Control Issues Research Articles

Optimized path planning and scheduling strategies for connected and automated vehicles at single-lane roundabouts.

This paper focuses on the cooperative driving challenges of connected and automated vehicles (CAVs) at single-lane roundabouts. First, a geometric path planning method is proposed for CAVs navigating a single-lane roundabout. Based on this method, a vehicle roundabout model is established. Four potential traffic scenarios for CAVs are established, and the optimal arrival times at conflict points are analyzed. By correlating the optimal arrival times at conflict points with the optimal entry times into the roundabout, the multi-vehicle coordination problem in complex intersections is simplified to a speed control issue during entry. Utilizing the principles of optimal control and Pontryagin minimization, two speed optimization strategies are proposed. Finally, MATLAB is employed for simulation analysis. The results indicate that the control strategy proposed in this paper enables the system to clearly identify potential conflicts between vehicles and implement an optimal control strategy, ensuring that vehicles can navigate the roundabout efficiently in terms of time and fuel without collisions. Additionally, the minimum time interval is established at 0.2 seconds to completely prevent vehicle collisions. In this study, the fusion problem involving two vehicles at a single conflict point is further expanded to encompass multiple vehicles at multiple conflict points. Thus, the efficient scheduling of multiple vehicles in single-lane roundabouts is realized.

Predictor-Based Neural Attitude Control of A Quadrotor With Disturbances

An attitude control issue is concerned for a quadrotor with external disturbances in this paper. For unknown system dynamics, predictor-based neural networks (NNs) are introduced, where prediction errors, angular velocities, are constructed, instead of tracking errors, for updating NNs' weights. This replacement reduces the occurrence of high-frequency oscillations in NNs' approximation. With this improved NNs, a predictorbased NN disturbance observer is then developed for compensation for external disturbances and NNs' approximation errors, and a normalization learning technique is employed for reduction of the number of learning parameters. A predictor-based neural attitude control strategy is proposed for a quadrotor with external disturbances. Furthermore, measurement noise are taken into account in our predictor-based neural attitude control strategy. The Lyapunov-based stability analysis shows that all closed-loop signals in the designed attitude system are semiglobally bounded. A numerical simulation and a hardware-in-loop experiment as well as outdoor flight verify the effectiveness of the proposed anti-disturbance attitude control strategy.

An improved sampled-data control for a nonlinear dynamic positioning ship with Takagi-Sugeno fuzzy model.

This article considered the sampled-data control issue for a dynamic positioning ship (DPS) with the Takagi-Sugeno (T-S) fuzzy model. By introducing new useful terms such as second-order term of time, an improved Lyapunov-Krasovskii function (LKF) was constructed. Additionally, the reciprocally convex method is introduced to bound the derivative of LKF. According to the constructed LKF, the sampling information during the whole sampling period was fully utilized, and less conservatism was obtained. Then, the stability condition, robust performance, mode uncertainty and sampled-data controller design were analyzed by means of the linear matrix inequality (LMI). Finally, an example was given to demonstrate the effectiveness of the proposed method.

Prescribed Fixed-Time Control for Constrained Uncertain Nonlinear Cyber-Physical Systems Against Deception Attacks.

In this note, a novel prescribed fixed-time adaptive tracking control scheme is developed to cope with the fixed-time tracking control issue for a category of constrained MIMO nonlinear cyber-physical systems (CPSs) with exogenous perturbations, which suffer from deception attacks started in controller-actuator (C-A) channel. Distinguished from the conservative dynamic surface control (DSC) schemes with a linear filter, a novel nonlinear filter is designed in our strategy, which can tackle the intrinsic issue of explosion of computational complexity and promote the system performance. Besides, a new barrier Lyapunov function (BLF) is designed to ulteriorly enhance the tracking performance on the basis of the prescribed performance function (PPF) approach. Prominently, the proposed control strategy could accommodate the exogenous interferences and deception attacks simultaneously. Furthermore, we have substantiated that the developed approach can not only make certain that all the tracking errors of the resulting closed-loop system, including output tracking errors and virtual tracking errors, enter a prespecified small region near equilibrium point with fixed-time convergence rate, but also guarantee them obey the corresponding constraints throughout the entire control operation, where the regulation time and the tracking accuracy level keep prior known and could be prespecified arbitrarily. Finally, the validity and effectiveness of the proposed control scheme are illustrated through a representative application instance.

