Control System In Order Research Articles

Analysis of the size of shredded particles in a multi-disc grinder

The result of a shredding process should be a product of specific dimensions obtained with the consumption of the minimum amount of energy per unit of weight. There are several parameters that affect the efficiency and quality of the shredding process (including temperature and rotational speed). The article presents the station of a multi-disk grinder whose design is based on a computer with a control and measurement application developed in the LabVIEW environment, a CMOS camera, and a multi-functional DAQ device. The station makes it possible to look for optimum settings of the control system in order to obtain an appropriate particle size. The size of the shredded particles is justified by the requirements of the downstream process: extrusion in the case of plastics and digestibility in the case of biological materials.

Иерархическая система нечеткого регулирования процесса получения ацетилена окислительным пиролизом природного газа

The paper describes a complex chemical-technological system of producing acetylene by oxidative pyrolysis of natural gas, for which ensuring technological safety is a prerequisite for its functioning. There have been discussed the ways of developing a control system for this process while ensuring its technological safety based on the definition of its area and security center. 
 A two-level control option is proposed, in which the upper level performs dynamic correction 
 of the tasks of the regulators of the local contours of the lower level, taking into account the safety requirements. The approach using the fuzzy logic apparatus to implement the work of the upper level of the control system in order to increase the technological safety of the process is proposed. The algorithm of the upper level of the control system is presented taking into account the frequency of obtaining information about the state of the process. To prevent an emergency in the intervals between obtaining information about the state of the process, it is proposed to use a mathematical model of the process with periodic adjustment of the input data used for calculations. The proposed version of the control system can reduce the number of emergency stops of the process, which will lead to saving resources and reducing environmental pollution.

Parametric Synthesis of a Robust Controller Based on the Method of Dominant Poles

In the paper a linear control system described by its characteristic polynomial with interval coefficients including parameters of controller linearly is considered. Problem of the research is finding parameters of a controller guaranteeing dynamic characteristics of a system despite interval parametric uncertainty of its object. It is proposed to base a controller synthesis on root quality indices: minimal stability degree and maximal oscillability degree. Desired values of these indices will be provided with the help of dominant poles method. Applying this method consists in placing a pair of complex-conjugate dominant poles; all other poles — unrestricted poles — will be placed by defining a right border of their allocation area on a complex plane. To apply dominant poles method, a feature of stability degree and oscillability degree to be determined by images of certain vertices of a parametric polytope was used. To synthesize a controller, it is proposed to divide its parameters in two groups: dependent ones and unrestricted ones. The first group of controller parameters is to provide desired allocation of dominant poles in one of vertices of parametric polytope (a dominant vertex). Unrestricted parameters of a controller are to provide desired distance between dominant poles and allocation area of unrestricted poles. To find coordinates of a dominant vertex and verifying vertices providing unrestricted poles allocation, an interval extension of basic phase equation of a root locus theory was developed. This resulted in interval phase inequalities, whose solution allows finding coordinates of desired vertices of characteristic polynomials coeffi cients polytope. Knowing a dominant vertex polynomial and dominant poles allows expressing dependent parameters of a controller from unrestricted ones. Obtained expressions allow placing unrestricted poles in a desired area of a complex plane. To do this, a D-partition by unrestricted parameters of a controller is performed in all verifying vertices of parametric polytope of a system. After choosing values of unrestricted parameters from intersection of all stability domains obtain during D-partition, dependent parameters of a controller can be calculated. An example of synthesizing a PID-controller guaranteeing desired values of dynamics characteristics for an interval control system of the fourth order is provided.

Toward Optimizing Dynamic Characteristics of Non-conventional TMDs in Multi-degree-of-Freedom Systems

This study proposes a new method toward optimizing the design of non-conventional tuned mass dampers in multi-degree-of-freedom systems. An important application of the proposed method is in mega-sub-controlled structures in which the seismic vibration of the system is controlled by using isolated sub-structures. The method estimates the optimum parameters of the sub-structures including frequency ratio and damping ratio based on formulations derived for optimal design of SDOF systems with tuned mass dampers. The method is verified by comparing the results with a numerical method. It is shown that the proposed method returns the optimum parameters with acceptable accuracy (less than 5% difference from numerical results), and in some cases the results are identical to the numerical method. In the final part, the method is applied to three mega-structures with different control systems in order to examine its accuracy in predicting the optimum parameters of the non-conventional tuned mass dampers. It is concluded that the method is efficient and can be used for optimal design of such systems.

