Stable System Research Articles

Endogenous Risk Exposure and Systemic Instability

Most research on systemic stability assumes an economy where banks are subject to exogenous shocks. However, in practice, banks choose their exposure to risk. I show that there exists a network risk-taking externality: the risk exposure choices made by connected banks are strategically complementary. Banks within financial networks, especially densely connected ones, become endogenously exposed to excessive risks. The theory offers several novel perspectives on policy debates. For instance, it suggests that limiting government bailouts to interbank exposures can effectively reduce endogenous systemic risk. This paper was accepted by Kay Giesecke, finance. Funding: This work was financially supported by the USC Dornsife Institute for New Economic Thinking Fellowship, the Marshall PhD Fellowship, and European Finance Association Doctoral Tutorial Best Paper Prize. Supplemental Material: The online appendix is available at https://doi.org/10.1287/mnsc.2022.01519 .

Takagi-Sugeno fuzzy gain controller for Vehicle-to-Grid (V2G) load frequency control

Load Frequency Control (LFC) has gained more importance with the introduction of deregulated Renewable Energy Sources (RES) connectivity with the grid. Electrical Vehicles (EVs) can feed electricity back into the grid in Vehicle-to-Grid (V2G) mode to maintain stability. However, the increasing number of EVs penetrating the grid causes frequency instability in the power system. If required, EVs may utilize bi-directional chargers to transfer power back to the grid in the V2G mode while they are charging or in a grid-connected state, restoring the frequency instability of the grid. The frequency restoration response time is important to reset the grid frequency fluctuations in the shortest time possible to avoid shutting down the power system. This paper presents a Takagi-Sugeno (T-S) fuzzy linear output controller for LFC in two-area systems with tie-line control. This work models EV batteries as a single lump of large-capacity battery energy storage systems. The EV's battery system provides ancillary power to the two-area power system to reset it to a steady state after a load disturbance. The T-S fuzzy controller's linear output dependency on its inputs enables it to respond efficiently to load variations in the nonlinear two-area power systems. The proposed controller parameters are evaluated from stability analyses and its robustness is tested with sensitivity analysis. It is compared with other fuzzy controllers, and it demonstrates a fast-settling time and reduced frequency deviation response.

FACTS: Present and Future

Flexible AC Transmission Systems (FACTS) are pivotal in modernizing power systems, enhancing their stability, controllability, and efficiency. Currently, FACTS devices such as Static VAR Compensators (SVCs), Static Synchronous Compensators (STATCOMs), and Unified Power Flow Controllers (UPFCs) are employed to manage power flow, mitigate system instabilities, and improve voltage regulation across transmission networks. These technologies address present challenges, including the integration of renewable energy sources, reduction of transmission losses, and enhancement of system reliability in the face of fluctuating power demands. However, the growing complexity of power grids, driven by the increasing penetration of intermittent renewable energy, electric vehicles, and distributed generation, necessitates advanced and scalable solutions. The future of FACTS lies in the development of more sophisticated, adaptive, and intelligent devices that leverage real-time data analytics, artificial intelligence, and machine learning to optimize power flow dynamically. Future advancements are expected to focus on enhancing the interoperability of FACTS with smart grid technologies, improving the resilience of power systems against cyber-physical threats, and facilitating the transition towards more decentralized and sustainable energy systems. Moreover, the integration of energy storage with FACTS devices could revolutionize their functionality, offering not only reactive power compensation but also energy balancing capabilities. This paper explores the current applications of FACTS and envisions their future role in addressing the evolving challenges of global power systems, emphasizing the importance of innovation and strategic investment in the ongoing transformation of electrical networks.

