Automatic Control Device Research Articles

On the influence of electric power quality on the decimation of currents and voltages of utility frequency

The electric power industry cannot develop without analyzing the factors that affect the shape of currents and voltages when determining the parameters of the electric network mode in the context of the introduction of modern means of intellectualization into the structure of power supply systems. The share of equipment affecting the electric power quality reaches 90% in modern electrical networks. This leads to the appearance of noise in the network that reduces the quality of electrical energy, voltage distortion by higher harmonic components in particular, and affects the adequacy of the parameters of the electrical network adopted by automatic control devices. The article presents the results of digital signal processing containing distortions in the form of a harmonic component with a decrease in the sampling frequency. It is shown that a decrease in the sampling frequency does not exclude the effect of higher harmonics on the result of processing signals, including high-frequency distortions.

Control of quality and modes of power supply systems using contactless devices

The article discusses the issues of creating contactless switching devices for automatic quality control and operation modes of power supply systems, using the developed contactless thyristor voltage relays, characterized by high reliability and speed, combining a sensitive system and a powerful final controlling element. Schemes with operating principles and experimental characteristics are given. It is proposed to use it to automatically turn on or off the booster transformer winding when the input voltage changes to maintain the rated voltage of electricity consumers, as well as to create a power regulator for capacitor banks of reactive energy compensating devices.

MATHEMATICAL MODEL OF THE RECEIVING PATH OF DIGITAL COMMUNICATION LINES

Modern trends in the development of digital communication lines of fixed information transmission services, as well as the characteristics of continuous channels today determine the noise immunity of radio receiving systems. The main directions of its increase in terms of the radio receiving device as a whole and the demodulator device in particular are as follows: reducing the frequency and nonlinear distortions of the signal in the linear path, increasing the stability and purity of the spectral line of oscillations of local oscillators, increasing the selectivity for the mirror and combination channels of reception, compensation for intersymbol and cross – polarization interference, improving the functioning of the automatic gain control device (reducing static and dynamic errors), improving the quality of the functioning of the carrier wave recovery device and the clock synchronization device. Taking into account all of the above factors in order to increase the overall noise immunity of a digital communication line is a very difficult and urgent task, the solution of which must begin with the development of a mathematical model of a continuous digital communication line channel. This article discusses the radio receiving path of a digital communication line in an urban environment. The obtained analytical expressions are aimed at interpreting the processes of converting digital signals in the structural elements of radio receiving systems. The originality of the mathematical model developed in the article lies in the fact that it additionally, in comparison with similar models, takes into account the following number of factors: frequency instability and phase fluctuations of oscillations of the local oscillator synthesizer, dynamic and static errors in the operation of automatic gain control devices, carrier vibration recovery devices and devices clock synchronization of radio receiving systems of digital signals.

Approaches to motion control intellectualization of a mobile robot

The paper considers the principles of intelligent motion control of mobile robots using the example of omni-wheel modules. The proposed design solution uses components of movement intelligence in any direction, receiving commands from a human operator or above a standing automatic control device, consisting of an angle of movement direction and the required distance of movement. This paper presents an embodiment of using omni-wheels to move a mobile robot over a flat surface. Features of device and application of drive with three omni-wheels in comparison with differential drive are considered. Kinematics, basic principles of motion control formation, hardware and software complex for its implementation are described. There were revealed two alternative methods of organization of drive control in conditions of shortage of low-level hardware resources on the basis of 8-bit microcontroller, their advantages and disadvantages have been analyzed. Process support and materials have been presented that allows realizing the competitive advantages of development while minimizing the cost of components. Features of mobile robot travel route development have been mentioned on the example of competitive practice.

PHOTOELECTRIC METHODS FOR AUTOMATIC LINEAR DENSITY CONTROL COTTON TAPES

The current problem of automatic control and stabilization of the weight of cotton belts at the spinning mill is highlighted. Structural diagrams are given and the principle of operation of an optoelectronic device for automatic control and stabilization of the weight of cotton bands is described. The principle of the optoelectronic method for monitoring the linear density of cotton tapes is stated.

