Sharif Digital Repository

This study provides preliminary work on the development of manual rehabilitation device for wearable and robotic manual applications. This work examines the motion of the fingers using the sensors. The developed mechanism is based on a combination of strain gauge sensors and a stepper motor, which forms the motion of the artificial thumb. In this thesis, the creation of an artificial thumb has been done with one degree of freedom, the movement and grabbing of lightweight objects. For grabbing objects, the command of controlling and keeping objects is performed through the IAR software and labVIEW software which is given to the stepper motor.This study describes the details of the work done... 

Different types of motion mechanisms can be found in any complicated or simple mechanical structure and linear motion is one of the most frequently used mechanisms for sure. In recent years, a wide variety of designs are developed to create linear motion, each one having many positive and negative points. Among already existing designs, those based on linear actuation are more considerable compared to those using a mechanical convertor to transform rotary motion to linear motion. This thesis presents two newly designed linear motors which utilize linear electromagnet actuators in their structures. In this study nonlinear models are developed for two linear motors. Although all conditions and... 

Energy management in vehicles is ann important issue, because it can significantly influence the performance of the vehicles and component sizing., Although the bbatteries have been widely used in electric vehicles (EVs), However the large current impact of battery cycle life is still a difficult problem that remains to be resolved and because of that, Hybrid Electric Vehicles (HEVs) areis the way that allows to to achievinge the advantages of both engines.Hybrid cars uses both an electric motor and internal combustion engine (ICE) used together, so, itwhich can benefit from the advantages of both engine types. ImprovImprovement ofing energy management in (HEVs) can providedeliver important... 

In the current era, the urgent need to reduce the use of fossil fuels and limit carbon emissions has highlighted the importance of shifting from traditional gasoline-powered vehicles to electric vehicles. The evolving landscape and challenges in the field of electric vehicles highlight the importance of ensuring the safety and reliability of energy storage systems. Lithium-ion batteries play a central role in electric vehicle technology, requiring thorough research efforts. Notably, the detection of internal short circuit, a common issue in lithium-ion batteries, has become a focus of researchers in recent years. This study aims to investigate the internal short circuit fault in lithium-ion... 

The purpose of this study was to investigate experimentally and modeling the process of gasification with supercritical water using waste motor oil. The effect of four important and influential parameters on the process, Temperature (350-450° C), Reaction time (15-45 minutes), Oil-to-Water volume ratio (0.2-0.4) and type of catalyst Consumption (Ni- NaOH- Na2CO3) was evaluated. Experimental experiments were designed and performed on the Design Expert software. The experimental results showed that the purity of hydrogen in the gas stream is more dependent on the temperature parameter and the higher purity is obtained with increasing temperature. Subsequently, as the oil concentration... 

This thesis represents a comprehensive view of electric vehicles from the macroeconomic policy in the energy sector perspective. In fact, in this thesis all the efficient factors in the presence of electric vehicles in the transport sector have been completely proceed. Environmental, economic, social and political factors, power grids and infrastructure are considered as the impressive factors. In order to check all factors comprehensively, Systems thinking based on dynamic system method is used. The causal relationships between all the variables which are involved in the presence of electric vehicles and related models to this thesis are simulated in VENSIM software. To investigate this... 

Compact linear accelerator is equipped with a single fixed motorized wedge that produces different wedge angles by combining an open and a wedged field in the appropriate proportions.
In this work, the required data for the Treatment Planning System, TPS were generated for utilizing Compact motorized wedge, MW and was verified by dosimetry. To verify MW, the accumulated wedge profiles at a depth of 10 cm for different wedge angles were measured using 2-D Profiler and were calculated the wedge angles using an analytical formula. The validity of effective wedge angles 2-D Profiler has been done by determining the wedge angles in accordance with ICRU-24 for compact MW and Telecobalt... 

Mass production of Plug-in Hybrid Electric Vehicle (PHEV) and requests for long trip capability necessisated development of fast charging station that can charge PHEV in a feuling time of a conventional vehicle. Fast charging station design requires a systematic approach to consider various related issues.
The aim of this thesis is to design a fast charging station. First, the daly demand for PHEV charging is modeled considering number and type of PHEV as well as level and pattern of daily driving of PHEV. Uncertainty in daily driving and in PHEV state of charge in the start of charging are also considered in modeling charging demand. An approach, then, is proposed for optimal design of... 

There is a class of small vertical take-off and landing flying vehicles that only have a dual coaxial engine on top and move based on the thrust vector control method. In this project in order to have better insight about the physical mechanism we are dealing with, a conceptual design of a prototype vehicle is first carried out. It is then followed by extraction of two and three dimensional dynamic models of the vehicle. By computer simulation and a simple dynamic analysis, the equations are verified and the movement of the aircraft is discussed for different flight phases  

The perpuse of this thesis is to design and fabricate a laboratory one degree of freedom stable platform under turbulences by model-based design method. To do this, different parts of the system were first modeled in the Solidworks software and then fabricated with various tools. With proper assembly of electronic and mechanical components, the original body of the system was created. Then, the controller motor with a stable platform which is attached to it was modeled and simulated in MATLAB software. Then, the parameters of the equations were calculated using standard identification tests and TCACS optimization algorithm. One of the challenges of this thesis is the malfunction of the... 