RETRACTED: Data–Driven Adaptive Fault–Tolerant Control for Floating Offshore Wind Turbines

Floating offshore wind turbines have increased in popularity owing to their adaptability for deep-water applications and high power generation efficiency. The control of floating offshore wind turbines, on the other hand, is very complex. The main challenges are the difficulty in precisely modelling floating offshore wind turbines and the higher failure rate of components. As a consequence, this study proposes a model-free adaptive fault-tolerant control system for blade root moment sensor failures. A model-free adaptive control approach is used to construct an individual pitch controller and a fault compensation to avoid mathematical modelling of floating offshore wind turbines. The proposed fault-tolerant control technique removes the need for fault detection and isolation by converting the fault dynamic compensation process into a real-time control issue for nonlinear systems. The fatigue, aerodynamics, structures, and turbulence code simulates and tests the proposed control strategy, and the results show that the proposed strategy can not only keep the wheel bearing load balanced but also reduce the movement of the floating platform and significantly reduce the bearing load of the floating offshore wind turbines. Furthermore, the output power is closer to the rated power, proving the strategy’s high fault tolerance in the face of repeated blade root moment sensor faults.

A study on microclimate monitoring and control inside greenhouse using fans automation

<span>Efficient microclimate management is crucial in enhancing crop yields in greenhouses. Factors like temperature, relative humidity, and ultraviolet (UV) index significantly impact crop quality. The absence of adequate ventilation mechanisms in greenhouses presents a challenge for temperature regulation. This study proposes a solution for tropical greenhouses by designing a system that automatically activates fans when temperatures rise above 30 °C. This system regulates temperature and cultivates optimal growth conditions for crops. It is supported by a web page that enables monitoring and adjustment of microclimate data. To accommodate individual crop requirements, the minimum temperature threshold for fan activation can be modified, enhancing the system's adaptability. The impact of the UV index on greenhouse temperature is also considered. The automation system decreases the temperature by around ±3 °C when the UV index hits 10. Nonetheless, its cooling impact wanes beyond the UV index of 10. A greenhouse automation system, equipped with fans and internet access, proves quite useful for agricultural environment management. It tackles the temperature control issue and offers varied solutions.</span>

Interleaved Periodic Event-Triggered Communications-Based Distributed Formation Control for Cooperative Unmanned Surface Vessels.

This article addresses the distributed formation control issue of cooperative unmanned surface vessels (USVs) under interleaved periodic event-triggered communications. First, an adaptive event-based control protocol is designed, where the event-based neural network (NN) scheme is developed to compensate for uncertain model dynamics. Upon the designed control protocol, an interleaved periodic event-triggered mechanism (IPETM) is subsequently proposed to achieve the communication objective. Unlike the common continuous event-triggered methods and periodic event-triggered methods, in which multiple nodes are allowed to trigger their events at the same time, the proposed IPETM ensures that USVs detect their events at different times to avoid the simultaneous event triggering of different nodes. By this virtue, traffic jamming in common wireless environments can be prevented, such that potential communication delays and faults are naturally avoided. In addition, the event detecting instants of the presented IPETM are also discrete and periodic, such that it can be performed under low-computational frequencies. Through Lyapunov-based analysis, it is verified that all closed-loop signals can converge to an arbitrary small compact set with exponential convergence rates. Simulation results demonstrate the effectiveness and superiority of the proposed control scheme.

