Controller Tuning Research Articles

Towards efficient control synthesis for nonlinear wave energy conversion systems: impedance-matching meets the spectral-domain

Existing studies within the literature that focus on designing parametric energy-maximizing controllers for Wave Energy Converter (WEC) systems predominantly rely on the impedance-matching (IM) principle, originally developed for linear time-invariant systems. Alternatively, iterative optimization routines are commonly employed for nonlinear WECs. However, these approaches often face a trade-off between effectiveness in maximizing energy extraction and computational efficiency. To address this limitation, this study proposes a computationally efficient controller tuning method for analogous synthesis in the case of nonlinear WECs. The proposed approach combines a statistical linearization technique known as spectral-domain modeling with the IM principle, to synthesize a Proportional–Integrative (PI) controller for a nonlinear WEC. Furthermore, a comparison is performed with two other synthesis methods: one based on a standard (i.e. linear) frequency-domain representation of the WEC that incorporates the IM principle, and the other employing a gradient-free optimization routine applied to the nonlinear time-domain model of the WEC for PI parameter tuning through exhaustive numerical search. A discussion on the effectiveness of each tuning method in maximizing energy absorption is provided, including an appraisal of their associated computational time requirements. Numerical analyses demonstrate that the proposed method, which integrates spectral-domain modeling and IM, can achieve (almost) optimal PI controller design for a nonlinear WEC. Furthermore, this study addresses the inaccuracies inherent in the frequency-domain approach and significantly reduces the computational time compared to the exhaustive search procedure. The findings of this research represent a significant advancement towards the development of simple, effective, and efficient IM-based techniques for synthesis of controllers in nonlinear WEC systems

Fe-Doped CoNi layered hydrogencarbonate hierarchical Nano-Array assisted growth of ZIF-67 as an efficient OER/UOR bifunctional catalyst reaction for Overall Urea-Water electrolysis

The design of efficient electrocatalysts for OER and UOR is essential for achieving sustainable hydrogen production and enabling simultaneous wastewater treatment. Here, a versatile fabrication method for the in-situ growth of ZIF-67 from hydrocarbonate as a template for three-dimensional hierarchical nano-arrays. This strategy provides an opportunity for controllably tuning the interfacial assembly of MOFs materials on precursor template nanomaterials. The obtained MIM@Fe0.1-CoNi CH/NF exhibited enhanced electrocatalytic performance as an electrocatalytic anode for the OER and UOR. The MIM@Fe0.1-CoNi CH/NF required only 194 mV and 285 mV overpotentials to achieve the current densities of 10 and 100 mA·cm−2 in the electrolyte of 1.0 M KOH, and the overpotentials in the 1.0 M KOH + 0.5 M Urea electrolyte requires only 1.31 V (vs.RHE) to achieve a current density of 10 mA·cm−2. Notably, (+)MIM@Fe0.1-CoNi CH/NF || Pt/C/NF(−) achieves 10 mA·cm−2 in urea-assisted electrolysis at only 1.36 V (vs.RHE). The excellent catalytic performance was attributed to the modification of the CoNi CH/NF template by Fe3+ and 2-MIM, which modulated the Ni2+ and Co2+ electronic structures and optimised the adsorption behaviour of the OER/UOR intermediates. Overall, this work provides a strategy for preparing desirable catalysts for clean energy and wastewater treatment.

Synthesis of NaYbF4:Er nanocrystals with controllable size, morphology, and multicolor upconversion luminescence for Anticounterfeiting applications

