A Note on Observer-Based Frequency Control for a Class of Systems Described by Uncertain Models

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Nirvana Popescu ◽  
Mircea Ivanescu ◽  
Decebal Popescu
Keyword(s):  
Uncertain Systems ◽  
Closed Loop ◽  
Frequency Control ◽  
Estimation Error ◽  
Closed Loop System ◽  
Robust Controller ◽  
Frequency Condition ◽  
Lyapunov Techniques ◽  
Type Criterion ◽  
Balancing Robot

This paper focuses on the robust control problem for a class of linear uncertain systems by using frequency techniques. The controller/observer dynamics are analyzed using Lyapunov techniques, in terms of the state and state estimation error, for an uncertainty constrained over a specified range. A Popov-type criterion, a “circle criterion,” defined as the Popov frequency condition and the uncertainty circle, is formulated. It is proved that the closed-loop system is robustly stable if the Popov condition holds at all frequencies. The proposed method is validated against a robust controller for a balancing robot (BR).

scholarly journals Design of delay observer-based controllers for uncertain time-lag systems

1999 ◽  
Vol 5 (2) ◽  
pp. 121-137 ◽  
Author(s):  
Magdi S. Mahmoud ◽  
Mohamed Zribi
Keyword(s):  
Uncertain Systems ◽  
Closed Loop ◽  
Time Lag ◽  
Linear Matrix ◽  
Time Lags ◽  
Matrix Inequalities ◽  
Closed Loop System ◽  
Delayed Measurements ◽  
Uncertain Time ◽  
Theoretical Developments

In this paper, the problem of designing observers and observer-based controllers for a class of uncertain systems with input and state time lags is considered. We construct delay-type observers in which both the instantaneous as well as the delayed measurements are utilized. Using feedback control based on the reconstructed state, the behavior of the closed-loop system is investigated. It is established that the uncertain time-lag system with delay observer-based control is asymptotically stable. Expressions for the gain matrices are given based on two linear-matrix inequalities. A numerical example is given to illustrate the theoretical developments.

scholarly journals Modeling and energy-based sway reduction control for tower crane systems with double-pendulum and spherical-pendulum effects

2019 ◽  
Vol 53 (1-2) ◽  
pp. 141-150 ◽  
Author(s):  
Menghua Zhang ◽  
Yongfeng Zhang ◽  
Bing Ji ◽  
Changhui Ma ◽  
Xingong Cheng
Keyword(s):  
Closed Loop ◽  
Double Pendulum ◽  
Control Methods ◽  
Spherical Pendulum ◽  
Closed Loop System ◽  
Tower Crane ◽  
Lyapunov Techniques ◽  
Payload Mass ◽  
System States ◽  
Invariance Theorem

As typical underactuated systems, tower crane systems present complicated nonlinear dynamics. For simplicity, the payload swing is traditionally modeled as a single-pendulum in existing works. Actually, when the hook mass is close to the payload mass, or the size of the payload is large, a tower crane may exhibit double-pendulum effects. In addition, existing control methods assume that the hook and the payload only swing in a plane. To tackle the aforementioned practical problems, we establish the dynamical model of the tower cranes with double-pendulum and spherical-pendulum effects. Then, on this basis, an energy-based controller is designed and analyzed using the established dynamic model. To further obtain rapid hook and payload swing suppression and elimination, the swing part is introduced to the energy-based controller. Lyapunov techniques and LaSalle’s invariance theorem are provided to demonstrate the asymptotic stability of the closed-loop system and the convergence of the system states. Simulation results are illustrated to verify the correctness and effectiveness of the designed controller.