The Imperative of Establishing the Mediterranean–Dead Sea Channel: Meeting the Demands of Escalating PV Electricity Production

The current landscape of electricity generation in Israel is significantly influenced by a marked increase in solar power output, primarily from photovoltaic (PV) facilities and plants. The rapid growth of solar energy within Israel’s self-sustained energy grid presents challenges for maintaining frequency stability and voltage equilibrium, limiting feasible solar electricity generation to approximately 12–14%. To expand these limits, integrating electrical storage solutions becomes imperative. An optimal proposal, tailored to Israel’s geographic location, involves constructing a conduit linking the Mediterranean and the Dead Sea. This initiative would include the installation of reservoirs and hydroelectric stations along the descent to the Dead Sea. Implementing such hydroelectric stations can help mitigate the impacts on frequency and voltage stability caused by the fluctuating nature of solar electricity production. Additionally, it can facilitate peak consumption management in the evening through hydroelectric generation, capable of delivering up to 320–330 MW of electrical power even in initial project phases. Furthermore, this strategic conduit offers additional benefits, such as enhancing PV electricity generation potential to 25–30% without exacerbating frequency control issues, producing an average of (150–180) × 103 m3 of desalinated water daily, and counteracting the steady decline of the Dead Sea, which currently recedes by about 1 m annually. Moreover, there are ancillary benefits from extensive desert area landscaping and the establishment of recreational health centers and resorts. A thorough analysis is imperative to estimate the potential increase in solar electricity generation, considering the unpredictable nature of PV outcomes. Additionally, it is crucial to explore the feasibility of using the Dead Sea for brine discharge from electrical hydro-storage plants as a key aspect of this comprehensive evaluation.

Fuzzy Adaptive Event-Triggered Consensus Control for Nonlinear Multiagent Systems With Output Constraints and DoS Attacks.

In this article, the fuzzy adaptive event-triggered consensus control issue is addressed for nonlinear multiagent systems (MASs) under output constraints and Denial of Service (DoS) attacks. First of all, fuzzy logic systems (FLSs) are utilized to approximate the unknown nonlinear functions. Then, a novel switching observer is constructed to observe the leader's state and handle DoS attacks. With the help of the exponent-dependent barrier Lyapunov functions (BLFs), the system output can be constrained within a preset region. Based on dynamic surface control (DSC) technique, the issue of computational complexity can be effectively avoided. Combining the designed switching observer and relative thresholds, a robust fuzzy adaptive event-triggered controller is developed, which ensures that the consensus output tracking errors converge to a small neighborhood of zero, and all signals in the closed-loop system keep bounded. Moreover, Zeno behavior can be avoided. Ultimately, simulation results are given to validate the feasibility and effectiveness of the proposed control strategy and theory.

Optimal control problems governed by a class of nonlinear systems

<abstract><p>This article suggested a solution to a flow control problem governed by a class of nonlinear systems called bilinear systems. The problem was initially well-posed, and after it was established that an optimal control solution existed, its characteristics were stated. After that, we demonstrated how to use various bounded feedback controls to make a plate equation's flow close to the required profile. As an application, we resolved the plate equation-governed partial flow control issue. The findings bring up a variety of system applications, which can be employed in engineering advancement.</p></abstract>

Medicines Policy and Drugstores in Serbia Until the Second World War

The paper analyzes the effects of medicines policy on the functional separation of pharmacy and drugstore businesses from the early 19th century to the Second World War. Attempts to maintain personal and professional interests in the delivery of medicines prompted the long-standing dispute between pharmacists and druggists over the control and trade of drugs and poisons. The issue of state control generated complex processes that emphasized the professional role of pharmacists as providers of pharmaceutical services and druggists as wholesalers of medicines.

