Sharif Digital Repository

The development of a complex software needs an abstraction mechanism which is called Model Driven Engineering mechanism. In order to have a successful model based process, we need an appropriate tool such as version control systems to support our model-based process. On the other hand, developers need a mechanism to synchronize them with VCS systems. One of the concerns in modeling languages is the compatibility and the consistency of the models and modeling languages during their evaluation. the focus of the former researches was mostly on the consistency of the models during their evaluation, and to this end, lots of approaches have been proposed for keeping the consistency of the models... 

Placement of control and bracing systems in a structure is one of the most important factors affecting the effectiveness of the system in reducing responses to earthquakes. In other words, a control system with a proven effectiveness in earthquake does not reduce the structure responses unless used with proper placement. The performance of Ribbed Bracing System (RBS) in enhancing seismic response of structures, especially in preventing the buckling of bracing under compression and removing residual displacements, is approved by analytical and experimental studies, but optimal placement of such systems in structures has not been studied yet. Hence, in this research the optimal placement... 

Travel time is the most significant element in choosing among different modes of transportation. In order to increase the public transportation’s utility we need to utilize some methods to reduce public transportation travel time and passenger delay. Bus system, as one of the major types of public transportation, is mainly influenced by the traffic flow more than other types of public transportation. In order to increase the bus system’s reliability we need to utilize a controlling system so that we could increase its movement discipline and reduce line’s disruption. In this research we proposed an optimization model based on bus holding strategy and the real-time data from the route. This... 

It is more than a century to study qualitative and quantitative behavior of structures against earthquakes will be benefited from laboratory studies. In fact, the best method for observing the behavior of a structure during an earthquake is earthquake simulation on the structure. Today, the most effective way to do these tests is simulating of earthquake by using of Shaking Table. The shaking table consists of three main parts: electronic, hydraulic and mechanical. The accuracy of earthquake simulation’s results are very important. In recent years, numerous studies on the dynamic behavior of the above components and the interactions between these components are performed. In this study, we... 

Nowadays, due to the increasing use of Air Handling Units (AHU) in buildings, reducing energy consumption and improving the performance of these devices is one of the most important goals of researchers in the field of heating, ventilation and air conditioning (HVAC) technology. The purpose of this project is to design an optimal control system in different parts of the Air Handling Unit in order to provide standard ambient and breathing conditions for the people. Therefore, the mathematical model of the multi-zone space and the equipment of the Air Handling Unit are studied as separate subsystems based on the laws of thermodynamics and heat transfer. The obtained equations provide a... 

The goal of this project is to propose an algorithm to detect human motion intent during level walking. The primary aim of this algorithm should be to reduce human-robot interaction forces by combining EMG and force signals. Human gait is composed of 6 different stages. During each stage, each muscle is activated differently so it is possible to detect human intent by a pattern recognition technique. However, due to the fact that EMG signals are unrepeatable and noisy, we propose that combining EMG, motion and interaction force signals may lead to more concise and repeatable estimates of human motion intent. As a result, this control approach is expected to reduce human robot interaction... 

Dynamic positioning system is a controller system used to maintain the position and heading of a vessel with no use of anchors, jack ups but only using the propellers installed on the vessel. A vessel has six degrees of freedom, including three rotations and three transfer. In dynamic positioning systems, the vessel is controlled only on the horizontal plane such that its position and heading are controlled according to predetermined values. To achieve this, position and heading of the vessel is determined and the controller system computes the direction and required power of each propeller. Preliminary systems utilized PID controllers. As the control science has advanced, model based... 

The control approaches in Exoskeletons are different from Autonomous robot. Because the Exoskeletons are in connection and interaction with the user. On the other hand they can use the wearer’s abilities such as intelligence, sensory organs, self-control and etc. Therefore, one of the most important parts of exoskeletons control algorithms is its interaction with the user. This part should recognize the goal and purpose of the wearer such as stopping, walking start, change in stepping and direction and etc. properly. Utilizing these algorithms properly, one can reduce the muscle activities and energy consumption up to 20 percent [1]. This investigations demonstrate the importance of the... 

Increasing the speed of marine transportation services for specific mission and rapidly movement of persons or product always have been considered major issue in maritime industry. In recent years different technology have been used by high speed vessels manufacturer for increasing the safety of crew and passengers at sea. Catamaran is one of the most important high speed craft in marine transportation industry. High speed catamaran nonlinear behavior in high velocity is causing longitudinal instability and large motions. Active control surfaces like hydrofoil and interceptor can be used for reducing high speed catamaran motions in waves. This control surfaces react an adequate action... 

