Control Configuration Research Articles

Model-predictive kinetic control with data-driven models on EAST

Abstract In this work, model-predictive control (MPC) was combined for the first time with singular perturbation theory, and an original plasma kinetic control method based on extremely simple data-driven models and a two-time-scale MPC algorithm has been developed. A comprehensive review is presented in this paper. Slow and fast semi-empirical models are identified from data, by considering the fast kinetic plasma dynamics as a singular perturbation of a quasi-static equilibrium, which itself is governed, on the slow time scale, by the flux diffusion equation. This control technique takes advantage of the large ratio between the time scales involved in magnetic and kinetic plasma transport. It is applied here to the simultaneous control of the safety factor profile, q(x), and of several kinetic variables, such as the poloidal beta parameter, βp, and the internal inductance parameter, li, on the EAST tokamak. In the experiments, the available control actuators were lower hybrid current drive (LHCD) and co-current neutral beam injection (NBI) from different sources. Ion cyclotron resonant heating (ICRH) and electron cyclotron resonant heating (ECRH) are used as additional actuators in control simulations. In the controller design, an observer provides, in real time, an estimate of the system states and of the mismatch between measured and predicted outputs, which ensures robustness to model errors and offset-free control. A number of control applications are described in the paper, either in nonlinear simulations with EAST-like parameters or in real experiments on EAST. Various controller configurations were tested, with up to three controlled variables chosen among q0 = q(x=0), q1 = q(x=0.5), βp and li. Both the extensive nonlinear simulations and the experiments described in this paper have demonstrated the relevance of combining model-predictive control, data-driven models and singular perturbation methods for plasma kinetic control.

Dynamically customizable 4D printed shape memory polymer biomedical devices: a review

Abstract There is an increased risk of complications and even surgical failures for various types of medical devices due to difficult to control configurations and performances, incomplete deployments, etc. Shape memory polymers (SMPs)-based 4D printing technology offers the opportunity to create dynamic, personalized, and accurately controllable biomedical devices with complex configurations. SMPs, typical representatives of intelligent materials, are capable of programmable deformation in response to stimuli and dynamic remodeling on demand. 4D printed SMP medical devices not only enable active control of configuration, performance and functionality, but also open the way for minimally invasive treatments and remote controllable deployment. Here, the shape memory mechanism, actuation methods, and printing strategies of active programmable SMPs are reviewed, and cutting-edge advances of 4D printed SMPs in the fields such as bone scaffolds, tracheal stents, cardiovascular stents, cell morphological regulation, and drug delivery are highlighted. In addition, promising and meaningful future research directions for 4D printed SMP biomedical devices are discussed. The development of 4D printed SMP medical devices is inseparable from the in-depth cooperation between doctors and engineers. The application of 4D printed SMP medical devices will facilitate the rapid realization of "smart medical care" and accelerate the process of "intelligentization" of medical devices.

Plasma photonic crystal ‘kaleidoscope’ with flexible control of topology and electromagnetism

Continuous development of photonic crystals (PCs) over the last 30 years has carved out many new scientific frontiers. However, creating tunable PCs that enable flexible control of geometric configurations remains a challenge. Here we present a scheme to produce a tunable plasma photonic crystal (PPC) ‘kaleidoscope’ with rich diversity of structural configurations in dielectric barrier discharge. Multi-freedom control of the PPCs, including the symmetry, dielectric constant, crystal orientation, lattice constant, topological state, and structures of scattering elements, has been realized. Four types of lattice reconfigurations are demonstrated, including transitions from periodic to periodic, disordered to ordered, non-topological to topological, and striped to honeycomb Moiré lattices. Furthermore, alterations in photonic band structures corresponding to the reconstruction of various PPCs have been investigated. Our system presents a promising platform for generating a PPC ‘kaleidoscope’, offering benefits such as reduced equipment requirements, low cost, rapid response, and enhanced flexibility. This development opens up new opportunities for both fundamental and applied research.Graphical

Nonlinear Model Predictive Control of Heaving Wave Energy Converter with Nonlinear Froude–Krylov Forces

