Elbrus Caferov - Academia.edu (original) (raw)

Papers by Elbrus Caferov

Research paper thumbnail of ISTANBUL TECHNICAL UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY AIRCRAFT STABILITY ANALYSIS AND CONTROL SYSTEMS DESIGN: AN ADAPTIVE APPROACH M.Sc. Thesis by

Research paper thumbnail of Building of Mathematical Model and Bang Bang Based PID Control for Fighter Aircraft with Real Flight Data: Modelling and Simulation

The main purpose of this study is to understand the basic problems encountered in the modeling of... more The main purpose of this study is to understand the basic problems encountered in the modeling of an aircraft with an agility concept and to guide the creation of a mathematical model. The most challenging part of the construction of the aircraft's mathematical model is the determination of the forces and moments of continuously changing air flow according to the flight regime and environmental conditions, as well as the thrust force and the moment generated by the engine in the event of a deviation from the motor axis. For aircraft having a concept of agility, big differences are observed in the relevant parameters depending on flight regime, angle of attack and altitude. Bang-Bang controller applied as inner loop control of highly maneuverable fighter aircraft with high nonlinear characteristic. Obtained results is compared with multivariable control methods such as LQR and H∞ controllers. INTRODUCTION Companies are required to carry out various operational and functional test...

Research paper thumbnail of Design of relay and variable structure observers for multi-input multi-output systems with time-lag

The paper deals with design principles of relay and variable structure observers for multi-input ... more The paper deals with design principles of relay and variable structure observers for multi-input multi-output systems with time-lag. We thus have suggested design methods and synthesis of state observers for multi-input multi-output (MIMO) systems with time lag. In the case of the relay observer, high amplification factor is used for the model of the observer. In both cases, namely, relay observer and variable-structure observer, the sliding modes are imposed on the system deliberately. Most importantly, for both the state observers considered the error equation of motion is proved to be globally asymptotically stable

Research paper thumbnail of Antropomorfik Robotların Dinamiği ve Uyarlamalı Kontrol Uygulamaları

Research paper thumbnail of New static output feedback stabilization and multivariable PID-controller design methods for unstable linear systems via an ILMI optimization approach

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2017

The design problem of a static output feedback controller and multivariable proportional-integral... more The design problem of a static output feedback controller and multivariable proportional-integral-derivative (PID) controller is investigated for linear time-invariant systems (LTI). First, the static output feedback stabilization problem is taken into consideration and then an iterative linear matrix inequality (ILMI) algorithm is developed for the synthesis of the controller. Second, choosing a multivariable PID control law, the whole system is transformed into a new augmented system represented in the form of a static output feedback control system. This method allows us to convert the multivariable PID controller design problem into a static output feedback synthesis problem. Thus, the proposed ILMI algorithm can as well be utilized for the design of the multivariable PID controller. Two numerical examples are presented to illustrate a practical application of the developed methodologies.

Research paper thumbnail of Time-varying sliding mode in rigid body motion controlled by magnetic torque

2015 International Workshop on Recent Advances in Sliding Modes (RASM), 2015

Research paper thumbnail of Computational phase portrait analysis of two nonlinear small satellite models

2009 4th International Conference on Recent Advances in Space Technologies, 2009

Two small satellite models are selected that are subject to gravity gradient in circular, low-alt... more Two small satellite models are selected that are subject to gravity gradient in circular, low-altitude orbits. The second one is passively controlled by a pitch momentum wheel. The aim of this work is to represent how the passive pitch bias momentum method affects the nonlinear attitude dynamics. The analysis is based on phase portraits, Poincare sections, and time responses. The

Research paper thumbnail of Three-axis attitude control of a small satellite by magnetic PD-like controller integrated with passive pitch bias momentum method

Proceedings of 5th International Conference on Recent Advances in Space Technologies - RAST2011, 2011

The attitude acquisition problem of a magnetic small satellite under effect of environmental dist... more The attitude acquisition problem of a magnetic small satellite under effect of environmental disturbances is solved by two methods. The first method stabilizes the nonlinear attitude in three-axis by purely electromagnetic actuation. The second method exploits the inertial stiffness provided by a pitch momentum wheel to gain insensitivity to disturbances. The simulation results obtained for the same initial conditions show the superiority of the non-aided method in terms of transient duration and energy consumption, on the other hand the disturbance rejection capability of the passively momentumbiased method. The steady state error can be reduced if the pitch bias momentum is employed passively whereas it is determined by the total magnitude of the disturbance torques in the case of purely magnetic control. The momentum wheel has a regularizing effect on the dynamics; it leads the system from irregularity to nonlinear stability then the magnetorquers become able to carry the states to equilibrium, also zero.

Research paper thumbnail of Purely magnetic spacecraft attitude control by using classical and modified sliding mode algorithms

2012 12th International Workshop on Variable Structure Systems, 2012

A modified sliding mode control algorithm for purely magnetic attitude control of small satellite... more A modified sliding mode control algorithm for purely magnetic attitude control of small satellites is proposed in this work. It is designed by following the steps characteristic to variable structure control method and magnetic attitude control problem. The asymptotical stability of the control law is proven by using theoretical and intuitive approaches together. The stability of the controller is verified by converging simulation results of the states. The aim is to obtain a controller superior to the sliding mode magnetic controller with continuous law in terms of steady state error under disturbance effect. The time responses of Euler angles indicate that the aim is reached. The necessity of modifying the classical reaching algorithm is made clear by comparing Euler angles' responses obtained using the classical and the modified sliding mode algorithms.

