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Issue Info: 
  • Year: 

    2024
  • Volume: 

    13
  • Issue: 

    25
  • Pages: 

    33-49
Measures: 
  • Citations: 

    0
  • Views: 

    16
  • Downloads: 

    0
Abstract: 

This article investigates the problem of simultaneous attitude and vibration control of a flexible spacecraft to perform high precision attitude maneuvers and reduce vibrations caused by the flexible panel excitations in the presence of external disturbances, system uncertainties, and actuator faults. Adaptive integral sliding mode control is used in conjunction with an attitude actuator fault iterative learning observer (based on sliding mode) to develop an active fault tolerant algorithm considering rigid-flexible body dynamic interactions. The discontinuous structure of fault-tolerant control led to discontinuous commands in the control signal, resulting in chattering. This issue was resolved by introducing an adaptive rule for the sliding surface. Furthermore, the utilization of the sign function in the iterative learning observer for estimating actuator faults has not only enhanced its robustness to external disturbances through a straightforward design, but has also led to a decrease in computing workload. The strain rate feedback control algorithm has been employed with the use of piezoelectric sensor/actuator patches to minimize residual vibrations caused by rigid-flexible body dynamic interactions and the effect of attitude actuator faults. Lyapunov's law ensures finite-time overall system stability even with fully coupled rigid-flexible nonlinear dynamics. Numerical simulations demonstrate the performance and advantages of the proposed system compared to other conventional approaches.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2022
  • Volume: 

    11
  • Issue: 

    1
  • Pages: 

    27-34
Measures: 
  • Citations: 

    0
  • Views: 

    36
  • Downloads: 

    0
Keywords: 
Abstract: 

A common method for controlling a group of parallel converters in decentralized control strategy structure in an island microgrid, the use is the droop-down characteristics of frequency ω-P and voltage E-Q. However, the problem with using this method is that the reactive power is not properly distributed (in proportion to the capacity of the micronutrients) between the micronutrients, which may lead to overload in the converters. Microgrids may also suffer from dynamic stability problems such as power fluctuations, which can be increased by switching between active and reactive power control. To avoid this problem, the X / R ratio of transmission lines is an important parameter that should be carefully considered in the design of micronutrient controllers. By linearizing and simplifying conditions, the control system conversion function model becomes a single input-single output system, which is efficient enough to show the relationship between control parameters such as slope of droop characteristics and derivative sentences, virtual impedance, and voltage controllers. Using this model, stability conditions for different parameters are analyzed. Also, to improve power distribution stability, common droop strategies are modified by adjusting the slope as well as adding nonlinear sentence sections. This approach reduces the coupling between active and reactive power control and reduces the dependence of power distribution on grid parameters such as the X / R ratio. To evaluate the reliability of the proposed model, the simulation results in a sample island microgrid in MATLAB software are presented.

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Issue Info: 
  • Year: 

    0
  • Volume: 

    1
  • Issue: 

    1
  • Pages: 

    47-47
Measures: 
  • Citations: 

    1
  • Views: 

    221
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 221

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Journal: 

AMIRKABIR

Issue Info: 
  • Year: 

    2013
  • Volume: 

    44
  • Issue: 

    2
  • Pages: 

    83-91
Measures: 
  • Citations: 

    0
  • Views: 

    397
  • Downloads: 

    0
Abstract: 

This paper describes a vehicle speed & vehicle-to-vehicle distance control algorithm for vehicle stop-and-go cruise control. So first, a complete dynamic model of car has been simulated that consists of an SI engine, automatic transmission. The vehicle longitudinal control scheme consists of a speed control algorithm and a distance control algorithm and throttle-brake control law. A desired acceleration for the vehicle has been designed using linear quadratic optimal control theory. It has been shown that the proposed control law provides good performance.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2017
  • Volume: 

    29
  • Issue: 

    1 (17)
  • Pages: 

    1-16
Measures: 
  • Citations: 

    0
  • Views: 

    1232
  • Downloads: 

    0
Abstract: 

In this paper a semi-active structural damage control strategy using MR dampers and Neural Networks is presented. A multilayer feed-forward neural network has been designed. The input layer is relative displacement of stories and the output layer is the voltage needed for MR damper. The neural network is learned to predict the voltage needed for MR damper that can minimize the Park & Ang damage index of structure. Genetic algorithm has been used to learn the neural network. The Park & Ang damage index of the structure has been used as the fittnees function of the genetic algorithm. To evaluate the structural control system a nonlinear 3 story benchmark building has been selected. The results show the the proposed structural control system can effectively reduce the Park & Ang damage index of the structure.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2024
  • Volume: 