The dopant concentration of lanthanide ions plays one of the critical roles to manipulate size/morphology, photon population pathway, or luminescence color/intensity in upconversion nanoparticles (UCNCs), which have a significant effect on their application developments. Herein, a strategy is demonstrated for simultaneous size, morphology and multicolor luminescence tuning in the single doped lanthanide activator Er3+ ion system through simply tuning the concentration of Er3+ ions. The doping of different Er3+ ion amounts in NaYbF4:Er nanocrystals can control nanoparticle size (from several hundreds to tens of nanometers) and morphology. Moreover, multicolor upconversion luminescence involving green, yellow, orange and red can be obtained in the NaYbF4:Er UCNCs by changing the excitation power density of 980 nm laser. Mechanistic studies reveal the size and morphology evolution process as well as saturation/cross relaxation effects induced tunable multicolor emissions. These nanocrystals have demonstrated promising potential applications in anticounterfeiting. Our results not only provide a simple and feasible route for simultaneous size/morphology control and multicolor upconversion luminescence tuning, but also can further expand the utility of UCNCs in the frontier applications ranging from optical encoding to information security.

Model-free control of a magnetically supported plate

Established model-based methods often use a combination of state feedback and observer to control complex systems. They rely on detailed mathematical models that are often hard to derive. Nonetheless, such methods may achieve a high level of accuracy, which justifies the cumbersome modelling. An alternative approach is model-free control, in a form introduced by Fliess and Join, where the system is approximated in a short time interval by a low-order differential equation with unknown parts, a so-called ultra-local model. This control method is a powerful tool, but the parametrisation and the concrete implementation may require time, effort, and experience. The present paper investigates the systematic tuning of a model-free controller for a magnetically supported plate that is modelled as an unstable multiple-input multiple-output system. Furthermore, the incorporation of model information into the model-free controller is investigated. These adaptations ultimately improve results by simplifying parameter tuning and interpretation of estimates. Several experiments are carried out on a test bed to show the capabilities of the proposed algorithms for set point stabilisation and trajectory tracking. The effects of the different parameters in the model-free controllers are addressed, and excellent robustness with respect to actuator faults is demonstrated. Filters for estimating derivatives and unknown quantities are designed using an open-source toolbox.

Power management and optimized control of hybrid PV-BESS-grid integrated fast EV charging stations

The rapid growth of on-road electric vehicles (EVs) empowered the increasing demand for charging stations, hindering widespread EV adoption due to factors like limited range and insufficient charging infrastructure. To address these concerns, the implementation of DC fast charging stations (FCSs) has emerged as a solution to reduce charging time and promote industry adoption. However, the integration of such FCSs poses challenges in terms of power management, power quality and charging service stability, especially in weak grid infrastructures. This paper proposes a power management strategy for a DC-FCS located near highways, aiming to provide stable, fast, and reliable charging services to EVs while minimizing grid dependency. The proposed strategy incorporates various energy sources and operation modes to ensure charging service stability. Additionally, an optimized tuning control based on an improved Snake optimization (ISO) algorithm is introduced to enhance the performance of the grid-connected voltage source inverters (VSIs) in the DC-FCS. The optimized tuning method using the proposed algorithm shows superior performance compared to other methods. Simulation and experimental tests validate the effectiveness of the proposed system, showcasing its potential for efficient management, stable charging service, and improved power quality in the DC-FCS.

Frequency Control of Interconnected Power System via SBO assisted Simultaneous Tuning Strategy in Presence of DFIG

To achieve the objectives of the automatic generation control (AGC) of wind integrated interconnected power system (WIIPS), better tuning and control strategies are required. This paper suggests simultaneous tuning strategy for the AGC and wind system controllers to improve the stability of the WIIPS. The bulk amount of wind is integrated into the grid using the doubly fed induction generator (DFIG) and its simplified model is used to simulate the WIIPS. Initially, classical controllers are opted in AGC mechanism to reduce the frequency disturbances caused by the load and wind generation uncertainties. Further, classical controllers of WIIPS are replaced with cascade controllers to enhance the system frequency profile during the disturbances. The optimal set of solutions of the classical and cascade controllers are examined by the satin bowerbird optimizer (SBO) with the help of integral square error as fitness function of the optimization problem. Comparisons are provided to show the merits of the WIIPS over normal interconnected power system, cascade controller over classical controller and simultaneous tuning strategy over regular tuning mechanism.

