Sharif Digital Repository

In this thesis, kinematic, dynamic modeling and simulation, and control of SQ15-06N industrial robot have been presented. This robot is mostly used in the painting industry. Studying the robot requires familiarity with the robot programming and the hardware used in the robot. In this research, robot characteristics such as repeatability, load carrying capacity and accessibility have been investigated. The principles of industrial robot programming and robot programming language have been studied. The use of simulation software is common due to cost savings, reduced time, no need for robots and controllers, and the ability to test programs in a virtual environment. For this purpose, the... 

The purpose of this thesis is to design and implement a controller for a Ducted-Fan in the landing and take-off phase using a linear quadratic tuning method based on differential game theory. This is a control method with a robust control approach and tries to see all the disturbances and unmodulated dynamics in the form of the second actor and produce a control command according to the worst behavior of the second actor. For this purpose, 6 DOF Ducted-Fan have been modeled. then The proposed controller is designed for a linearized model around the hover point. In the next step, the performance of the proposed controller is compared with the SlidingMode Controller. Also, the parameters of... 

In this project, a fault-tolerant attitude control system is developed for thruster-driven satellites. The proposed method has the advantage over current state-of-the-art approaches in that it does not require a fault detection and isolation system. Generalized moments are generated by a robust controller that is designed using mixed sensitivity H_∞ and μ-synthesis by DK-iteration. Moreover, a pulse-width modulation technique with quadratic programming optimization is tuned to map the controller outputs to thruster on-off commands as efficiently as possible. The controller is designed to tolerate up to ±30% perturbations in inertia properties and thrust degradations up to 90% of the nominal... 

This thesis addresses the problem of configuration selection for an urban air mobility EVTOL aircraft utilizing a robust controller approach.First of all, to arrive at a final configuration, different feasible concepts for an urban transportation EVTOL aircraft have been proposed and studied during several brainstorming sessions. As a result, five potentially viable configurations have been selected for further investigation and analysis. These preliminary designs have been nominated utilizing the method of decision matrices and considering the design team and control system designer’s selection criteria. Finally, a tilt-rotor tandem-wing configuration has been selected to go through the... 

The primary purpose of this research is to model, control and simulate a flexible and fully actuated satellite, equipped with twelve on-off thruster actuators, in rendezvous and docking maneuver. Flexibility of the satellite is modeled by considering two flexible and asymmetrical multi section solar panels with rotational springs and dampers in joints, attached to a central rigid body. Solar panel sections have been modeled in the form of Euler-Bernoulli beam by using assumed mode method and taking into account finite bending mode-shapes. The governing differential equations are obtained using Lagrange method. Then, the dynamic model is validated by comparing the simulation results of the... 

The purpose of this thesis is to control the attitude of a tail-sitter UAV in transition phase (from hover to cruise and vice versa). This UAV has a pusher shrouded fan propulsive. Due to the fact that in transition phase the dynamic model of the UAV is associated with a significant uncertainties and the stability is more important than the performance, robust controller has been used. The propulsion part of the tail-sitter UAV can be assumed as a separate ducted fan UAV. In the first step both UAVs have been designed. then, in order to have an accurate model of UAV, the dynamics of actuators, including the engine and servo motor, has been identified. Then, modeling and verification for both... 

The 6DOF modelling and robust attitude control of two tethered satellites using tether tension moments is studied in this thesis. In this regard, the coupled rotational and translational dynamics of two satellites connected by a tether in the presence of Earth’s gravitational perturbation, aerodynamic drag, solar radiation pressure and third body effects (Sun and Moon) and also uncertainties in some of physical parameters of system and sensor’s outputs is modelled. Moreover, the tether attachment point to the satellites is different from their center of mass and its effect on dynamics of the system is taken into consideration. Then, the attitude of both satellites are controlled using robust... 

In this study the problem of position and attitude control of a Spacecraft has been investigated under position and attitude constraints as well as uncertainties in mass, moments of inertia, thrust vector error, and external disturbances. The Lyapunov theory is utilized for deriving the appropriate controls. Two kinds of controls are derived in the first step. The first kind has been derived using direct Lyapunov method and the second by the use of back-stepping method. Obtained simulation results prove that the first control scheme is more suitable for a Spacecraft control, since it has less computational effort, convenient selection of control parameters, and especially it has less... 

In this project roll channel autopilot of an agile flight vehicle has been studied. In skid-to-turn tactical flight vehicles according to the type of control strategy, for achievment of acceleration commands, the roll angular velocity should be kept near zero. In usual autopilot design, effects of channels on each others is ignored. But three channels of agile flight vehicles have some mutual effects, that consists of kinematic, inertial and aerodynamic couplings. In the case of roll channel dynamics, aerodynamic couplings are dominant and apears because of two factors: roll induced moment and roll cross coupling moment.
After study and aerodynamic modeling of mentioned factors, based... 

Recent developments in space industry and the great tendency for definition of efficient, precise and low cost missions are the main reasons for the growing interest in satellites formation flight. Regarding the aforementioned, the study of the multiple satellite control methods is the subject of the present project. In this project, the governing equations of motion of satellite formation flight are developed. Based on this development, it is shown that the satellite linear equations of motion like many other linear system presentations, can not sufficiently model the real system. Therefore, some of the most famous uncertainties in space dynamics such as semimajor axis and eccentricity... 