Wave energy holds significant promise as a renewable energy source due to the consistent and predictable nature of ocean waves. However, optimizing wave energy devices is essential for achieving competitive viability in the energy market. This paper presents the application of a nonlinear model predictive controller (MPC) to enhance the energy extraction of a heaving point absorber. The wave energy converter (WEC) model accounts for the nonlinear dynamics and static Froude–Krylov forces, which are essential in accurately representing the system’s behavior. The nonlinear MPC is tested under irregular wave conditions within the power production region, where constraints on displacement and the power take-off (PTO) force are enforced to ensure the WEC’s safety while maximizing energy absorption. A comparison is made with a linear MPC, which uses a linear approximation of the Froude–Krylov forces. The study comprehensively compares power performance and computational costs between the linear and nonlinear MPC approaches. Both MPC variants determine the optimal PTO force to maximize energy absorption, utilizing (1) a linear WEC model (LMPC) for state predictions and (2) a nonlinear model (NLMPC) incorporating exact Froude–Krylov forces. Additionally, the study analyzes four controller configurations, varying the MPC prediction horizon and re-optimization time. The results indicate that, in general, the NLMPC achieves higher energy absorption than the LMPC. The nonlinear model also better adheres to system constraints, with the linear model showing some displacement violations. This paper further discusses the computational load and power generation implications of adjusting the prediction horizon and re-optimization time parameters in the NLMPC.

New Safety Feedback Control Design to Guarantee Adequate Frequency Performance in Microgrids

ABSTRACTSafety analysis of power systems is concerned with the system's ability to maintain critical variables within specified limits following a disturbance. Frequency control adequacy has become increasingly important as the system inertia decreases due to the increase in renewable energy penetration. Various controllers for inverters have been proposed to improve the system frequency response and few are capable to ensure the safety of the response. In this article, a diesel‐wind energy system is considered and modeled as a switching system between normal, faulted, and post‐fault modes. A safety feedback controller is designed as a supplementary signal for a wind turbine generator such that the speed of the diesel generator stays within a permissible range in the presence of a finite energy disturbance. Numerical results on the modified 33‐bus microgrid system obtained of the proposed novel approach indicate that the suggested control configuration can guarantee adequate frequency response without excessive conservativeness.

Design of sawtooth-shaped acoustic metasurface for sound field manipulation

Currently, the goal of research on acoustic metasurfaces is mainly focused on achieving ultimate sound wave control, which often requires complex structural design. However, complex structures are often difficult for manufacturing and large-scale applications. To this end, our study proposes a sawtooth-shaped metasurface with a simple configuration, easy fabrication and good wave control capability. First, we use "apparent wavefront theory" and "lattice diffraction theory" to predict the main reflected angles of sawtooth metasurfaces. Then, numerical simulations were performed to validate the theories used and to analyze the conditions of their applicability. Finally, several sawtooth metasurfaces were designed to realize different functions such as large-angle reflection, acoustic focusing and uniform diffusion, which can also be verified experimentally. In general terms, the sawtooth-shaped metasurface has broad prospects in the field of acoustics.

Z/E configuration controlled by a Taxus sesquiterpene synthase facilitating the biosynthesis of (3Z,6E)-α-farnesene

Plant enzymes often present advantages in the synthesis of natural products with specific configurations. Farnesene is a pharmacologically active sesquiterpene with three natural Z/E configurations, among which the enzyme selectively responsible for the biosynthesis of (3Z,6E)-α-farnesene remains elusive. Herein, a sesquiterpene synthase TwSTPS1 biosynthesizing (3Z,6E)-α-farnesene as the major product was identified from Taxus wallichiana through genome mining. Utilizing molecular dynamics simulations and mutation analysis, the catalytic mechanism of TwSTPS1, especially Z/E configuration control, was explored. Moreover, the crucial residues associated with the specific catalytic activity of TwSTPS1 was elucidated through mutagenesis experiments. The findings contribute to our understanding of the Z/E configuration control by plant terpene synthases and also provide an alternative tool for manipulating (3Z,6E)-α-farnesene production using synthetic biology.