PID controller tuning based on PSO and dominant pole placement

This paper proposed a new approach for proportional integral derivative (PID) controller tuning. particle swarm optimization (PSO) algorithm and dominant pole placement were used for PID controller tuning. Minimizing the estimation criterion with integral of absolute error (IAE) and overshoot by PSO algorithm, we determined the dominant pole and crossover frequency satisfying the maximum sensitivity and phase margin. This dominant pole and crossover frequency were used in order to design the PID controller. It satisfied robust stability and improves the control effect of the system to balance the trade-off between overshoot and settling time. We simulated this approach for SOPDT model. A simulation results were given to demonstrate the effectiveness of this approach.

Double-Loop-Optimization-Based Joint Parameter Tuning for Dynamic Matrix Control With Validation in Intelligent Cigarette Drying Process

Double-Loop-Optimization-Based Joint Parameter Tuning for Dynamic Matrix Control With Validation in Intelligent Cigarette Drying Process

A decentralized control strategy for improved batch tablet coating process operation

This paper proposes a control strategy for batch tablet film-coating processes using readily available process instrumentation. Outlet air conditions (temperature and relative humidity), which impact coating quality, are controlled by the manipulation of inlet air temperature and coating spray rate. Controller design, tuning and validation rely on the use of a dynamic process simulator, calibrated using data collected from a pilot plant coating unit. The final 2 × 2 decentralized PI controller demonstrated good performance for both setpoint tracking and disturbance rejection in simulation. Additionally, controlled variable setpoints were determined to maximize plant profits considering batch duration and energy consumption as optimization criteria. For the case study considered, the total batch processing time can potentially be reduced by 40 % while simultaneously reducing energy usage by 30 %, in comparison with the more conservative fixed recipe approach typically adopted in production.

Controllable and reversible electric field tuning of photoluminescence response in lanthanide ions doped ferroelectric films

The rare-earth doped ferroelectric photoluminescence (PL) phosphors are attracting considerable interest because of their flexible structure, wide band gap and high-quality fluorescence signal emission. Although the change of PL performance in different samples have been solved to a certain extent, how to achieve the tuning of PL intensity in one sample sensitively and reversibly is still an issue. In this work, we present an "electric-elastic-optical" coupled structure of 0.94Bi0.5Na0.5TiO3–0.06BaTiO3:1 mol%Eu3+ (BNTBT:Eu)/ 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 (PMN-PT) heterostructures, which transfers strain from the PMN-PT to the BNTBT:Eu film via the converse piezoelectric effect and dynamically modulates the PL response of the epitaxial thin film. Our findings demonstrate that the PL response of the thin film can be effectively and linearly tuned under the influence of an external electric field. The relative change in the PL intensity (ΔI/I) of the BNTBT:Eu film was found to be linearly correlated with the lateral strain of the substrate. We also propose a novel design strategy for detecting strain, with significant implications for using BNTBT:Eu/PMN-PT heterostructures as sensors for integrating piezophotonic devices. This work provides valuable insights into the feasibility of electric field tuning of PL performance, which could inspire future research endeavors in the fields of nanophotonics, optical storage technology and photovoltaics.

CONTROL DE MICRO MECANIZADO NO CONVENCIONAL BASADO EN ANÁLISIS DE PARÁMETROS MULTIVARIABLES UTILIZANDO UN SISTEMA DE INFERENCIA DIFUSA

Non-conventional manufacturing processes, such as pulsed electrochemical machining, are strategies for manufacturing metal components that optimize tool life. This is achieved by implementing non-traditional techniques based on electrolysis to remove metal in a controlled environment without generating contact between the tool and the workpiece. These characteristics allow a reduction in the resources required for the development of components with complex morphology on high-strength materials in many application fields, such as aerospace, medical, and precision tools. However, the characteristic features of non-linearity in this kind of process increase the complexity of the development of automatic control through traditional algebraic techniques in the regulation of uniform material wear. In this context, a non-traditional solution based on techniques derived from artificial intelligence bounded by fuzzy logic and genetic algorithms is presented for the tuning and automatic control of the pulsed electrochemical machining process. Furthermore, the efficiency is evaluated by analyzing the over-cutting phenomenon and the precision in developing linear polygonal machining on a micrometer scale. Keywords: Modern manufacturing, fuzzy logic, automatic control, electrolysis, genetic algorithms.