Application of SHAP and Multi-Agent Approach for Short-Term Forecast of Power Consumption of Gas Industry Enterprises

Currently, machine learning methods are widely applied in the power industry to solve various tasks, including short-term power consumption forecasting. However, the lack of interpretability of machine learning methods can lead to their incorrect use, potentially resulting in electrical system instability or equipment failures. This article addresses the task of short-term power consumption forecasting, one of the tasks of enhancing the energy efficiency of gas industry enterprises. In order to reduce the risks of making incorrect decisions based on the results of short-term power consumption forecasts made by machine learning methods, the SHapley Additive exPlanations method was proposed. Additionally, the application of a multi-agent approach for the decomposition of production processes using self-generation agents, energy storage agents, and consumption agents was demonstrated. It can enable the safe operation of critical infrastructure, for instance, adjusting the operation modes of self-generation units and energy-storage systems, optimizing the power consumption schedule, and reducing electricity and power costs. A comparative analysis of various algorithms for constructing decision tree ensembles was conducted to forecast power consumption by gas industry enterprises with different numbers of categorical features. The experiments demonstrated that using the developed method and production process factors reduced the MAE from 105.00 kWh (MAPE of 16.81%), obtained through expert forecasting, to 15.52 kWh (3.44%). Examples were provided of how the use of SHapley Additive exPlanation can increase the safety of the electrical system management of gas industry enterprises by improving experts’ confidence in the results of the information system.

Sustainable and Reusable Modified Membrane Based on Green Gold Nanoparticles for Efficient Methylene Blue Water Decontamination by a Photocatalytic Process.

Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and sustainable nanocomposite material based on green gold nanoparticles for MB water remediation was developed. Starting from the reducing and stabilizing properties of some compounds naturally present in Lambrusco winery waste (grape marc) extracts, green gold nanoparticles (GM-AuNPs) were synthesized and deposited on a supporting membrane to create an easy and stable system for water MB decontamination. GM-AuNPs, with a specific plasmonic band at 535 nm, and the modified membrane were first characterized by UV-vis spectroscopy, X-ray diffraction (XRD), and electron microscopy. Transmission electron microscopy analysis revealed the presence of two breeds of crystalline shapes, triangular platelets and round-shaped penta-twinned nanoparticles, respectively. The crystalline nature of GM-AuNPs was also confirmed from XRD analysis. The photocatalytic performance of the modified membrane was evaluated under natural sunlight radiation, obtaining a complete disappearance of MB (100%) in 116 min. The photocatalytic process was described from a pseudo-first-order kinetic with a rate constant (k) equal to 0.044 ± 0.010 min-1. The modified membrane demonstrated high stability since it was reused up to 20 cycles, without any treatment for 3 months, maintaining the same performance. The GM-AuNPs-based membrane was also tested with other water pollutants (methyl orange, 4-nitrophenol, and rhodamine B), revealing a high selectivity towards MB. Finally, the photocatalytic performance of GM-AuNPs-based membrane was also evaluated in real samples by using tap and pond water spiked with MB, obtaining a removal % of 99.6 ± 1.2% and 98.8 ± 1.9%, respectively.

Internal Electric Fields and Structural Instabilities in Insulating Transition Metal Compounds: Influence on Optical Properties

AbstractThis work reviews new ideas developed in the last two decades which play a key role for understanding the optical properties of insulating materials containing transition metal (TM) cations. Initially, this review deals with compounds involving d4 and d9 ions where the local structure of the involved MX6 complexes (M=dn cation, X=ligand) is never cubic but distorted, a fact widely ascribed to the Jahn‐Teller (JT) effect. Nevertheless, that assumption is often wrong as the JT coupling requires an orbitally degenerate ground state in the initial geometry a condition not fulfilled even if the lattice is tetragonal. For this reason, the equilibrium geometry of d4 and d9 complexes in low symmetry lattices, is influenced by two factors: (i) The effects, usually ignored, of the internal electric field, ER, due to the rest of lattice ions on the active electrons localized in the MX6 unit. (ii) The existence of structural instabilities driven by vibronic interactions that lead to negative force constants. As first examples of these ideas, we show that the equilibrium structure, electronic ground state of KZnF3:Cu2+, K2ZnF4:Cu2+ and K2CuF4 obey to different causes and only in KZnF3:Cu2+ the JT effect takes place. These ideas also explain the local structure and optical properties of CuF2, CrF2 or KAlCuF6 compounds where the JT effect is symmetry forbidden and those of layered copper chloroperovskites where the orthorhombic instability explains the red shift of one d−d transition under pressure. In a second step, this review explores stable systems involving d3, d5 or d9 cations, where the internal electric field, ER, is responsible for some puzzling phenomena. This is the case of ruby and emerald that surprisingly exhibit a different color despite the Cr3+‐O2− distance is the same. A similar situation holds when comparing the normal (KMgF3) and the inverted (LiBaF3) perovskites doped with Mn2+ having the same Mn2+‐F distance but clearly different optical spectra. The role of ER is particularly remarkable looking for the origin of the color in the historical Egyptian Blue pigment based on CaCuSi4O10.

