SDRE-based high performance feedback control for nonlinear mechatronic systems

2019 ◽  
Vol 38 (4) ◽  
pp. 1164-1176
Author(s):  
Slawomir Jan Stepien ◽  
Paulina Superczynska ◽  
Damian Dobrowolski ◽  
Jerzy Dobrowolski
Keyword(s):  
Control Problem ◽  
High Performance ◽  
Computational Effort ◽  
Control Technique ◽  
Feedback Gain ◽  
Nonlinear Feedback ◽  
Mechatronic System ◽  
Mechatronic Systems ◽  
Content Type ◽  
State Dependent

Purpose The purpose of the paper is to present modeling and control of a nonlinear mechatronic system. To solve the control problem, the modified state-dependent Riccati equation (SDRE) method is applied. The control problem is designed and analyzed using the nonlinear feedback gain strategy for the infinite time horizon problem. Design/methodology/approach As a new contribution, this paper deals with state-dependent parametrization as an effective modeling of the mechatronic system and shows how to modify the classical form of the SDRE method to reduce computational effort during feedback gain computation. The numerical example compares described methods and confirms usefulness of the proposed technique. Findings The proposed control technique can ensure optimal dynamic response, reducing computational effort during control law computation. The effectiveness of the proposed control strategy is verified via numerical simulation. Originality/value The authors introduced an innovative approach to the well-known SDRE control methodology and settled their research in the newest literature coverage for this issue.

Enhanced Composite Nonlinear Control Technique using Adaptive Control for Nonlinear Delayed Systems

2020 ◽  
Vol 13 (3) ◽  
pp. 396-404
Author(s):  
Sonal Singh ◽  
Shubhi Purwar
Keyword(s):  
Adaptive Control ◽  
Actuator Saturation ◽  
Input Saturation ◽  
Chemical Reactor ◽  
Control Technique ◽  
Control Law ◽  
Nonlinear Feedback ◽  
Composite Nonlinear Feedback ◽  
Delayed Systems ◽  
Analysis Of Stability

Background and Introduction: The proposed control law is designed to provide fast reference tracking with minimal overshoot and to minimize the effect of unknown nonlinearities and external disturbances. Methods: In this work, an enhanced composite nonlinear feedback technique using adaptive control is developed for a nonlinear delayed system subjected to input saturation and exogenous disturbances. It ensures that the plant response is not affected by adverse effect of actuator saturation, unknown time delay and unknown nonlinearities/ disturbances. The analysis of stability is done by Lyapunov-Krasovskii functional that guarantees asymptotical stability. Results: The proposed control law is validated by its implementation on exothermic chemical reactor. MATLAB figures are provided to compare the results. Conclusion: The simulation results of the proposed controller are compared with the conventional composite nonlinear feedback control which illustrates the efficiency of the proposed controller.

scholarly journals Design of Satellite Attitude Control Algorithm Based on the SDRE Method Using Gas Jets and Reaction Wheels

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Luiz C. G. de Souza ◽  
Victor M. R. Arena
Keyword(s):  
Attitude Control ◽  
Control Algorithm ◽  
Controller Design ◽  
Algorithm Design ◽  
Large Angle ◽  
Space Mission ◽  
Control Technique ◽  
Gas Jets ◽  
State Dependent ◽  
Highly Nonlinear

An experimental attitude control algorithm design using prototypes can minimize space mission costs by reducing the number of errors transmitted to the next phase of the project. The Space Mechanics and Control Division (DMC) of INPE is constructing a 3D simulator to supply the conditions for implementing and testing satellite control hardware and software. Satellite large angle maneuver makes the plant highly nonlinear and if the parameters of the system are not well determined, the plant can also present some level of uncertainty. As a result, controller designed by a linear control technique can have its performance and robustness degraded. In this paper the standard LQR linear controller and the SDRE controller associated with an SDRE filter are applied to design a controller for a nonlinear plant. The plant is similar to the DMC 3D satellite simulator where the unstructured uncertainties of the system are represented by process and measurements noise. In the sequel the State-Dependent Riccati Equation (SDRE) method is used to design and test an attitude control algorithm based on gas jets and reaction wheel torques to perform large angle maneuver in three axes. The SDRE controller design takes into account the effects of the plant nonlinearities and system noise which represents uncertainty. The SDRE controller performance and robustness are tested during the transition phase from angular velocity reductions to normal mode of operation with stringent pointing accuracy using a switching control algorithm based on minimum system energy. This work serves to validate the numerical simulator model and to verify the functionality of the control algorithm designed by the SDRE method.

