Continuous Control Systems Research Articles

Development of an STM32 Microprocessor System for Automatic Continuous Remote Temperature Control in an Intensive Flow of People

This article discusses the fundamental principles of non-contact temperature measurement, technical solutions that translate them into practice in order to automate temperature control and improve the current epidemiological situation in the world in connection with coronavirus infection, as well as a proposal for a new technical solution that is more affordable, which will increase coverage of the use of automatic systems for monitoring the body temperature of people in public places, and a description of the following steps for its implementation.

Algorithm for Finding Feedback in a Problem with Constraints for One Class of Nonlinear Control Systems

For a continuous nonlinear control system on a finite time interval with control constraints, where the right-hand side of the dynamics equations is linear in control and linearizable in the vicinity of the zero equilibrium position, we consider the construction of a feedback according to the Kalman algorithm. For this, the solution of an auxiliary optimal control problem with a quadratic functional is used by analogy with the SDRE approach.Since this approach is used in the literature to find suboptimal synthesis in optimal control problems with a quadratic functional with formally linear systems, where all coefficient matrices in differential equations and criteria can contain state variables, then on a finite time interval it becomes necessary to solve a complicated matrix differential Riccati equations, with state-dependent coefficient matrices. This circumstance, due to the nonlinearity of the system, in comparison with the Kalman algorithm for linear-quadratic problems, significantly increases the number of calculations for obtaining the coefficients of the gain matrix in the feedback and for obtaining synthesis with a given accuracy. The proposed synthesis construction algorithm is constructed using the extension principle proposed by V. F. Krotov and developed by V. I. Gurman and allows not only to expand the scope of the SDRE approach to nonlinear control problems with control constraints in the form of closed inequalities, but also to propose a more efficient computational algorithm for finding the matrix of feedback gains in control problems on a finite interval. The article establishes the correctness of the application of the extension principle by introducing analogs of the Lagrange multipliers, depending on the state and time, and also derives a formula for the suboptimal value of the quality criterion. The presented theoretical results are illustrated by calculating suboptimal feedbacks in the problems of managing three-sector economic systems.

A System for Noise Control of the Technical Condition of Railroad Bridges and Tunnels in Seismically Active Regions

The authors analyze the technical condition of objects of railroad communications with modern bridges, tunnels, stations, overpasses, crossings and power installations. It is noted that, based on the specific features of such objects, control of their technical condition in most cases is carried out at certain intervals. At the same time, existing continuous control systems do not always adequately assess the technical condition of rail infrastructure objects due to the presence of additional noises in the processed signals at the time when a malfunction occurs. In this regard, one of the possible options is proposed for "continuous" monitoring of the beginning of changes in the technical condition of railroad tracks by means of noise technologies. It is pointed out that when the technical condition of rail infrastructure changes, vibration signals caused by the impact of rolling stock contain noises in addition to the useful component. The use of correlation and spectral analysis technologies, as well as other traditional methods does not allow ensuring the adequacy of the control results, due to the influence of the noise on useful vibration signals. Therefore, technologies are proposed for split analysis of the useful signal and the noise received from vibration, as well as for forming informative attributes of identification of the technical condition of rail infrastructure. In this case, the estimates of the characteristics of the useful signal and the noise are used as the main carrier of diagnostic information. Due to the simplicity and reliability of the developed theoretical algorithms, the implementation of the technical equipment and its installation in all objects of the railroad track present no particular difficulties. At the same time, the implementation of the Noise system will ensure real-time control of the beginning of changes in the technical condition of railroad tracks during the movement of the rolling stock. This, in turn, will allow timely detection of malfunctions, significantly enhancing the safety of passenger and cargo rail transportation.

Destruction of the hydraulic unit shaft: Why it is possible?

