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Dr. Argyrios Zolotas
Cranfield University

Basic Info


Research Keywords & Expertise

0 Control Engineering
0 Railway Systems
0 Robust Control
0 fault diagnosis and fault-tolerant control
0 autonomous systems

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Short Biography

A versatile, analytical and dynamic professional with 20 years R&D experience in the university sector. Having strong quantitative background and expertise in engineering and technology (and practical engineering applications that are dynamically complex, typified by the kinds of systems in the Rail, Aerospace, process and energy industry), and a highly regarded international academic profile in Systems and Control Engineering. Project lead (and co-Lead) on research projects funded by the public sector and by industry. Fellow of the (UK) Higher Education Academy and Senior Member of the IEEE. Awarded a Visiting Professorship with Grenoble INP (hosted by GIPSA lab) in 2018. Recipient (together with co-authors) of IMECHE’s Railway Division John Jarrett Davis Prize 2015 for the research paper “Passive suspensions for ride quality improvement of two-axle railway vehicles”. Recipient (together with co-authors) of ICSAE 2016’s Best Paper Award –in topic Control Systems Engineering- for paper title “Improved PID control for Tilting Trains”. Dr Zolotas has been Associate Editor on the IEEE Transactions Control Systems Technology (for 6 years, 2012-2018) and on IET Proceedings Control Theory and Applications (for 5 years, 2013-2018), his current main Associate Editor role is with the IEEE CSS Letters (since 2017).

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Project

Project Goal: Aerial inspection / NDT

Starting Date:01 October 2019

Current Stage: IUK-Canada collaborative project

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Project

Project Goal: Future technology

Starting Date:26 September 2019

Current Stage: DSTL funded project

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Journal article
Published: 11 June 2021 in IEEE Access
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This paper presents a unique security approach for detecting cyber-attacks against embedded systems (ESs). The proposed approach has been shaped within an architectural framework called anomalous resource consumption detection (ARCD). The approach’s detection mechanism detects cyber-attacks by distinguishing anomalous performance and resource consumption patterns from a pre-determinable reference model. The defense mechanism of this approach acts as an additional layer of protection for ESs. This technique’s effectiveness was previously evaluated statistically, and in this paper, we tested this approach’s efficiency computationally by using the support-vector machine algorithm. The datasets were generated and collected based on a testbed model, where it was run repeatedly under different operation conditions (normal cases (Rs) versus attacked cases). The executed attack scenarios are (1) denial-of-service (DoS), (2) brute force (BF), (3) remote code execution (RCE), and man-in-the-middle (MITM). A septenary tuple model, which consists of seven determinants that are analyzed based on seven statistical criteria, is the core of the detection mechanism. The prediction accuracy in terms of classifying anomalous patterns compared to normal patterns based on the confusion matrix revealed promising results, proving this approach’s effectiveness, where the final results confirmed very high prediction accuracies in terms of distinguishing anomalous patterns from the typical patterns. Therefore, integrating the ARCD concept into the operating system’s instructions will help software developers to augment the security countermeasures of the ESs. Adopting the ARCD approach will pave the way for software engineers to build secure operating systems in line with the embedded system’s capabilities, without depleting its resources.

ACS Style

Abdulmohsan Aloseel; Saba Al-Rubaye; Argyrios Zolotas; Carl Shaw. Attack-Detection Architectural Framework Based on Anomalous Patterns of System Performance and Resource Utilization—Part II. IEEE Access 2021, 9, 87611 -87629.

AMA Style

Abdulmohsan Aloseel, Saba Al-Rubaye, Argyrios Zolotas, Carl Shaw. Attack-Detection Architectural Framework Based on Anomalous Patterns of System Performance and Resource Utilization—Part II. IEEE Access. 2021; 9 (99):87611-87629.

Chicago/Turabian Style

Abdulmohsan Aloseel; Saba Al-Rubaye; Argyrios Zolotas; Carl Shaw. 2021. "Attack-Detection Architectural Framework Based on Anomalous Patterns of System Performance and Resource Utilization—Part II." IEEE Access 9, no. 99: 87611-87629.