Development of Robust Excitation Controller for Synchronous Generator

2014 ◽  
Vol 573 ◽  
pp. 328-333
Author(s):  
R. Ramya ◽  
K. Selvi ◽  
M. Tamilvanan
Keyword(s):  
Output Voltage ◽  
Closed Loop ◽  
Synchronous Generator ◽  
Local Mode ◽  
Small Signal ◽  
Closed Loop System ◽  
Robust Controller ◽  
Sensitivity Approach ◽  
Single Machine Infinite Bus ◽  
The Stability

This paper deals with the design and evaluation of robust excitation controller for a single-machine infinite-bus power system. The design of the regulator guarantees the stability of the closed loop system and ensures the output voltage is maintained within an acceptable threshold. In addition, it damps out local mode oscillations for small signal disturbances. The designed robust controller is also analyzed under change in step input and disturbance, which limits the heavy oscillations on the speed ω and voltage. Glover-McFarlane loop shaping algorithm is applied in designing the robust excitation controller. Two different techniques such as Optimal control and mixed sensitivity approach is used in this paper. The performance of the AVR was analyzed and compared with IEEE type2 Exciter.

Uniform robust exact differentiator based adaptive robust control for a class of nonlinear systems

2017 ◽  
Vol 40 (9) ◽  
pp. 2901-2911 ◽  
Author(s):  
Zhangbao Xu ◽  
Dawei Ma ◽  
Jianyong Yao
Keyword(s):  
Robust Control ◽  
Nonlinear Systems ◽  
Closed Loop ◽  
Lyapunov Method ◽  
Adaptive Robust Control ◽  
Experimental Results ◽  
Closed Loop System ◽  
Robust Controller ◽  
Performance Simulation ◽  
The Stability

In this paper, an adaptive robust controller with uniform robust exact differentiator has been proposed for a class of nonlinear systems with structured and unstructured uncertainties. The adaptive robust controller is integrated with an uniform robust differentiator to handle the problem of the incalculable part of the derivative of virtual controls and the differential explosion happened in backstepping techniques. The stability of the closed loop system is demonstrated via Lyapunov method ensuring a prescribed transient and tracking performance. Simulation and experimental results are carried out to verify the advantages of the proposed method.

scholarly journals Robust LFC Strategy for Wind Integrated Time-Delay Power System Using EID Compensation

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3223 ◽  
Author(s):  
Liu ◽  
Zhang ◽  
Zou
Keyword(s):  
Time Delay ◽  
Power System ◽  
Closed Loop ◽  
Frequency Control ◽  
Loop System ◽  
Load Frequency Control ◽  
System Stability ◽  
Linear Matrix ◽  
Closed Loop System ◽  
The Stability

This paper presents an active disturbance rejection control (ADRC) technique for load frequency control of a wind integrated power system when communication delays are considered. To improve the stability of frequency control, equivalent input disturbances (EID) compensation is used to eliminate the influence of the load variation. In wind integrated power systems, two area controllers are designed to guarantee the stability of the overall closed-loop system. First, a simplified frequency response model of the wind integrated time-delay power system was established. Then the state-space model of the closed-loop system was built by employing state observers. The system stability conditions and controller parameters can be solved by some linear matrix inequalities (LMIs) forms. Finally, the case studies were tested using MATLAB/SIMULINK software and the simulation results show its robustness and effectiveness to maintain power-system stability.

Qualitative Robustness and Its Role in the Robust Control of Uncertain Engineering Systems

2011 ◽  
Author(s):  
Nagini Devarakonda ◽  
Rama K. Yedavalli
Keyword(s):  
Control Systems ◽  
Uncertain Systems ◽  
Closed Loop ◽  
Quantitative Information ◽  
Engineering Systems ◽  
Closed Loop System ◽  
Qualitative Information ◽  
Loop Control ◽  
Qualitative Robustness ◽  
Ecological Principles

This paper addresses the issue of robustness of linear uncertain systems. In addition to the conventional notion of robustness based on quantitative information, in this paper, a new and novel perspective of qualitative robustness is introduced. The qualitative robustness measure is inspired by ecological principles and is based on the nature of interactions and interconnections of the system. Thus, using the proposed framework, the robustness of engineering systems can be assessed both from quantitative as well as qualitative information. This type of analysis from both viewpoints sheds considerable insight on the desirable nominal system in engineering applications. Using these concepts it is shown that a specific quantitative set of matrices labeled ‘Target Sign Stable Matrices’ are the best nominal matrices. These concepts are then extended to closed loop control systems and problem of control design and for ease in design a new set of matrices ‘Target Pseudosymmetric Matrices’ are introduced which enhance the class of desirable closed loop system matrices. Examples are included to illustrate these concepts.

