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RISS 인기검색어
- 검색키워드
- 저자 : Mohammad Reza Gharib (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
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Quantitative-fuzzy Controller Design for Multivariable Systems with Uncertainty
Mohammad Reza Gharib,Armin Daneshvar 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.6
This work serves as a pioneer contribution in terms of application of Quantitative Feedback Theory(QFT) methodology and fuzzy logic method to design a controller for MIMO systems. Due to the presence of uncertainty in multivariable dynamic systems, the application of robust control methods for achieving high accuracy in tracking is inevitable. On the other hand, application of QFT to MIMO uncertain systems still remains to be one of the most difficult control problems for engineers. In this paper, authors attempt to simplify the MIMO control problem by proposing a new algorithm which joins QFT and fuzzy techniques. In order to illustrate the utility of the proposed algorithm, its application on a two degree of freedom link robot manipulator is depicted. Initially, a QFT controller is designed for each link to overcome the track and disturbance rejection problems. Then, a bi-level tuned PDfuzzy controller is employed as one strategy for curbing probable errors in the previous controller. The controller design was carried in the following stages; first, a linear PD controller independently applied to each actuator. Then, fuzzy rules were developed to design a fuzzy PD controller. Fuzzy controller normalizing parameters were regulated according to maximum PD control errors. In the second stage, named nonlinear tuning, other parameters of the fuzzy controller were tuned using genetic algorithms. Finally,nonlinear simulations of arbitrary path tracking shows that the proposed controller has a consistent tracking ability,and also it can clearly be seen that the mentioned approach is precise and very simple in comparison to other MIMO control techniques.
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Gharib Zahra,Yazdani Maziar,Bozorgi-Amiri Ali,Tavakkoli-Moghaddam Reza,Taghipourian Mohammad Javad 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.3
Construction material delivery to post-disaster reconstruction projects is challenging because of the resource and time limitations that follow a large-scale disaster. There is compelling evidence that inadequate planning jeopardises the success of a large number of post-disaster reconstruction projects. Thus, the current study proposes an integrated approach to facilitate the procurement planning of construction materials following a large-scale disaster. The proposed approach clustered the location of construction projects using a differential evolution (DE)-K-prototypes, a new partitional clustering algorithm based on DE and K-prototypes, method. Then, using a permanent matrix prioritises cluster points based on route reliability-affecting factors. The model’s objectives are to minimise the total travel time, maximise the reliability of the route, and minimise the total weighted undelivered materials to projects. In the case of distribution of material through land vehicles, the possibility of breakdowns in the vehicle is considered, allowing for the determination of vehicle breakdown under various scenarios and the minimisation of undelivered materials to projects. As a result of the uncertain character of the disaster, the demands of construction projects are fuzzy, and Jimenez’s method is used to handle it. Due to the complexity of the problem, two algorithms are proposed, a multi-objective evolutionary algorithm based on decomposition (MOEA/D) and a non-dominated sorting genetic algorithm-II (NSGA-II). The results confirm that the proposed MOEA/D has a higher accuracy while NSGA-II has a shorter computational time. By providing new theoretical perspectives on disaster recovery strategies in the construction sector, this study contributes to the growing body of knowledge about disaster recovery strategies in the sector. The findings of this study can be employed to develop an integrated planning system for the delivery of construction materials to post-disaster reconstruction projects in disaster-prone countries.
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Buckling Analysis of Groove Corroded Pipe Due to Axial Pressure with Finite Element Method
Ehsan Rajabiani,Mohammad Reza Gharib,Ali Koochi 한국강구조학회 2021 International Journal of Steel Structures Vol.21 No.5
The loss of metal in pipes due to corrosion usually results in localized pits with various depths and irregular shapes on their external and internal surfaces. In this paper, the eff ects of external corrosion defects on the axial buckling pressure of pipes are studied. Nonlinear numerical analysis based on the Finite elements method has been applied for solving this problem. Buckling due to axial pressure is studied for corroded pipes and compared with intact pipe due to the same load and theory results. This analysis is evaluated for diff erent ratios of corrosion geometric parameters consisting of corrosion depth ratio, corrosion length ratio, and corrosion angle. Pipe length to diameter ratios 20 and 25 have been considered to reach optimum results and better re s ponse. In addition, the critical loads have been investigated. The obtained results demonstrate that corrosion depth’s eff ect on the buckling strength reduction is more than the corrosion length eff ect. Also, the infl uence of the corrosion angle is less than the eff ects of corrosion depth and corrosion length.
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