A comparison on effectiveness of financial control structure b/w divisional secretariat divisions of jaffna & Kilinochchi districts

The success and survival of an organization depends on effective utilization of resources. Every organization needs to adopt effectiveness of financial control system in order to get optimum utilization from their resources. Financial control is at the core of every organizations fulfilling its mission and achieving its goals while providing safeguards to protect organizational resources. The objectives are to evaluate on the prevailing effectiveness of financial control system, to identify which factors are mostly influencing the effectiveness of the financial control system and to recommend a crackdown action and suitable structured changes. Conceptualization model includes control environment, internal control, financial planning, budgetary control and auditing to evaluate the effectiveness of financial control system in Jaffna and Kilinochchi DS divisions. To analyse the effectiveness of financial control system, 124 employees were taken as sample from the seven DS division for each district. Data were collected from 109 employees of Accounting Department related with accounting works by questionnaires. Method of analysis specifically considered unilabiate analysis and independent sample t test. The study reveals that there are high level of implemented financial control system in both districts. But, implemented financial control system in kilinochchi is higher than Jaffna and there is a significant difference between both districts. Further, some recommendations are given to government and police makers to achieve the perfect level of financial control system.

Performance Assessment of FO-PID Temperature Control System Using a Fractional Order LQG Benchmark

In this paper, a fractional order LQG benchmark is proposed for the control performance assessment of fractional order control systems. Similar to the conventional LQG benchmark, the fractional order LQG performance benchmark curve is determined by the numerical calculation method, which avoids the calculation of the complex interaction matrix. The fractional order process model is discretized via fractional order calculus. Meanwhile, the fractional order integral is introduced into the conventional LQG cost function. Then solving the linear quadratic Gaussian problem under the fractional order model and fractional control, the optimal input and output variances are determined for different weighting factors and the performance curves can be achieved. The comparison between fractional order LQG and the conventional LQG shows the improvement of the proposed benchmark under the same condition. The proposed benchmark can provide a more direct and superior reference standard to evaluate the performance of fractional order control system. Finally, a case study of fractional order PID(FO-PID) controller in industrial heating furnace temperature control experiment with model matching and model mismatch conditions is used to verify the effectiveness of the proposed benchmark.

Experimental Approach of Various Controller Tuning Methods for Integrating Processes With Dead Time

PID control is widely used in industrial control systems in order to adjust the controller gains according to change in plants. In this proposed work, controller tuning is performed automatically based on various tuning formula. The responses of various tuning methods for integrating process are analyzed for process with dead time.

Magnitude of Voltage Sags Prediction Based on the Harmonic Footprint for Application in DG Control System

Grid condition information extraction is very important for converter control systems in order to perform special functionalities, especially grid support during low voltage ride through (LVRT). As a part of grid condition detection, the voltage sag detection provides information about the start of a fault and obtains indices that determine the behavior of the whole control system of the converter during a fault. Estimation of the magnitude of voltage sag (MoVS) is essential for obtaining proper grid support. This paper presents an algorithm for MoVS (as defined in IEEE Std 1564-2014) prediction. The existence of correlation between magnitudes of a set of low-order harmonics during the transient of voltage PQ events with MoVS is for the first time determined and statistically proved. Correlation is mathematically formulated and the prediction function is obtained on the basis of real grid measurements. Complete algorithm for magnitude prediction is explained, and its possible application in distributed generation control is prese-nted. It is shown that significant time gain is achieved, which may be used as an additional benefit in LVRT operation.

Parametric synthesis of a robust PID-controller for interval control system with aperiodic transient process

The paper is dedicated to a problem of synthesizing a PID-controller, which provides and aperiodical transient process of desired duration in a control system of the third order with interval parametric uncertainty. To solve the problem, a new method of synthesis was developed. It is based on a decomposing a characteristic polynomial of a considered system in two multipliers: dominant polynomial, which determines allocation of a dominant pole and, consequently, quality of a transient process in a considered system, and non-dominant polynomial, which determines allocation of all other system poles. In order to provide a desired allocation of system poles, parameters of a PID-controller are divided to unrestricted ones and dependent ones. The research resulted in algebraic expressions for calculating dependent parameters of a PID-controller and a system of inequalities for finding its unrestricted parameter. Developed method of a PID-controller parametric synthesis allows placing an interval real dominant pole according to desired control quality and placing all other poles of a system in a desired part of a complex plane to provide necessary degree of a robust pole domination.