Journal article
Published: 11 June 2021 in IEEE Access
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This paper presents a novel security approach called Anomalous Resource Consumption Detection (ARCD), which acts as an additional layer of protection to detect cyberattacks in embedded systems (ESs). The ARCD approach is based on the differentiation between the predefined standard resource consumption pattern and the anomalous consumption pattern of system resource utilization. The effectiveness of the proposed approach is tested in a rigorous manner by simulating four types of cyberattacks: a denial-of-service attack, a brute-force attack, a remote code execution attack, and a man-in-the-middle attack, which are executed on a Smart PiCar (used as the testbed). A septenary tuple model consisting of seven parameters, representing the embedded system’s architecture, has been created as the core of the detection mechanism. The approach’s efficiency and effectiveness has been validated in terms of range and pattern by analyzing the collected data statistically in terms of mean, median, mode, standard deviation, range, minimum, and maximum values. The results demonstrated the potential for defining a standard pattern of resource utilization and performance of the embedded system due to a significant similarity of the parameters’ values at normal states. In contrast, the attacked cases showed a definite, observable, and detectable impact on resource consumption and performance of the embedded system, causing an anomalous pattern. Thus, by merging these two findings, the ARCD approach has been developed. ARCD facilitates building secure operating systems in line with the ES’s capabilities. Furthermore, the ARCD approach can work along with existing countermeasures to augment the security of the operating system layer.

ACS Style

Abdulmohsan Aloseel; Saba Al-Rubaye; Argyrios Zolotas; Hongmei He; Carl Shaw. A Novel Approach for Detecting Cyberattacks in Embedded Systems Based on Anomalous Patterns of Resource Utilization-Part I. IEEE Access 2021, 9, 103204 -103229.

AMA Style

Abdulmohsan Aloseel, Saba Al-Rubaye, Argyrios Zolotas, Hongmei He, Carl Shaw. A Novel Approach for Detecting Cyberattacks in Embedded Systems Based on Anomalous Patterns of Resource Utilization-Part I. IEEE Access. 2021; 9 (99):103204-103229.

Chicago/Turabian Style

Abdulmohsan Aloseel; Saba Al-Rubaye; Argyrios Zolotas; Hongmei He; Carl Shaw. 2021. "A Novel Approach for Detecting Cyberattacks in Embedded Systems Based on Anomalous Patterns of Resource Utilization-Part I." IEEE Access 9, no. 99: 103204-103229.

Conference paper
Published: 12 April 2021 in Thermosense: Thermal Infrared Applications XLIII
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Diagnosis and prognosis of failures for aircrafts’ integrity are some of the most important regular functionalities in complex and safety-critical aircraft structures. Further, development of failure diagnostic tools such as Non-Destructive Testing (NDT) techniques, in particular, for aircraft composite materials, has been seen as a subject of intensive research over the last decades. The need for diagnostic and prognostic tools for composite materials in aircraft applications rises and draws increasing attention. Yet, there is still an ongoing need for developing new failure diagnostic tools to respond to the rapid industrial development and complex machine design. Such tools will ease the early detection and isolation of developing defects and the prediction of damages propagation; thus allowing for early implementation of preventive maintenance and serve as a countermeasure to the potential of catastrophic failure. This paper provides a brief literature review of recent research on failure diagnosis of composite materials with an emphasis on the use of active thermography techniques in the aerospace industry. Furthermore, as the use of unmanned aerial vehicles (UAVs) for the remote inspection of large and/or difficult access areas has significantly grown in the last few years thanks to their flexibility of flight and to the possibility to carry one or several measuring sensors, the aim to use a UAV active thermography system for the inspection of large composite aeronautical structures in a continuous dynamic mode is proposed.

ACS Style

Muflih Alhammad; Nicolas P. Avdelidis; Shakeb Deane; Clemente Ibarra-Castanedo; Shashank Pant; Parham Nooralishahi; Mohammad Ahmadi; Marc Genest; Argyrios Zolotas; Luca Zanotti-Fragonara; Julio Valdes; X. P. V. Maldague. Diagnosis of composite materials in aircraft applications: towards a UAV active thermography inspection approach. Thermosense: Thermal Infrared Applications XLIII 2021, 11743, 1174306 .

AMA Style

Muflih Alhammad, Nicolas P. Avdelidis, Shakeb Deane, Clemente Ibarra-Castanedo, Shashank Pant, Parham Nooralishahi, Mohammad Ahmadi, Marc Genest, Argyrios Zolotas, Luca Zanotti-Fragonara, Julio Valdes, X. P. V. Maldague. Diagnosis of composite materials in aircraft applications: towards a UAV active thermography inspection approach. Thermosense: Thermal Infrared Applications XLIII. 2021; 11743 ():1174306.