scholarly journals Robust LPV Control for Attitude Stabilization of a Quadrotor Helicopter under Input Saturations

2020 ◽  
Vol 5 (2) ◽  
pp. 98-111 ◽  
Author(s):  
Seif-El-Islam Hasseni ◽  
Latifa Abdou
Keyword(s):  
Closed Loop ◽  
Robust Stabilization ◽  
Cuckoo Search ◽  
Parametric Uncertainties ◽  
Closed Loop System ◽  
Robust Controller ◽  
Attitude Stabilization ◽  
Lpv Control ◽  
Compensation Technique ◽  
Attitude Model

This article investigates the robust stabilization of the rotational subsystem of a quadrotor against external inputs (disturbances, noises, and parametric uncertainties) by the LFT-based LPV technique. By establishing the LPV attitude model, the LPV robust controller is designed for the system. The weighting functions are computed by Cuckoo Search, a meta-heuristic optimization algorithm. Besides, the input saturations are also taken into account through the Anti-Windup compensation technique. Simulation results show the robustness of the closed-loop system against disturbances, measurement noises, and the parametric uncertainties.

Noise Suppression of Optical Voltage Transducer by a Robust Control

2011 ◽  
Vol 418-420 ◽  
pp. 185-191
Author(s):  
Li Jing Li ◽  
Bing Jun Li ◽  
Lan Bi ◽  
Xi Zhang ◽  
Chun Xi Zhang
Keyword(s):  
Robust Control ◽  
Measurement Accuracy ◽  
Closed Loop ◽  
Noise Suppression ◽  
Design Criterion ◽  
Linear Matrix ◽  
Closed Loop System ◽  
Robust Controller ◽  
Voltage Transducer ◽  
Loop Detection

This paper investigates an H∞ robust controller for improving the measurement accuracy of the Optical Voltage Transducer with noise and parameter uncertainty. Firstly, the optical voltage transducer based on closed-loop detection is analyzed, and the model of the system is established concerning noise and uncertainty. Secondly, according to the model, this paper is theoretically devoted to the study of the Robust control for meeting the design target, while guarantees that the closed-loop system is asymptotically stable. Furthermore, we give a design criterion in terms of linear matrix inequality for the Robust control in the presence of noise and uncertainty. Finally, the experimental results demonstrate the effectiveness and feasibility of the robust controller.

scholarly journals On the Practical Output Feedback Stabilization for Nonlinear Uncertain Systems

2009 ◽  
Vol 14 (2) ◽  
pp. 145-153 ◽  
Author(s):  
A. Benabdallah
Keyword(s):  
Output Feedback ◽  
Uncertain Systems ◽  
Closed Loop ◽  
Feedback Stabilization ◽  
Feedback Controller ◽  
Practical Stability ◽  
Closed Loop System ◽  
Output Feedback Controller ◽  
Output Feedback Stabilization ◽  
Nonlinear Uncertain Systems

In this paper, we treat the problem of output feedback stabilization of nonlinear uncertain systems. We propose an output feedback controller that guarantees global uniform practical stability of the closed loop system.

Robust Controller Design to Achieve Active Damping for a MEMS Microphone

2008 ◽  
Author(s):  
Jinli Qu ◽  
Ronald N. Miles ◽  
N. Eva Wu
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Active Damping ◽  
Closed Loop System ◽  
Robust Controller ◽  
Nonlinear Simulation ◽  
Mems Microphone ◽  
And Performance ◽  
The Stability ◽  
Robust Controller Design

This paper presented an H∞-controller design to achieve active damping for a MEMS microphone system. The parametric uncertainties introduced by linearization process were modeled. The stability and performance of the closed-loop system were analyzed for the uncertain microphone model and both were shown to be robust. The nonlinear simulation further verifies that the controller offers the desired performance.

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