scholarly journals How to Select the Number of Active Pumps during the Operation of a Pumping Station: The Convex Hyperbola Charts

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1474
Author(s):  
Araceli Martin-Candilejo ◽  
Francisco Javier Martin-Carrasco ◽  
David Santillán
Keyword(s):  
Specific Energy ◽  
Analytic Solution ◽  
Iterative Algorithms ◽  
Computational Effort ◽  
Control Technique ◽  
Pumping Station ◽  
Operation Control

This research aims to identify the number of pumps that should be working at any moment during the operation of a pumping station in order to provide the desired volume of water whilst consuming the least amount of energy. This is typically done by complex iterative algorithms that require much computational effort. The pumping station should pump the desired volume of water V* using the least specific energy e* (energy per volume). In the methodology of this article, the shape of the curves e*–V* was analyzed. The result is that such curves present a convex hyperbola shape. This is a straightforward analytic solution that does not require any iterations. The representation of the Convex Hyperbolas Charts will indicate the best pump combination during the operation of a pumping station. Therefore, this is a straightforward resource for practitioners: the curves immediately tell engineers the number of pumps that should be turned on, depending on the desired volume of water to pump. The elaboration of such charts only requires the use of any calculation sheet, only once, and it is a permanent resource that can be used at any time during the operation. In addition, the Convex Hyperbolas Charts are completely compatible and complementary with any other operation control technique.

scholarly journals Rough diamonds in emerging markets: legacy, competitiveness, and sustained high performance

2019 ◽  
Vol 26 (3) ◽  
pp. 363-386
Author(s):  
Seung Ho Park ◽  
Gerardo R. Ungson
Keyword(s):  
Human Capital ◽  
Emerging Markets ◽  
High Performance ◽  
Core Competencies ◽  
Market Potential ◽  
Government Support ◽  
Screening Tests ◽  
Institutional Voids ◽  
Content Type ◽  
Over Time

Purpose The purpose of this paper is to uncover the underlying drivers of sustained high performing companies based on a field study of 127 companies in Brazilian, Russian, Indian and Chinese (BRIC) and Association of Southeast Asian Nations (ASEAN) emerging markets. Understanding these companies provides a complementary way of appraising the growth, development and transformation of emerging markets. The authors synthesize the findings in an overarching framework that covers six strategies for building and sustaining legacy that leads to the succession of intergenerational wealth over time: overcoming institutional voids, inclusive markets, deepening localization, nurturing government support, building core competencies and harnessing human capital. The authors relate these strategies to different levels of development using Prahalad and Hart’s BOP framework. Design/methodology/approach This study examines the underlying drivers of sustained high-performance companies based on field studies from an initial set of 105,260 BRIC companies and close to 500 companies in ASEAN. The methods employed four screening tests to arrive at a selection of the highest-performing firms: 70 firms in the BRIC nations and 58 firms from ASEAN. Following the selection, the authors constructed cases using primary interviews and secondary data, with the assistance of Ernst & Young and with academic colleagues in Manila. These studies were originally conducted in two separate time periods and reported accordingly. This paper synthesizes the findings of these two studies to arrive at an extended integrative framework. Findings From the cases, the authors examine six strategies for building and sustaining legacy that lead to high performance over time: overcoming institutional voids, creating inclusive markets, deepening localization, nurturing government support, building core competencies and harnessing human capital. To address the evolving state of institutional voids in these countries, the authors employ similar methods to hypothesize the placement of these strategies in the context of the world economic pyramid, initially formulated as the “bottom of the pyramid” framework. Originality/value This paper synthesizes and extends the authors’ previous works by proposing the concept of legacy to describe the emergence and succession of local exemplary firms in emerging markets. This study aims to complement extant measures of nation-growth based primarily on GDP. The paper also extends the literature on institutional voids in shifting the focus from the mix of voids to their evolving state. Altogether, the paper provides a complementary narrative on assessing the market potential of emerging markets by adopting several categories of performance.