Chicago/Turabian Style

Muflih Alhammad; Nicolas P. Avdelidis; Shakeb Deane; Clemente Ibarra-Castanedo; Shashank Pant; Parham Nooralishahi; Mohammad Ahmadi; Marc Genest; Argyrios Zolotas; Luca Zanotti-Fragonara; Julio Valdes; X. P. V. Maldague. 2021. "Diagnosis of composite materials in aircraft applications: towards a UAV active thermography inspection approach." Thermosense: Thermal Infrared Applications XLIII 11743, no. : 1174306.

Journal article
Published: 08 March 2021 in ISA Transactions
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The paper presents the first classical internal model control (IMC) design in the context of railway carbody roll control. We propose a simple control approach for a recent hydraulically actuated vehicle body roll concept that offers limited carbody roll. The IMC approach addresses both preview- and nulling-type tilt setups, highlighting related benefits and limitations. The design provides a model simplification process that facilitates PI and PID-type control structures without the need for complex optimization. A simple, yet practical, tool for the industrial rail rolling stock engineer in vehicle control design is offered. Vehicle roll performance is rigorously studied on the deterministic (curving acceleration response) and stochastic (ride quality) trade off. Simulations are performed on an in-house multibody dynamics software package employing a realistic nonlinear railway vehicle model and allow to appropriately assess the performance of preview and nulling type tilt performance. The results obtained confirm that preview tilt control offers the better tilt performance as it utilizes a tilt command reference, and highlighted that nulling-type tilt performance remains at a relatively comparable level with the former.

ACS Style

Egidio Di Gialleonardo; Matteo Santelia; Stefano Bruni; Argyrios Zolotas. A simple active carbody roll scheme for hydraulically actuated railway vehicles using internal model control. ISA Transactions 2021, 1 .

AMA Style

Egidio Di Gialleonardo, Matteo Santelia, Stefano Bruni, Argyrios Zolotas. A simple active carbody roll scheme for hydraulically actuated railway vehicles using internal model control. ISA Transactions. 2021; ():1.

Chicago/Turabian Style

Egidio Di Gialleonardo; Matteo Santelia; Stefano Bruni; Argyrios Zolotas. 2021. "A simple active carbody roll scheme for hydraulically actuated railway vehicles using internal model control." ISA Transactions , no. : 1.

Journal article
Published: 25 February 2021 in Sensors
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Unmanned Aerial Vehicles (UAVs) that can fly around an aircraft carrying several sensors, e.g., thermal and optical cameras, to inspect the parts of interest without removing them can have significant impact in reducing inspection time and cost. One of the main challenges in the UAV based active InfraRed Thermography (IRT) inspection is the UAV’s unexpected motions. Since active thermography is mainly concerned with the analysis of thermal sequences, unexpected motions can disturb the thermal profiling and cause data misinterpretation especially for providing an automated process pipeline of such inspections. Additionally, in the scenarios where post-analysis is intended to be applied by an inspector, the UAV’s unexpected motions can increase the risk of human error, data misinterpretation, and incorrect characterization of possible defects. Therefore, post-processing is required to minimize/eliminate such undesired motions using digital video stabilization techniques. There are number of video stabilization algorithms that are readily available; however, selecting the best suited one is also challenging. Therefore, this paper evaluates video stabilization algorithms to minimize/mitigate undesired UAV motion and proposes a simple method to find the best suited stabilization algorithm as a fundamental first step towards a fully operational UAV-IRT inspection system.

ACS Style

Shashank Pant; Parham Nooralishahi; Nicolas Avdelidis; Clemente Ibarra-Castanedo; Marc Genest; Shakeb Deane; Julio Valdes; Argyrios Zolotas; Xavier Maldague. Evaluation and Selection of Video Stabilization Techniques for UAV-Based Active Infrared Thermography Application. Sensors 2021, 21, 1604 .

AMA Style

Shashank Pant, Parham Nooralishahi, Nicolas Avdelidis, Clemente Ibarra-Castanedo, Marc Genest, Shakeb Deane, Julio Valdes, Argyrios Zolotas, Xavier Maldague. Evaluation and Selection of Video Stabilization Techniques for UAV-Based Active Infrared Thermography Application. Sensors. 2021; 21 (5):1604.

Chicago/Turabian Style

Shashank Pant; Parham Nooralishahi; Nicolas Avdelidis; Clemente Ibarra-Castanedo; Marc Genest; Shakeb Deane; Julio Valdes; Argyrios Zolotas; Xavier Maldague. 2021. "Evaluation and Selection of Video Stabilization Techniques for UAV-Based Active Infrared Thermography Application." Sensors 21, no. 5: 1604.