Hydraulic units produce around 20% from the total world energy and almost 75% from total renewable energy as well as play a vital role in providing energy system stability. The shaft is one of the key lifetime-determining elements for hydraulic units. Its durability, lifetime, fatigue and fracture resistance define reliability and safety of a hydraulic unit in general. Despite the presence of functioning continuous and periodic hydraulic unit technical condition control systems, there are several known cases of shaft destruction leading to their replacement, long downtimes and significant financial losses for energy industries.The goal of this research is determining main reasons for shaft destruction in hydraulic power plant operating conditions. Using computational modeling for a large vertical high-head hydraulic unit as an example shows that a growing crack doesn't significantly influence shaft dynamic properties. As a result, even a long through crack may escape detection by present vibration diagnostics systems. At the same time, non-destructive metal state control methods are also not always effective due to structural design features and large size of hydraulic unit shafts.To prevent serious incidents in the future there is a suggestion to improve vibration diagnostics data-processing algorithms, introducing an additional diagnostic sign – a ratio of registered double rotation frequency runout values to runouts at rotation frequency, which allows to identify a hydraulic unit with a growing shaft circumferential crack even with vibration state meeting compliance norms and requirements. Additionally, it is necessary to estimate residual HU shaft lifetime through calculation taking into account possible initial cracks not revealed previously by non-destructive control.

A neural network model used in continuous grain dryer control system

Due to the nonlinearity, strong coupling and hysteresis of the parameters used in measuring the grain drying process, it is always a challenge to perform accurate control of the drying system. The purpose of this paper is to describe the design of a suitable neural network model to control the grain dryer more effectively. First, the operating mechanism of a continuous grain dryer and the principle of the heat and mass transfer that can be used in the process of grain drying was analyzed before an intelligent control system was designed accordingly. Second, an intelligent control system based on the Back Propagation Neural Network (BPNN) was developed. The BPNN was the optimal model selected based on a series of comparative test results. According to the BPNN prediction of the moisture content of dried rice, the system could adjust the rate of grain discharge of the dryer, and then control the drying process accurately. Finally, the neural network control model was simulated using computer simulation technology, and was optimized by comparing analysis results with experimental results. The results showed that the optimized intelligent control system using BPNN has the advantage of strong stability and good noise handling, and could have great potential for future implementation studies.

Justification of chosen values of the weight coefficients of the compaction value for continuous compaction control systems for vibration rollers

The problem of monitoring the compaction of road construction materials in structural construction is currently relevant. The methods of quality control of compaction of road construction materials currently used in Russia during quality inspection do not provide a way to estimate more than 0.1% of the total compaction area. Today there is a wide variety of continuous compaction monitoring systems for vibratory rollers. Such systems allow operators of vibratory rollers to monitor the condition of compacted material in real time, which significantly improves the quality of road construction. The operation of most monitoring systems is based on the compaction index obtained from the analysis of the acceleration spectrum of the vibratory drum. When a new soil compaction monitoring system is only starting to be developed, it is necessary to develop and test in the field a new, more perfect compaction indicator, and to compare it with the existing compaction values. A field research has provided us with signals from vibration acceleration sensors placed on the frame of a vibratory drum and acceleration spectra of the vibratory drum using ZETLAB software made by ETMS. To calculate the proposed indicator, the received data was processed in STATISTICA v.10. The final correlation analysis was performed using the CORREL function found in MS Excel 365 and its financial and scientific data analysis tool. As a result of this correlation analysis, it was found that the proposed Compaction Value has the highest coefficient of linear correlation with the value of the dynamic deformation module Evd in all areas of the field research. In this regard, it can be concluded that using the proposed Compaction Value is reasonable in the development of a new continuous monitoring system for compaction of road-building materials with vibratory rollers.

A method for monitoring the violation of the integrity of pipeline communications using a radio wave vibration sensor

The article discusses the implementation of a continuous vibroacoustic control system, in order to detect leaks and quickly prevent emergencies, describes the principles of their functioning. The existing method of recognizing leaks is considered. The analysis of non-contact methods for measuring vibration parameters is carried out, radio wave methods are highlighted as the most promising. A non-contact radio wave vibration sensor is considered, which is introduced into the pipeline monitoring system. The proposed systems of vibroacoustic control allow one to effectively diagnose the state of the pipeline at low time costs and with a low error in detecting a useful signal. The physical and mathematical meaning of the method being introduced was also considered. The scope of application of the research results relates to industries (heat power, gas and oil fields), in which complex dynamic objects are used with the need to use a non-contact method for monitoring vibration and displacement parameters.

