Comparison of Mechanical Properties of Al-TiB2 Composite in as Cast, Heat Treated and Extruded Condition

, M.Sc. Thesis Sharif University of Technology Khodabakhsh Pirkalani, Maryam (Author) ; Varahram, Naser (Supervisor) ; Davami, Parviz (Supervisor)

Abstract

This research focused on mechanical properties of Al-TiB2 composite in as cast, heat treated and extruded condition. The composites were produced by mixing Al-Ti and Al-B master alloyes. Since some engineering parts during service are supposed to tolerate severe wear conditions, in this research abrasive wear condition was wxamined using pin on disk method. In a fixed load and abrasive disk, composites showed better resistance against wear in comparison with matrix alloy. Furtheremore, T6 heat treatment made composites more resistant against abrasive wear. Finally the best wear resistance was accompolished when composite was extruded and then heat treated. While increase in reinforcement...

Multi-objective genetic algorithm for hover stabilization of an insect-like flapping wing

, Article Applied Mechanics and Materials ; Volume 332 , 2013 , Pages 50-55 ; 16609336 (ISSN) ; 9783037857335 (ISBN) Khodabakhsh, H ; Banazadeh, A ; Sharif University of Technology

2013

Abstract

This paper describes latest results obtained on modeling, simulation and controller design of an insect-like Flapping Wing Micro Air Vehicle (FWMAV). Because of the highly nonlinear and time varying nature of insect flight and the inability to find an equilibrium point, linearization of the model without compromising the accuracy is not possible. Therefore, to address the problem of designing a controller capable of stabilizing and controlling the FWMAV around a hovering point, a metaheuristic optimization approach is proposed, based on the time averaging theorem. The results show that a controller, designed using the proposed method, is capable of stabilizing the FWMAV effectively around...

Control of Locomotion in a Two-Leg Robot with Uncertain Frictional Effects

, M.Sc. Thesis Sharif University of Technology Khodabakhsh, Mohammad (Author) ; Vosoughi, Golamreza (Supervisor)

Abstract

Microrobots design and manufacturing has been one of interesting fields in robotics in recent decades. They have been designed in various types so far. In this paper a two-leg microrobot is simulated and controlled by using LuGre friction model.
The proposed microrobot is driven by a piezoelectric actuator mounted between centers of two legs. The piezoelectric is actuated by a frequency near the natural frequency of the robot. The nonlinear dynamical equations of the system are obtained considering LuGre friction model. To control the system, the equations of motion are linearized using feedback linearization method. Then a stabilizing control law is designed and the robot model is...

Removing undesired effects of mass/inertia on transparency using artificial neural networks in a haptic mechanism

, Article ICCAS 2010 - International Conference on Control, Automation and Systems, 27 October 2010 through 30 October 2010, Gyeonggi-do ; 2010 , Pages 156-161 ; 9781424474530 (ISBN) Khodabakhsh, M ; Boroushaki, M ; Vossoughi, G ; Sharif University of Technology

2010

Abstract

In this paper, Artificial Neural Networks (ANN) has been used to identify the dynamics of robots used in haptic and master slave devices in order to improve transparency. In haptic and master slave devices, transparency depends on some factors such as robot's mass and inertia, gravitational forces and friction [1]. In such systems, mass and inertia of the robot has an undesirable effect on the system outputs, which should be neutralized for improved transparency. The main purpose of this paper introducting a method to neutralize the undesirable effects of mass and inertia of the robot. A recurrent multilayer perceptron (RMLP) is used in a way that the inputs and outputs of the neural network...

Reliability-based Multidisciplinary Design Optimization of an Aeroelastic Projectile

, M.Sc. Thesis Sharif University of Technology Khodabakhsh, Amir Hossein (Author) ; Pourtakdoust, Hossein (Supervisor)

Abstract

In this research, Reliability-Based Multidisciplinary Design Optimization has been addressed. For this purpose, the main concepts in reliability-based design are investigated and the design methods based on reliability are explained. Providing a unified formulation to implement the optimal design structure based on the reliability, is the second part of this research. It has been intended to present a suitable structure for the design process considering the existing formulas and considering the numerical solutions. An aeroelastic projectile has been chosen as the target system for implementing the proposed process in the present study. The third section of this document has been dedicated...