Journal article
Published: 15 January 2021 in Electronics
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Increasing levels of autonomy impose more pronounced performance requirements for unmanned ground vehicles (UGV). Presence of model uncertainties significantly reduces a ground vehicle performance when the vehicle is traversing an unknown terrain or the vehicle inertial parameters vary due to a mission schedule or external disturbances. A comprehensive mathematical model of a skid steering tracked vehicle is presented in this paper and used to design a control law. Analysis of the controller under model uncertainties in inertial parameters and in the vehicle-terrain interaction revealed undesirable behavior, such as controller divergence and offset from the desired trajectory. A compound identification scheme utilizing an exponential forgetting recursive least square, generalized Newton–Raphson (NR), and Unscented Kalman Filter methods is proposed to estimate the model parameters, such as the vehicle mass and inertia, as well as parameters of the vehicle-terrain interaction, such as slip, resistance coefficients, cohesion, and shear deformation modulus on-line. The proposed identification scheme facilitates adaptive capability for the control system, improves tracking performance and contributes to an adaptive path and trajectory planning framework, which is essential for future autonomous ground vehicle missions.

ACS Style

Natalia Strawa; Dmitry I. Ignatyev; Argyrios C. Zolotas; Antonios Tsourdos. On-Line Learning and Updating Unmanned Tracked Vehicle Dynamics. Electronics 2021, 10, 187 .

AMA Style

Natalia Strawa, Dmitry I. Ignatyev, Argyrios C. Zolotas, Antonios Tsourdos. On-Line Learning and Updating Unmanned Tracked Vehicle Dynamics. Electronics. 2021; 10 (2):187.

Chicago/Turabian Style

Natalia Strawa; Dmitry I. Ignatyev; Argyrios C. Zolotas; Antonios Tsourdos. 2021. "On-Line Learning and Updating Unmanned Tracked Vehicle Dynamics." Electronics 10, no. 2: 187.

Journal article
Published: 01 October 2020 in Bulletin of Electrical Engineering and Informatics
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The industrial norm of tilting high speed trains, nowadays, is that of Precedence tilt (also known as Preview tilt). Precedence tilt, although succesfull as a concept, tends to be complex (mainly due to the signal interconnections between vehicles and the advanced signal processing required for monitoring). Research studies of early prior to that of precedence tilt schemes, i.e. the so-called Nulling-type schemes, utilized local-per-vehicle signals to provide tilt action (this was essentially a typical disturbance rejection-scheme) but suffered from inherent delays in the control). Nulling tilt may still be seen as an important research aim due to the simple nature and most importantly due to the more straightforward fault detection compared to precedence schemes. The work in this paper presents a substantial extension conventional to robust H∞ mixed sensitivity nulling tilt control in literature. A particular aspect is the use of optimization is used in the design of the robust controller accompanied by rigorous investigation of the conflicting deterministic/stochastic local tilt trade-off

ACS Style

Fazilah Hassan; Argyrios Zolotas; Shaharil Mohd Shah. H∞ mixed sensitivity optimization for high speed tilting trains. Bulletin of Electrical Engineering and Informatics 2020, 9, 1854 -1860.

AMA Style

Fazilah Hassan, Argyrios Zolotas, Shaharil Mohd Shah. H∞ mixed sensitivity optimization for high speed tilting trains. Bulletin of Electrical Engineering and Informatics. 2020; 9 (5):1854-1860.

Chicago/Turabian Style

Fazilah Hassan; Argyrios Zolotas; Shaharil Mohd Shah. 2020. "H∞ mixed sensitivity optimization for high speed tilting trains." Bulletin of Electrical Engineering and Informatics 9, no. 5: 1854-1860.

Journal article
Published: 11 May 2020 in Electronics
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Proposed is the facilitation of fault-tolerant capability in autonomous systems with particular consideration of low computational complexity and system interface devices (sensor/actuator) performance. Traditionally model-based fault-tolerant/detection units for multiple sensor faults in automation require a bank of estimators, normally Kalman-based ones. An AI-based control framework enabling low computational power fault tolerance is presented. Contrary to the bank-of-estimators approach, the proposed framework exhibits a single unit for multiple actuator/sensor fault detection. The efficacy of the proposed scheme is shown via rigorous analysis for several sensor fault scenarios for an electro-magnetic suspension testbed.

ACS Style

Kyriakos M. Deliparaschos; Konstantinos Michail; Argyrios C. Zolotas. Facilitating Autonomous Systems with AI-Based Fault Tolerance and Computational Resource Economy. Electronics 2020, 9, 788 .

AMA Style

Kyriakos M. Deliparaschos, Konstantinos Michail, Argyrios C. Zolotas. Facilitating Autonomous Systems with AI-Based Fault Tolerance and Computational Resource Economy. Electronics. 2020; 9 (5):788.