Highly stable Brillouin laser with controllable tuning based on fiber ring resonator

The design and fabrication processes of the stimulated Brillouin laser (SBL) are complex, and it is affected by many factors such as temperature and resonance shift. In this study, we have fabricated a Brillouin laser using a fiber ring resonator with Q factor = 7.1 × 108 and resonance depth (h) = 96%. The free spectral range automatic feedback control technology is proposed to realize the accurate matching of the resonant mode and the Stokes mode. The influence of temperature on the SBL frequency shift is suppressed. The fluctuation range of SBL’s frequency decreases by 5 times. The maximum steady state output of the SBL at the best matching position is realized, and the output power fluctuation range decreases by 15 times. The power stability of the SBL reaches 4.85 × 10−6, which is improved by two orders of magnitude. This simple scheme provides convenience for the application of the SBL, such as sensing and other applications.

Design and Implementation of PID Controller for the Cooling Tower's pH Regulation Based on Particle Swarm Optimization PSO Algorithm

The PH regulation of cooling tower plant in southern fertilizers company (SCF) in Iraq is important for industry pipes protection and process continuity. According to the Mitsubishi standard, the PH of cooling water must be around (7.1 to 7.8). The deviation in PH parameter affects the pipes, such as corrosion and scale. Acidic water causes pipes to corrode, and alkaline water causes pipes to scale. The sulfuric acid solution is used for PH neutralization. The problem is that the sulfuric acid is pumped manually in the cooling tower plant every two or three hours for PH regulation. The manual operation of the sulfuric acid pump makes deviations in the PH parameter. It is very difficult to control the PH manually. To solve this problem, a PID controller for PH regulation was used. The reason for using the PID controller is that the PH response is irregular through the neutralization process. The methodology is to calculate the transfer function of the PH loop using the system identification toolbox of MATLAB, to design and implement a PID controller, to optimize the PID controller response using particle swarm optimization PSO algorithm, and to make a comparison among several tuning methods such as Ziegler Nichols (ZN) tuning method, MATLAB tuner method, and PSO algorithm tuning method. The results showed that the PSO-based PID controller tuning gives a better overshoot, less rise time, and an endurable settling time than the other tuning methods. Hence, the PH response became according to the target range. The experimental results showed that the PH regulation improved using the PSO-based PID controller tuning.

Pump-power-controlled L-band wavelength-tunable mode-locked fiber laser utilizing nonlinear polarization evolution in all-polarization-maintaining fibers

We present for the first time, to the best of our knowledge, the pump-power-controlled, all-polarization-maintaining (all-PM), all-fiber configured, wavelength-tunable mode-locked fiber laser in the L-band (1565 to 1625 nm). A tuning range over 20 nm (1568.2 to 1588.9 nm) is attained simply by varying the pump power between 45 and 115 mW. Our work represents the first demonstration of wavelength tuning in all-PM configured nonlinear polarization evolution (NPE) lasers. The non-mechanical and electrically controllable tuning method offers ease of use and cost efficiency within an advanced all-PM, all-fiber design, indicating promising adaptability to diverse wavelength bands.

Synthesis of Tetrasubstituted Alkenes by Rhodium-Catalyzed Regioselective Cyano Transfer.

We describe herein a novel, general, and robust approach to structurally diversified alkenyl nitriles through a Rh-catalyzed cyano transfer reaction between alkynyl-malononitrile derivatives and aryl/alkenyl boronic acids. This reaction exhibits high chemo- and regioselectivity and a broad substrate scope. The tetrasubstituted alkenyl dinitriles (34 examples, average 58% yield) are obtained through substrate tuning and ligand control.