Active disturbance rejection control for fractional-order PID control system research

The active disturbance rejection control (ADRC) extended to the fractional-order control system, fractional-order proportional–integral (PI) and proportional–integral–derivative (PID) controllers are the most commonly used controller. This paper presents a simple fractional-order control system combined with ADRC control system. By treating the fractional-order as a common disturbance and actively rejecting it, an ADRC can achieve the desired response. External disturbance, sensor noise, and parameter disturbance is also estimated using extended state observer. Simulation on ADRC fractional order model stability analyzes. The results showed that, ADRC fractional order control system object has good control performance.

Investigation of the axial load effect on the vibration and topography of the AFM oblique four-layered piezoelectric micro-cantilever

In this paper, the vibration behavior of atomic force microscopy (AFM) micro-cantilever (MC) with a piezoelectric layer in the non-contact mode considering the axial load in the air medium was studied. In the dynamic modes of AFM nano-robot, parameters such as amplitude, frequency and motion phase are used as feedback factors in the control system in order to extract sample surface information and the nanoparticle voltage. Consequently, to extract these parameters, the vibration analysis of the MCs of this nano-robot is essential. Additionally, because of the wide-spread applications of oblique MCs, applying the axial and transverse forces into the model is absolutely necessary. In order to simulate the AFM four-layered piezoelectric MC with the axial displacement, Timoshenko beam theory as well as modified couple stress theory has been used. Considering the axial displacement in the modeling not only leads to more degrees of freedom, but also has increased the amount of calculations. To extract the equations of the system, energy method has been used, and then, the FEM was applied to discrete the equations. To verify the accuracy of the results, the frequency and time responses of FEM have been compared with the results of the 3D mode simulation obtained by COMSOL software and experimental results. The comparison of results indicates that modifying the modeling by considering the axial displacement has increased the accuracy of the frequency and time responses. The error percentage of the first frequency response is 0.42% and the error percentage of the time response is 0.0053%. Furthermore, to examine the effect of MC geometry on its vibrational behavior, frequency and time responses of three common geometries of AFM MCs have been extracted. The results illustrate the improvement of modeling in all three geometries. Then, the sample surface topography of MCs at the first and second excitation frequencies in contact with rectangular roughnesses demonstrated the decline of time delay at the second excitation frequency. The results of the topography simulation in the air environment show that the roughness’s trend is better at the second mode than at the first mode. Finally, the effect of MC angle on the topography of the rectangular MC surfaces in contact with the rectangular roughness in 2D and 3D modes was examined in the presence and the absence of axial load. The results show that in the presence of the axial displacement in modeling, by increasing of MC angle, the topography quality increases drastically.

Optimal Dynamic Harmonic Extraction and Suppression in Power Conditioning Applications

Power quality in electrical systems is a basic requirement that should be guaranteed. Nonetheless, the increase of power-electronics-based applications and other nonlinear loads have induced harmonic distortion degrading the power quality; therefore, effective methods to measure and suppress such distortion need to be developed. The main contributions of this article are the following: the development of a novel fast-converging optimal estimator to determine online the harmonic components of a time-varying signal, which can be used for analysis and control purposes; the usage of the estimator to generate reference signals for an optimal control system in order to suppress the harmonics components; and the experimental validation of the proposed methodology as a feasible solution for industrial applications. The proposal considers practical assumptions such as the signal to be analyzed is corrupted with noise and contains time-varying harmonics (i.e., no steady-state condition is assumed). As an application of the harmonic estimator, the following two experimental tests are carried out: first, the optimal determination of the harmonic components of the current waveform in a nonlinear load, and second, the usage of harmonics information to mitigate them through of an active power filter, which is controlled by using an optimal trajectory tracking control scheme.