Chicago/Turabian Style

Kyriakos M. Deliparaschos; Konstantinos Michail; Argyrios C. Zolotas. 2020. "Facilitating Autonomous Systems with AI-Based Fault Tolerance and Computational Resource Economy." Electronics 9, no. 5: 788.

Journal article
Published: 15 January 2020 in IEEE Transactions on Services Computing
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ACS Style

Evagoras Makridis; Kyriakos Deliparaschos; Evangelia Kalyvianaki; Argyrios Zolotas; Themistoklis Charalambous. Robust Dynamic CPU Resource Provisioning in Virtualized Servers. IEEE Transactions on Services Computing 2020, 1 -1.

AMA Style

Evagoras Makridis, Kyriakos Deliparaschos, Evangelia Kalyvianaki, Argyrios Zolotas, Themistoklis Charalambous. Robust Dynamic CPU Resource Provisioning in Virtualized Servers. IEEE Transactions on Services Computing. 2020; ():1-1.

Chicago/Turabian Style

Evagoras Makridis; Kyriakos Deliparaschos; Evangelia Kalyvianaki; Argyrios Zolotas; Themistoklis Charalambous. 2020. "Robust Dynamic CPU Resource Provisioning in Virtualized Servers." IEEE Transactions on Services Computing , no. : 1-1.

Journal article
Published: 02 December 2019 in International Journal of Electrical Power & Energy Systems
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The paper considers the impact of Demand Side Response events on the supply power profile and energy efficiency of widely distributed aggregated loads applied across commercial refrigeration systems. Responses to secondary grid frequency static DSR events are investigated. Experimental trials are conducted on a system of refrigerators representing a small retail store, and subsequently on the refrigerators of an operational superstore in the UK. Energy consumption and energy savings during 3 h of operation pre- and post-secondary DSR, are discussed. In addition, a simultaneous secondary DSR event is realised across three operational retail stores located in different geographical regions of the UK. A Simulink model for a 3Φ power network is used to investigate the impact of a synchronised return to normal operation of the aggregated refrigeration systems post DSR on the local power network. Results show ∼1% drop in line voltage due to the synchronised return to operation. Analysis of energy consumption shows that DSR events can facilitate energy savings of between 3.8% and 9.3% compared to normal operation. This is a result of the refrigerators operating more efficiently during and shortly after the DSR. The use of aggregated refrigeration loads can contribute to the necessary load-shed by 97.3% at the beginning of DSR and 27% during the 30 minutes of a DSR, based on results from a simultaneous DSR event carried out on three retail stores.

ACS Style

Ibrahim M. Albayati; Andrey Postnikov; Simon Pearson; Ronald Bickerton; Argyrios Zolotas; Chris Bingham. Power and energy analysis for a commercial retail refrigeration system responding to a static demand side response. International Journal of Electrical Power & Energy Systems 2019, 117, 105645 .

AMA Style

Ibrahim M. Albayati, Andrey Postnikov, Simon Pearson, Ronald Bickerton, Argyrios Zolotas, Chris Bingham. Power and energy analysis for a commercial retail refrigeration system responding to a static demand side response. International Journal of Electrical Power & Energy Systems. 2019; 117 ():105645.

Chicago/Turabian Style

Ibrahim M. Albayati; Andrey Postnikov; Simon Pearson; Ronald Bickerton; Argyrios Zolotas; Chris Bingham. 2019. "Power and energy analysis for a commercial retail refrigeration system responding to a static demand side response." International Journal of Electrical Power & Energy Systems 117, no. : 105645.

Journal article
Published: 03 July 2019 in Cities
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The paper introduces a novel indicator of urban built form termed Form Signature. Generic models of four urban built forms are developed including pavilion, terrace, court and a newly introduced tunnel-court which are used to compare and contrast their land-use performance and density characteristics. Selecting plot ratio and site coverage as the most popular and appropriate density indicators, the simultaneous relationship to each of the considered urban built forms is shown graphically with the number of storeys, plan depth and cut-off angle as the main variables of interest. For existing urban areas, the resulting graphs provide a robust tool for statistical analysis of contexts such as climate, economy, energy and crime potential and establish their relationship to form and density. To show the value of the contribution, analysing 32 case studies from 19 cities in different global locations showed an insignificant relationship between climate and form/density of urban areas, while practically depicting that urban areas built in court form acquire higher cut-off angle compared to terrace form urban developments. For the planning of future urban areas, the resulting relationships provide an application-oriented urban planning tool to facilitate the most effective land-use method in order to achieve sustainable cities. Examples showing the potential of the tool for future statistical energy and social analysis of urban areas are provided. Finally, a relative comparison shows that the newly-introduced tunnel-court form achieves the greatest density while pavilion achieves the lowest.