DFT investigation of the adsorption and sensing ability of pure, Al and Ca-doped B12N12 nanocages toward thalidomide drug

In recent years, nanomaterials (NM) have been proven to be efficiency and applicable in several fields of our daily life, including in drug delivery systems. Herein, density functional theory (DFT) molecular modelling is used to probe the ability of pure, Al and Ca doped B12N12 fullerene-like nanocage for the detection and the sensing of thalidomide (TLD) drug. Thus, wB97XD/6-311G(d,p) level has been employed to study the structure-property relationship between the aforementioned NM and TLD. It turns from the analysis of thermodynamic parameters that all NMs investigated can spontaneously fix TLD at their external surface to form stable adsorbent-adsorbate molecular systems in standard conditions. The values of the Gibbs free adsorption energy for the most stable B12N12-TLD state is for instance found to be −8.97 and −6.98 kcal/mol in gas and aqueous phases respectively. QTAIM analyses, complemented by analyses of non covalent interactions through the reduced gradient density (RDG) revealed that the systems are further stabilized by a dative B-O bond as well as a strong N-H…N hydrogen bond between the adsorbent and the adsorbate. The HOMO-LUMO energy difference of CaB12N12 is found to reduced by about 36.42 % upon the adsorption of TLD, proving the interesting sensitivity of this NM toward the drug investigated. Finally, pure B12N12 and CaB12N12 are appropriate for the sensing of TLD in both gas phase and aqueous medium, the former NM even prensenting a release time of about 3.36 x 10−6 s in gas phase from the theoretical point of view.

Numerical investigation on the strategy of separating burner-flame thermoacoustics

Thermoacoustic instability in combustion systems is contingent upon the thermoacoustic properties of the burner when coupled with a flame. In instances where the burner is acoustically transparent, a straightforward approach involves the separation of the burner from its corresponding flame. Acoustic velocity measurement at the upstream of the burner, in such cases, can be equated with the acoustic velocity at the downstream of the burner due to its transparency. However, when the burner possesses a complex geometry with inherent acoustic properties, this separation strategy becomes pivotal. Near-field acoustics immediately following the burner may influence the effectiveness of this separation. Additionally, burners are typically characterized in the absence of a flame (cold condition), with a common assumption that the acoustic properties of the burner remain unchanged in the presence of the flame (hot condition). This paper employs numerical simulations to scrutinize these assumptions and the separation strategy of the burner from the flame. Utilizing direct numerical simulation and an acoustic network approach, we compare the direct evaluation of the total transfer matrix of the burner with flame against the separate evaluation of the burner and flame, derived from linearized Rankine-Hugoniot relations.

