Sharif Digital Repository

In the present study, an adaptive sliding mode control method was employed to control a fish robotic system using the method of hardware in the loop. Following the introduction of the nonlinear model for the robot, elongated body theory, suggested by Lighthill, was used to analyze fish movements. Lighthill’s theory inspired from slender body theory in aerodynamics scope could be viable to exercise upon the carangiform mode of swimming. By simplifying Lighthill’s equations in planar motion of fish robot, the number of degrees of freedom exceeds the number of the control variables. In view of the fact that the presented model is an under-actuated model, there exist some parametric and... 

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 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... 

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... 

There is many sources of uncertainty in the power plants such as continuous changes of the ambient temperature and the climate condition. The controller of the boiler-turbine unite should be robust against uncertainties and overcome the changes in the operating condition. In this regard, a robust adaptive variable structure control scheme (RAVCS) is proposed to control a nonlinear multi-input multi-output (MIMO) model of industrial boiler-turbine unite, in the presence of unknown parameters and bounded uncertainties as well as external disturbances. Moreover, a robust controller based on and in the presence of rational deviation in parameters, is designed. To investigate the zero... 

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... 

Drill strings are subjected to complex coupled dynamics. Therefore, accurate dynamic modeling, which can represent the physical behavior of real drill strings, is of great importance for system analysis and control. The most widely used dynamic models for such systems are the lumped element models which neglect the system distributed feature. In this thesis, an infinite-dimensional model for the vibrational dynamics of the drill-string, called neutral-type time delay model, is modified to investigate the coupled axial-torsional vibrations in drill strings. This model is derived directly from the distributed parameter model by employing the d’Alembert method. Coupling of axial and torsional... 

The effects of adding nanoparticles in partitioning of α-amylase in polymer/salt aqueous two phase system (ATPS) was studied in this research. First the binodal curves of magnesium sulfate salt with PEGs 2000,3000,4000,6000 and 10000 at 23 ° C has been plotted and the suitable system which was PEG 6000/ magnesium sulfate has been selected for studying the partitioning of enzyme. Thereupon the partition coefficient of α-amylase was measured and then effect of adding silica and graphene oxide nanoparticles was investigated. It was observed that nanoparticles caused a dramatic increase in partition coefficient and yield recovery (of top phase). For further investigation the partitioning of... 

No one bears thinking about undergoing a surgery by an unexpirienced surgeon, the consideration of which implies the prominence of effective surgical trainings. The advent of utilizing haptic interfaces as a novelty in this field has led to a more promising surgery education. These haptic interfaces consist of three communicating parts namely: operator’s hand, haptic robot, and tissue virtual environment. Design and implementation of a proper controller in order to stabilize the haptic interface during surgery simulation, with acceptable transparency, is still novel an otherwise challenging research field. In this thesis we consider an appropriate nonlinear model for both virtual tissue as... 

The main goal of this project is to design and implement an Endoscopic Sinus Surgery Simulator using a nonlinear model relating the force and displacement of the surgery tool interacting with the virtual sinus tissue. This model approximately matches the force-displacement data attained from the experiments conducted on the real sinus tissues. To simulate the behavior of the sinus tissue in a virtual environment, a haptic device is utilized which imitates the behavior of the surgery tool interacting with the tissue model. The haptic device in this project is a Falcon Robot. Because of the uncertainties in the parameters of the robot and the operator’s hand model (which is considered in the... 

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... 

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... 

Proper operation of a spark ignition engine is required by comfort demands of a vehicle driver and governmental legislations. Therefore it is essential to monitor, within an online technique, the engine and detect any fault which disrupts its operation. The gas exchange path (including the intake and exhaust subsystems) is an important part of turbocharged engines responsible for accurate control of both engine power and emissions. Monitoring the path for fault detection and isolation (FDI) has been always demanded due to many failures it may face since the turbocharger exasperates the harsh working conditions for components involved in the path. This paper presents a novel model-based... 

Endoscopic sinus surgery is a minimally invasive surgery. Today, for the education of such surgeries, the surgical simulators are used. They could be used for both training of such a technique and pre operation planning. One of the features that could improve the efficiency of these systems and prepare the effective interaction with them is haptic.
In this thesis, an inexpensive sinus surgery simulator has been designed and implemented such that the operator could see sinus nasal in real time and could detect collisions between tool and virtual environment.
In this research, a 3D surface rendered model that extracted from 2D CT images has been used for construction of virtual... 

The hand is an important part of the human body, the loss of all or part of it greatly reduces a person's ability to perform daily tasks. For people who have lost this significant organ, replacing it with an artificial limb that can meet some of their needs is essential. Today, all robotic prostheses use electromyographic (EMG) signals from the remaining muscles of the disabled limb as input signals. Classifying the EMG signal and converting it to a control signal faces serious challenges. Variation of signal properties over time, electrode slippage, muscle fatigue, changes in muscle contraction intensity, and changes in limb position and direction are some of these challenges. Therefore, a... 

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... 

In this research, experimental study and modeling of biodiesel production process from microalgae has been investigated. First, to have a biomass with suitable lipid content, a novel two-step process based on cultivation under nutrient sufficient followed by cultivation under nitrogen starvation condition has been proposed. Then the effect of using different organic and inorganic carbon sources on this process has been investigated which the results indicated that sodium acetate had a better performance compare to other carbon sources. In the following, the effect of using different light regimes on growth rate, lipid content and fatty acid composition have been investigated. Experimental... 

Dealing with natural and handmade radioactive materials and sources is of major aspects of nuclear science and technology. Useful applications of these materials and sources in different fields, such as energy production and health physics, caused the necessity of developing the detection and radiation protection methods. Each of these methods uses different equipment and approaches which are based on different kinds of radiations and radioactive sources. Despite the given ability of radiation detection, in some cases, recognition, distinguish, and estimation of a source radiation level is impossible due to bad effects of these equipment on measured spectrum. Detection of neutron spectrum in... 

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... 

Laparoscopic surgery which is categorized under Minimal Invasive Surgery, has many advantages over conventional open surgery. Despite the beneficial effect of this method on patients, surgeons suffer difficulties in utilizing the method. Robotic surgery has been constituted as the answer to remove the difficulties yet retain the advantages.
In the so-called robotic surgery, the tool is handed to a robotic arm, i.e., the slave robot, which is installed and positioned at the bed side. The surgeon sits before a comfortable console and uses a joystick-like robot, i.e., the master robot, to manipulate the slave robot. The vision is also provided by a robotic camera holder and shown in a...