scholarly journals Study of the stability of fuzzy controllers by an estimation of the attraction regions: A Vector Norm approach

2002 ◽  
Vol 8 (3) ◽  
pp. 221-231 ◽  
Author(s):  
J.-Y. Dieulot ◽  
A. El Kamel ◽  
P. Borne
Keyword(s):  
Fuzzy Controller ◽  
Domain Of Attraction ◽  
Constant Term ◽  
Open Loop ◽  
Region Of Attraction ◽  
Open Loop System ◽  
Controlled System ◽  
Disjoint Sets ◽  
The Stability ◽  
Vector Norms

A fuzzy controller with singleton defuzzification can be considered as the association of a regionwise constant term and of a regionwise non linear term, the latter being bounded by a linear controller. Based on the regionwise structure of fuzzy controller, the state space is partitioned into a series of disjoint sets. The fuzzy controller parameters are tuned in order to ensure that theith set is included into the domain of attraction of the preceding sets of the series. If the first set of the series is included into the region of attraction of the equilibrium point, the overall fuzzy controlled system is stable. The attractors are estimated with the help of the comparison principle, using Vector Norms, which ensures the robustness with respect to uncertainties and perturbations of the open loop system.

scholarly journals Influence of time delay on fractional-order PI-controlled system for a second-order oscillatory plant model with time delay

2017 ◽  
Vol 66 (4) ◽  
pp. 693-704 ◽  
Author(s):  
Talar Sadalla ◽  
Dariusz Horla ◽  
Wojciech Giernacki ◽  
Piotr Kozierski
Keyword(s):  
Time Delay ◽  
Fractional Order ◽  
Open Loop ◽  
Second Order ◽  
Loop System ◽  
Tracking Performance ◽  
Controlled System ◽  
Tuning Method ◽  
Fractional Order Pi Controller ◽  
The Stability

Abstract The paper aims at presenting the influence of an open-loop time delay on the stability and tracking performance of a second-order open-loop system and continuoustime fractional-order PI controller. The tuning method of this controller is based on Hermite- Biehler and Pontryagin theorems, and the tracking performance is evaluated on the basis of two integral performance indices, namely IAE and ISE. The paper extends the results and methodology presented in previous work of the authors to analysis of the influence of time delay on the closed-loop system taking its destabilizing properties into account, as well as concerning possible application of the presented results and used models.

Deflection Control of Electrostatically Actuated Micro Cantilevers via Fuzzy Controller

2016 ◽  
Author(s):  
Mohammad Khadembashi ◽  
Hamid Moeenfard ◽  
Amir H. Ghasemi
Keyword(s):  
Passive Control ◽  
Fuzzy Controller ◽  
Open Loop ◽  
Beam Deflection ◽  
The Novel ◽  
Lagrange Equations ◽  
Controlled System ◽  
Single Level ◽  
Electrostatically Actuated ◽  
Micro Structures

The objective of this paper is to develop a novel two-level supervised fuzzy controller to stabilize the response of electrostatically actuated microbeams beyond their pull-in range. To this end, Lagrange equations are utilized to derive the differential equations governing the dynamic behavior of the system. To investigate the possibility of using a passive control strategy, the static behavior of the system is studied in detail. Through some open loop simulations, the qualitative and quantitative dependence of the beam deflection to the applied voltage and system parameters are studied. Based on the understanding obtained from these studies, a single level fuzzy controller is designed to control the response of the microstructure. In order to enhance the performance of the closed-loop system, another higher level supervisory fuzzy controller is designed to tune the maximum allowable voltage the lower level controller can apply. Simulation results reveal that both single level and multi-level fuzzy controllers can extend the travel range of the microbeams beyond its pull-in range. However the rise time, overshoot and settling time in the multilevel controlled system is far better than that of a simple single level fuzzy controller. The novel controller presented in this paper can be applied in most intrinsically nonlinear nano/micro structures to help them to have more efficient regulations and command tracking maneuvers.

scholarly journals Closed loop Fuzzy Logic Controlled Interleaved DC-to-DC converter Fed DC Drive System