Phytosynthesized Nanoparticles as Novel Antifungal Agent for Sustainable Agriculture: A Mechanistic Approach, Current Advances, and Future Directions

Due to rapidly changing environmental conditions, virulent pathogens have arisen continuously that invades the crops and badly affects their yield and quality of the cash crops which results in economic losses. To overcome the prevalent infection of fungal pathogens, there is an utmost need to develop alternative techniques that avoid conventional agriculture practices. The use of various chemical fungicides is not an environmentally sustainable solution to fungal diseases because it produces environmental contamination and is dangerous for human health. Nanotechnology provides solutions to disease control issues in a significant way. The scientific and industrial systems are being changed by this development. Similarly, nano-based instruments are highly promising in the agriculture sector, particularly for the production of powerful formulations that require appropriate distribution of agrochemicals, nutrients, pesticides/insecticides, and even growth regulators for improved efficiency of use. Nanotechnology provides an inexpensive, environmentally friendly, and alternative effective monitoring of agricultural fungal pathogens. Green nanotechnology is an innovative methodology that revolutionized the field of agriculture to solve these problems. Despite increasing plant growth, nanoparticles meet the agriculture demand for high yield. This study mainly focuses on the promise of various methods for the treatment of fungal diseases through nanoparticles.

CREATIVE TASK AS A FORM OF FINAL CONTROL FOR FUTURE JOURNALISTS: THE VIEWPOINT OF STUDENTS

The article is devoted to the issue of final control for core disciplines in the specialty 061 «Journalism». The survey of more than 100 students of the Department of Journalism in V. N. Karazin Kharkiv National University was held. It is presenting the students’ vision of a creative task as a form of verification test or exam. The questions were about the distribu- tion of points for certain types of tasks, features of creative tasks’ preparation, problems of creative tasks’ production in the distance learning setting etc. The survey provided different forms of answers: both option selection and extended comments. Questionnaires were filled out by students of the Bachelor and Master levels, full-time and correspondence courses and by graduates of the Department of Journalism.It was found that the majority of students see the creative task as a mandatory component of the verification test or exam. At the same time, the ideal form of final control is considered to be combined (a presentation of a creative task and a theory test). It was established that journalism students prefer individual production of creative works, although they assume team formats.The main challenges for future journalists in the distance learning setting within the context of creative tasks’ production are highlighted. It was found that after the beginning of the full-scale phase of the Russian-Ukrainian war, the number of difficulties increased and they became more frequently related to the inner state of students. A search for motivation or inspiration, work under stress, finding topics for materials are most often mentioned problems by respondents. The problems of education organizing by universities have faded into the background compared to the quarantine restrictions’ period caused by the coronavirus pandemic.It was concluded that despite the existing difficulties of the distance learning, students still consider a creative task as a form of final control for core disciplines in the both prepared in advance and done during the exam ways.

The essence and practical application of state financial control mechanisms in Ukraine

Entry. The article examines the issue of state financial control, audit, it’s mechanisms in the present. An aim is to reveal the essence of state financial control mechanisms and their practical application in modern Ukraine.
 Results. The essence of the mechanisms of the formation and development of state audit as a complex state-management and social-economic education, which includes the identified and integrated five components of the main mechanisms (social-economic, organizational-legal, information-communication, personnel, research), which allows implementing the functions of state financial control with an impact on efficiency and effectiveness, as well as its accountability to society and the state.

Robust fuzzy model predictive control for nonlinear discrete‐time systems

SummaryThis paper studies the issue of Robust Fuzzy Model Predictive Control (RFMPC) of nonlinear discrete‐time systems in the presence of disturbance. To this end, Takagi‐Sugeno (T‐S) fuzzy model is adopted in order to characterize uncertain nonlinear systems and facilitate providing controller for such systems. Non‐parallel distributed compensation (non‐PDC) technique is applied to design improved RFPMC with better performance. The optimization problem of RFMPC is represented in terms of linear matrix inequalities (LMIs) so as to decrease online computational burden. Besides, feasibility and stability which are decisive factors in MPC theory are investigated for the proposed method. Ultimately, two examples including cart‐damper‐spring system are simulated to evaluate the results of this research work.

