor (with automatic change in height of the blade) does the same thing. In this study, structural and software design of intelligent interceptor is done. In software field, optimal and PID controller are designed for interceptor system and the performances are studied in MATLAB SimuLink. The results... 

Smart structures are the combination of structure, smart material, electronics and control technologies. Changing the shape of the structures by smart actuators is one of the most important applications of Shape Memory Alloy (SMA) in these structures. Having used these actuators, we can effortlessly and continuously deform and reshape the structures. Nevertheless, working with SMA actuated smart structures has one obvious drawback that is their hysteretic and nonlinear behavior, making modeling and control of these structures complex. Another difficulty in the control of smart structures is their great sensitivity to the actuating force that reduces the controllability of these structures.... 

This research is trying to investigate the control algorithms of unknown control direction systems. Since Nussbaum function is the most common method which in used for these systems this research focus on this algorithm to overcome control the effect of unknown control direction. This research study the performance of different control algorithms in controlling such systems followed by analysis of two control modes of continuous and discrete using Nussbam Function. Additionally, in continuous mode, the performance of two methods of backstepping and liding mode has been compared on the given system in variety of situation. Results demonstrate that backstepping method shows better performance... 

Vacuum assisted resin transfer molding (VARTM) is one of the most efficient and low cost process in composite industries. In this process, the preform is covered by a flexible vacuum bag and resin flows into the mold with applying vacuum pressure at the vent. The main objective in VARTM process is preventing voids and dry spots formation in final composite part because these defects may significantly deteriorate the mechanical properties of a structure. Flow front is an important parameter in this process which have a high influence on the void formation. Resin flow control is required to prevent dry spots or micro voids during the VARTM process. In general, the flow control is classified... 

In this thesis, fuzzy logic is used to suggest a simple algorithm in guidance and control suitable for upper stage decoupler transfer with finite and continuous thrust. It is attempted to improve injection accuracy utilizing classic guidance and control methods and fuzzy logic, while unpredictable errors exist. Orbital perturbations, uncertainties in thrust vector, and initial injection errors in parking orbit, are considered in order to actualize results. In this research, Lambert guidance, velocity to be gained, and fuzzy logics are used for upper stage guidance. Fuzzy-PD control is designed and applied into the upper stage. Final results show acceptable position errors and suitable fuel... 

Diabetes is one of the most epidemic metabolic disease which needs to be controlled through medications. The main objective of this study is to model and control diabetes type1 with exercise. It is important to choose an appropriate yet simple model based on which the design of the controller is accomplished (Bergman model is the one which is appropriate for this purpose). On the other hand, a comprehensive model which is used as the virtual patient has been chosen to assess the performance of the controller designed based on simple mode. The chosen comprehensive model is Cinar’s model. A good control of diabetes was achieved when the glucose blood (GB) of the two models almost had the same... 

The present research intends to design a controller for modular reconfigurable manipulator robots. Manipulators are made up of several links and joints. By attachment of links and joints in different ways, one may make a variety of robot configurations in modular reconfigurable manipulators.
To meet modularity and reconfiguration needs, hybrid control architecture was selected which contains a central supervisory section and distributed controllers located on individual modules. Central supervisory section specifies the trajectory of the robot and other control tasks like position control, speed control and etc. are performed by distributed controllers. In hybrid architecture, dynamic... 

Suspension systems play a significant role in vehicles. They are responsible for providing ride comfort to the passengers and maintain car handling. Vibrations induced by the road can cause harmful effects on human body and this reveals the importance of designing and controlling the suspension system. Semi-active control is a reliable and safe method that has attracted a great deal of attention in the suppressing the car vibration. MR damper is a sample of semi-active control method. In most of the studies that have been done in literature the human body model has not been considered in designing the control strategy. In this study, a complete model of suspension system integrated with the... 

The satellite attitude control problem is to determine the torque that is produced by actuators in such a way that, the satellite reaches to a desired final state from an initial state. If we do not consider the structural and dynamical equations of actuators and its effects in the system’s equations, the control problem is simple and can be solve easily. But, when the dynamic of the actuators and practical constraints associated with them and the equations of the system are to be considered, due to the dependence of these equations, solving the satellite attitude control is not simple like before. That is why, no effective method is presented to solve it. One of the most widely used... 

