Decentralized periodic control of interconnected systems with fixed modes

Automatica ◽  
2021 ◽  
pp. 110038
Author(s):  
Ankit Deshmukh ◽  
Arun Ghosh
Author(s):  
المختار الأحمر

الملخّص يتناول البحث علاقة الفطرة بالشريعة في التفكير الإسلامي، وما تطرحه هذه العلاقة سواء على مستوى بيان الجوانب المتعلقة بخَلْق الإنسان وما فُطِر عليه ابتداء، وهذا البعد يمثّل الجانب التكوني في مفهوم الفطرة، أو على المستوى المتعلق بالشريعة وفطريتها، أي أنها جارية وفق ما يدركه العقل وتشهد به الفطرة، وهذا البعد يمثّل الجانب التشريعي الذي يطرحه مفهوم الفطرة. لقد زخرت أغلب الكتابات بتناول جانبا واحدا مما يتيحه أو يعكسه مفهوم الفطرة، لكن البحث في العلاقة التناسبية بين الفطرة والشريعة، وما يتيحه هذا النظر المتلازم بين المفهومين على مستوى الإمكانات المتعلقة بقدرات الإنسان الفطرية في فهم وتعقّل الخطاب الشرعي والأحكام التكليفية، والوقوف على غاياته ومقاصده، يبقى في حاجة إلى البحث والاستقصاء. ولذلك تأتي هذه الدراسة لتسليط الضوء على الجانب التشريعي والتكويني في علاقة الشريعة بالفطرة، باعتبارهما نظامين متلازمين يتيحان فهم طبيعة الشريعة وأحكامها ومقاصدها من جهة، وتحديد جوهر وماهية الإنسان الفطرية وإمكاناته في تعقّل هذه الشريعة من جهة ثانية.                  الكلمات المفتاحية: الفطرة، الشريعة، الدين، التكاليف، العقل. Abstract This research addresses the relationship between premordial human nature (fitrah) and Islamic law (SharÊÑah) within the frame of Islamic thought, while exploring the questions it raises at two levels. The first level explains the aspects related to the creation of man and what has initially been bestowed upon him, which represents the evolutionary aspect of the concept of fiÏrah. The second level is related to SharÊÑah and its nature, which evolves according to what is percieved by reason and witnessed by fiÏrah; this represents the legislative aspect presented by the concept of fiÏrah. The majority of studies to date address a single aspect of the illustrations of the concept of fiÏrah. However, research on the dialectic relationship between fiÏrah and SharÊÑah and what its relevant concurrent view provides at the level of potentials related to human innate capacities in understanding and realizing SharÊÑah discourse and mandatory provisions as well as understanding its objectives  remains scarce and requires further research and investigation. Therefore, this study intends to shed light on the legislative and evolutionary aspects of the relationship between SharÊÑah and fiÏrah as two interconnected systems that allow for the understanding of the nature of SharÊÑah, its provisions and purposes, as well as identifying the essence of human innate nature and its potential in perceiving SharÊÑah. Keywords: human nature (fiÏrah), Islamic law (SharÊÑah), religious mandates (TakÉlif), religion, intellect (ÑAqal).


Author(s):  
Jatin K Pradhan ◽  
Arun Ghosh

It is well known that linear time-invariant controllers fail to provide desired robustness margins (e.g. gain margin, phase margin) for plants with non-minimum phase zeros. Attempts have been made in literature to alleviate this problem using high-frequency periodic controllers. But because of high frequency in nature, real-time implementation of these controllers is very challenging. In fact, no practical applications of such controllers for multivariable plants have been reported in literature till date. This article considers a laboratory-based, two-input–two-output, quadruple-tank process with a non-minimum phase zero for real-time implementation of the above periodic controller. To design the controller, first, a minimal pre-compensator is used to decouple the plant in open loop. Then the resulting single-input–single-output units are compensated using periodic controllers. It is shown through simulations and real-time experiments that owing to arbitrary loop-zero placement capability of periodic controllers, the above decoupled periodic control scheme provides much improved robustness against multi-channel output gain variations as compared to its linear time-invariant counterpart. It is also shown that in spite of this improved robustness, the nominal performances such as tracking and disturbance attenuation remain almost the same. A comparison with [Formula: see text]-linear time-invariant controllers is also carried out to show superiority of the proposed scheme.


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