Research paper thumbnail of ISTANBUL TECHNICAL UNIVERSITY INSTITUTE OF SCIENCE AND TECHNOLOGY AIRCRAFT STABILITY ANALYSIS AND CONTROL SYSTEMS DESIGN: AN ADAPTIVE APPROACH M.Sc. Thesis by

Research paper thumbnail of Building of Mathematical Model and Bang Bang Based PID Control for Fighter Aircraft with Real Flight Data: Modelling and Simulation

The main purpose of this study is to understand the basic problems encountered in the modeling of... more The main purpose of this study is to understand the basic problems encountered in the modeling of an aircraft with an agility concept and to guide the creation of a mathematical model. The most challenging part of the construction of the aircraft's mathematical model is the determination of the forces and moments of continuously changing air flow according to the flight regime and environmental conditions, as well as the thrust force and the moment generated by the engine in the event of a deviation from the motor axis. For aircraft having a concept of agility, big differences are observed in the relevant parameters depending on flight regime, angle of attack and altitude. Bang-Bang controller applied as inner loop control of highly maneuverable fighter aircraft with high nonlinear characteristic. Obtained results is compared with multivariable control methods such as LQR and H∞ controllers. INTRODUCTION Companies are required to carry out various operational and functional test...

Research paper thumbnail of Design of relay and variable structure observers for multi-input multi-output systems with time-lag

The paper deals with design principles of relay and variable structure observers for multi-input ... more The paper deals with design principles of relay and variable structure observers for multi-input multi-output systems with time-lag. We thus have suggested design methods and synthesis of state observers for multi-input multi-output (MIMO) systems with time lag. In the case of the relay observer, high amplification factor is used for the model of the observer. In both cases, namely, relay observer and variable-structure observer, the sliding modes are imposed on the system deliberately. Most importantly, for both the state observers considered the error equation of motion is proved to be globally asymptotically stable

Research paper thumbnail of Antropomorfik Robotların Dinamiği ve Uyarlamalı Kontrol Uygulamaları

Research paper thumbnail of New static output feedback stabilization and multivariable PID-controller design methods for unstable linear systems via an ILMI optimization approach

TURKISH JOURNAL OF ELECTRICAL ENGINEERING & COMPUTER SCIENCES, 2017

The design problem of a static output feedback controller and multivariable proportional-integral... more The design problem of a static output feedback controller and multivariable proportional-integral-derivative (PID) controller is investigated for linear time-invariant systems (LTI). First, the static output feedback stabilization problem is taken into consideration and then an iterative linear matrix inequality (ILMI) algorithm is developed for the synthesis of the controller. Second, choosing a multivariable PID control law, the whole system is transformed into a new augmented system represented in the form of a static output feedback control system. This method allows us to convert the multivariable PID controller design problem into a static output feedback synthesis problem. Thus, the proposed ILMI algorithm can as well be utilized for the design of the multivariable PID controller. Two numerical examples are presented to illustrate a practical application of the developed methodologies.

Research paper thumbnail of Time-varying sliding mode in rigid body motion controlled by magnetic torque

2015 International Workshop on Recent Advances in Sliding Modes (RASM), 2015

Research paper thumbnail of Computational phase portrait analysis of two nonlinear small satellite models

2009 4th International Conference on Recent Advances in Space Technologies, 2009

Two small satellite models are selected that are subject to gravity gradient in circular, low-alt... more Two small satellite models are selected that are subject to gravity gradient in circular, low-altitude orbits. The second one is passively controlled by a pitch momentum wheel. The aim of this work is to represent how the passive pitch bias momentum method affects the nonlinear attitude dynamics. The analysis is based on phase portraits, Poincare sections, and time responses. The

Research paper thumbnail of Three-axis attitude control of a small satellite by magnetic PD-like controller integrated with passive pitch bias momentum method

Proceedings of 5th International Conference on Recent Advances in Space Technologies - RAST2011, 2011

The attitude acquisition problem of a magnetic small satellite under effect of environmental dist... more The attitude acquisition problem of a magnetic small satellite under effect of environmental disturbances is solved by two methods. The first method stabilizes the nonlinear attitude in three-axis by purely electromagnetic actuation. The second method exploits the inertial stiffness provided by a pitch momentum wheel to gain insensitivity to disturbances. The simulation results obtained for the same initial conditions show the superiority of the non-aided method in terms of transient duration and energy consumption, on the other hand the disturbance rejection capability of the passively momentumbiased method. The steady state error can be reduced if the pitch bias momentum is employed passively whereas it is determined by the total magnitude of the disturbance torques in the case of purely magnetic control. The momentum wheel has a regularizing effect on the dynamics; it leads the system from irregularity to nonlinear stability then the magnetorquers become able to carry the states to equilibrium, also zero.

Research paper thumbnail of Purely magnetic spacecraft attitude control by using classical and modified sliding mode algorithms

2012 12th International Workshop on Variable Structure Systems, 2012

A modified sliding mode control algorithm for purely magnetic attitude control of small satellite... more A modified sliding mode control algorithm for purely magnetic attitude control of small satellites is proposed in this work. It is designed by following the steps characteristic to variable structure control method and magnetic attitude control problem. The asymptotical stability of the control law is proven by using theoretical and intuitive approaches together. The stability of the controller is verified by converging simulation results of the states. The aim is to obtain a controller superior to the sliding mode magnetic controller with continuous law in terms of steady state error under disturbance effect. The time responses of Euler angles indicate that the aim is reached. The necessity of modifying the classical reaching algorithm is made clear by comparing Euler angles' responses obtained using the classical and the modified sliding mode algorithms.