In robotic, Underactuated systems are interesting subject to study. Underactuated system, is a system that have fewer actuator than degrees of freedom. Underactuated systems are composed of active and passive joints. passive joints are existed, in order to decrease the weight, cost, and energy consumption. Usually, control of these systems are difficult. Underactuated systems have acceleration constraint. This property make the control method have fundamental constraint. So that controller dynamic could not be a smooth function of states of system. So most of standard method in control, such as feedback linearization, are not applicable. Local linearizing methods, because of... 

Control of line of sight (LOS) orientation is a fundamental prerequisite for virtually all dynamic applications in which an optical sensor is used to obtain images. In this research, a 3 DOF parallel mechanism is utilized to build a stable platform for high precision satellite photography. The platform may be designed based on the Stewart platform concept. The stability is obtained by controlling the roll, pitch and yaw of the mechanism. To apply linear control techniques and to use roll-pitch and yaw rates and also their absolute values, an active stable platform is designed. Line Of Sight (LOS) is a position vector from origin of a topocentric-horizontal system to the satellite of... 

Air-handling unit (AHU) is one of the installations that is responsible to control the temperature and humidity inside a space using the heating, cooling, humidifier and drying air. At present, energy efficiency in building is an important issue to maintain the comfort conditions. One of the most common ways to optimize the performance of industrial installations is the use of control systems, which leads to the reduction in both of the costs and energy consumption. In this research, a multivariable nonlinear dynamic model of the AHU with one zone in the VAV (variable air volume) system for working in summer is considered. At first, introduction, limitations and driving the equations for the... 

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... 

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... 

Modern science and technology’s desire is increasing for Control Algorithms Testing Instruments which allow testing autonomics due to advancement in robotic science and increased application for autonomics. In this Thesis, a manufactured tester is equipped with sensors to allow data acquisition and Control algorithms tests for RC helicopters, which are a variety of autonomics. For this purpose; a manufactured 3-DOF tester was used and for control application purposes one degree of freedom was added and it was made to 4-DOF. Also, Mechanical defections which cause vibration resonance failing was solved. In the end, a data acquisition system with an appropriate rate for signal gathering and... 

The project aims to design and build a device that is capable of manipulation and control of micro-scale objects in dry and fluid medium. Among all the micro-manipulation methods, the use of magnetic fields has many applications. Because it has the ability to work without direct contact and also within a specified range for living tissue, is safe. To achieve this goal,manipulation systems ever made, were studied. Then, by presenting a conceptual design and the use of appropriate dynamic models for describing the behavior of micro-robot, the system performance was simulated. After this stage, The detailed design of the closed-loop system which must controls the position of the micro-robot... 

In this research, a study on Mirror Neuron and Active learning method was done based on the human capability of using their past knowledge in order to understand new systems faster and with more accuracy. Mirror ALM, A new modeling technique based on ALM was proposed that is capable of merging the IDS planes of an old system in order to improve the output of the modeling for a new system. This new technique was tested on a 3D function, state estimation of an inverted pendulum and finally in control procedure of an inverted pendulum. The results of the tests were compared with the classic ALM method to recognize the advantages and disadvantages of the introduced method. The results showed... 

In this work inspiring from the nature a control method is proposed for a stable rhythmic walking in a seven-link underactuated biped robot. Stable walking is a very important issue in biped robots and proposing a dynamically stable pattern of motion with the capability of acceleration and learning is our main purpose. It is tried that the presented method make the robot have a human like motion. This method controls dynamically the hybrid model of robot’s movement and stabilizes it by converging the time-invariant constraints considered to make this movement. Moreover, in addition to providing a suitable gait for the bipod robot, a robust control method is designed to improve the ability of... 

In this thesis the resilience of a neural network is examined under structural perturbation.The network consists of Spiking neurons with specific dynamics or they are binary neurons and the network is non-spiking. Neural network is a multi-dimensional and multi-stable system therefore we can map their dynamical equations to effective one-dimensional equation with one parameter which shows the environmental conditions.The resilience of the system is evaluated with respect to changes in weights and edges of the network and the the resilience pattern of the system is obtained.Finally, the recovery and control methods are briefly discussed