Development and validation of intelligent load control for VRF air-conditioning system with deep learning based load forecasting

Variable refrigerant flow (VRF) air-conditioning systems have seen significant growth in Asia and its application is expanding globally. Despite the expanded application, most previous studies have focused on developing fault detection and diagnostics to achieve energy-efficient operations than on predicting power consumption. It's very difficult to predict the electrical consumption owing to its complex system configuration and various control strategies. A new control strategy is described for optimal adjustment of the desired target level based on time series forecasting using the optimized sequence to sequence model for VRF systems. Sequence to sequence (seq2seq) model with attention mechanism and Bayesian optimization is developed to predict accurate hourly and daily forecasts and rapid feedback control for fluctuating power consumption for VRF systems. The optimized seq2seq model is integrated into the intelligent load control (ILC). ILC can be used to manage VRF systems by dynamically prioritizing indoor units for curtailment using both quantitative inputs and qualitative rules. Overall, the results demonstrate that the deep learning based control allows coordination of the controllable loads of VRF systems in three commercial buildings. ILC with deep learning manages the power consumption within a desired target level, as well as indoor temperature reflecting the status of controlled indoor units, as objective functions of the control algorithm.

Optimizing the Landing Stability of Blended-Wing-Body Aircraft with Distributed Electric Boundary-Layer Ingestion Propulsors through a Novel Thrust Control Configuration

The imperative for energy conservation and environmental protection has led to the development of innovative aircraft designs. This study explored a novel thrust control configuration for blended-wing-body (BWB) aircraft with distributed electric boundary-layer ingestion (BLI) propulsors, addressing the issues of sagging and altitude loss during landing. The research focused on a small-scale BWB demonstrator equipped with six BLI fans, each with a 90 mm diameter. Various thrust control configurations were evaluated to achieve significant thrust reduction while maintaining lift, including dual-layer sleeve, separate flap-type, single-stage linkage flap-type, and dual-stage linkage flap-type configurations. The separate flap-type configuration was tested through ground experiments. Control experiments were conducted under three different experimental conditions as follows: deflection of the upper cascades only, deflection of the lower cascades only, and symmetrical deflection of both cascades. For each condition, the deflection angles tested were 0°, 10°, 20°, 30°, 40°, 50°, and 60°. The thrust reductions observed for these three conditions were 0%, 37.5%, and 27.5% of the maximum thrust, respectively, without additional changes in the pitch moment. A combined thrust adjustment method maintaining a zero pitch moment demonstrated a linear thrust reduction to 20% of its initial value. The experiment concluded that the novel thrust control configuration effectively adjusted thrust without altering the BLI fans’ rotation speed, solving the coupled lift–thrust problem and enhancing BWB landing stability.

Protección sísmica de estructuras civiles mediante dispositivo INERTER en la provincia de Huancayo

This research work proposes the use of a Tuned-Mass-Damper-Inerter (TMDI), which combines a new configuration of passive vibration control using an “Inerter”. This two-terminal mechanical flywheel device, based on the well-known Tuned-Mass-Damper (TMD), generates resistance forces proportional to the relative acceleration of its terminals. TMDI takes advantage of the “mass amplification effect” of Inerter to improve performance compared to TMD. For harmonically excited primary linear systems, closed-form analytical software is modeled to obtain optimal design and tuning parameters of the TMDI, using established methods. It is observed that, with proper distribution of the dampers, the TMDI system is more effective in suppressing vibrations close to the natural frequency of the uncontrolled primary system and is more resistant to the effects of detuning and misdistribution. Furthermore, the results of the modeled structures show the effectiveness of the TMDI, modeled as a classical damper, in suppressing the fundamental mode of vibration for linear MDOF structures. The incorporation of the Inerter in the proposed TMDI configuration can replace part of the vibrating mass, achieving lightweight passive vibration control solutions or improving structural performance. The solution proposed and modeled with traditional dampers behaves linearly, in line with current performance trends for minimally damaged structures protected by passive control devices. Additionally, optimized TMDI is applied for vibration suppression and displacement control, offering optimal seismic protection.

Investigating water quality dynamics in distribution networks with dynamically adaptive connectivity

ABSTRACT Water distribution networks with dynamically adaptive connectivity offer greater operational flexibility. While this strategy has demonstrated improvements in pressure management and network resiliency, further research is needed to better understand its impact on water quality dynamics. This paper investigates the short-term variability of disinfectant residuals in a real-world distribution network operated with dynamic connectivity. We simulate water quality dynamics under two control configurations with pressure control and automatic flushing valve operations. Our simulation results inform the development of flow variability metrics to reveal the relationship between changing hydraulic conditions and increased water quality dynamics. These metrics can (i) improve observability by supporting the placement of additional water quality monitoring locations and (ii) enhance controllability by enabling the formulation of optimization problems that incorporate hydraulic surrogates for modelling water quality. Furthermore, we validate the identified regions of increased water quality dynamics using continuous disinfectant data from a large-scale experimental programme. Our findings emphasize the need for further analytical and experimental research to manage water quality in distribution networks with dynamically adaptive connectivity and hydraulic control.