Command filter‐based adaptive event‐triggered control for switched nonlinear systems with full state constraints

AbstractAn adaptive event‐triggered control issue based on command filter and dynamic surface control is studied for switched nonlinear systems with full state time‐varying constraints in this article. To handle state constraints, the nonlinear mapping conversion technique is used. Radial basis function neural networks (RBFNNs) are utilized to approximate unknown nonlinear continuous functions. Adaptive control algorithm is designed based on command filtered backstepping technology. Novel even triggered control is constructed for two different cases in the switching interval. Furthermore, all signals in the switched system are proved to be semi‐globally uniformly ultimate bounded (SGUUB) by the aid of dynamic surface control method under arbitrary switching. Meanwhile, all states do not violate the preset constraints and Zeno phenomenon is avoided. The validity of the presented approach is confirmed through a numerical simulation result.

Current sharing and voltage restoration based on determination of transmission line resistance considering constant power loads in direct current microgrids

SummaryMaintaining proper current sharing among distributed generation (DG) units while regulating the output voltage is a challenging control issue in DC microgrids. The conventional droop control is widely used at the primary level of control to tackle this issue, but this method faces some limitations in voltage control and current sharing. To address this problem, this paper presents a new distributed secondary control method that determines the resistance of transmission lines by injecting an external pulse to the reference voltage of each converter and measuring output voltage and current changes. The proposed secondary control signal, denoted as , enables simultaneous proportional current sharing and voltage restoration in the DC microgrid by correcting the droop coefficients based on the determined resistances. In order to ensure the stability of the proposed method, the small signal stability analysis of the closed‐loop system is conducted, considering various parameter changes. In contrast to similar methods, the proposed method introduces a new hybrid technique of voltage setpoint shifting and droop parameter adjustment that achieves precise proportional current sharing and voltage restoration, even when faced with varying resistive loads and constant power loads (CPLs). Additionally, the proposed method demonstrates outstanding characteristics, such as high convergence speed, the ability to determine transmission line resistances instead of assuming them to be known, and robustness in plug‐and‐play scenarios and communication system failures. The simulation results in MATLAB and experimental tests confirm the effectiveness of the proposed method.

Software Control of the Movement of a Differential Drive Robot for Different Friction Models

Introduction. Designing motion control systems for mobile robots requires the construction of mathematical models. Researchers have repeatedly addressed this topic. In particular, works have been published on the calculations of multiphysical processes, modeling the movement of various types of wheels under certain conditions. In addition, the dynamics of deformable contacting bodies during sliding, rolling and rotation, issues of autonomy and controllability of mobile robots were considered. Note, however, that the dynamics and positioning accuracy of wheeled robots is largely determined by friction. The literature does not present studies on the dynamics of a robot with a differential drive taking into account the interrelationships of sliding, spinning and rolling friction effects based on the theory of multicomponent friction. Research in this area can reveal new dynamic effects. Based on the data obtained in this way, it is possible to improve the accuracy of positioning in building mathematical control models. The presented work aims at investigating the movement of an automatic device with a differential drive taking into account three contact models: nonholonomic, Coulomb friction, and multicomponent models.Materials and Methods. The scheme of a two-wheeled robot with differential drive and continuous movement on the support surface was adopted as the basic one. The movement of the device was provided through software control. The dynamics was described in the form of Appel equations. Mathematical models were used for calculations, taking into account friction in different ways. Coordination of the actions of the mechanism was formed at a dynamic level. The control actions were the moments of the wheel motors. When visualizing the models under study, the built-in numerical methods of the Wolfram Mathematica system were used with a minimum accuracy of 10-6.Results. When building a mathematical model, the equations for the angular velocities of the wheels were determined. The authors took into account the presence of a contact site and derived the equations of dynamics of a differential drive robot. The elements of the system were force and moment projections, indicators of platform spin, masses, angular accelerations, and inertia of the wheels. It was shown how control actions were formed within the framework of nonholonomic mechanics. The model of engines that created a moment of control on the driving wheels was described. The solution was derived as the relationship between the inductance of the conductors of electric motors and the operation of the power supply. Three models describing the dynamics of a differential drive robot were examined in detail. The first model was nonholonomic. The second and third included a system of equations for the dynamics of a differential drive robot for a general case with a contact platform. At the same time, in the second model, the switching time in the engine was ignored and the Coulomb friction was involved. In the third model, a parameter to determine the speed of transients in the engine was introduced, and Pade decomposition was involved. This was a model with multicomponent friction. The calculation results were shown in the form of graphs. On them, the studied models were visualized in the form of curves of different colors. Comparison of the graphs showed in which cases, after the completion of transients, the control provided the required accuracy. These were models 1 and 2. In model 3, the software control generated an error in the angular velocity of rotation of the platform. This error could not be predicted within the framework of the 1st and 2nd models. In all the systems considered, the sliding speed of the wheels in the transverse direction dropped to zero. The condition of continuous motion of the support wheel was obtained and validated.Discussion and Conclusion. Software control is acceptable in models that do not take into account wheel friction during simultaneous sliding, spinning and rolling (general case of spatial motion). However, it is important to consider the relationship between these processes and multicomponent friction. This is required for the robot to perform program movements more accurately. It was established that software control in a model that takes into account the friction of spinning and rolling caused deviations from the program values of the angular velocity of the platform. The results obtained can be used in the building of a control system with predictive models.

