Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link

This work addresses the robust control of processes of the form <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mrow><mo>(</mo><mi>s</mi><mo>)<...

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Main Authors: Saddam Gharab, Vicente Feliu Batlle
Format: Article
Language:English
Published: MDPI AG 2023-08-01
Series:Fractal and Fractional
Subjects:
Online Access:https://www.mdpi.com/2504-3110/7/9/646
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author Saddam Gharab
Vicente Feliu Batlle
author_facet Saddam Gharab
Vicente Feliu Batlle
author_sort Saddam Gharab
collection DOAJ
description This work addresses the robust control of processes of the form <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mrow><mo>(</mo><mi>s</mi><mo>)</mo></mrow><mo>=</mo><mi>K</mi><mo>·</mo><msup><mi>e</mi><mrow><mo>−</mo><mi>τ</mi><mo>·</mo><mi>s</mi></mrow></msup><mo>/</mo><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>T</mi><mo>·</mo><msup><mi>s</mi><mi>λ</mi></msup><mo>)</mo></mrow></mrow></semantics></math></inline-formula> with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo><</mo><mi>λ</mi><mo>≤</mo><mn>2</mn></mrow></semantics></math></inline-formula>. A new method for tuning fractional-order <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mi>I</mi></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mi>D</mi></mrow></semantics></math></inline-formula> controllers is developed. The stability is assessed based on the frequency domain tuning of the regulators to control such delayed fractional-order underdamped processes. In order to analyze the closed-loop stability and robustness, the new concept of <i>Robust High-Frequency Condition</i> is introduced. The analysis based on that demonstrates that each controller has a different region of feasible frequency specifications, and, in all cases, they depend on their fractional integral or derivative actions. Finally, an application example, the position control of a teleoperated manipulator with a flexible link, is presented. Simulations and experiments illustrate that the region of feasible frequency specifications defined at low and high frequencies allows us to obtain robust controllers that fulfill frequency requirements.
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spelling doaj.art-f7e37fe84ecd4df3bf84986af2697d152023-11-19T10:48:14ZengMDPI AGFractal and Fractional2504-31102023-08-017964610.3390/fractalfract7090646Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible LinkSaddam Gharab0Vicente Feliu Batlle1Instituto de Investigaciones Energéticas y Aplicaciones Industriales, 13005 Ciudad Real, SpainEscuela Técnica Superior de Ingeniería Industrial, Universidad de Castilla La Mancha, 13071 Ciudad Real, SpainThis work addresses the robust control of processes of the form <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>G</mi><mrow><mo>(</mo><mi>s</mi><mo>)</mo></mrow><mo>=</mo><mi>K</mi><mo>·</mo><msup><mi>e</mi><mrow><mo>−</mo><mi>τ</mi><mo>·</mo><mi>s</mi></mrow></msup><mo>/</mo><mrow><mo>(</mo><mn>1</mn><mo>+</mo><mi>T</mi><mo>·</mo><msup><mi>s</mi><mi>λ</mi></msup><mo>)</mo></mrow></mrow></semantics></math></inline-formula> with <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo><</mo><mi>λ</mi><mo>≤</mo><mn>2</mn></mrow></semantics></math></inline-formula>. A new method for tuning fractional-order <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mi>I</mi></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mi>D</mi></mrow></semantics></math></inline-formula> controllers is developed. The stability is assessed based on the frequency domain tuning of the regulators to control such delayed fractional-order underdamped processes. In order to analyze the closed-loop stability and robustness, the new concept of <i>Robust High-Frequency Condition</i> is introduced. The analysis based on that demonstrates that each controller has a different region of feasible frequency specifications, and, in all cases, they depend on their fractional integral or derivative actions. Finally, an application example, the position control of a teleoperated manipulator with a flexible link, is presented. Simulations and experiments illustrate that the region of feasible frequency specifications defined at low and high frequencies allows us to obtain robust controllers that fulfill frequency requirements.https://www.mdpi.com/2504-3110/7/9/646time delayfractional order systemsflexible robotsteleoperated robotsfractional order control
spellingShingle Saddam Gharab
Vicente Feliu Batlle
Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link
Fractal and Fractional
time delay
fractional order systems
flexible robots
teleoperated robots
fractional order control
title Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link
title_full Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link
title_fullStr Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link
title_full_unstemmed Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link
title_short Fractional Control of a Class of Underdamped Fractional Systems with Time Delay—Application to a Teleoperated Robot with a Flexible Link
title_sort fractional control of a class of underdamped fractional systems with time delay application to a teleoperated robot with a flexible link
topic time delay
fractional order systems
flexible robots
teleoperated robots
fractional order control
url https://www.mdpi.com/2504-3110/7/9/646
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