Recent progress of JT-60SA project toward plasma operation

Abstract Superconducting tokamak JT-60SA plays an essential role in fusion research and development by supporting and complementing ITER project, providing directions to the DEMO design activity and fostering next generation scientists and engineers. Since the incident of the Equilibrium Field coil #1 during the Integrated Commissioning (IC) in March 2021, both EU and JA Implementing agencies (IAs) have examined how to ensure safety operation of JT-60SA by mitigating the risk of possible discharge occurrence inside the cryostat. Based on the experience of the Global Paschen tests, the IAs have established a strategy of risk mitigation measures, which is a combination of (i) reinforcement of insulation, (ii) avoiding unnecessary voltage application to the coil systems and (iii) immediate de-energization of the coils when deteriorated vacuum condition is detected. Thanks to the considerable efforts of the Integrated Project Team (IPT) members, the IC restarted in May 2023. After the confirmation of superconducting state of coil systems (TF, EF and CS), the coil energization test and the plasma operation (OP-1) starts. The first plasma was successfully achieved on 23 October 2023 with a limited value of applied voltage and current to the coils. The plasma configuration control will be also confirmed with low plasma current and low auxiliary heating power conditions. Based on the IO-F4E-QST collaboration, activities of JT-60SA have been shared with the IO and provided an important lesson learned for ITER assembly and commissioning, and will provide an outstanding contribution to fusion research at large. After OP-1, Maintenance & Enhancement phase 1 (M/E-1) starts from January 2024, in which in-vessel components are installed, and heating system and diagnostic system are extensively upgraded to allow high power heating experiment planned in OP-2. In order to make the best use of JT-60SA, newly organized JT-60SA experiment team will refine the research plan in the future high heating power operation phase.

A 10 kV/400 V SiC Based DC-DC Converter With Input-Series-Output-Parallel Configuration and Three-Loop Control

A 10 kV/400 V SiC Based DC-DC Converter With Input-Series-Output-Parallel Configuration and Three-Loop Control

Synthesis of model heterojunction interfaces reveals molecular-configuration-dependent photoinduced charge transfer

Control of the molecular configuration at the interface of an organic heterojunction is key to the development of efficient optoelectronic devices. Due to the difficulty in characterizing these buried and (probably) disordered heterointerfaces, the interfacial structure in most systems remains a mystery. Here we demonstrate a synthetic strategy to design and control model interfaces, enabling their detailed study in isolation from the bulk material. This is achieved by the synthesis of a polymer in which a non-fullerene acceptor moiety is covalently bonded to a donor polymer backbone using dual alkyl chain links, constraining the acceptor and donor units in a through space co-facial arrangement. The constrained geometry of the acceptor relative to the electron-rich and -poor moieties in the polymer backbone can be tuned to control the kinetics of charge separation and the energy of the resultant charge-transfer state giving insight into factors that govern charge generation at organic heterojunctions.

Supervisory Control for Dynamic Feature Configuration in Product Lines

In this paper a framework for engineering supervisory controllers for product lines with dynamic feature configuration is proposed. The variability in valid configurations is described by a feature model. Behavior of system components is achieved using (extended) finite automata and both behavioral and dynamic configuration constraints are expressed by means of requirements as is common in supervisory control theory. Supervisory controller synthesis is applied to compute a behavioral model in which the requirements are adhered to. For the challenges that arise in this setting, multiple solutions are discussed. The solutions are exemplified in the CIF toolset using a model of a coffee machine. A use case of the much larger Body Comfort System product line is performed to showcase feasibility for industrial-sized systems.

Heterogeneous Electrochemical Carbon Dioxide Reduction in Aqueous Medium Using a Novel N4-Macrocyclic Cobalt Complex.