Necessary and sufficient conditions for assignability of dichotomy spectra of continuous time-varying linear systems

We consider a version of the pole placement problem for continuous time-varying linear systems. Our purpose is to prove that uniform complete controllability is equivalent to possibility of arbitrary assignment of the dichotomy spectrum. The main ingredients of the proof are the reduction of system to upper triangular form and the use of the concept of uniform complete stabilization. To illustrate the theoretical result, we consider scalar continuous time-varying control systems. For these systems we provide a simple necessary and sufficient condition for uniform complete controllability and if this condition holds, then we construct an explicit control to assign the dichotomy spectrum.

Advanced control strategies for bioprocess chromatography: Challenges and opportunities for intensified processes and next generation products

Recent advances in process analytical technologies and modelling techniques present opportunities to improve industrial chromatography control strategies to enhance process robustness, increase productivity and move towards real-time release testing. This paper provides a critical overview of batch and continuous industrial chromatography control systems for therapeutic protein purification. Firstly, the limitations of conventional industrial fractionation control strategies using in-line UV spectroscopy and on-line HPLC are outlined. Following this, an evaluation of monitoring and control techniques showing promise within research, process development and manufacturing is provided. These novel control strategies combine rapid in-line data capture (e.g. NIR, MALS and variable pathlength UV) with enhanced process understanding obtained from mechanistic and empirical modelling techniques. Finally, a summary of the future states of industrial chromatography control systems is proposed, including strategies to control buffer formulation, product fractionation, column switching and column fouling. The implementation of these control systems improves process capabilities to fulfil product quality criteria as processes are scaled, transferred and operated, thus fast tracking the delivery of new medicines to market.

Synthesis of non-stationary continuous nonlinear control systems by the generalized Galerkin method

Synthesis of non-stationary continuous nonlinear control systems by the generalized Galerkin method

The continuous grease level control system in the backup chamber of the motor-axle bearing box of electric locomotives

The continuous grease level control system in the backup chamber of the motor-axle bearing box of electric locomotives

Semiglobal optimal feedback stabilization of autonomous systems via deep neural network approximation

A learning approach for optimal feedback gains for nonlinear continuous time control systems is proposed and analysed. The goal is to establish a rigorous framework for computing approximating optimal feedback gains using neural networks. The approach rests on two main ingredients. First, an optimal control formulation involving an ensemble of trajectories with ‘control’ variables given by the feedback gain functions. Second, an approximation to the feedback functions via realizations of neural networks. Based on universal approximation properties we prove the existence and convergence of optimal stabilizing neural network feedback controllers.

Entropy for Practical Stabilization

For deterministic continuous time nonlinear control systems, $\varepsilon $-practical stabilization entropy, and practical stabilization entropy are introduced. Here the rate of attraction is specified by a $\mathcal{KL} $-function. Upper and lower bounds for the diverse entropies are proved, with special attention to exponential $\mathcal{KL}$-functions. The relation to feedbacks is discussed; the linear case and several nonlinear examples are analyzed in detail.

Algorithmic Support of Adaptive Automatic Control Systems with Data Compression

Introduction. The exponential growth of measurement information caused by ongoing complication of technical and production facilities necessitates the development of improved or brand new information and measurement systems, including those performing adaptive automatic control functions. Automatic criteria-based selection and reduction of measurement information continuously supplied by multi-parameter sources characterizing the objects under study require algorithms ensuring reconfiguration of automatic control systems during operation. In comparison with automatic control systems based on time-division channelling, the considered adaptive systems provide timely information on the pre-emergency and emergency operation of a facility.Aim. To develop an algorithmic support for adaptive automatic control systems using asynchronous-cyclic and parallel-sequential operating algorithms, as well as to compare the proposed algorithms in terms of their, control reliability, compression ratio, operation speed and the error associated with multi-channelling.Materials and methods. The algorithms proposed for supporting the operation of adaptive systems were developed on the basis of queuing theory and simulation modelling using the MatLab/Simulink programming languages, C++.Results. The developed algorithmic support for automatic control systems based on asynchronous-cyclic analysis of deviations allows the amount of redundant information to be reduced by more than 4 times and the operation speed to be increased by 1.5 times. The developed algorithmic support for automatic control systems based on parallel-sequential analysis of deviations allows the error associated with multi-channelling to be reduced by 1.4 times, thereby bringing the control reliability of such systems closer to that of continuous-control systems. An analysis of the graphs of the error associated with multi-channelling showed that the automatic control systems based on parallel-sequential operational algorithms are invariant to the law of distribution of input quantities, compared to the systems based on asynchronous-cyclic operational algorithms.Conclusions. The proposed algorithmic support can significantly decrease the redundancy of information and improve the metrological characteristics of automatic control systems. The use of the developed algorithms in automatic control systems based on time-division channelling render their control reliability comparable with that of continuous-control systems.