scholarly journals In VitroActivities of Daptomycin-, Vancomycin-, and Teicoplanin-Loaded Polymethylmethacrylate against Methicillin-Susceptible, Methicillin-Resistant, and Vancomycin-Intermediate Strains of Staphylococcus aureus

2011 ◽  
Vol 55 (12) ◽  
pp. 5480-5484 ◽  
Author(s):  
Yuhan Chang ◽  
Wen-Chien Chen ◽  
Pang-Hsin Hsieh ◽  
Dave W. Chen ◽  
Mel S. Lee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
High Performance ◽  
Low Dose ◽  
Antibacterial Activities ◽  
High Dose ◽  
Bone Cements ◽  
Antibacterial Effects ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTThe objective of this study was to evaluate the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with daptomycin, vancomycin, and teicoplanin against methicillin-susceptibleStaphylococcus aureus(MSSA), methicillin-resistantStaphylococcus aureus(MRSA), and vancomycin-intermediateStaphylococcus aureus(VISA) strains. Standardized cement specimens made from 40 g PMMA loaded with 1 g (low-dose), 4 g (middle-dose) or 8 g (high-dose) antibiotics were tested for elution characteristics and antibacterial activities. The patterns of release of antibiotics from the cement specimens were evaluated usingin vitrobroth elution assay with high-performance liquid chromatography. The activities of broth elution fluid against differentStaphylococcus aureusstrains (MSSA, MRSA, and VISA) were then determined. The antibacterial activities of all the tested antibiotics were maintained after being mixed with PMMA. The cements loaded with higher dosages of antibiotics showed longer elution periods. Regardless of the antibiotic loading dose, the teicoplanin-loaded cements showed better elution efficacy and provided longer inhibitory periods against MSSA, MRSA, and VISA than cements loaded with the same dose of vancomycin or daptomycin. Regarding the choice of antibiotics for cement loading in the treatment ofStaphylococcus aureusinfection, teicoplanin was superior in terms of antibacterial effects.

scholarly journals Overproduction of Ristomycin A by Activation of a Silent Gene Cluster in Amycolatopsis japonicum MG417-CF17

2014 ◽  
Vol 58 (10) ◽  
pp. 6185-6196 ◽  
Author(s):  
Marius Spohn ◽  
Norbert Kirchner ◽  
Andreas Kulik ◽  
Angelika Jochim ◽  
Felix Wolf ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gene Cluster ◽  
High Performance ◽  
Pathogenic Bacteria ◽  
Genome Mining ◽  
Gene Clusters ◽  
Von Willebrand Disease ◽  
Biosynthesis Gene Cluster ◽  
Content Type ◽  
Bioinformatic Tools

ABSTRACTThe emergence of antibiotic-resistant pathogenic bacteria within the last decades is one reason for the urgent need for new antibacterial agents. A strategy to discover new anti-infective compounds is the evaluation of the genetic capacity of secondary metabolite producers and the activation of cryptic gene clusters (genome mining). One genus known for its potential to synthesize medically important products isAmycolatopsis. However,Amycolatopsis japonicumdoes not produce an antibiotic under standard laboratory conditions. In contrast to mostAmycolatopsisstrains,A. japonicumis genetically tractable with different methods. In order to activate a possible silent glycopeptide cluster, we introduced a gene encoding the transcriptional activator of balhimycin biosynthesis, thebbrgene fromAmycolatopsis balhimycina(bbrAba), intoA. japonicum. This resulted in the production of an antibiotically active compound. Following whole-genome sequencing ofA. japonicum, 29 cryptic gene clusters were identified by genome mining. One of these gene clusters is a putative glycopeptide biosynthesis gene cluster. Using bioinformatic tools, ristomycin (syn. ristocetin), a type III glycopeptide, which has antibacterial activity and which is used for the diagnosis of von Willebrand disease and Bernard-Soulier syndrome, was deduced as a possible product of the gene cluster. Chemical analyses by high-performance liquid chromatography and mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS), and nuclear magnetic resonance (NMR) spectroscopy confirmed thein silicoprediction that the recombinantA. japonicum/pRM4-bbrAbasynthesizes ristomycin A.