Information FUZZY-technologies in energy

The provisions for voltage mode group control using automatic control devices for the operation of power transformers with voltage regulation under load have been developed. This approach allows to select the rational voltage with minimal economic damage due to energy losses. The provisions are based on the use of fuzzy logic methods.

Device for automatic pressure regulation in a chamber with a liquid technological medium isolated from the pressure source

The functional capabilities of traditional devices for automatic pressure control of various liquid media are analyzed. A diagram of a device for smoothly changing the pressure of a liquid process medium in a chamber with a built-in metal bellows hydraulic displacer, the cavity of which is connected by a pressure-drain pipeline with built-in proportional flow regulator and a shut-off valve with a pressure source for the liquid working medium, is considered. Smooth pressure change is ensured by changing the switching frequency of the shut-off valve.

A Novel Automatic Inflow-Regulating Valve for Water Control in Horizontal Wells.

Horizontal wells are prone to water coning and imbalanced inflow profile problems because of reservoir heterogeneity, the “heel-toe” effect, and different water avoidance heights. To solve these problems, an automatic inflow control device (AICD) technology is developed, as the traditional inflow control device (ICD) technology is frequently invalid after water breakthrough. In this study, a novel water control tool, an automatic inflow-regulating valve (AIRV), was designed to balance inflow profiles before water breakthrough and to limit water inflow after water breakthrough. With the use of a movable part, the AIRV can quickly distinguish fluids and limit the water output based on differences in fluid properties and the swirling flow principle. The water control efficiency and ability of the AIRV were simulated and optimized using computational fluid dynamics (CFD) software and verified experimentally using a water control testing system specially designed for the AIRV. We observed that (1) the total water force on the movable component of the AIRV is notably larger than that of oil because the swirling intensity of water is significantly higher than that of oil; moreover, the force directions of water and oil are opposite to each other. (2) The AIRV is sensitive to the flow rate and fluid viscosity but not to fluid density. (3) A higher water cut results in a higher AIRV pressure loss. The results of the CFD simulation and experimental test demonstrated that the AIRV has a significant water control ability and efficiency, particularly under conditions of a high production rate and high water cut. Thus, the AIRV can be used to enhance the control of water inflow before and after water breakthroughs in horizontal wells.

Pengaturan Irigasi Berbasis Iot Untuk Persawahan

Water is the most important part of the agricultural system that cannot be replaced by other media, the problem is that on agricultural land with a limited amount of water this water must be divided equally by all farmers. Often there are disputes between farmers over fighting for water. In the traditional irrigation system, there is generally someone appointed by the residents to manage irrigation in the fields. This officer will open the lid of the irrigation system by hoeing the rice fields and waiting for the water to fill the rice fields to a predetermined limit. But there are frequent water thefts by residents who can't wait to queue. This study aims to design an automatic control device for water flow in rice fields that can make it easier to provide water to the rice fields. The design of the system begins with the use of an Arduino Uno microcontroller, as a system controller, a servo motor to open and close the floodgates, NodeMCU for communication with Telegram and a water level to set a water volume level limit in a rice field can be formulated by measuring the area of land multiplied by the water level. Officers can provide instructions via Telegram installed on the smartphone, so opening and closing the floodgates can be done remotely. With this system, it can help officers and farmers to manage the water supply schedule without having to go to the fields to open rice fields and wait for the water to reach its maximum limit. This system works well if it is supported by a good irrigation network infrastructure

Exploratory Research to Improve Energy-Efficiency of a Ground-Coupled Heat Pump Utilizing an Automatic Control Device of Circulation Pump Speed