In this thesis, the theory of robust control is applied to design a controller for hover flight of a tail-sitter unmanned aerial vehicle with 2 ducted-fan propulsion. The control surface deflection (in propeller slipstream) is considered as the input controller of the system. The aircraft dynamical model is developed based on the assumption of no aerodynamic loads on other parts of uav in low speed flight associated with the hovering condition. The controller is primarily designed using both classical and modern control techniques. Then H ∞ and µ synthesis approaches are applied to design the robust controller. The results obtained from different approaches are compared. It is shown that... 

In this thesis, the theory of robust control is applied to design a controller for the longitudinal dynamics of a tail-sitter jet engine unmanned aerial vehicle. The engine thrust deflection is considered as the input controller of the system. The aircraft dynamical model is developed based on the assumption of no aerodynamic loads in low speed flight associated with the hovering condition. The controller is primarily designed using both classical and modern control techniques. Then and synthesis approaches are applied to design the robust controller. The results obtained from different approaches are compared. It is shown that the robust controller techniques are more stable and robust... 

One of the most important processes in the manufacture of mechanical parts in the industry is the machining process. High-speed milling is growing in aerospace, automotive, and many other industries due to advantages such as high material removal rates and better surface finish. However, the instability caused by self-excited vibration (chatter) is not only one of the main limitations for the productivity and quality of the workpiece but also reduces the life of machines and tools. In this research, after introducing the matter of milling flexible parts, the basic concepts of machining are first described, and common terms in machining are explained. Then, a review of past research has been... 

Today, the need to access very small environments is felt in various medical, industrial, biological and military fields. Due to their small size, microrobots have the ability to perform tasks that would be very difficult to do on a larger scale, but this ability of microrobots makes feeding and controlling them challenging. There are several methods for providing power and control of microrobots, which include their internal or external stimulation, among which the magnetic stimulation method is used in this research, which does not cause damage to body tissues.In this thesis, an electromagnetic system with nine cylindrical coils is used to control the three-dimensional movement of magnetic... 

Optimizing the energy consumption of air conditioning systems has gained great importance in recent years. In addition, maintaining thermal comfort and air quality in buildings is important. The multi-evaporator air conditioning system, which is a direct expansion system, shows the complex and distributed structure of air conditioning systems due to the thermal connection between zones and its large scale. The modeling of these systems is associated with uncertainties. Therefore, designing a suitable control structure for multi-zone systems is very important to achieve optimal energy consumption and maintain comfort conditions in the presence of uncertainty. Model predictive control has been... 

Capsule endoscopy is a minimally invasive diagnostic technology for gastrointestinal diseases providing images from the human’s digestion system. Developing a robust and real-time localization algorithm to determine the orientation and position of the endoscopic capsule is a crucial step toward medical diagnostics. In this thesis, we propose a novel model-aided real-time localization approach to estimate the position and orientation of a magnetic endoscopic capsule swimming inside the stomach. In the proposed method, the governing equations of the motion of an ellipsoidal capsule inside the fluid, considering different hydrodynamics interactions, are derived. Then, based on the dynamic... 

Nowadays electricity power has a key role in developing various aspects of the world. The great importance of fossil fuel power plants come from their large contribution in electricity power generation. Among the different fossil fuel power generation technologies, supercritical power plants have great advantages. They are an advanced power generation technology with high plant efficiency, high coal utilization and low emission. Their complexity and existing many unavoidable uncertainty sources in their dynamic such as changes of ambient temperature, climate condition and wear of components make their control challenging. To overcome mentioned problems and achieving a good performance, a... 

Due to the importance of recognizing the underwater and the existence of danger to human life in this environment, the use of AUVs has greatly expanded. To build and use these vehicles, we need to model dynamic behavior, and control these systems. The nonlinear dynamics of the AUV makes it difficult to use common linear controllers. On the other hand, the coefficients used in dynamic equations have uncertainty and changes, and as a result, dynamic analysis may be probably un-accurate. If the controller is designed, the controller must be self-tuning and robust to be able to withstand changes and uncertainty. Adaptive control is an approach for controlling such systems. The main idea in... 

Today, cancer mortality is one of the most important problems, even considering the scientific advances that offer more effective solutions to treat some diseases, providing a way to prevent and treat this disease is one of the most important issues that engineers have considered. This is achieved by designing a controller to minimize the size of the cancer tumor population, increase healthy cells, optimize treatment time, and drug dose.To achieve this goal, pharmacokinetic, pharmacodynamic, tumor growth, and healthy cell growth models, and mathematical models for subsystems that affect tumor growth, such as the angiogenic system, have been studied to develop a single mathematical model. In... 

Through the last decades, due to environmental issues and to confine CO2 emission and also dependency to the fossil fuels, renewable energy resources has been developed. It’s been expected up to 2035, the renewable energy resources will be scaled three times and among those resources, the wind energy will stand prominently. Out of this king of renewable resource, the horizontal wind turbine has been subjected in this research. The focus of is to design the controller in third of a 2 MW turbine operation by which stable rotor speed and nominal output power to be attained. Besides, to enhance the accuracy of the wind turbine profiles, the TURBSIM software (At the National Renewable Energy...