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Author

Elbrous M. Jafarov

Other affiliations: Istanbul Bilgi University
Bio: Elbrous M. Jafarov is an academic researcher from Istanbul Technical University. The author has contributed to research in topics: Sliding mode control & Lyapunov function. The author has an hindex of 10, co-authored 52 publications receiving 573 citations. Previous affiliations of Elbrous M. Jafarov include Istanbul Bilgi University.


Papers
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Journal ArticleDOI
TL;DR: A comparative analysis with a plenty of simulation results soundly confirmed that the performance of developed variable structure PID controller is better under than those of both classical PID controller and an existing variable structure controller with PID-sliding surface.
Abstract: In this brief, a new variable structure proportional-integral-derivative (PID) controller design approach is considered for the tracking stabilization of robot motion. The work corroborates the utility of a certain PID sliding mode controller with PID sliding surface for tracking control of a robotic manipulator. Different from the general approach, the conventional equivalent control term is not used in this controller because that needs to use the matching conditions and exact full robot dynamics knowledge, which involves unavailable parameter uncertainties. Though the sliding surface includes also the integral error term, which makes the robot tracking control problem complicated, the existence of a sliding mode and gain selection guideline are clearly investigated. Moreover, different from uniformly ultimately boundedness, the global asymptotic stability of the robot system with proposed controller is analyzed. The sliding and global stability conditions are formulated in terms of Lyapunov full quadratic form and upper and lower matrix norm inequalities. Reduced design is also discussed. The proposed control algorithm is applied to a two-link direct drive robot arm through simulations. The simulation results indicate that the control performance of the robot system is satisfactory. The chattering phenomenon is handled by the use of a saturation function replaced with a pure signum function in the control law. The saturation function results in a smooth transient performance. The proposed approach is compared with the existing alternative sliding mode controllers for robot manipulators in terms of advantages and control performances. A comparative analysis with a plenty of simulation results soundly confirmed that the performance of developed variable structure PID controller is better under than those of both classical PID controller and an existing variable structure controller with PID-sliding surface.

154 citations

Journal ArticleDOI
TL;DR: Robust flight control laws based on variable structure control (VSC) theory and Lyapunov V-function method are designed for a simplified aircraft model F-18 and simulation results are presented to show the effectiveness of the design methods.
Abstract: Robust flight control laws based on variable structure control (VSC) theory and Lyapunov V-function method are designed for a simplified aircraft model F-18. A min-max control (MMC) and VSC laws are derived, for multi-input multi-output (MIMO) systems with plant uncertainties and input disturbance. Two types of robust feedback controllers MMC and VSC for uncertain MIMO systems are considered. For both cases the existence conditions of a stable sliding mode and the robust asymptotic stability in uncertain MIMO systems by MMC and VSC are investigated. For the design of an MMC and VSC, measurable states and sliding surface are chosen so that the zero dynamics of the system are stable. An application of tracking and positioning of VSC of longitudinal dynamics is presented. Finally, simulation results are presented to show the effectiveness of the design methods.

102 citations

Journal ArticleDOI
TL;DR: It is proven that the state trajectories reach the newly designed sliding manifold in finite time even under the effect of four realistically modeled disturbance components and parametric uncertainty of all inertia matrix entries.

49 citations

Journal ArticleDOI
TL;DR: In this paper, the sliding mode observers design techniques for MIMO and as a simple example for SISO systems are systematically advanced as a first purpose, and the advanced design techniques are generalized to the design of a new modification of sliding mode observer for uncertain MISO systems with time-delay.
Abstract: In this paper, the sliding mode observers design techniques for MIMO and as a simple example for SISO systems are systematically advanced as a first purpose. Design parameters are selected such that on the defined switching surface always is generated asymptotically stable sliding mode. Moreover, observer state error dynamics is globally robustly asymptotically stable. Then, advanced design techniques are generalized to the design of a new modification of sliding mode observers for uncertain MIMO systems with time-delay. Robust sliding and global asymptotic stability conditions are derived by using Lyapunov-Krasovskii V-functional method. By these conditions observer parameters are designed such that an asymptotically stable sliding mode always is generated in observer and observer state error dynamics is robustly globally asymptotically stable. The main results are formulated in terms of Lyapunov matrix equations and inequalities. Design example for AV-8A Harrier VTOL aircraft with simulation results using MATLAB-Simulink show the effectiveness of proposed design approaches.