2018 ◽  
Vol 7 (2.24) ◽  
pp. 397
Author(s):  
R Elavarasu ◽  
C Christober Asir Rajan
Keyword(s):  
Fuzzy Logic ◽  
High Frequency ◽  
Closed Loop ◽  
Open Loop ◽  
Open Loop System ◽  
Controlled System ◽  
Voltage Doubler ◽  
Dc Drive ◽  
The Time Domain ◽  
High Frequency Ac

This paper deals with comparison of responses of PI and Fuzzy Logic controlled DC-to-DC converter Fed DC motor (FLCDDCDCM) systems. The DC input is converted into high frequency AC using full bridge inverter. The output is stepped up using a transformer and then it is rectified using voltage doubler rectifier. The open loop system with T filter at the output is simulated. The closed loop PI & FLC based DDCDCM systems are designed, modeled and simulated using Matlab/Simulink. The time domain parameters of FL controlled system are compared with those of PI controlled system. The results indicated that FL controlled DDCDCM system has better response than PI controlled DDCDCM system. 

Optimal Design of a Stable Fuzzy Controller for Beyond Pull-In Stabilization of Electrostatically Actuated Circular Microplates

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Mohsen Bakhtiari-Shahri ◽  
Hamid Moeenfard
Keyword(s):  
Noise Suppression ◽  
Fuzzy Controller ◽  
Single Mode ◽  
Open Loop ◽  
Positioning Systems ◽  
Electrostatically Actuated ◽  
Proposed Model ◽  
Linguistic Rules ◽  
The Stability ◽  
Stability Enhancement

The current paper aims to provide an optimal stable fuzzy controller to extend the travel range of a pair of flexible electrostatically actuated circular microplates beyond their pull-in limit. The single mode assumption is utilized to derive the equation of motion of the system based on a Lagrangian approach. The static behavior of the system is studied using the proposed model, and the utilized assumption and the relevant results are closely verified by nonlinear finite element simulations. The open-loop dynamic analysis is also performed to derive the linguistic rules governing the voltage-deflection behavior of the system. The mentioned rules are then employed for designing a fuzzy controller, which controls the deflection of the microplates. The controller is then optimized to provide better response specifications. The performance of the optimal fuzzy controller is compared with that of the optimal proportional–integral–derivative (PID) controller and obvious superiorities in terms of noise suppression and stability enhancement are observed. To guarantee the stability of the closed-loop system, another higher level controller is designed to oversee the behavior of the fuzzy controller. Simulation results reveal that the superintended fuzzy controller can prevent instability, while fairly extending the travel range of system and providing it with a better transient response. The suggested design approach proposed in this paper may be used to improve the performance of many nano/micro devices and nano/micro positioning systems.

scholarly journals Dynamic Stability of Open-Loop Hopping

2006 ◽  
Vol 129 (3) ◽  
pp. 275-284 ◽  
Author(s):  
Jorge G. Cham ◽  
Mark R. Cutkosky
Keyword(s):  
Sensory Feedback ◽  
Motor Pattern ◽  
Open Loop ◽  
Legged Robots ◽  
Open Loop System ◽  
System Parameters ◽  
Model Driven ◽  
The Stability ◽  
And Control ◽  
Hopping Model

Simulations and physical robots have shown that hopping and running are possible without sensory feedback. However, stable behavior is often limited to a certain range of the parameters of the open-loop system. Even the simplest of hopping systems can exhibit unstable behavior that results in unpredictable nonperiodic motion as system parameters are adjusted. This paper analyzes the stability of a simplified vertical hopping model driven by an open-loop, feedforward motor pattern. Periodic orbits of the resulting hybrid system are analyzed through a generalized formula for the system’s Poincare Map and Jacobian. The observed behavior is validated experimentally in a physical pneumatically actuated hopping machine. This approach leads to observations on the stability of this and similar systems, revealing inherent limitations of open-loop hopping and providing insights that can inform the design and control of dynamic legged robots capable of rapid and robust locomotion.