Why are companies still struggling to reach higher continuous improvement maturity levels? Empirical evidence from high performance companies

2015 ◽  
Vol 27 (3) ◽  
pp. 316-327 ◽  
Author(s):  
Daniel Jurburg ◽  
Elisabeth Viles ◽  
Carmen Jaca ◽  
Martin Tanco
Keyword(s):  
Continuous Improvement ◽  
Measurement System ◽  
High Performance ◽  
Basque Country ◽  
Holistic Approach ◽  
Special Focus ◽  
Structured Interviews ◽  
Northern Spain ◽  
Content Type ◽  
High Performing

Purpose – Continuous improvement (CI) is regarded as a powerful approach to achieve business excellence. However, the implementation is not simple as it involves managing a considerable amount of tangible and intangible factors throughout the whole organization. The purpose of this paper is to fill the gap by presenting first-hand information about how companies really implement and organize their CI processes. Design/methodology/approach – The study was based on semi-structured interviews in ten high performing companies in the Basque Country, a region in northern Spain well known for its business quality. The objective was to analyze the state of their CI processes, putting special focus on how the organizational structure integrates with the CI processes and what are the characteristics of the corresponding measurement system. Findings – The study shows a lack of company-wide focus on CI, little written evidence of previous improvement activities, unclear improvement process owner, and poor use of adequate measurement systems to monitor CI. Practical implications – Managers should understand that is not enough to guarantee their own commitment and provide the structure, since in order to become learning organization, a different holistic approach towards the CI process must be adopted. Originality/value – While most previous work on this field have focused primarily on how to implement different techniques in order to achieve better productive performance, this study presents empirical research from a more holistic approach, assessing the characteristics affecting CI by considering strategy, structure, and the measurement system.

Transformational leadership and employee creativity

2015 ◽  
Vol 53 (5) ◽  
pp. 894-910 ◽  
Author(s):  
Swati Mittal ◽  
Rajib Lochan Dhar
Keyword(s):  
Transformational Leadership ◽  
Knowledge Sharing ◽  
Leadership Style ◽  
High Performance ◽  
Hierarchical Regression ◽  
Medium Size ◽  
Employee Creativity ◽  
Content Type ◽  
Managerial Implications ◽  
Transformational Leadership Style

Purpose – Among the different styles of leadership, transformational leadership has gained most attention from organisational researchers and academics. Although transformational leadership and its work-associated outcomes have been examined in previous literature, only a small number of studies highlighted the role of transformational leadership style in fostering employee creativity, mediated through their creative self-efficacy (CSE) in the context of Indian organisations. The purpose of this paper is to observe the effect of transformational leadership on employee creativity in small and medium sized IT companies, where CSE is proposed as a mediator and knowledge sharing as a moderator through which a transformational leader tends to influence the creativity of the employees. Design/methodology/approach – Data were gathered from 348 manager-employee dyads of small and medium size IT companies operating in India. They replied to questions about their leader’s transformational leadership style, employee CSE, knowledge sharing and creativity. Findings – Findings of the present study, derived from a hierarchical regression analysis, using the data of 348 manager-employee dyads from Indian IT SMEs professionals, revealed that CSE mediates the relation between transformational leadership and employee creativity. In addition, knowledge sharing acts as a moderator for CSE and employee creativity. Research limitations/implications – A sample size is one probable limitation of the study. Another limitation of the study is that factors used for the survey were self-reported by the respondents. Self-reporting may not always produce reliable and accurate response. Practical implications – Based on the results, this study presents strong theoretical and managerial implications that can be used by IT organisations to evaluate the consequence of transformational leadership on employee creativity. Through transformational leadership style, leader can develop CSE and employee creativity to do things in a better way and develop knowledge sharing in employees for high performance. Therefore, the IT industry need to understand that creativity is one of the approaches to attaining and sustaining competitive advantage. In addition, it is important for them to find out more about the relation between transformational leadership, CSE and employee creativity. Originality/value – The study adds to the existing literature by illuminating the process through which transformational leadership has a significant effect on fostering CSE and employee creativity.

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