40 citations

Journal ArticleDOI
TL;DR: In this paper, robust delay-independent stabilization of multivariable single state-delayed systems with mismatching parameter uncertainties and matching/mismatching external disturbances are considered and two types of robust sliding mode controllers design techniques are advanced.
Abstract: In this paper, robust delay-independent stabilization of multivariable single state-delayed systems with mismatching parameter uncertainties and matching/mismatching external disturbances are considered. To achieve this goal, two types of robust sliding mode controllers design techniques are advanced. The first is an integral sliding mode controller design modification to Shyu and Yan type controller design. The mismatching sliding conditions are parametrically obtained by using the Lyapunov-Razumikhin-Hale method and formulated in terms of some matrix norm inequalities. In the second contribution, a new combined sliding mode controller design technique for the stabilization of multivariable single state-delayed systems with mismatching parameter perturbations is advanced by using the Lyapunov-Krasovskii V-functional method. The sliding, global stability and delay-dependent β-stability conditions are parametrically obtained and formulated in terms of matrix inequalities. A sliding mode controller design e...

38 citations


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Book
01 Sep 2014
TL;DR: It is quite impossible to include in a single volume of reasonable size, an adequate and exhaustive discussion of the calculus in its more advanced stages, so it becomes necessary, in planning a thoroughly sound course in the subject, to consider several important aspects of the vast field confronting a modern writer.
Abstract: WITH the ever-widening scope of modern mathematical analysis and its many ramifications, it is quite impossible to include, in a single volume of reasonable size, an adequate and exhaustive discussion of the calculus in its more advanced stages. It therefore becomes necessary, in planning a thoroughly sound course in the subject, to consider several important aspects of the vast field confronting a modern writer. The limitation of space renders the selection of subject-matter fundamentally dependent upon the aim of the course, which may or may not be related to the content of specific examination syllabuses. Logical development, too, may lead to the inclusion of many topics which, at present, may only be of academic interest, while others, of greater practical value, may have to be omitted. The experience and training of the writer may also have, more or less, a bearing on both these considerations.Advanced CalculusBy Dr. C. A. Stewart. Pp. xviii + 523. (London: Methuen and Co., Ltd., 1940.) 25s.

881 citations

Journal ArticleDOI
TL;DR: In this paper, a general systematic approach is proposed to solve the disturbance observer design problem for robotic manipulators without restrictions on the number of degrees of freedom (DOF), the types of joints, or the manipulator configuration.

354 citations

Journal ArticleDOI
TL;DR: This paper attempts to address the literature review of PID control in an era of control system and bio-medical applications by surveying the development of classical PID to the integration of intelligent control to it.
Abstract: This article provides a study of modern and classical approaches used for PID tuning and its applications in various domains. Most of the control systems that are implemented to date with the use of PID control because of its simple structure, ease of implementation, and active research in tuning the PID for a long time. The techniques reviewed in the paper are in the order from classical to modern optimization rules used for the PID tuning. This paper attempts to address the literature review of PID control in an era of control system and bio-medical applications. The development of classical PID to the integration of intelligent control to it, has been surveyed by consideration of various application domains. The primary purpose of this document is to provide a detailed point of information for the people to understand the command of PID in different application areas.

216 citations

Journal ArticleDOI
TL;DR: This paper reviews the applications of recent observers to chemical process systems and classify them into six classes, which differentiate them with respect to their features and assists in the design of observers.

197 citations

Journal ArticleDOI
TL;DR: The constructed adaptive neural control has been rigorously proved that it can guarantee the semiglobally uniformly ultimate boundedness of all signals in the closed-loop system.
Abstract: An adaptive neural control strategy for multiple input multiple output nonlinear systems with various constraints is presented in this paper. To deal with the nonsymmetric input nonlinearity and the constrained states, the proposed adaptive neural control is combined with the backstepping method, radial basis function neural network, barrier Lyapunov function (BLF), and disturbance observer. By ensuring the boundedness of the BLF of the closed-loop system, it is demonstrated that the output tracking is achieved with all states remaining in the constraint sets and the general assumption on nonsingularity of unknown control coefficient matrices has been eliminated. The constructed adaptive neural control has been rigorously proved that it can guarantee the semiglobally uniformly ultimate boundedness of all signals in the closed-loop system. Finally, the simulation studies on a 2-DOF robotic manipulator system indicate that the designed adaptive control is effective.

159 citations