Sharif Digital Repository

With the continued improvement of sequencing technologies, the prospect of genome-based medicine is now at the forefront of scientific research. To realize this potential, however, a revolutionary sequencing method is needed for the cost-effective and rapid interrogation of individual genomes. Generally there are key factors in the definition and evalution of sequencing methods: 1-read length, 2-throughput, 3-read accuracy, 4-read depth, and 5-cost per base. The purpose of developing new sequencing methods is making better at least one of these factors. In order to reach the goal of rapid and low-cost sequencing method, one cannot rely only on current techniques. Improvements of current... 

The Delta parallel robot is used extensively in many industries, including packaging, because of its superior speed and precision. In this project a Delta robot was designed and then controlled specifically for use in the production line of a plastic container factory. In order to optimally design the robot, a number of desirable fitness functions were defined thus: minimizing the dimensions of the robot for a specific desired workspace, minimzing the effect of the robot’s weight on its actuators and satisfying the demands of the “Design for Control” approach. Design for control means considering the complexity of controlling a system while designinig it. Therefore the remaining fitness... 

An essential requirement for performing robotic assisted surgery on a freely beating heart is a prediction algorithm which can estimate the future heart trajectory with a high accuracy in a long horizon. The main objective of this research was measurement and prediction of the heart motion for robotic assisted beating heart surgery. In this study, first the feasibility of a stereo infrared tracking system for measuring the free beating heart motion was investigated by experiments on a heart motion simulator. Simulator experiments revealed a high tracking accuracy when the capturing times were synchronized and the tracker pointed at the target from an appropriate distance.Then, the heart... 

Inspired by the behavior of creatures in nature, including fish, generating propulsive forces under water has attracted great interest in recent years. Various tools such as computer software and experimental laboratory observations can be used to study the movements for different types of fishes. In this research, two thin fins, the shape of which is inspired by fish tail, will be investigated as a simplified model under non-viscous and incompressible fluid conditions using the experimental results and Ansys CFX software. For this purpose, the fin is considered once as a unforked rigid cantilever and again as a rigid forked cantilever with a constant water inlet speed of 10 cm per second.... 

The human body has more than 600 muscles that cause movement. Disability and motor disorders are some of the problems that people may face due to some factors such as accident, spinal cord injuries, disorders and brain damage, and the presence of a problem in neurological commands due to stroke. One of the proposed methods for solving the problems of people with motor disorder is the use of exoskeletons to generate stimulus. Exoskeletones are electromechanical devices designed to assist human movement, and patients are used to correct their movements using specific motor patterns. Exoskeletones can also be used as an auxiliary device for carrying heavy loads. Many studies have been conducted... 

In recent years, the seat suspension system in commercial vehicles, industry, agriculture, transportation and … have been focused by researchers. Designing the spring-damper isolators for vehicle’s seat can be an achievable and suitable strategy to increase the comfort and decrease the risk of injuries in vehicles. In this research, the effect of vibrations due to road roughness has been examined by dynamic modeling of a vehicle in combination with the human body model. Thus by using spring-damper isolators and genetic algorithm, we try to optimize the performance of the system. Designing parameters includes the stiffness and viscosity of seat isolator and our target functions include the... 

In the recent decade many researches have been done on optimizing urban traffic. The invention of single-axel two-wheeled vehicle -which is also known as Segway- is toward this goal. This vehicle was invented in 2002 by Dean Kaman. The Segway doesn’t need fossil fuels, occupies very little space, is very convenient to use and its parallel wheel configuration makes it compact enough to be maneuvered through most spaces. After the invention of the Segway, two wheel balancing robots has attracted more attention and in recent researches Passenger-carrying capacity has been considered. In this project, by taking into account passenger-carrying capacity and possibility of wheel slippage, an exact... 

Due to small size, flexibility, and low cost of manufacturing, micorobots are potentially suitable for implementation in a broad range of applications. Control and inspection, medical utilities, manufacturing and micromanipulation of small-sized devices with nano-metric precisions, and precise measurements are some of the most important applications of microrobots. Mobile microrobots are one of the significant divisions of microrobots that are capable of movement with small steps and possess a motion range of at least several times the robot’s body length. In this project, Modulated Friction Inertial Drive (MFID) is utilized as a mechanism for creating a mobile microrobot. The micorobot is... 

In this thesis, modeling and dynamic analysis of a micro-robot motion in stick-slip-jump mode are studied. Stick-slip is one of the more common principles of locomotion for micro-robots. Stick-slip locomotion relies on friction, and requires the robot to continuously maintain contact with the substrate. By increasing the actuation force on the micro-robot (i.e. by increasing the input voltage amplitude or frequency), the micro-robot losses contact with the substrate, and the stick-slip principle is no longer valid. Under this condition, instead of the stick-slip mode, a combination of stick-slip motion and jumps governs the locomotion. We refer to this as stick-slip-jump locomotion. In... 

Providing energy for small but out-of-access devices has led industries to harvest energy from the environment, especially environmental vibrations. The problem of vibrational energy harvesters with linear behavior, is their small bandwidth and consequently, their high sensitivity to frequency content and excitation spectra. Particularly in random excitations with vibrational energy spreading over a frequency range, linear harvesters do not seem appropriate. Under these conditions, harvesters with nonlinear stiffness are possible substitutes for linear systems. However, prediction and estimation of the behavior of systems with nonlinear stiffness under random excitation has been complicated,... 

