Sharif Digital Repository

In this project the main aim is to model the interaction between the cytoskeleton and cell membrane. In order to model the membrane and cytoskeleton it is used a discrete model, which contains several beads. For modeling the interaction between the beads it is used different kinds of energies. It is used four potentials in a 2D model for modeling the interaction between the membrane beads and it is used SSLJ potential in order to model the interaction between the cytoskeleton and cell membrane. Furthermore, this potential is used to model the interaction between the cytoskeleton filaments. Due to this potential, the cytoskeleton filaments can cross each other in the 2D model. For modeling... 

In this work dynamic behavior of a two body TSS with main satellite as rigid body is studied and effects of tether elasticity and tension on the satellite dynamic are indicated in station keeping phase and circular orbit. Also a simplified modeling is introduced which could be used in nonlinear controller design. Lagrange and extended Lagrange method is used to derive equations of motion. It is shown that longitudinal vibration of tether has small effect on satellite attitude and angular velocity and because of high frequency it can be decoupled from satellite dynamic. In the simplified model, orbital motion is decoupled from equations of TSS and main satellite dynamic. Effect of decoupling... 

A sliding mode nonlinear controller has been developed to control a monohull hard-chine planing vessel. Planing vessels has been used for shoreward marine missions. On the other hand, according to vast shores of our country, offshore applications could be of extra importance for us. Autopilot of a vessel consists of two stages: trajectory design and trajectory control. In this project, trajectory control is being done using sliding-mode nonlinear control method, considering the fact that according to nonlinear dynamics of planing vessels, linear control would not show desirable results. In this dissertation, after description of main information about planing vessels and prior researches,... 

Systems that are electrostatically actuated have found a vast role in MEMS application. This technology is used in optical systems, sensors, micro switches, and deformable mirrors. Raising the use of these systems in fields that needs better performance highlighted the need to accurate study of dynamics and control of electrostatic actuated systems in micro scale. This work is dedicated to design of an estimation and control system for a micro-beam that is actuated by electrostatic. After a comprehensive survey on pervious works that are done on dynamic, applications, fabrication and control of these systems dynamic of the system is fully derived. The environmental factors like fringing... 

According to high nominal pressure and controllable flow, variable displacement axial piston pumps are used widely in hydraulic industry. However, there still exist many problems and limitations in the areas of design, controllers and performance. To solve the problems without wasting time and money in making prototypes, an accurate dynamic model of the pump is required which predicts pump behavior under various control signals and loads. The lack of simple and practical methods of measuring describing parameters of pump dynamics, makes investigation and verification of such a model very challenging. In this thesis, literature review is presented in a wide range. After investigating of... 

Synchronization means to control the response system to follow the drive system. It first began in 1990 in a paper by Pecora and after that it is used in many applications like secure communication. Another application for synchronization which is introduced here is identification of chaotic systems. According to the research done, this application hasn’t been in the literature as it is known to us. Synchronization papers usually devide into two parts. In one of them the parameters of the systems are unknown, so adaptive laws are used to estimate the parameters. In the other part, the parameters are taken known. It is not mentioned in the first group that the estimation would converge to the... 

Control and guidance of a vehicle is vital for it to do its mission correctly. Guidance system and decisional algorithms used in it need exact information of instantaneous position, velocity, and attitude of the guided vehicle to determine and issue proper guiding commands.
Estimation algorithms and navigation sensors are two necessary tools for navigation. In the first section of present study, the reentry head equations of motion are derived and a 6-DOF simulation is done for it. In the second section, measurements of sensors will be simulated using results of the first section and existing reference models for sun position vector and earth magnetic field. The third section appertains... 

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... 

In this study, by INS and auxiliary acoustic sensors data fusion, underwater navigation algorithm is implemented and validated by computer simulations. Extended Kalman Filter based on perturbation analysis is used as combination algorithm. The outputs of the INS forms equations of mechanism. The variational variables are state variables estimated in the Kalman filter. Because of the weakness of the GPS signals due to electromagnetic signals Attenuation in water, acoustic sensors are used as auxiliary sensors in underwater navigation. Here those acoustic sensors that implementing them in this country is impossible or very costly would not be examined.In this research the output of Doppler... 

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... 

Despite the advancement of technology in the world still some parts of the work are done by human hands. Gloves that increase fingers force can cause less fatigue, greater accuracy and efficiency in carrying out their duties in person.Also patients with muscle weakness due to M.S. or apoplexy, or elderly people are unable to do the simplest tasks. A wearable robotic glove that can restore hand function can increase the quality of life for people with mobility problems. The aim of this research is to design, build and control a conceptual prototype of a flexible wearable robot to increase fingers force by cable mechanism; and in this glove, force and position control concurrently is done by... 

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... 

Navigation is the science of determining the velocity and attitude of a moving object in every given moment. There have been many methods for navigation. Nowadays with the advancement of technology, advanced navigation systems have been developed. Although each of these navigation systems have their pros and cons, in order to improve the overall performance of the system and to solve their problems, these systems are integrated.The goal of this project is to present an integrated cascade method to decrease error and also decrease dependence on GPS. In this project, INS, DVL & GPS are integrated with the cascade method.To achieve this, INS-GPS and INS-DVL integration are first performed. The...