Sharif Digital Repository

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... 

Nowadays, Automation and Robots have many industrial and non-industrial applications. One of the most important of Robotic applications in industries for speed increasing, is utilizing them for packing procedures on production lines. Speed and accuracy enhancement, low-error repeatability, and cost reduction are benefits if using robots. Delta robot, is one of the parallel robots which is consists of three arms each connected to universal joints at the base and can reach high speeds.Delta robot can be optimized in 1. Performance speed, 2.accuracy, 3. Maximum payload, 4. Workspace and dexterious workspace and 5. Costs reduction. Since it’s not possible to fully optimize all goals... 

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... 

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... 

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 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... 

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... 

Low back pain (LBP) problems are of concern to many researchers specially physiologists, biomedical engineers and... .biomechanical models can help us to furthering our knowledge of the mechanical characteristics of the spine and its neural control to know more about potential mechanisms of injury. This thesis involves computational model of lumbar spine to generate and control its flexion-extension movement.
Model has involved 7 links: 5 lumbar vertebrae, pelvis and trunk. Desired trajectory has been generated for rhythmic and discrete motion by the central pattern generators (CPGs). And then controller has produced torque of joints to track desired trajectory. CPGs have been... 

Modeling and Control are fundamental issues for fish robots, which can play basic roles in design, optimization, fabrication, and eventually utilization of them. A review on the literature reveals the shortage of an analytical closed form model with little simplifications and high precision, and also control works based on such models. Studying LAEBT theory, it is shown that this theory is suitable for determining the forces produced due to the tail movements considered in the present work, and then it is used to determine the forces. Experimental investigations by means of the setup made for this purpose showed that the obtained equations for the forces have got acceptable precision.... 

Performing a safe and effective endoscopic sinus and skull based surgery (ESSS), requires special training programs to gain sufficient hand-eye coordination and instrument manipulation skills. In this regard, virtual-based haptic surgical training systems have been considered among the medical students and residents as an effective approach for training practices. Therefore, in this study, the development of a haptic training system for ESSS, based on an animal model has been addressed. By conducting various indentation and relaxation experiments, mechanical properties of the specific sino-nasal regions of sheep head, as a function of force, displacement and tool insertion rate, for three... 

In this thesis, modeling and robust sliding mode control of a snake-like robot with holonomic constraints in tracking of desired paths such as serpenoidal motion is addressed. By considering more real conditions and holonomic constraints, the kinematic and dynamic equations of a semi active robot are obtained using Kane's method. In the next step, based on the obtained results, diverse control theory for getting ability of tracking different paths in environment with different frictions are investigated. Robust control theory is chose to design a controller that has ability of adaption robot’s motion in different environments. For this reason, Sliding Mode Control that has many applications... 

Nowadays, many researches are inspired by nature and living creatures in order to build various scientific and industrial products such as robots, because of the highest level of creativity which is used in creating them along with their high level of efficiency in power consumption and designing parameters. Underactuated Robots are the type of robots which have more degrees of freedom comparing to the number of operators. As a result their optimum control has a lot of complications. Brachiating robots are designed and built based on an inspiration from long armed apes (Gibbons). This type of monkey is highly skilled in twisting in trees and traversing. This type of movement benefits from... 

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.... 

Microrobots are generally suitable for implementation of certain works in miniature dimensions such as micro assembly, microsurgery, adaption with small animals and so on. In this way, there is special position for mobile microrobots capable of moving in the range of more than theirs dimensions. Achivieng to high resolution and high speed locomotion are the challenging issues in the microrobot’s development in which much effort has been done.The goal of this project is dynamic modeling and velocity control of an A-shaped microrobot with with nanometric locomotion. During this project, first the dynamic modeling of microrobot is investigated and simplified based on the previous studies.... 

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... 

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... 

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,... 

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... 

Laser ultrasonic is a novel method for measuring sheet parameters. In this technique an intense pulse is irradiated to the target which instantaneously vaporizes the surface layer into the high temperature and high pressure plasma. Expansion of plasma produces shock wave that propagates through the surface. Mechanical properties of target can be calculated by measuring and analyzing produced shock wave. In this project wave propagation is simulated using finite element and numerical-computation methods. The numerical-computation simulation was performed using lamb wave equations. ANSYS software was employed for finite element simulation. The results corroborate each other. Next, simulation... 

• Brachiation robot is a kind of under-actuated robots. A brachiating robot is a type of a mobile arm that is capable of moving from branch to branch similar to a long-armed ape. The purpose of this thesis is control of a two link Brachiation robot. The purpose of this thesis is control of a two link Brachiation robot using neural network and geometry control. For this purpose a genetic algorithm based training Neural Network is used to produce a suitable path for the second link of the robot and then using input-output linearization method, the second link is controlled to follow the path. The simulations shows that the Nero Controller designed in this thesis is suitable. The controller can...