Generation of Multiwavelength Fibre Laser based on Erbium-Doped Fibre Amplifier with Lyot Filter

A ring cavity setup consisting of erbium-doped fibre amplifier (EDFA) as the optical pump and lyot filter aids in the production of a multiwavelength spectrum. The wavelength of EDFA pumps in photons range of 1530 nm to 1560 nm, respectively. Using maximum power of 18 dBm and a single mode fibre (SMF) of 10 km length, the number of peak lasing lines produced between 3 dB spectral range is 51. Tuning of the polarization controller (PC) to a specific angle helps provide the most stable lasing line. Stability test is done on the output multiwavelength fibre laser (MWFL) over a time period to analyze the wavelength stability.

Frequency Control of Interconnected Power System via SBO assisted Simultaneous Tuning Strategy in Presence of DFIG

To achieve the objectives of the automatic generation control (AGC) of wind integrated interconnected power system (WIIPS), better tuning and control strategies are required. This paper suggests simultaneous tuning strategy for the AGC and wind system controllers to improve the stability of the WIIPS. The bulk amount of wind is integrated into the grid using the doubly fed induction generator (DFIG) and its simplified model is used to simulate the WIIPS. Initially, classical controllers are opted in AGC mechanism to reduce the frequency disturbances caused by the load and wind generation uncertainties. Further, classical controllers of WIIPS are replaced with cascade controllers to enhance the system frequency profile during the disturbances. The optimal set of solutions of the classical and cascade controllers are examined by the satin bowerbird optimizer (SBO) with the help of integral square error as fitness function of the optimization problem. Comparisons are provided to show the merits of the WIIPS over normal interconnected power system, cascade controller over classical controller and simultaneous tuning strategy over regular tuning mechanism.

Tunable acoustic transmission control and dual-mode ventilated sound insulation by a coupled acoustic metasurface

Tunable acoustic transmission control and dual-mode ventilated sound insulation by a coupled acoustic metasurface

Tunable polarization control with self-assembled arrays of anisotropic plasmonic coaxial nanocavities

Polarization control with nanostructures having a tunable design and allowing inexpensive large-scale fabrication is important for many nanophotonic applications. For this purpose, we developed and experimentally demonstrated nanostructured plasmonic surfaces based on hexagonal arrays of anisotropic coaxial nanocavities, which can be fabricated by a low-cost self-assembled nanosphere lithography method. Their high polarization sensitivity is achieved by engineering anisotropy of the coaxial nanocavities, while the optical response is enhanced by the excitation of surface plasmon resonances. Particularly, varying the geometrical parameters of the coaxial nanocavities, namely the height and tilt angle of their central core nanoellipsoids, the plasmonic resonance wavelengths as well as the polarization-selective behavior can be individually tuned in the entire visible and near-infrared spectral regions, which makes such nanostructures good candidates for the implementation of polarization-controlled optical switches and polarization-tunable filters. Moreover, the developed nanostructures demonstrate sensitivity up to 1335 nm/RIU in refractive index sensing.

Fractional High-Order Differential Feedback Controller Based on Meta-Heuristic Algorithms for Automatic Voltage Regulator

In this study, optimally parameter tuning of fractional high-order differential feedback controller (FHODFC) for an automatic voltage regulator (AVR) system regulating the terminal voltage of the synchronous generator is presented. Recently developed meta-heuristic optimization techniques named honey badger algorithm (HBA) and gorilla troops optimizer (GTO) have been employed for the first time in order to optimally determine ten different parameters of the FHODFC. The performance of the proposed controllers, that is, HBA-FHODFC and GTO-FHODFC, is analyzed in terms of transient and steady state responses, and robustness against uncertainties and external disturbances. In addition, their performance is compared to a FHODFC of which parameters were tuned by using particle swarm optimization algorithm in a previous study. The results indicate that the proposed HBA-FHODFC and GTO-FHODFC controllers provide zero overshoot and better results in terms of settling time and objective function then the PSO tuned FHODFC. Therefore, the proposed controllers can be used as an effective method in the AVR system.