In this work dynamic behavior of a two body TSS with main satellite as rigid body is studied and effects of tether elasticity and tension on the satellite dynamic are indicated in station keeping phase and circular orbit. Also a simplified modeling is introduced which could be used in nonlinear controller design. Lagrange and extended Lagrange method is used to derive equations of motion. It is shown that longitudinal vibration of tether has small effect on satellite attitude and angular velocity and because of high frequency it can be decoupled from satellite dynamic. In the simplified model, orbital motion is decoupled from equations of TSS and main satellite dynamic. Effect of decoupling... 

Anaerobic digestion is a useful process that is very important, addition to producing methane as energy source, it can be used for treatment of solid waste and sewage sludge. This process due to the presene of chemical and biological reactions and abundant chemical species, is very complicated and sensitive, so it is very unstable against any kind of change. as for the large importance of the process, we need control and optimization. In order to improving the performance of the process and increasing biogas and methane production, we should control and optimize the process. ADM1 is principal and the most accurate model for this process, a variety of reduced order models used to design... 

With the spread of threats against industrial control systems, preserving the security of these systems faces serious challenges. On the other hand, with the increase of communication between industrial control networks and external communication networks, the entry points of these networks have also increased and this exposes them to IP network threats. Beside that, traditional attacks on these systems, which generally occur by infiltrating the internal network, are also constantly changing and becoming more complex. These attacks mainly have a phase of hiding the attack from the monitoring systems, which eliminates the possibility of identifying the attacker's operations to a great extent... 

Event-triggered control is used in various systems because of its capacity to optimize resources, improve responsiveness, and increase efficiency. Unlike the old time-based approaches, event-based control executes the necessary actions only when certain events or conditions occur, leading to the desired response. This strategy is used in scenarios where events occur irregularly, or are difficult to predict, and allows the system to conserve resources by maintaining the current state until the control signal needs to be updated. An event-triggered control strategy implemented using a secret sharing scheme enhances security across multiple systems; Especially in scenarios where sensitive... 

One of the crucial ways to reduce the energy costs of buildings is to improve the energy efficiency of HVAC systems. Heating, Ventilation, and Air Conditioning (HVAC) refer to the systems used to adjust the heating and cooling within a building. Control of these systems has great importance due to their excessive energy usage. Various control methods have shown a potential for considerable savings in building operation costs. In this research, a Model Predictive Controller (MPC) is applied to perform optimal control actions. MPC opens up numerous opportunities to improve energy efficiency in the operation of HVAC systems because of their capability to consider constraints, prediction of... 

In this dissertation, a data-driven model predictive control (MPC) algorithm has been developed to control unknown linear time invariant systems. This algorithm only needs past measured input-output data of the system and an upper bound on the order of the system to derive the system output to a desired value. To improve the transient response of the system, we define two filters on the performance and the effort terms of cost function of the optimization problem. Moreover, the Hankel matrices used in the optimization problem are updated online based on a multi-step event-triggered MPC scheme to deal with uncertainties and disturbances. With this method, the computational load of this... 

Successful deployment of the next-generation safety-critical systems (e.g., self-driving cars or assistive robots) requires certifying their safety during their operation. Therefore, there is an urgent need for developing safe controllers that respect the system’s constraints all the time. Safety, however, is the bare minimum requirement for any safety-critical system, and it is desired to design safe controllers that achieve as much performance as possible. Most existing results in the literature consider either optimal control design without safety specifications or safe control design with only short-sighted optimality. However, long-term optimality based on long-horizon optimization is... 

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... 

Heating, Ventilation and Air-Conditioning (HVAC) systems of buildings consume an excessive amount of energy and emit even more amounts of carbon, all around the world. Rule-Based Control (RBC) algorithms, which switch the facilities on and off according to the measurements of the building’s sensors, are the most frequently utilized controllers in HVAC systems. Due to the conservative settings of the comfort-zone in RBC strategies, energy consumption increases by a large amount. One of the most conventional ways to improve the energy efficiency along with providing the thermal comfort of the occupants of the building, is model predictive control (MPC) algorithms. In order for MPC to work... 

The term "data-driven" was first introduced in computer science and has entered the vocabulary of controlled engineering in recent years. So far, several classes of data-driven-control (DDC) methods have been introduced, which are identified by different names in the literature such as data-driven control, data-based control, modeless control, model-free adoptive control, iterative feedback tuning and virtual reference feedback tuning.Data-driven control includes all control theories and methods in which the controller directly and using the input-output data of the control system or knowing the processed data and without explicit knowledge of the mathematical model of the system (unlike... 

Benefiting from the great potential of the mathematical tool of fractional calculus, fractional order proportional integral (FOPI) and proportional integral derivative (FOPID) controllers have been proposed as the next generations for the popular PI and PID controllers. On the other hand, the integral performance indices such as the integral square error (ISE), integral square time error (ISTE), integral absolute error (IAE) and integral time absolute error (ITAE) are commonly used in design and evaluate of the performance of practical control systems. Considering these points, the present thesis deals with optimal tuning of the free parameters of fractional order PI and PID controllers, to...