Molecular catalysts represent an exceptional class of materials in the realm of electrochemical carbon dioxide reduction (CO2RR), offering distinct advantages owing to their adaptable structure, which enables precise control of electronic configurations and outstanding performance in CO2RR. This study introduces an innovative approach to heterogeneous electrochemical CO2RR in an aqueous environment, utilizing a newly synthesized N4-macrocyclic cobalt complex generated through a dimerization coupling reaction. By incorporating the quaterpyridine moiety, this cobalt complex exhibits the capability to catalyze CO2RR at low overpotentials and reaches near-unity CO production across a wide potential range, as verified by the online mass spectrometry and in situ attenuated total reflectance-Fourier transform infrared spectroscopy. Comprehensive computational models demonstrate the superiority of utilizing quarterpyridine moiety in mediating CO2 conversion compared to the counterpart. This work not only propels the field of electrochemical CO2RR but also underscores the promising potential of cobalt complexes featuring quaterpyridine moieties in advancing sustainable CO2 conversion technologies within aqueous environments.

Attitude collaborative control strategy for space gravitational wave detection

This paper proposes a high-precision attitude cooperative control strategy for three spacecraft in space gravitational wave detection. Firstly, based on the layout of optical components on the spacecraft and factors such as external interference and model uncertainty, a relative attitude model based on the Euler angle is constructed for the characteristics of small angle motion in differential wavefront sensing mode. Secondly, aiming at the cooperative control problem of multi drag-free attitude control system after the laser link capture between two spacecraft is completed, an attitude control method based on consensus mode cooperative control strategy is proposed. It combines local neighbourhood error from star sensing and differential wavefront sensing with an adaptive controller for equilateral triangle configuration control. Additionally, a cooperative control strategy based on laser measurement information is established to improve control accuracy by avoiding star sensors with low accuracy. Simulation results indicate that the control accuracy of the consistency mode and its sub-mode laser measurement mode is superior to the master-slave and cyclic modes, achieving better than 5×10−6 rad. The laser measurement mode demonstrates the highest accuracy, with relative attitude control accuracy reaching 1.5×10−7 rad, meeting the requirements for space gravitational wave detection.

Reverse-Selective Anion Separation Relies on Charged "Hourglass" Gate.

According to the hydration size and charge property of separated ions, the transport channel can be constructed to achieve precision ion separation, but the ion geometry as a separation parameter to design the channel structure is rarely reported. Herein, a reverse-selective anion separation membrane composed of a metal-organic frameworks (MOFs) layer with a charged "hourglass" channel as an ion-selective switch to manipulate oxoanion transport is developed. The gate in "hourglass" with tetrahedral geometry similar to the oxoanion (such as SO2- 4, Cr 2O2- 7, and MnO- 4) boosts the transmission effect oxoanion much larger than Cl- through geometric matching and Coulomb interaction. Specific channel structure exhibits an abnormal selectivity for SO2- 4/Cl- of 20, Cr 2O2- 7/Cl- of 6.6, and MnO- 4/Cl- of 4.0 in a binary-ion system. The transfer behavior of SO2- 4 in the channel revealed by molecular dynamics simulation and density functional theory calculation further indicates the mechanism of the abnormal separation performance. The universality of the membrane structure is validated by the formation of different nitrogen-containing modified layers, which also achieves in situ growth of the MOFs layer, and exhibits similar reversal separation performance. The geometric configuration control of ion transport channels presents a novel effective strategy to realize the precise separation of target ions.

High-performance, miniaturized and configurable power and control unit for electrospray thrusters

High-performance, miniaturized and configurable power and control unit for electrospray thrusters

Anti-Disturbance Bumpless Transfer Control for a Switched Systems via a Switched Equivalent-Input-Disturbance Approach

This paper concentrates on the issue of anti-disturbance bumpless transfer (ADBT) control design for switched systems. The ADBT control design problem refers to designing a continuous controller and a switching rule to ensure the switched system satisfies the ADBT property. First, the concept of the ADBT property is introduced. Then, via a switched equivalent-input-disturbance (EID) methodology, a switched EID estimator is formulated to estimate the impact of external disturbances within the switched system. Second, a bumpless transfer control is then constructed via a compensator integrating an EID estimation. Finally, the effectiveness of the presented control scheme is verified by controlling a switching resistor–inductor–capacitor circuit on the Matlab platform. Above all, a new configuration for ADBT control of switched systems is established via a switched EID methodology.