Türkiye’s Foreign Relations with Regional Blocs in Sub-Saharan Africa: The Case of AU and ECOWAS

Strong foreign relations among nations are crucial for fostering global stability, economic growth, and cross-cultural understanding. A stable global system that resolves conflicts through dialogue rather than confrontation benefits from positive foreign relations. This paper examines Türkiye’s changing foreign policy approach towards Sub-Saharan African regional blocs, with an emphasis on their political, cultural, and economic facets. Türkiye’s strategic involvement with influential regional bodies such as the African Union (AU) and the Economic Community of West African States (ECOWAS), among others, reflects its broader objective to expand its influence and cultivate multifaceted partnerships across the African continent. The scope of this paper is limited to the AU and ECOWAS. Through a comprehensive analysis, the paper evaluates Türkiye’s economic initiatives, including trade agreements and investment flows, as well as its contributions to infrastructure development. The findings established Türkiye’s peacekeeping roles, cultural diplomacy, diplomatic efforts, and educational exchanges. Through the investigation of these diverse aspects, the conclusion outlines a comprehensive understanding of Türkiye’s place in geopolitical dynamics and regional integration in Sub-Saharan Africa.

Peacetime Maritime Law Enforcement by Warships

ABSTRACT The scope and methods of maritime law enforcement by warships in peacetime are evolving, triggering international armed conflicts. A core issue is how to distinguish between law enforcement activities and military operations at sea. The construction of an international law regime for peacetime maritime law enforcement by warships will help to reduce the incidence of armed conflicts. This is consistent with the need for a strict interpretation of the principle of prohibiting the threat or use of force under the United Nations Charter. Based on the principles of prohibiting the use of force, the peaceful use of the seas and considerations of good faith, it is possible to establish a stable international legal system for maritime law enforcement by warships. The system would be based on the United Nations Convention on the Law of the Sea (UNCLOS) and would operate primarily through implementing agreements as its main model.

Lyapunov-based distributed secondary frequency and voltage control for distributed energy resources in islanded microgrids with expected dynamic performance improvement

Microgrids (MGs) can effectively integrate the high penetration distributed energy resources (DERs) for the energy and environmental crisis. Still, fluctuations in intermittent DERs may lead to severe frequency and voltage deviations or even the instability of islanded MGs. Secondary control has successfully compensated for the frequency and voltage deviations. Research on secondary control mainly focused on steady-state operating objectives, i.e., frequency and voltage recovery and power sharing. Still, improving the dynamic responses of secondary control is crucial for system-stable operation, especially in the presence of synchronous DERs. This is because these units can cause undesired oscillatory modes, leading to system instability. In addition, because of the line impedance effect, accurate reactive power sharing is usually ignored when voltage recovery is considered. This will lead to an overload of MGs. To improve the dynamics of secondary control while trading off voltage regulation and reactive power sharing, we propose a Lyapunov-Function (LF)–based distributed secondary control strategy. In the proposed LF-based control strategy, the frequency, voltage, and power information are introduced into feedback control based on the Lyapunov stability theorem. Therefore, the improved frequency and voltage deviations and accurate power sharing can be guaranteed when the Lyapunov function asymptotically attenuates to zero. The inherent conflict between voltage regulation and reactive power sharing is addressed by converging the average voltage to the rated reference. Besides, the improved dynamic performance of secondary control is achieved by considering global power variations, which are obtained by distribution-level phasor measurement units. Global power variations can establish control actions to dampen system oscillations and accelerate system restoration. Furthermore, the controller design method based on the Lyapunov stability theorem can naturally promise the stability of the proposed secondary frequency and voltage controllers. Numerical simulations on the IEEE 34-bus system validate that the proposed control strategy can ensure the significantly improved dynamic performance of secondary control while achieving steady-state operation objectives.

Digital twin-based multi-granularity synchronisation for production-warehousing under batch processing mode

Batch production is a cost-effective way that boosts efficiency in manufacturing systems. As customer demands become increasingly customised, there is a growing need to consolidate numerous small-batch orders. However, if batch production exceeds the optimal level, it may lead to the premature completion of customer orders, causing temporary congestion in the finished goods warehouse and prolonged resource occupation. Consequently, an essential focus of this study pertains to coordinating decision-making units like workshops and warehouses within batch production setups to ensure stable system operation amidst dynamic customer demands. The proposed solution encompasses a Digital Twin-based Multi-level Synchronised Control System (DTMCS) framework, featuring the Multi-granularity Synchronised Control Mechanism (MgSCM) and a collaborative optimisation model for batch production and warehouse planning. By examining a practical case study from a paint manufacturing company, the research delves into the effects of four synchronised control patterns on various system performance metrics, such as operating costs, equipment and warehouse utilisation rates, and system stability. Overall, this study provides an adaptable and cost-effective solution for enhancing production-logistics synchronisation.