ACS Style

Ehsan Ahmadian; Behzad Sodagar; Glen Mills; Hugh Byrd; Chris Bingham; Argyrios Zolotas. Sustainable cities: The relationships between urban built forms and density indicators. Cities 2019, 95, 102382 .

AMA Style

Ehsan Ahmadian, Behzad Sodagar, Glen Mills, Hugh Byrd, Chris Bingham, Argyrios Zolotas. Sustainable cities: The relationships between urban built forms and density indicators. Cities. 2019; 95 ():102382.

Chicago/Turabian Style

Ehsan Ahmadian; Behzad Sodagar; Glen Mills; Hugh Byrd; Chris Bingham; Argyrios Zolotas. 2019. "Sustainable cities: The relationships between urban built forms and density indicators." Cities 95, no. : 102382.

Journal article
Published: 01 June 2019 in Applied Energy
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Aggregated electrical loads from massive numbers of distributed retail refrigeration systems could have a significant role in frequency balancing services. To date, no study has realised effective engineering applications of static firm frequency response to these aggregated networks. Here, the authors present a novel and validated approach that enables large scale control of distributed retail refrigeration assets. The authors show a validated model that simulates the operation of retail refrigerators comprising centralised compressor packs feeding multiple in-store display cases. The model was used to determine an optimal control strategy that both minimised the engineering risk to the pack during shut down and potential impacts to food safety. The authors show that following a load shedding frequency response trigger the pack should be allowed to maintain operation but with increased suction pressure set-point. This reduces compressor load whilst enabling a continuous flow of refrigerant to food cases. In addition, the authors simulated an aggregated response of up to three hundred compressor packs (over 2 MW capacity), with refrigeration cases on hysteresis and modulation control. Hysteresis control, compared to modulation, led to undesired load oscillations when the system recovers after a frequency balancing event. Transient responses of the system during the event showed significant fluctuations of active power when compressor network responds to both primary and secondary parts of a frequency balancing event. Enabling frequency response within this system is demonstrated by linking the aggregated refrigeration loads with a simplified power grid model that simulates a power loss incident.

ACS Style

A. Postnikov; I.M. Albayati; S. Pearson; C. Bingham; R. Bickerton; A. Zolotas. Facilitating static firm frequency response with aggregated networks of commercial food refrigeration systems. Applied Energy 2019, 251, 113357 .

AMA Style

A. Postnikov, I.M. Albayati, S. Pearson, C. Bingham, R. Bickerton, A. Zolotas. Facilitating static firm frequency response with aggregated networks of commercial food refrigeration systems. Applied Energy. 2019; 251 ():113357.

Chicago/Turabian Style

A. Postnikov; I.M. Albayati; S. Pearson; C. Bingham; R. Bickerton; A. Zolotas. 2019. "Facilitating static firm frequency response with aggregated networks of commercial food refrigeration systems." Applied Energy 251, no. : 113357.

Journal article
Published: 01 February 2019 in Vehicle System Dynamics
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ACS Style

Xiang Zheng; Argyrios Zolotas; Roger Goodall. Combined active suspension and structural damping control for suppression of flexible bodied railway vehicle vibration. Vehicle System Dynamics 2019, 58, 198 -228.

AMA Style

Xiang Zheng, Argyrios Zolotas, Roger Goodall. Combined active suspension and structural damping control for suppression of flexible bodied railway vehicle vibration. Vehicle System Dynamics. 2019; 58 (2):198-228.

Chicago/Turabian Style

Xiang Zheng; Argyrios Zolotas; Roger Goodall. 2019. "Combined active suspension and structural damping control for suppression of flexible bodied railway vehicle vibration." Vehicle System Dynamics 58, no. 2: 198-228.

Journal article
Published: 01 August 2018 in Fractional Calculus and Applied Analysis
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We present PLC-based fractional-order controller design for an industrial-oriented water tank volume control application. The system comprises input delay which is a typified characteristic in such industrial process control applications. The particular contribution of this work is on discrete fractional-order PID implementation via PLC and its application to the aforementioned realistic water tank test bed. Stability and robustness properties of fractional-order discrete PID feedback-loops for different approximation methods and orders are also shown. Fractional-order controllers are obtained for a variety of stability margin choices, and benefits of the non-integer-order controllers compared to the integer-order PID control are illustrated via simulation and experimental runs on a realistic test-bed.