Development of a Smart Learning-Based Distributed Load Alleviation System for Future Generation of Aeroelastic Wings

, Ph.D. Dissertation Sharif University of Technology Khodabakhsh, Amir Hossein (Author) ; Pourtakdoust, Hossein (Supervisor)

Abstract

In the pursuit of designing next-generation aircraft, several key challenges such as emission reduction, environmental compatibility, and energy consumption optimization are paramount. These challenges are addressed simultaneously in a multi-objective optimal design process, often leading to the emergence of innovative architectures. These architectures aim to enhance aerodynamic efficiency, extend range, minimize fuel consumption, and consequently, reduce aircraft emissions. One of the pivotal factors in augmenting the overall efficiency of an aircraft is the reduction in weight and thinning of the wings. This reduction in mass increases the slenderness ratio and leads to structures with...

3d Design of a Microfluidic Chip for Anticancer Drugs Screening

, M.Sc. Thesis Sharif University of Technology Hashemi, Maryam Sadat (Author) ; Mashayekhan, Shohreh (Supervisor) ; Saadatmand, Maryam (Supervisor)

Abstract

Nowadays, advanced and inexpensive pre-clinical methods for investigating the effects of anti-cancer drugs are expanding. One of the latest three-dimensional laboratory modeling for evaluating the effects of drugs is the use of tumor-on-chip technology, which actually models the physiological system of the body through three-dimensional scaffolds, multicellular cultures, and shaped vascular systems. In this study, three-dimensional culture of cancer cells was performed in the form of spheroids. A chip of U-shaped microstructures with and without gaps was used to trap cells and form cancer spheroids. We simulated the simultaneous effect of drug and oxygen concentration distribution inside the...

Modeling of a planar microrobot using lugre friction model

, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010 ; Volume 8, Issue PARTS A AND B , November , 2010 , Pages 633-639 ; 9780791844458 (ISBN) Khodabakhsh, M ; Vossoughi, G. R ; Kamali, A ; Sharif University of Technology

2010

Abstract

Microrobots design and manufacturing has been one of interesting fields in robotics in recent years. Various legged designs have been proposed in the literature. All designs rely on friction for locomotion. In this paper the dynamic model of a planar two-legged microrobot is presented using LuGre friction model. LuGre friction model is more realistic model, reducing uncertainties of the microrobot dynamic model, providing a better prediction for both design and control applications. The proposed microrobot is driven by a piezoelectric actuator mounted between centers of two legs. One of important issues in modeling of microrobots is to determine the friction force between robot and...

Modeling and Flight Controller Design of an Insect-Like Flapping Wing in Hover

, M.Sc. Thesis Sharif University of Technology Khodabakhsh, Hamid Reza (Author) ; Banazadeh, Afshin (Supervisor)

Abstract

There are many applications for micro aerial vehicles (MAV) and in nature they are flying as birds and insects. It can be said that a MAV that can mimic flying capabilities of birds and insects can be used as a solution for flying in low Reynolds number regimes. It seems that Flapping Wing MAVs have better performance than fixed and rotary wings MAV in low Reynolds number regimes. So far there haven’t been many theories and methods introduced for controlling flapping wing MAVs and many researches failed to provide a convenient way for designing an effective controller. On the other hand, models presented in literature for aerodynamics, dynamics and kinematics of flapping wing are not...

Estimation of Brain Connectivity Via Deep Neural Network

, M.Sc. Thesis Sharif University of Technology Khodabakhsh, Alireza (Author) ; Shamsollahi, Mohammad Bagher (Supervisor)

Abstract

The human brain is one of the most complex and least understood systems in nature. In recent decades, numerous studies have been conducted to identify the behavior of this system. One of the areas of brain research is the investigation of the connections between different regions of the brain during a presumed process or in a resting state. Among various types of brain connections, effective connectivity provides researchers with higher-level information on brain behavior compared to other connections, but also entails greater computational complexity. In recent years, researchers have aimed to provide an estimator with the maximum desirable capabilities, and with the advent of (deep) neural...