The plasmid-borne hipBA operon of Klebsiella michiganensis encodes a potent plasmid stabilization system.

Klebsiella michiganensis is a medically important bacterium that has been subject to relatively little attention in the literature. Interrogation of sequence data from K. michiganensis strains in our collection has revealed the presence of multiple large plasmids encoding type II toxin-antitoxin (TA) systems. Such TA systems are responsible for mediating a range of phenotypes, including plasmid stability ('addiction') and antibiotic persistence. In this work, we characterize the hipBA TA locus found within the Klebsiella oxytoca species complex (KoSC). The HipBA TA system is encoded on a plasmid carried by K. michiganensis PS_Koxy4, isolated from an infection outbreak. Employing viability and plasmid stability assays, we demonstrate that PS_Koxy4 HipA is a potent antibacterial toxin and that HipBA is a functional TA module contributing substantially to plasmid maintenance. Further, we provide in silico data comparing HipBA modules across the entire KoSC. We provide the first evidence of the role of a plasmid-encoded HipBA system in stability of mobile genetic elements and analyse the presence of HipBA across the KoSC. These results expand our knowledge of both a common enterobacterial TA system and a highly medically relevant group of bacteria.

A robust approach to transformer fault diagnosis: integrating time-current loci analysis with statistical feature extraction

The accurate differentiation of inrush currents and inter-turn faults in power transformers is critical for ensuring the reliability and safety of electrical power systems. Traditional methods often face challenges in distinguishing between these conditions due to their overlapping characteristics, leading to potential misoperations and system instability. This paper presents a novel solution through the introduction of the time-current loci (TIL) method, which effectively addresses this critical issue by providing a robust mechanism for classifying normal operating conditions, inrush currents, and inter-turn faults. The TIL method involves plotting time against current over a single cycle, generating distinct loci patterns that serve as a visual and analytical foundation for classification. By extracting and analyzing key statistical features from these loci, the method enhances the accuracy of fault detection. Specifically, the rate of change in time and current is used to determine the orientation of the TIL curve, with additional features such as the mean orientation and skewness being computed to capture the unique geometric properties associated with each operating condition. This approach simplifies the analysis process, eliminating the need for complex machine learning algorithms and reducing computational demands, making it highly suitable for real-time implementation. Experimental validation was carried out using a 1 kVA, 230 V/230 V transformer under various operating conditions, and the results demonstrated the effectiveness of the TIL method in reliably distinguishing between normal conditions, inrush currents, and inter-turn faults. The visual nature of the loci plots not only aids in accurate classification but also provides an intuitive understanding of transformer behavior, facilitating quick and informed decision-making by operators. This advancement addresses a critical challenge in transformer protection, offering a more reliable and efficient solution compared to traditional techniques.

Enhanced emulsification properties of microalgae protein through gellan gum conjugation: Mechanistic insights and applications in curcumin encapsulation and delivery