ACS Style

Arkadiusz Mystkowski; Argyrios Zolotas. PLC-based discrete fractional-order control design for an industrial-oriented water tank volume system with input delay. Fractional Calculus and Applied Analysis 2018, 21, 1005 -1026.

AMA Style

Arkadiusz Mystkowski, Argyrios Zolotas. PLC-based discrete fractional-order control design for an industrial-oriented water tank volume system with input delay. Fractional Calculus and Applied Analysis. 2018; 21 (4):1005-1026.

Chicago/Turabian Style

Arkadiusz Mystkowski; Argyrios Zolotas. 2018. "PLC-based discrete fractional-order control design for an industrial-oriented water tank volume system with input delay." Fractional Calculus and Applied Analysis 21, no. 4: 1005-1026.

Articles
Published: 15 February 2018 in Vehicle System Dynamics
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Active suspensions for railway vehicles have been a topic of research for a number of decades and while their applications in service operation are limited, it seems clear that they will in due course see widespread adoption. Railway suspension design is a problem of compromise on the non-trivial trade-off of ride quality versus track following (guidance), and the skyhook damping control approach has been paramount in illustrating the potential benefits. Since skyhook damping control, various advanced control studies appeared contributing to redefine the boundaries of the aforementioned trade-off. Yet there is no study on the impact of fractional order (FO) methods in the context of skyhook railway active suspensions and in particular related to skyhook damping control. This is the area to which this paper strongly contributes. We present findings from a current project on FO controllers for railway vehicles active suspensions, in particular work on the effect of FO methods in basic skyhook damping control schemes, i.e. pure and intuitively based skyhook. First, we present a brief review of conventional skyhook damping control and then proceed to a rigorous investigation of the impact of FO on the ride quality/track following trade-off. The relevant benefits from FO methods are appraised and new insights highlighted.

ACS Style

Argyrios C. Zolotas; Roger M. Goodall. New insights from fractional order skyhook damping control for railway vehicles. Vehicle System Dynamics 2018, 56, 1658 -1681.

AMA Style

Argyrios C. Zolotas, Roger M. Goodall. New insights from fractional order skyhook damping control for railway vehicles. Vehicle System Dynamics. 2018; 56 (11):1658-1681.

Chicago/Turabian Style

Argyrios C. Zolotas; Roger M. Goodall. 2018. "New insights from fractional order skyhook damping control for railway vehicles." Vehicle System Dynamics 56, no. 11: 1658-1681.

Journal article
Published: 05 February 2018 in Energies
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The UK National Grid has placed increased emphasis on the development of Demand Side Response (DSR) tariff mechanisms to manage load at peak times. Refrigeration systems, along with HVAC, are estimated to consume 14% of the UK’s electricity and could have a significant role for DSR application. However, characterized by relatively low individual electrical loads and massive asset numbers, multiple low power refrigerators need aggregation for inclusion in these tariffs. In this paper, the impact of the Demand Side Response (DSR) control mechanisms on food retailing refrigeration systems is investigated. The experiments are conducted in a test-rig built to resemble a typical small supermarket store. The paper demonstrates how the temperature and pressure profiles of the system, the active power and the drawn current of the compressors are affected following a rapid shut down and subsequent return to normal operation as a response to a DSR event. Moreover, risks and challenges associated with primary and secondary Firm Frequency Response (FFR) mechanisms, where the load is rapidly shed at high speed in response to changes in grid frequency, is considered. For instance, measurements are included that show a significant increase in peak inrush currents of approx. 30% when the system returns to normal operation at the end of a DSR event. Consideration of how high inrush currents after a DSR event can produce voltage fluctuations of the supply and we assess risks to the local power supply system.

ACS Style

Ibrahim M. Saleh; Andrey Postnikov; Corneliu Arsene; Argyrios C. Zolotas; Chris Bingham; Ronald Bickerton; Simon Pearson. Impact of Demand Side Response on a Commercial Retail Refrigeration System. Energies 2018, 11, 371 .

AMA Style

Ibrahim M. Saleh, Andrey Postnikov, Corneliu Arsene, Argyrios C. Zolotas, Chris Bingham, Ronald Bickerton, Simon Pearson. Impact of Demand Side Response on a Commercial Retail Refrigeration System. Energies. 2018; 11 (2):371.