Kinematics and force analysis of a 6 degrees of freedom 3-UPS mechanism with triangular platform for haptic applications

, Article International Conference on Control, Automation and Systems ; 2012 , Pages 694-698 ; 15987833 (ISSN) ; 9781467322478 (ISBN) Khodabakhsh, M ; Sadeghpour, M ; Hassanpour, S ; Vossoughi, G ; Sharif University of Technology

2012

Abstract

This paper presents inverse dynamics equations for a 3-UPS mechanism using virtual work principle. This mechanism has three UPS legs connecting the base to a triangular platform. By changing the orientation of leg's actuators a non-symmetric mechanism with a suitable workspace near the origin without any singularity is obtained. Direct and inverse kinematics Jacobian matrices of the mechanism are obtained by the Newton-Euler approach. Then the inverse dynamics problem is solved using the principle of virtual work, so that the force and torque of active actuators have been obtained by having external forces (force and torque) acted on the platform. Force analysis of the 3-UPS mechanism has...

Experimental and computer based simulation study of WAG process

, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Taheri, S ; Kharrat, R ; Ghazanfari, M. H ; Khodabakhsh, M ; Sharif University of Technology

2006

Abstract

In reservoirs that have been water flooded or gas injected, it is still a significant amount of the remaining oil. Water alternative gas injection is a tertiary oil recovery method which was used for the first time in Canada for recovering remained oil in place of reservoir. The pore-scale mechanisms of this process are not fully understood yet. Such knowledge is essential for accurate modelling of reservoir. In this study various experiments on the WAG process is carried out by means of high pressure glass type micromodel instrument. The micromodel apparatus in this experiment was capable to operate at pressures up to 3500 Psi and temperatures up to 85°C which is similar to conventional...

Model Checking of Stochastic Activity Networks

, M.Sc. Thesis Sharif University of Technology Maryam Bagheri (Author) ; Movaghar, Ali (Supervisor)

Abstract

Modeling and performance evaluation of the real time distributed systems is a significant problem. Stochastic activity network is one of the high level models used for this purpose. This network is an extension of generalized stochastic Petri net which is more powerful and flexible than other Petri net extensions. Checking the satisfiability of properties such as performance, dependability and user's expected properties is considerable in these models. Thus, using the approaches and generating modeling and model checking tools with the mentioned purpose is attractive. A model checker automatically checks the correctness of the system behaviors as properties against the model by getting the...

Robust Estimation and Control of a Planet Lander

, M.Sc. Thesis Sharif University of Technology Ahmadvand, Reza (Author) ; Kiani, Maryam (Supervisor)

Abstract

This study has focused on the important problem of landing on a planet as an important current and future space mission. In this regard, dynamics modeling and integrated state estimation and control problems have been investigated in different views. To this aim, first a novel concurrent representation for translational and rotational kinematics has been developed based on the extension of modified Rodrigues parameters to dual space. This parameter set, called dual modified Rodrigues parameters (DMRP), is then utilized to establish an integrated roto-translational dynamic. The proposed DMRP-based kinematics and dynamics have been verified via comparison to traditional methods of...

Optimal Energy Trading in a Smart Grid Based on Extremum-seeking Algorithm

, M.Sc. Thesis Sharif University of Technology Asgari, Houman (Author) ; Babazadeh, Maryam (Supervisor)

Abstract

Prevalent deployment of Distributed Energy Resources(DERs) in the demand side of electrical energy grids has several advantages such as greenhouse gases emission reduction, mitigation of power losses in the distribution grids and abatement of the dependency on the wholesale generation companies. At the same time, it paves the way for the advent of local interactive energy trading frameworks. In the following thesis, a distributed data-driven algorithm is developed for market-clearing in a community-based local energy market. The social welfare maximization is considered as the objective of the energy trading. The production and demand of electricity are the decision variables of sellers and...