The emulsification properties of microalgae protein (MP) are poor, especially under acidic and neutral conditions, which may limit the broad applications of MP in food processing. This study aims to explore the effects of gellan gum (GG) on the emulsification properties of MP. Firstly, MP-GG complexes were prepared and their structures characterized. Subsequently, MP-GG complexes stabilized emulsions were prepared and their stability evaluated. Finally, these emulsions were employed for the encapsulation and delivery of curcumin to evaluate their potential as an efficient nutrient delivery medium. Results indicated that MP-GG complexes were formed under various pH conditions, with pH 6 identified as optimal for complexes stability (zeta-potential value was −31 mV). UV–vis and fluorescence spectroscopy demonstrated that GG did not significantly alter the MP's structure but induced slight conformational changes, leading to the burial of some amino acid residues. Zeta potential measurements confirmed that MP-GG complexes were stabilized by strong electrostatic repulsions. The increase of GG content was conducive to providing more negative charge and promoting the dissolution and dispersion of the MP-GG complexes (MP: GG = 1: 1). Emulsions stabilized by MP-GG complexes exhibited smaller droplet sizes and improved stability compared to those stabilized by MP alone, especially at oil phase volume fractions of 60 % and 70 %. Rheological analysis indicated that GG enhanced emulsion stability by increasing viscosity, and higher oil phase volume fractions facilitated better MP-GG complexes adsorption on oil droplets, strengthening network structures of emulsions. During in vitro simulated gastrointestinal digestion, emulsions with a 70 % oil phase exhibited higher curcumin retention rate (31.09 %) and lower curcumin bioaccessibility (13.23 %) compared to those with a 60 % oil phase. This suggests that emulsions with higher oil phase volume fractions may be more suitable for colon-targeted curcumin delivery, with potential applications in promoting colon health. These findings confirm that the complexation of MP and GG was an effective way to improve the emulsification properties of MP. Emulsions stabilized by MP-GG complexes can serve as stable nutritional delivery systems for fat-soluble bioactive compounds.

Development of a Mammalian Cell Line for Stable Production of Anti-PD-1.

Background/Objectives: Immune checkpoint blockade, particularly targeting the programmed cell death 1 (PD-1) receptor, is a promising strategy in cancer immunotherapy. The interaction between PD-1 and its ligands, PD-L1 and PD-L2, is crucial in immune evasion by tumors. Blocking this interaction with monoclonal antibodies like Nivolumab can restore anti-tumor immunity. This study aims to develop a stable expression system for Nivolumab-based anti-PD-1 in the Chinese Hamster Ovary (CHO) DG44 cell line using two different expression vector systems with various signal sequences. Methods: The heavy chain (HC) and light chain (LC) of Nivolumab were cloned into two expression vectors, pOptiVEC and pcDNA3.3. Each vector was engineered with two distinct signal sequences, resulting in the creation of eight recombinant plasmids. These plasmids were co-transfected into CHO DG44 cells in different combinations, allowing for the assessment of stable antibody production. Results: Both pOptiVEC and pcDNA3.3 vectors were successful in stably integrating and expressing the Nivolumab-based anti-PD-1 antibody in CHO DG44 cells. This study found that the choice of signal sequence significantly influenced the quantity of antibodies produced. The optimization of production conditions further enhanced antibody yield, indicating the potential for large-scale production. Conclusions: This study demonstrates that both pOptiVEC and pcDNA3.3 expression systems are effective for the stable production of Nivolumab-based anti-PD-1 in CHO DG44 cells. Signal sequences play a critical role in determining the expression levels, and optimizing production conditions can further increase antibody yield, supporting future applications in cancer immunotherapy.

Improving extensions for the global uniform asymptotic stability of continuous-time nonlinear systems

This paper considers the classical problems of global asymptotic stability (GAS) of nonlinear autonomous (time-invariant) systems and global uniform asymptotic stability (GUAS) of nonlinear non-autonomous (time-varying) systems. By imposing new conditions on the Lyapunov function and its derivative, the state convergence to the origin from any initial condition with bounded norm in the classical setting is extended to the initial conditions with unbounded norms in the present work. The proposed new notions of stability are called extended global asymptotic stability (EGAS) and extended global uniform asymptotic stability (EGUAS) in this paper. The proposed Lyapunov-based criteria yield the global asymptotic stability of the origin and fixed-time/predefined-time attractiveness of any selected neighbourhood of the origin. The result is that the dynamical behaviour of the state trajectories from the convergence time point of view is improved considerably. The relationship between the smoothness and input-to-state stability (ISS) properties is also studied from a quantitative point of view. Under some new sufficient conditions, it is shown that dynamical systems with smaller Lipschitz constants represent smaller ultimate bounds, and as a result, are more robust. The desirable dynamical behaviour and robustness property of the proposed stability notion makes it comparable with the finite/fixed/predefined/prescribed (exact) stable systems that are naturally non-Lipschitz at the origin. Numerical results illustrate the effectiveness of the proposed theoretical results.