Ground-coupled heat pumps (GCHPs) are an efficient thermal energy production system that can satisfy the gap between heating and air-conditioning. Be that as it may, exploratory research on GCHPs is still lacking. The first objective of this article is to describe a utilitarian energy-efficiency improvement device for a vertical GCHP system that includes a buffer tank (BT) between the heat pump unit and the fan coil units and user supply, utilizing the quantitative regulation of water flow rate with a variable-speed circulation pump. At that point, the investigative estimations are utilized to test the performances of the GCHP system in various operating modes. Fundamental efficiency parameters (coefficient of performance (COP) and CO2 emission) are achieved for one month of running utilizing two control strategies of the GCHP—standard and optimized regulation of the water pump speed—and a benchmarking of these parameters is achieved. Exploratory research has indicated higher efficiency of the system for the flow regulation solution utilizing a BT and programmed control equipment for the circulation pump speed compared with the standard regulation solution (COPsys with 7–8% higher and CO2 emission level 7.5–8% lower). The second objective is to elaborate a simulation model of the necessary heat/cold in heating and air-conditioning periods, utilizing the Transient Systems Simulation (TRNSYS) program. Finally, the simulation, acquired utilizing the TRNSYS program, is analyzed and compared with experimental information, leading to a good agreement and, along these lines, the simulation model is approved.

DESIGN TIMED FSM WITH VHDL MOORE PATTERN

Context. The relevance of the work consists in the development of computer-aided design methods for automatic real-time logic control devices by developing a single template in a synthesized subset of the hardware description language in the style of automatabased programming with implementation on the PLD hardware platform (FPGA, CPLD). Development of the description template for timed control finite state machines (FSM) in the hardware description language VHDL, automated synthesis and implementation of the model in PLD (FPGAs, CPLDs) using Xilinx ISE, subsequent analysis of the received circuit implementation for compliance with values of timing parameters of the circuit after implementation.Objective. The aim of the work is to develop principles for constructing models of timed control FSM in the VHDL hardware description language. In this work, we solved the problem of constructing a pattern for describing models of timed control Moore FSM using VHDL, automated synthesis and implementation of the obtained VHDL model in PLDs (FPGA, CPLD) using Xilinx ISE and subsequent analysis of the resulting circuit implementation for compliance with values of timing parameters of the circuit after implementation.Method. Realization of models’ parameters of timed FSM in logical control systems using VHDL statements. Development of VHDL language constructions of timed FSM models for timing parameters implementation that provide the correct automated synthesis and implementation of these models in PLDs (FPGA, CPLD) using CAD tools Xilinx ISE.Results. Synthesis and implementation of proposed templates of VHDL-models of timed control Moore FSM in logic control systems by XILINX ISE CAD tools confirmed the receipt of not redundant circuits in PLD (FPGA, CPLD), and simulation after implementation showed the efficiency of such models.Conclusions. The work solves the problem of computer-aided design of timed control FSM in real-time logic control systems. To solve this problem, VHDL-models of timed control Moore FSM were developed, which made it possible to implement control FSM with time constraints, timeouts and output delays. Automated synthesis and simulation of VHDL models based on the developed templates confirmed the efficiency and correctness of the proposed models.The scientific novelty of the work consists in the further development of methods for constructing templates of HDL models of timed control Moore FSM, which made it possible to implement control FSM with time constraints, timeouts and output delays, as well as perform their correct automated synthesis and simulation.The practical value of results is in the development of procedures for constructing VHDL models of timed Moore control FSM in real-time logic control systems, which made it possible to automate the synthesis of control FSM taking into account the possibility of processing external events and implementing arbitrary delays for output signals and to increase the flexibility and speed of designed systems. The developed procedures can be useful for designers of timed control FSM in Xilinx ISE.

Modernization of Automatic Chemical Control of TPP Power Units Based on Conductivity and PH Measurements

Increasing the volume and tightening the quality standards for the water heat carrier of power units require the modernization of the chemical control system at thermal power plants (TPPs). The development of information technologies ensures the creation of automated systems of chemical-technological monitoring (SCTM) and individual devices focused on the application of reliable and inexpensive analyzers such as conductometers and pH meters with data processing using algorithms of any complexity. SCTM of feed and boiler water based on measurements of specific conductivity and pH were developed and tested under industrial conditions. Together with NPP Tekhnopribor (Moscow), a new generation analyzer Leader-APK, similar to the latest generation analyzer AMI Deltacon Power (SWAN Company), was developed. Using the analyzer in the chemical control system of a power unit of combined cycle gas turbine power plants (CCGT) allows reducing the number of automatic control devices by seven units.