Design of Microfluidic Chip for 3D Cell Culture

, M.Sc. Thesis Sharif University of Technology Ghobadi, Faezeh (Author) ; Saadatmand, Maryam (Supervisor)

Abstract

Understanding biological systems requires extensive knowledge of individual parameters, and to study the processes of cell differentiation and cell behavior, a suitable environment must be created with the physiological conditions of the human body. For this purpose, with the knowledge of microfluidics, a microenvironment can be provided to study the behavior of cells on a small scale. The use of bone tissue model microfluidic chips is an alternative and new method in which it is possible to study the behavior of cells to differentiate into bone and to examine the toxicity of drugs, which in itself can help in the effective and successful treatment of these cases show. Therefore, in this...

Navigation and Control of a Free-Flying Satellite for Cargo Transportation and Placement in Intra-Vehicular Environment

, M.Sc. Thesis Sharif University of Technology Moosavi, Farzan (Author) ; Kiani, Maryam (Supervisor)

Abstract

The main topic of this research is the navigation and control of a free-flying satellite with a robot manipulator while transferring and placing cargo on a space station. After connecting the cargo module, astronauts and robots need to deliver the available loads to the desired modules in a space station. Capturing an object or cargo is a critical issue studied extensively so far. However, delivery and placing of the cargo at the target point have not been investigated yet, to the best of the author’s knowledge; hence, this is a primary motivation for conducting the proposed research. After capturing the payload, the position and attitude of the manipulator with respect to the station’s...

Fabrication the Hydrogel Microfibers Using Bioprinter with Application in Cardiovascular Model

, M.Sc. Thesis Sharif University of Technology Heidari, Faranak (Author) ; Saadatmand, Maryam (Supervisor)

Abstract

Cardiovascular disease (CVD) currently remains a considerable challenge for clinical treatments. CVDs account for N17.5 million deaths per year and will predictably increase to 23.6 million by 2030. The main purpose is to create human model systems to study the effect of disease mutations or drug treatment on the heart. In addition, engineered cardiac tissues are considered promising candidates to be transplanted to improve the function of diseased hearts. For engineered active tissues/organs, 3D bioprinting can fabricate complex tissue architecture with a spatiotemporal distribution of bioactive substances (cells, growth factors, and others) to better guide tissue regeneration. However,...

Utilizing Gaussian Processes to Learn Dynamics of Unknown Torques Acting on a Spacecraft

, M.Sc. Thesis Sharif University of Technology Baradaran, Behdad (Author) ; Kiani, Maryam (Supervisor)

Abstract

Accurate and fast attitude estimation of a rigid body plays an essential role in the performance of a vehicle’s control system, especially aerospace vehicles. Ample works have been done to increase the accuracy and speed of the attitude estimation process, but all have been developed according to a model-based approach. This approach assumes that the torques acting on the body have a known dynamical model that is used for the attitude estimation. The purpose of the present research is to estimate the attitude via a model-free approach, i. e. dynamics of the torques acting on the body are no longer assumed to be known, and its learning is the next step. Thus, the problem formulation of this...

Stabilization and Pole-Placement by Structurally-Constrained Controllers: A Graph-Theoretic Approach

, M.Sc. Thesis Sharif University of Technology Moushaee, Pegah (Author) ; Babazadeh, Maryam (Supervisor)

Abstract

This thesis presents a new approach to design structural output feedback controllers with stabilization and pole-placement at desired points on the S plane. It is assumed that the linear time-invariant system has no fixed mode corresponding to the specified control structure, outside the desired region of the closed-loop poles, such that the structural controller design problem is theoretically feasible. To this end, the structural output controller design problem is first transformed into a structurally equivalent problem based on the solution of a set of discrete linear programs. Then, by using the resultant structure, a new method is proposed for designing static and dynamic control loops...