Attention Theory and Training Research

1987 ◽  
Vol 31 (6) ◽  
pp. 648-651 ◽  
Author(s):  
James G. Connelly ◽  
Christopher D. Wickens ◽  
Gavan Lintern ◽  
Kelly Harwood
Keyword(s):  
Mental Workload ◽  
Open Loop ◽  
Flight Simulation ◽  
Complex Task ◽  
Time Sharing ◽  
Attention Theory ◽  
Stimulus Response ◽  
Training Research ◽  
Complex Training ◽  
The Stability

This study used elements of attention theory as a methodological basis to decompose a complex training task in order to improve training efficiency. The complex task was a microcomputer flight simulation where subjects were required to control the stability of their own helicopter while acquiring and engaging enemy helicopters in a threat environment. Subjects were divided into whole-task, part-task, and part/open loop adaptive task groups in a transfer of training paradigm. The effect of reducing mental workload at the early stages of learning was examined with respect to the degree that subordinate elements of the complex task could be automated through practice of consistent, learnable stimulus-response relationships. Results revealed trends suggesting the benefit of isolating consistently mapped sub-tasks for part-task training and the presence of a time-sharing skill over and above the skill required for the separate subtasks.

Open Loop Stability on Hybrid Synchronous Motor

2010 ◽  
Vol 121-122 ◽  
pp. 860-865
Author(s):  
Xue Zhen Chen
Keyword(s):  
Permanent Magnet ◽  
Harmonic Distortion ◽  
Synchronous Motor ◽  
Open Loop ◽  
Mathematics Model ◽  
Distortion Factor ◽  
Part D ◽  
Fraction Length ◽  
The Stability ◽  
Loop Stability

This paper searched open loop stability on hybrid synchronous motor which is made of a permanent magnet part and a reluctance part, there is important influence for the ratio k, the fraction length of the permanent magnet part, and the displaced angle α, the between the two part d-axis, the small-signal mathematics model was derived based on d-q reference frame, and optimized the appropriate k and α value considering the stability and the harmonic distortion factor (THD), The simulation results show that the model is correct.

scholarly journals Actuator Saturated Fuzzy Controller Design for Interval Type-2 Takagi-Sugeno Fuzzy Models with Multiplicative Noises

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 823
Author(s):  
Wen-Jer Chang ◽  
Yu-Wei Lin ◽  
Yann-Horng Lin ◽  
Chin-Lin Pen ◽  
Ming-Hsuan Tsai
Keyword(s):  
Nonlinear Systems ◽  
Fuzzy Controller ◽  
Controller Design ◽  
Actuator Saturation ◽  
Design Method ◽  
Fuzzy Model ◽  
The Stability ◽  
Interval Type ◽  
Takagi Sugeno

In many practical systems, stochastic behaviors usually occur and need to be considered in the controller design. To ensure the system performance under the effect of stochastic behaviors, the controller may become bigger even beyond the capacity of practical applications. Therefore, the actuator saturation problem also must be considered in the controller design. The type-2 Takagi-Sugeno (T-S) fuzzy model can describe the parameter uncertainties more completely than the type-1 T-S fuzzy model for a class of nonlinear systems. A fuzzy controller design method is proposed in this paper based on the Interval Type-2 (IT2) T-S fuzzy model for stochastic nonlinear systems subject to actuator saturation. The stability analysis and some corresponding sufficient conditions for the IT2 T-S fuzzy model are developed using Lyapunov theory. Via transferring the stability and control problem into Linear Matrix Inequality (LMI) problem, the proposed fuzzy control problem can be solved by the convex optimization algorithm. Finally, a nonlinear ship steering system is considered in the simulations to verify the feasibility and efficiency of the proposed fuzzy controller design method.

Improving the efficiency of a wastewater treatment plant by fuzzy control and neural networks

2001 ◽  
Vol 43 (11) ◽  
pp. 189-196 ◽  
Author(s):  
M. Bongards
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Fuzzy Controller ◽  
Control Strategies ◽  
Treatment Plant ◽  
Municipal Wastewater Treatment ◽  
Controlled System ◽  
Measurement Results ◽  
Predictive Controller

One of the main problems in operating a wastewater treatment plant is the purification of the excess water from dewatering and pressing of sludge. Because of a high load of organic material and of nitrogen it has to be buffered and treated together with the inflowing wastewater. Different control strategies are discussed. A combination of neural network for predicting outflow values one hour in advance and fuzzy controller for dosing the sludge water are presented. This design allows the construction of a highly non-linear predictive controller adapted to the behaviour of the controlled system with a relatively simple and easy to optimise fuzzy controller. Measurement results of its operation on a municipal wastewater treatment plant of 60,000 inhabitant equivalents are presented and discussed. In several months of operation the system has proved very reliable and robust tool for improving the system's efficiency.

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