Chicago/Turabian Style

Ibrahim M. Saleh; Andrey Postnikov; Corneliu Arsene; Argyrios C. Zolotas; Chris Bingham; Ronald Bickerton; Simon Pearson. 2018. "Impact of Demand Side Response on a Commercial Retail Refrigeration System." Energies 11, no. 2: 371.

Proceedings article
Published: 01 November 2017 in 2017 European Modelling Symposium (EMS)
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This paper presents preliminary work from a current study on large refrigeration pack network. In particular, the simulation model of a typical refrigeration system with a single pack of 6 compressor units operating as fixed volume displacement machines is presented, and the potential of delivering static FFR with a large population of such packs is studied. Tuning of the model is performed using experimental data collected at the Refrigeration Research Centre in Riseholme, Lincoln. The purpose of modelling is to monitor the essential dynamics of what resembles a typical supermarket convenience-type store and to measure the capacity of a massive refrigeration network to hold off a considerable amount of load in response to FFR DSR event. This study focuses on investigation of the aggregated response of 150 packs (approx. 1 MW capacity) with refrigeration cases on hysteresis and modulation control. The presented model captures interconnected dynamics (refrigerant flow in the system linked to temperature control and the system's refrigerant demand and to compressors' power consumption). Type of refrigerant used for simulation is R407F. Refrigerant properties such as specific enthalpy, pressure and temperature at different state points are computed on each time step of simulation with REFPROP.

ACS Style

Andrey Postnikov; Argyrios Zolotas; Chris Bingham; Ibrahim M. Saleh; Corneliu Arsene; Simon Pearson; Ronald Bickerton. Modelling of Thermostatically Controlled Loads to Analyse the Potential of Delivering FFR DSR with a Large Network of Compressor Packs. 2017 European Modelling Symposium (EMS) 2017, 163 -167.

AMA Style

Andrey Postnikov, Argyrios Zolotas, Chris Bingham, Ibrahim M. Saleh, Corneliu Arsene, Simon Pearson, Ronald Bickerton. Modelling of Thermostatically Controlled Loads to Analyse the Potential of Delivering FFR DSR with a Large Network of Compressor Packs. 2017 European Modelling Symposium (EMS). 2017; ():163-167.

Chicago/Turabian Style

Andrey Postnikov; Argyrios Zolotas; Chris Bingham; Ibrahim M. Saleh; Corneliu Arsene; Simon Pearson; Ronald Bickerton. 2017. "Modelling of Thermostatically Controlled Loads to Analyse the Potential of Delivering FFR DSR with a Large Network of Compressor Packs." 2017 European Modelling Symposium (EMS) , no. : 163-167.

Journal article
Published: 26 July 2017 in IEEE Transactions on Circuits and Systems I: Regular Papers
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The output voltage regulation problem of a PWM-based dc-dc buck converter under various sources of uncertainties and disturbances is investigated in this paper via an optimized active disturbance rejection control (ADRC) approach. Aiming to practical implementation, a new reduced-order generalized proportional integral (GPI) observer is first designed to estimate the lumped (possibly time-varying) disturbances within the dc-dc circuit. By integrating the disturbance estimation information raised by the reduced-order GPI observer into the output prediction, an optimized ADRC method is developed to achieve optimized tracking performance even in the presence of disturbances and uncertainties. It is shown that the proposed controller will guarantee the rigorous stability of the closed-loop system, for any bounded uncertainties of the circuit, by appropriately choosing the observer gains and the bandwidth factor. Experimental results illustrate that the proposed control solution is characterized by improved robustness performance against various disturbances and uncertainties compared with traditional ADRC and integral model predictive control (MPC) approaches.

ACS Style

Jun Yang; Hongyu Cui; Shihua Li; Argyrios Zolotas. Optimized Active Disturbance Rejection Control for DC-DC Buck Converters With Uncertainties Using a Reduced-Order GPI Observer. IEEE Transactions on Circuits and Systems I: Regular Papers 2017, 65, 832 -841.

AMA Style

Jun Yang, Hongyu Cui, Shihua Li, Argyrios Zolotas. Optimized Active Disturbance Rejection Control for DC-DC Buck Converters With Uncertainties Using a Reduced-Order GPI Observer. IEEE Transactions on Circuits and Systems I: Regular Papers. 2017; 65 (2):832-841.

Chicago/Turabian Style

Jun Yang; Hongyu Cui; Shihua Li; Argyrios Zolotas. 2017. "Optimized Active Disturbance Rejection Control for DC-DC Buck Converters With Uncertainties Using a Reduced-Order GPI Observer." IEEE Transactions on Circuits and Systems I: Regular Papers 65, no. 2: 832-841.