Application Analysis of PLC Technology in Automatic Control of Ship Auxiliary Machinery

Gao, M., 2020. Application analysis of plc technology in automatic control of ship auxiliary machinery. In: Bai, X. and Zhou, H. (eds.), Advances in Water Resources, Environmental Protection, and Sustainable Development. Journal of Coastal Research, Special Issue No. 115, pp. 130-132. Coconut Creek (Florida), ISSN 0749-0208.In the process of ships sailing on the sea, auxiliary machinery and equipment play an indispensable role, which not only can provide necessary services for ships, but also can ensure the normal navigation of ships. As an advanced technology, PLC technology of mechanical automation control has obvious characteristics, flexible and convenient operation and wide functions. The application of PLC technology in the automatic control system of ship auxiliary machinery is studied and analyzed to provide more favorable support for stable navigation of ships. In the application process of PLC ship auxiliary machinery control system, incomplete information, insufficient data and other uncertain factors will also have a great impact on the system, which will threaten the reliability of the system. Therefore, it is of great significance and far-reaching influence to strengthen the application of PLC technology in automatic control devices of ship auxiliary machinery.

EXPERIMENTAL VERTIFICATION FOR APPLYING NEUTRAL EQUILIBRIUM MECHANISM AS MULTIPLE VIRTUAL PIERS OF DISASTER RELIEF BRIDGE

The purpose of this research is to develop an active-control mechanism and its control law, to reduce the deformation of the relief bridge and weight of construction materials and improve the effective span of the bridge. The counter-force (control force) mechanism, provided by Neutral Equilibrium Mechanism, NEM, is applied to exert a counter-force at the selected position of the bridge and maintain the deflection at this selected position to be zero. This proposed NEM is used as a counter-force mechanism, which is an automatic control device consisting of a pair of pressed steel strands, rotary cantilever arm mechanisms, a displacement sensor and a controller to form as a virtual pier. In this study, these proposed counter-force mechanisms are installed at the positions of 1/3 and 2/3 span of the bridge: the effective span is only 1/3 of the original span, the maximum bending moment and maximum deflection is only 1/9 and 1/27 of the original bridge, respectively. The experimental results display that the ideal behavior of this NEM can be fully achieved in the dynamic moving load test. The deflection and the bending moment of the bridge at the position of installing these NEMs are near zero. The goals of reducing deformation and improving the carrying capacity of the bridge are realized.

Experimental investigation of solar water heater equipped with a solar collector using waste oil as absorber and working fluid

In this study, a novel solar water heater system is proposed. Its flat plat collector uses waste engine oil as absorber and heat transfer fluid at the same time, and it is equipped with a controlled sun tracker photovoltaic system to maximize the collected solar irradiation. A photovoltaic system is designed and incorporated to supply the various DC electrical devices (electronic control system, oil pump, etc). The various experimental tests carried out under the real climatic conditions of Tipaza, which is located in Algerian coast, showed that this system is effective; it can meet the hot water needs for the households in wintry time. Indeed, the results were very satisfactory since the system reaches an acceptable heating temperature, 50°, in less than three hours; with heating efficiency mean rate convergence of 65% while its maximum efficiency reaches 80%. In addition, the system can work with domestic electricity as an appoint auxiliary source in the case of the absence of sunlight (climatic conditions, cloudy sky or night) with an automatic control device.

VERIFICATION AND OPTIMISATION OF PRESELECTED EXPOSURE PARAMETERS IN SCREENING MAMMOGRAPHY: A CENTRAL COMPOSITE DESIGN METHODOLOGY.

In screening mammography, the automatic exposure control (AEC) device selects the optimum exposure parameters for each patient exposure. In practice, this device is calibrated to deliver an optimum figure of merit (FOM) for each set of exposure parameters. This study utilises the central composite design methodology to verify the operating level of the AEC performance for polymethyl methacrylate (PMMA) thicknesses of 4 and 5cm. Quadratic surface plots reveal that the exposure parameters of the default AEC mode are optimised for the 4-cm thickness of the PMMA. However, the exposure parameters of the 5-cm thickness of PMMA need fine-tuning to obtain a maximum value for the FOM.