Finite-Time Adaptive Fuzzy-Neural-Network Control of Active Power Filter

In this paper, an adaptive fuzzy-neural-network (AFNN) control using nonsingular terminal sliding mode control is proposed for active power filter (APF) as a current controller to attenuate the effect of unknown external disturbances and modeling uncertainties. First, the dynamic model for APF is built in which both the system parameter variations and external disturbance are considered. Then, a nonsingular terminal sliding mode control based on the backstepping (NTSMB) approach is presented for the current control system to solve singularity point problem and realize the fast and finite-time convergence. Moreover, AFNN is designed to relax the requirement of the prior knowledge of system parameters to improve the robustness of NTSMB. In the AFNN strategy, AFNN framework is designed to mimic the NTSMB, where the parameters are adjusted online by the adaptive law derived from the projection algorithm and the Lyapunov stability analysis, to guarantee tracking performance and stability of the closed-loop system. Simulation studies demonstrate that the proposed control methods exhibit excellent performance in both steady-state and transient operation compared to traditional sliding mode control. Experimental results are provided using a fully digital control system in order to validate the performance of the proposed controller.

Modeling a fractional order control system with a high-inertia control object using the example of an antenna rotator stabilization system

The paper considers the problem of achieving high quality control of the system with an object having a high-inertia component. Modeling a stabilization system with a classical proportional-integral-differential controller (PID controller) showed that when using such a controller, it is not possible to achieve the desired control quality due to the long time needed to establish a transition process with the required overshoot. We suggested a hypothesis that using a fractional order PID controller (FPID controller) it is possible to solve this problem. We carried out mathematical modeling of the system with the FPID controller and revealed that the FPID controller can significantly reduce the time needed to establish the transition process of the system under consideration. The study describes elements with fractal impedance based on a resistive-capacitive medium, and gives a description of their model. The adequacy of the mathematical model is confirmed by means of the sheet-oriented model in the LTSpice program using the selected model. Conclusions are made about the feasibility and necessity of conducting research in the field of design and manufacture of a FPID controller and elements with fractal impedance

НАУКОВО-МЕТОДИЧНИЙ ПІДХІД ДО ВИЗНАЧЕННЯ МІСЦЯ ВАЛЮТНОГО РЕГУЛЮВАННЯ В СИСТЕМІ ДЕРЖАВНОЇ ЕКОНОМІЧНОЇ ПОЛІТИКИ УКРАЇНИ

На підставі проведеного аналізу запропоновано авторське визначення поняття «валютне регулювання». Крім того, досліджено особливості системи валютного регулювання, а також визначено його місце в системі державного регулювання економіки України. Доведено, що валютне регулювання характеризується не тільки як елемент валютної політики, а й як складова частина загальної системи інструментів економічної політики держави.

Parallel Architecture of Reconfigurable Hardware for Massive Output Active Noise Control

Filtered-x Least Mean Squares (FxLMS) is an algorithm commonly used for Active Noise Control (ANC) systems in order to cancel undesired acoustic waves from a sound source. There is a small number of hardware designs reported in the literature, that in turn only use one reference signal, one error signal and one output control signal. In this paper, it is proposed a 3-dimensional hardware-based version of the widely used FxLMS algorithm, using one reference microphone, 18 error microphones, one output and a FIR filter of 400[Formula: see text] order. The FxLMS algorithm was implemented in a Xilinx Artix 7 FPGA running at 25 MHz, which allowed to update the filter coefficients in 32.44[Formula: see text] s. The main idea behind this work is to propose a pipelined parallelized architecture to achieve processing times faster than real time for the filter coefficients update. The main contribution of this work is not the ANC technique itself, but rather the proposed hardware implementation that utilizes integer arithmetic, which provided an acceptable error when benchmarked with a software implementation. This parallel system allows a scalable implementation as an advantage of using FPGA without compromising the computational cost and, consequently, the latency.

Approximate Controllability of Infinite-Dimensional Degenerate Fractional Order Systems in the Sectorial Case

We consider a class of linear inhomogeneous equations in a Banach space not solvable with respect to the fractional Caputo derivative. Such equations are called degenerate. We study the case of the existence of a resolving operators family for the respective homogeneous equation, which is an analytic in a sector. The existence of a unique solution of the Cauchy problem and of the Showalter—Sidorov problem to the inhomogeneous degenerate equation is proved. We also derive the form of the solution. The approximate controllability of infinite-dimensional control systems, described by the equations of the considered class, is researched. An approximate controllability criterion for the degenerate fractional order control system is obtained. The criterion is illustrated by the application to a system, which is described by an initial-boundary value problem for a partial differential equation, not solvable with respect to the time-fractional derivative. As a corollary of general results, an approximate controllability criterion is obtained for the degenerate fractional order control system with a finite-dimensional input.