Performance and stability analysis of interacting multiple model estimator under unobservable packet loss

For a system with packet loss, if the estimator cannot observe the packet-loss status (PLS), the system is called an unobservable-packet-loss (UPL) system. Otherwise, it is called an observable-packet-loss (OPL) system. This paper studies the interacting multiple model (IMM) estimator for UPL systems, and the main contributions are twofold. (i) Estimation accuracy of the unobservable PLS. For an unstable UPL system, we prove that the UPL system will become an OPL one with time, since the PLS can be exactly estimated with time. For a stable UPL system, there exists an accuracy threshold such that the estimation accuracy of the PLS cannot be better than this threshold. (ii) Stability of the IMM estimator. For an unstable UPL system, we establish a necessary and sufficient condition: there exists a threshold such that the IMM estimator is stable almost everywhere if and only if the packet-arrival rate is greater than this threshold. For a stable UPL system, we show that the IMM estimator is stable, no matter what value the packet-arrival rate is.

Application of model predictive control scheme for piezoelectric ceramic micro-displacement

Abstract Currently, in the domain of micro-control technology, many operations need to meet the standard of nanometer-level positioning. As a high-precision micro-displacement element, piezoelectric ceramics are widely used in the field of micro-control due to their characteristics such as no need for transmission devices, high resolution, large output force, small size, and fast response speed. However, the inherent hysteresis nonlinearity of piezoelectric ceramics can lead to decreased displacement accuracy, oscillation, and even system instability. Therefore, eliminating the influence of nonlinear characteristics and improving displacement accuracy possess significant practical importance. In this paper, a model predictive control scheme is designed, which achieves faster response speed and higher accuracy compared to traditional control methods such as Proportional Integral Derivative control. Relevant simulations and tests have been conducted. In this scheme, hysteresis nonlinearity is first modeled and then compensated through feedforward, thereby simplifying the displacement control of piezoelectric ceramics into a more manageable linear problem. Subsequently, a linear model predictive control method is adopted to control the entire system. Both simulation and experimental results have verified the effectiveness of this control method.

Vehicle platoon safety considering the vehicle cut-in: A coupled reinforcement learning and model predictive control approach

A longitudinal platoon control method based on Twin Delayed Deep Deterministic Policy Gradient (TD3) and Model Predictive Control (MPC) is proposed to solve the problems of low following efficiency and system instability in longitudinal platoon control. Firstly, Dynamic Bayesian Network (DBN) and Long Short-Term Memory (LSTM) network are introduced to identify the driving behavior of bystanders and derive the MPC objective constraint function containing three indicators of following, comfort and fuel consumption according to the platoon dynamics equation. Secondly, the system prediction model and cost function are introduced into the action-critic network of TD3 to solve the problem of no model training in the traditional TD3 algorithm and to speed up the training speed and accuracy of the network. On this basis, a Bellman equation is proposed to calculate the time-domain difference error and the expected loss function to solve the TD3 network overestimation problem. Finally, the joint simulation platform is built to simulate the platoon driving conditions and compare with the DDPG optimization algorithm and the traditional MPC algorithm respectively. The results show that the improved TD3-MPC algorithm satisfies the constraints and the spacing error is controlled within 0.3 m, and the vehicle speed changes more smoothly in the scenario of speed fluctuation in the front vehicle, and the ride comfort of the platoon is improved, and it has better robustness in the scenario of vehicle cut-in. The experimental results show that when the vehicle speeds are 20, 40, and 60 km/h, compared to MPC, the average spacing errors are reduced by 27.56%, 25.64%, and 28.04%, respectively, and compared to DDPG-MPC, the average spacing errors are reduced by 6.59%, 8.77%, and 7.86%, respectively.