Most propulsion systems use nozzles to increase the velocity of exhaust gas. Therefore, the efficiency of nozzles is important. Losses due to geometry and physical phenomena inside the nozzle define this efficiency. The length and divergence angle of the nozzle, the throat diameter, the Reynolds number, and the specifications and the combinations of fuel have a direct impact on these losses. Solid propellant rockets are widely used and today optimization of rockets is most noticeable. On the other hand, in different phases of design and optimization, empirical experiments are necessary, which are costly in real dimensions. The use of laboratory motors with specific considerations decrease... 

In this thesis, the problem of offline trajectory optimization of a flying vehicle has been solved. Terrain following/ terrain avoidance has been considered as a guiadanec strategy of vehicle. The point-mass model in three dimensional space for flight simulation and the transfer functions for modeling of vehicle dynamics has been used. One of the constraints of this problem is related to engine’s dynamic behavior, which is not considered in the privious works. So in this thesis at first, a turbofan engine has been modeled and it’s static and dynamic model has been obtained. Then, the effect of engine’s dynamic model in the trajectory optimization has been investigated. The results show that... 

“Motor Theory” of speech perception discusses the role of motor competence in speech perception. Motor  Competence  is  accessed,  simulating  the  gestures  which  lead  to  the  heard  voice  signals.  Simulating is done using mirror neurons which share similar feelings between sender and receiver. Empathy,  caused  by  usage  of  mirror  neurons,  probably  caused  some  sort  of  link  between  inward  motor gestures and outward semantic categories at the origin of language. Some degree of linkage between sound and meaning is what we call “Sound Symbolism”. Along  with  describing  the  link  between  Motor  Theory  and  Sound  Symbolism,  this  thesis  took  two  approaches to analyze... 

People are increasingly using private vehicles as a result of the ever-increasing population growth worldwide and the increasing number of travel requests through the transportation network. There are many problems associated with the use of private vehicles on the transportation network, including traffic congestion and air pollution. To address the existing demand, decision-makers have always sought effective modes to respond to the existing situation. For passengers, the proposed modes of transportation should offer the same level of convenience and affordability as a private vehicle. In recent years, shared mobility has become increasingly popular. This mode of transportation has... 

In the past few decades, a considerable number of researches is devoted to study different challenges of ridesharing systems. Thus, this paper presents a mathematical optimization model to find the exact solution of the dynamic dial-a-ride problem with a fleet of electric autonomous vehicles and charging stations. Furthermore, time windows at which model strives to serve trip requests, are defined over origin and destination of passengers. Contrary to many previous works, charging behavior of vehicle battery at charging station is modeled to follow the actual nonlinear function in real world. In addition, vehicles are able to charge the battery whether fully or partially, whichever is more... 

In today’s world, people’s tendency to use their own vehicles is relatively high since private cars provide more convenience, better safety, and better time management than public transportation, but cause more traffic in the streets. Ride-sharing is one of the management tools that has attracted a lot of attention in recent years to mitigate the traffic congestion. Also, electric vehicles are used for public transportation in many parts of the world to achieve a sustainable environment. In this study, we assume that passengers’ origin, destination, and preferred time windows for pick-up and drop-off are known in advance. The aim of the study is to determine the sequence of visiting travel... 

During the past decade the ever increasing volume of greenhouse gases due to fossil fuels consumption have made humans to seek for alternative, non-polluting fuels as an effective strategy to reduce pollution and prevent environmental issues thereof. Electric cars are today known as one of the most effective solutions for this purpose. Of course, transition from gasoline-powered cars to electric cars in a wide scale is not technically possible in short term due to technological and infrastructural limitations. As a result, this lengthy process would lead to emergence of a combinational transportation system including both gas and electric-powered vehicles. The major differences between these... 

The goal of this research is to solve the traffic assignment of electric vehicles with considering trip chains. Limited driving range of electric vehicles is considered as one the most important obstacles for the development of these cars. The worry that the battery will run out of power before the destination is an important issue regarding the electric cars and people usually experience it more in trip chains. In this research, a complementary model and a linearization method is used for traffic assignment. In determining shortest paths in the traffic assignment, in addition to considering the travel time and the distance limit, the constraint of passing through activity nodes is... 

Video games, as a form of entertainment, have gained widespread attention and usage among all age groups, especially children and adolescents. With a wide variety of game genres and difficulty levels, they offer the opportunity to assess cognitive performance in individuals based on inter-individual differences and variable characteristics such as age, gender, and literacy level. The aim of this research is to study the brain response and gaze dynamics of individuals in a computer game (endless runner) based on electroencephalogram (EEG) signals and eye tracker data. The research process consists of two phases: "Brain Signal Processing in Motor Imagery Tasks" and "Reward and Punishment... 

This dissertation focuses on modeling human hand movements post-stroke to understand rehabilitative interventions. The model consists of a multi-layer neural network as the motor cortex in the brain and a two-degree freedom biomechanical model with six muscles for the simulation of hand movement in the horizontal plane. A passive robotic device has been designed and manufactured to record planar hand movements. Movements during reaching tasks have been recorded in 24 chronic stroke patients, as well as 18 healthy subjects, using the robotic device. Statistical analysis of the data showed that movements in a particular direction (NW-SE) are more sensitive to stroke, improve after...