    12
  • Issue: 

    3
  • Pages: 

    146-147
Measures: 
  • Citations: 

    0
  • Views: 

    8
  • Downloads: 

    0
Abstract: 

We are writing to express my appreciation for the insightful article on pain management in trauma patients and its critical role in improving patient outcomes. The current protocol utilizing acetaminophen and opiate agents has proven to be significantly effective. However, Recent studies have indicated that the combination of acetaminophen and NSAIDs can provide superior analgesic effects compared to either agent alone, potentially surpassing the effect of opioids The current protocol utilizing acetaminophen and opiate agents has proven to be significantly effective. However, Recent studies have indicated that the combination of acetaminophen and NSAIDs can provide superior analgesic effects compared to either agent alone, potentially surpassing the effect of opioids. Integrating NSAIDs into the pain management protocol could offer several benefits, including enhanced Pain Relief (3) and Reduced Opioid Consumption. we believe that incorporating acetaminophen plus NSAIDs into the existing pain management algorithm could be a valuable step towards optimizing care for trauma patients. Enclosed is a revised proposed algorithm based on your previously published protocol for the management of acute pain in trauma patients.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Issue Info: 
  • Year: 

    2004
  • Volume: 

    19
Measures: 
  • Views: 

    181
  • Downloads: 

    82
Abstract: 

IN THIS PAPER, A NOVEL control TECHNIQUE BASED ON IMPROVED FFT (FAST FOURIER TRANSFORM) algorithm IS PROPOSED TO OVERCOME THE DRAWBACKS OF UNIFIED POWER QUALITY CONDITIONER (UPQC) control TECHNIQUE BASED ON FOURIER ANALYSIS. BECAUSE OF THE INHERENT TIME DELAY OF FFT algorithm BASED control TECHNIQUE, UPQC (WITH THIS control TECHNIQUE) CAN NOT BE USED FOR COMPENSATING VARIABLE LOAD CURRENT PERTURBATIONS, WHEREAS, THE PROPOSED control TECHNIQUE COMPENSATE PERTURBATIONS OF LOAD CURRENT IN VARIOUS CONDITIONS. BY USING THIS NOVEL control TECHNIQUE, DC LINK VOLTAGE VARIATION IS NOT CONSIDERABLE, BECAUSE THE TIME DELAY FOR EXTRACTING THE FUNDAMENTAL COMPONENT OF LOAD CURRENT (WHICH HAVE GREAT EFFECT ON DC LINK CAPACITOR VOLTAGES) DECREASES SIGNIFICANTLY. ANALYSIS AND MODELING OF THE UPQC WITH FFT control TECHNIQUE AND PROPOSED control SCHEME AS WELL AS SIMULATION RESULTS ARE PRESENTED. RESULTS SHOW THAT THE ACCURACY OF PROPOSED METHOD IS BETTER THAN FFT control TECHNIQUE AND UNSYMMETRICAL, DYNAMIC AND VARIABLE LOAD CURRENT CAN BE COMPENSATED WITHOUT ANY CONSIDERABLE TIME DELAY.

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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Writer: 

Issue Info: 
  • End Date: 

    1395
Measures: 
  • Citations: 

    3
  • Views: 

    181
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 181

Writer: 

Issue Info: 
  • End Date: 

    1395
Measures: 
  • Citations: 

    0
  • Views: 

    172
  • Downloads: 

    0
Keywords: 
Abstract: 

Yearly Impact:   مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 172

Issue Info: 
  • Year: 

    621
  • Volume: 

    19
  • Issue: 

    1
  • Pages: 

    1-11
Measures: 
  • Citations: 

    0
  • Views: 

    19
  • Downloads: 

    15
Abstract: 

A novel nonlinear controller is proposed to track active and reactive power for a Brushless Doubly-Fed Induction Generator (BDFIG) wind turbine. Due to nonlinear dynamics and the presence of parametric uncertainties and perturbations in this system, sliding mode control is employed. To generate a smooth control signal, dynamic sliding mode method is used. Uncertainties bound is not required in the suggested algorithm, since the adaptive gain in the controller relation is used in this study. Convergence of the sliding variable to zero and adaptive gain to the uncertainty bound are verified using Lyapunov stability theorem. The proposed controller is evaluated in a comprehensive simulation on the BDFIG model. Moreover, output performance of the proposed control algorithm is compared to the conventional and second-order sliding mode and proportional-integral-derivative (PID) controllers.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

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