Erratum to “Algorithms for U-Model-Based Dynamic Inversion (UM-Dynamic Inversion) for Continuous Time Control Systems”

Erratum to “Algorithms for U-Model-Based Dynamic Inversion (UM-Dynamic Inversion) for Continuous Time Control Systems”

Guest Editorial Special Issue on Fault Diagnosis and Adaptive Fault-Tolerant Control for Automatic Control Systems

Due to the recent rapid developments in communication and networking technologies as well as computer science, the complexity of automatic control systems has increased significantly. To ensure the safety and the reliability of such systems under continuous operation, real-time supervision and control systems have now to run in parallel. These developments challenge scientists and engineers to come up with advanced fault diagnosis (FD) and fault-tolerant control (FTC) approaches that can monitor the abnormal changes in automatic control systems promptly. The objective is to maintain safe operating conditions that avoid severe performance degradation. The tasks involved in meeting the objective consist of fault detection, estimation, localization, isolation, feasible control strategies, and maintenance actions.

Global controllability tests for geometric hybrid control systems

This paper introduces a novel geometric framework to define and study hybrid systems. We exploit the geometry and topology of the set of jump points, where the instantaneous change of dynamics takes place, in order to gain controllability for the system. This approach allows us to describe new global controllability tests for hybrid control systems. We illustrate these results with several examples where none of the continuous control systems are controllable, but the associated hybrid system is controllable because of the characteristics of the jump set.

Algorithms for U-Model-Based Dynamic Inversion (UM-Dynamic Inversion) for Continuous Time Control Systems

To setup a universal proper user toolbox from previous individual research publications, this study generalises the algorithms for the U-model dynamic inversion based on the realisation of U-model from polynomial and state-space described continuous-time (CT) systems and presents the corresponding U-control system design in a systematic procedure. Then, it selects four CT dynamic plants plus a wind energy conversion system for simulation case studies in Matlab/Simulink to test/demonstrate the proposed U-model-based design procedure and dynamic inversion algorithms. This work can be treated as a U-control system design user manual in some sense.

Iterative Learning Control for Singular Network Control System with Time-Delay and Data Dropout

Since the object becomes more and more complicated and the existed data dropout and network-introduced time-delay are random and varying in network control system (NCS), the traditional control method is more and more difficult to obtain a good control effect. In this paper, the iterative learning control (ILC) issue for a class of linear continuous singular network control system (SNCS) with time-delay and data dropout is investigated. According to the λ norm and expectation algorithm, the convergence condition of the system is derived. At last, simulation example shows the effectiveness and superiority of the presented method.

Experimental research of vertical movements and accelerations of the drum vibrations of the DM-617 vibratory roller during soil compaction

Rheological modeling of how the elements of a vibratory roller during soil compaction interact with each other allows the optimization of parameters of the roller and soil compaction modes based on the study of the obtained model, as well as the improvement of the soil compaction continuous control system, and the solution of other practically important tasks. To verify the models, it is required to compare the calculation results for the models with experimental data. The paper includes the results of experimental studies of the acceleration range for the vibratory drum of the DM-617 vibratory roller during soil compaction in the steady vibration mode, when the vibration is turned on, and when it is turned off. It is established that during the compaction of the soil in question in the range Evd = 14…25 MPa, the range of vertical movements and accelerations of the vibratory drum in the steady vibration mode does not depend on the soil density. When the vibration is turned on, the vertical movements and accelerations of the drum is 1.5…2 times higher than those of the steady mode. When the vibration is turned off, the vertical movements are increased by 1.5…2 times when passing the resonance zone, and the drum accelerations do not exceed the range of those in the steady vibration mode. The obtained results allow the mathematical models of vibratory rollers during soil compaction to be verified not only in the steady vibration modes, but also in transient modes, including passing the resonance areas when switching the vibration on and off.