Driverless Planning and Decision-Making based on GRU

In the wake of the swift advancement of artificial intelligence, driverless technology has progressively emerged as a revolutionary technology. The existing driverless technology primarily relies on advanced sensors, artificial intelligence and machine learning algorithms, with a view to perceiving and analyzing the surrounding environment in real time, and making driving decisions accordingly. At the present time, despite the fact that driverless technology has introduced a lot of convenience to human travel, it still encompasses a significant number of challenges, such as safety, perception technology, vehicle control, road planning, cost and other issues. In a similar vein, the safety issue is an unavoidable part of the discussion on the driverless. Driverless vehicles require robust system safety and protection mechanisms. This paper is designed to establish a data model by analyzing the NGSIM dataset, and to probe the driverless perception capability and decision-making on intelligence in behavior-aware motion perspective with GRU approach. Eventually, it was concluded that neither too many nor too few neighboring vehicles should be taken into account when forecasting the trajectory of each vehicle in the coming years, while the appropriate neighboring vehicles should be selected to achieve the best prediction results.

Improving approaches to the management, accounting and control of receivable debt in the period of martial law

In the period of martial law, when the economy of enterprises becomes especially vulnerable, the issues of management and control of receivables become critical. Bad and questionable debts become not only an element of financial losses, but also an important indicator of economic instability, which can lead to the threat of bankruptcy of enterprises. One of the key challenges of managing accounts receivable in martial law is uncertainty and unpredictability. Conflicting circumstances lead to changes in consumer demand, production processes and supply chains, which increases the risk of buyer insolvency. Businesses must improve their approaches to identifying and managing bad and doubtful debts. In this context, the formation of a reserve for doubtful debts becomes an extremely important aspect of the receivables management strategy. Improving the control of receivables also involves the effective use of technology and innovation. Automation of payment monitoring processes, identification of risky customers and analysis of financial stability can contribute to prompt response to changes and timely adoption of strategic decisions. The threat of bankruptcy of enterprises in the conditions of martial law requires from the management not only an effective response to current problems, but also a strategic vision of the future. Improving approaches to management, accounting and control of receivables during the period of martial law in Ukraine is an important task that requires an integrated approach to financial management. Stability in these conditions can be achieved through a sound strategy, improved processes and a relentless study of market and economic trends. The structure of subaccount 361 «Settlements with domestic buyers» has been improved. In particular, it is recommended to introduce new sub-accounts of the fourth order for detailing the terms of debt repayment by debtors and taking into account the periods of non-repayment. The model «Receivables 365: distribution and control by maturity» was developed, within which it is recommended to expand the ranges of classification of current receivables by maturity within one year. This will contribute to the strengthening of internal control over current receivables, taking into account the terms of its repayment by counterparties, and will allow determining the most critical calculations from the point of view of the approaching terms of their payment.