Design and Implementation of an Automatic Indirect Hybrid Solar Dryer for Households and Small Industries

The agricultural sector in most developing nations is seriously impacted with post-harvest losses emanating mainly from the use of inappropriate drying and storage facilities. With regard to these limitations identified, this works discusses the design, the construction and test of an indirect hybrid solar dryer for home and industrial applications. The dryer consists of solar collector, drying chamber, axial fans, photovoltaic solar panels, battery and automatic control devices. The dryer performance was evaluated with tomatoes slices under two drying modes i.e. the solar drying and hybrid solar drying modes. A maximum chamber temperature of 46°C was recorded in the hybrid mode under an average insolation of 318.74W/m 2 while 39.9°C was attained in the solar mode with an average insolation condition of 303.7W/m 2 . The average drying rate in hybrid mode was computed as 19.7g/h with 6.83% efficiency whereas 10.5g/h was obtained in solar mode with 4.8% efficiency. On the basis of moisture content, the drying test revealed that the quality of the product dried using the hybrid dryer was superior compared to that dried with simple solar dryer alone. Hence proving that this new technology is a viable alternative to open sun drying as well as solar drying methods since the incorporation of a backup heater does not only shortens the retention time, but also allows for a continuous drying process during poor weather conditions and at night.

Обеспечение когерентности цифровой обработки сигналов токов и напряжений электроэнергетических систем при снижении частоты дискретизации

The development of Russia’s electric power industry includes, as one of important objectives, step by step intellectualization of the electric power system under the conditions of decentralized generating capacities and wide use of facilities on the basis of renewable energy sources. The Smart Energy System of Russia national project implies construction of digital substations equipped with state of the art relayprotection and automatic control devices, which exchange instantaneous values of currents and voltages. In implementing such exchange, a need may arise to decrease or increase the signal sampling frequency for optimally suiting to the process tasks. The results from analyzing the effects of digital processing involving loss of coherence of power frequency voltage and current signals, which arise in decreasing the sampling frequency, are presented. It is shown that, if the coherence requirements are not complied with in decimation, this will result in significant errors in estimating the signal parameters. It is also shown that for determining the current and voltage signals sine wave distortion degree due to loss of coherence in processing, it is advisable to use a normalized mutual correlation ratio. It has been demonstrated based on simulation results that for signals containing high frequency harmonic components, incoherent samplingaggravates the distorting effect; it is also pointed out that in analyzing distortion effects on power frequency signals, it is important to take into account the initial phases of high frequency harmonic components.

Training in metrology sphere for machine building

In order to meet the requirements for quality management of machine-building products and metrological support, the company analyzed the existing standards for confi rming the consistency of requirements. Federal state educational standards of higher education of two levels (bachelor’s degree and specialty) of the mechanical engineering profi le (ensuring the unity of measurements (GSEEI) and the professional standard of a metro specialist) were selected for the analysis. The obtained results are used in the implementation of term papers. It is recommended to cover issues related to measuring devices and automatic control devices in related disciplines, and to include the topic "Main areas of activity in the fi eld of metrological support of the enterprise".

Синтез универсального многомерного измерительно-пускового органа релейной защиты

With the application of microprocessor systems, which allow the information arriving from measurement instruments to be analyzed in a more comprehensive manner, relay protection and automatic control (RP&AC) devices have gained a wider scope of functions and more efficient performance characteristics.Better sensitivity of RP&AC devices can be achieved by increasing the number of observed parameters that characterize the operation conditions of the electric network component being protected. The article describes an approach to developing a universal multidimensional measuring and starting element that uses a specified combination of measured parameters and is able to replace the majority of existing measuring and starting elements, and which can also be used as part of a multiparametric relay protection device. The approach that involves multidimensional monitoring of the electric network operating conditions entails the need of tuning the measuring and starting element setpoints with the use of mesh functions and rectangular approximation of the actuation domains, thus opening the possibility of drawing up protection characteristics with an arbitrary form. For reducing the stored data volume and decreasing the computation burden on the processor, the setpoint refinement technology is used, which allows the protection characteristic to be shaped maximally close to the ideal one. Examples of tuning the multiparametric starting element using the technology of conditional setpoints are given.