Kernel methods for the approximation of discrete-time linear autonomous and control systems

Methods from learning theory are used in the state space of linear dynamical and control systems in order to estimate relevant matrices and some relevant quantities such as the topological entropy. An application to stabilization via algebraic Riccati equations is included by viewing a control system as an autonomous system in an extended space of states and control inputs. Kernel methods are the main techniques used in this paper and the approach is illustrated via a series of numerical examples. The advantage of using kernel methods is that they allow to perform function approximation from data and, as illustrated in this paper, allow to approximate linear discrete-time autonomous and control systems from data.

Model-Based Quality Control System for Error Reduction in the Thermoforming Process

Model-based quality control has the potential to reduce the reject rate in the production of fiber-reinforced plastics (FRP) components. After all the cross-market establishment of FRP, undesirable quality deviations often occur with new materials or component shapes. The quality control uses the component quality (e.g. component angle, crystallinity, fiber orientation, pore content) as the control variable. As a key component of the control, a process model is developed to link the process parameters (press pressure, press duration and tool temperature) with the quality parameters. Knowledge of the process-determining cause-effect relationships is necessary to ensure that different quality parameters are in the target value at the same time. Based on experimental tests, these interrelationships are determined using methods of statistical test planning and serve as the basis for model-based quality control. As a result, it has been shown that the targeted control of the component angle is possible in a range of about ±1° by using the control parameters, tool temperature and pressure, which have a significant influence on the quality. In the next step, further quality characteristics are included in the control system in order to demonstrate the ability to control the quality of complex component specifications. Model-based quality control is particularly promising for the reduction of the process run-in phase and thus for the reduction of the reject rate.

Sensitivity Analysis and Control Methodology for Linear Engine Alternator

<div class="section abstract"><div class="htmlview paragraph">Linear engine alternator (LEA) design optimization traditionally has been difficult because each independent variable alters the motion with respect to time, and therefore alters the engine and alternator response to other governing variables. An analogy is drawn to a conventional engine with a very light flywheel, where the rotational speed effectively is not constant. However, when springs are used in conjunction with an LEA, the motion becomes more consistent and more sinusoidal with increasing spring stiffness. This avoids some attractive features, such as variable compression ratio HCCI operation, but aids in reducing cycle-to-cycle variation for conventional combustion modes. To understand the cycle-to-cycle variations, we have developed a comprehensive model of an LEA with a 1kW target power in MATLAB<sup>®</sup>/Simulink, and an LEA corresponding to that model has been operated in the laboratory. This MATLAB<sup>®</sup>/Simulink numerical model has been used to examine the sensitivity of the LEA dynamics and performance parameters to changes in the design and operating inputs. The sensitivity analysis provides insight into the pathway for improving and optimizing the design, as well as an assessment of the effects of modeling assumptions on the reliability of predictions. A difficulty during the modeling is associated with the cycle-to-cycle energy balance for the LEA, and it is clear that this difficulty is reflected in real-world LEA control. If the alternator consumes more energy in a cycle than the engine provides, the system moves towards a stall. If the alternator consumes less energy, then the stroke, compression ratio and maximum translator velocity must rise steadily from cycle-to-cycle until efficiency losses curb the increase. The authors have recognized that the control of this energy balance in the model affects sensitivity analysis and must, therefore, mimic the real world intended control methodology. To understand the LEA behavior further, a control methodology was developed based on the basic feedback control systems in order to monitor the compression ratio of the single cylinder LEA system from cycle-to-cycle, with a view of keeping compression ratio substantially constant. Initially, the LEA system behavior was analyzed with and without the external controller, mainly to highlight the importance and need for an external control methodology. Further, two different control strategies were implemented and investigated. Finally, the cycle-to-cycle variations were studied as spring stiffness increased, by introducing combustion stochastics. With the proposed controller strategies and the addition of stiff springs, the cycle-to-cycle variations were reduced, and the LEA system operated steadily.</div></div>