Transparency is a measure of performance in haptic devices. In order to improve transparency and reduce the difference between the impedance transmitted to the user and the target impedance it is necessary to compensate for the dynamics of the haptic device. Due to stability reasons improvement of transparency is limited. Passivity as a stability criterion has been used widely in design and analysis of haptic devices. Since passivity is a conservative criterion, it acts as an obstacle in improving transparency of the haptic interfaces. In this project instead of passivity, robust stability of the interaction is studied in the presence of parametric uncertainties due to variations in user... 

Oil and natural gas today are one of the most important sources of human energy supply, so that crude oil Percentage and natural gas provide 25% of the world's energy. Until now, vertical drilling methods have been used to extract oil and gas. In recent years, due to vertical drilling constraints, for extraction and access to places that can not be achieved by vertical drilling, Horizontal drilling has been increased. In horizontal drilling, a variety of vibrations including longitudinal, torsional, and lateral take place. These vibrations, if not controlled, can damage the equipment and the drilling field, as well as reduce the efficiency of the drilling process and increase the process... 

Low back pain (LBP), the leading cause of disability worldwide, remains one of the most common and challenging occupational musculoskeletal disorders. The effective assessment of LBP injury risk, and the design of appropriate treatment modalities and rehabilitation protocols, require accurate estimation of the mechanical spinal loads during different activities. This study aimed to: 1) develop a novel 2D beam-column finite element control-based model of the lumbar spine and compare its predictions for muscle forces and spinal loads to those resulting from a geometrically-matched equilibrium-based model; 2) test, using the foregoing control-based finite element model, the validity of the... 

Sign language is the first and most important communication way between hearing impaired community, but the biggest issue within them is simply that most of them can't effectively communicate with most hearing people. If sign language can be translated to text or speech automatically, deaf people will be able to communicate with all the others. Sign language contains more than six thousands signs, in which, deaf people make use of hands and sometimes facial expression to do that. So far, three main approaches have been used to recognize posture and position of hand: 1) vision-based: using images of 1-3 camera(s), based on image processing; 2) glove-based: using sensory glove(s) and motion... 

Over the years, The robots have entered the human community in addition to the factories and industrial centers, and a new branch in the field of robotics called social robots has been created. Such robots can become a personal companion for children and elderly people who accompany that person at home or outside. Social robots can even be used as a platform for health services or as a vendor in stores. The interaction of humans and robots in social robots and communicating with the audience is the main part of this series of robots. Human-robot interaction can be divided into three parts: visual, auditory and facial or body movements. Also, the behavior of a social robot must be as natural... 

This research focuses on the robust mobile robot localization exploiting motion information acquired from an optical mouse operating based on optical flow technology. Most techniques of visual motion measurement are based on the well research discipline called “optical flow”. Theoretically, optical flow as a method of localization can be highly accurate, but it is sensitive to the noise and surface texture/optical characteristics and distance variations between the CCD detector and surface. As one could not achieve acceptable results in practical situations, to handle these problems, we propose to attach an acceleration – gyro (INS) sensor on the CCD detector (optical mouse) to improve the... 

Nowadays exoskeltons are developed because of improvements carried out in mechatronic technologies, to use in applications such as human rehabilitation and power augmentation. By reason of interaction between exoskeleton robot and human, an appropriate control strategy should be considered to implement regulated interaction force between them. As an example there are situations that a person wants to carry heavy load with this robot without suffering from weight of the load, so control of robot movements is of great importance. The aim of this thesis is dedicated to develop and implement a control strategy achieving minimum ineraction force in a 2 degree of freedom lower limb exoskeleton.... 

The purpose of this study is to develop model predictive control approach to control a turbocompressor. The turbocompressor which is consisted of a gas turbine and a centrifugal compressor is manufactured for providing the necessary pressure for gas transport via the gas transmission network. The turbocompressor control system regulates the compressor outlet pressure by controlling the rotational speed of the gas turbine, while preventing the surge phenomenon in the compressor. Surge is a serious instability in the compressor that is associated with periodic fluctuations in system variables and can cause heavy damage to expensive machine parts.In this research, model predictive control has... 

The main purpose of this project is to propose a control method for medical robots (such as rehabilitation and surgical robots), such that they can be moved conveniently by the users’s hand while he senses a controllable resistance. For that purpose, a Model Reference Adaptive Impedance Control method is developed for controlling the robot end-effector impedance in Cartesian coordinates. The proposed nonlinear controller and the desired impedance model are presented in Cartesian coordinates of the robot end-effector which is sensible for the human user. The adaptation law is derived and a corresponding Lyapunov stability is provided to prove the asymptotic tracking of the impedance model. By... 

In this thesis, coordination of a group of autonomous agents, through a scalable control structure and with very limited communications, is addressed. Inter-agent action functions are designed to guarantee the network connectivity. Two coordinator agents with different natures are designed. One is attractive and is named leader-agent (LA). The other is repulsive and is named shepherd-agent (SA). Under the assumption that both coordinators locally affect the group, we have proved that the governing equation of the whole group may have variable order.
By using nonlinear control techniques, coordination algorithms are designed to move the group on a predefined path or to a destination. It...