Automatic control system refers to the use of someAutomatic control device, automatically control some key parameters in production, so that they will deviate when affected by external interference (disturbance)Normal stateIt can be automatically adjusted to return to the value range required by the process.Production processThe various process conditions in can not be static.Especially in chemical production, most of them areContinuityProduction and equipment are interrelated. When the process conditions of one of the equipment change, some parameters of other equipment may fluctuate more or less, deviating from the normal process conditions.of courseAutomatic adjustmentIt means no direct participation of people.[1]
The automatic control system is composed of controller and controlled object.However, to achieve complex control tasks, a typical automatic control system usually also includes: setting elementsActuator, measuring and transmitting elements andComparison element[2]。
Historical development
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After more than 20 years of development, China's industrial automatic control system device manufacturing industry has made great progress, especially since the 1990sIndustrial automatic control systemThe output of the device manufacturing industry has always maintained an annual growth of more than 20%.In 2011, China's industrial automatic control system device manufacturing industry has made remarkable achievements.Completed throughout the yearTotal industrial output value205.604 billion yuan;Product sales revenue199.673 billion yuan,Year on year growth24.66%;Total profit realized20.284 billion yuan, up 28.74% year on year.Domestic automatic control systems have made breakthroughs in the fields of thermal power, fertilizer and oil refining.
Chineseindustrial automation market subjectMainly from hardware and software manufacturersSystem integrator, ProductsdistributorEtc.In the field of software and hardware products, the middle and high end market is almost monopolized by foreign famous brand products, and this situation will still be maintained;staysystem integration In the field, multinational companies occupy the high-end of the manufacturing industry, with profoundIndustry backgroundThe system integration companies with rich application experience are full of competitiveness.
In the industrial automation market, there is a mismatch between supply and demand.The customer needs to be complete and able to meet their own needsmanufacturing processOfelectric control system , andsupplierAll kinds of standardized device products are provided.Different industries have great differences in electrical control, and even customers in the same industry have different needs due to different processes.This contradiction between supply and demand creates development space for the industrial automation industry.
With the increasing competition in the industrial automatic control system device manufacturing industry, mergers and acquisitions among large industrial automatic control system device manufacturing enterprisescapital operation More and more frequently, domestic excellent industrial automatic control system device manufacturers are paying more and more attention to the research on the industry market, especially the research onIndustrial developmentEnvironment and productspurchaserIn-depth research.
Given valueConstant, the system output is required to be close to the given value with a certain precisionExpected valueSystem.asProduction processTemperature, pressure, flow, liquid levelMotor speedSuch automatic control systems are constant value systems.
Servo control system
The given value is unknownTime functionChange, the output is required to follow the change of the given value.Such as following a satelliteradar antennaSystem.
Automatic control system has been widely used inhuman societyAll areas of.
In industry, for metallurgy, chemical industryMachinery manufacturingVarious problems encountered in the production processphysical quantity, including temperature, flow, pressure, thickness, tension, speed, position, frequency, phase, etc., all have corresponding control systems.On this basis, by adoptingdigital computerIt also establishes better control performance andDegree of automationHigherdigital control system , and those with dual functions of control and managementprocess control system 。Applications in agriculture include automatic water level control system, automatic operation system of agricultural machinery, etc.
In addition, on theOffice Automation, library management, traffic management and even daily household chores, automaticcontrol technology They also have practical applications.along withcontrol theoryAnd the development of control technologyapplication area It is still expanding, involving almost all fields such as biology, medicine, ecology, economy and society.
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Relevant textbooks
Title: Automatic Control System/General Higher EducationfifteenNational planning textbooks
Introduction: This book is a national planning textbook for the "Tenth Five Year Plan" of general higher education (higher vocational education). This book aims at the characteristics of higher vocational education,Theoretical knowledgeThe explanation of "must be adequate" focuses on the cultivation of application ability, which will be difficult to understandAutomatic control principleThe content of is inserted into the explanation of the automatic control system.The book introduces the closed-loop control system of DC speed regulation, reversible DCSpeed control system, DCPulse widthSpeed regulation system, digital DC speed regulation systemasynchronous motorchangeSlip rateSpeed governing system, asynchronous motorFrequency control systemEtc.
This book is divided into three chapters: the first chapter mainly focuses onphysical process The general description of common detection elements, common motors andpower electronics Operating principle of power supply circuit and other basic components (4~30 class hours).Chapter 2 includes system mathematical model, MATLAB software and its applicationsystem performance Analysis andSystem calibrationEtc.This chapter focuses on the relationship between transfer function andSystem block diagramStart with Simulinksystem simulation Analysis, mainly qualitative analysis, describes the impact of each link (and each parameter) on the system performance and the ways to improve the performance (24 class hours).Chapter 3 is the working principle, performance analysis and system commissioning of various common typical automatic control systems (16~48 class hours).This book provides readers with a complete set of basic knowledge → automatic control principle → automatic control system → specific circuit → system debugging → troubleshootingcognitive processAnd aIntegrating theory with practiceThe content is comprehensive and rich.This book is characterized by new content, integrating theory with practice, highlighting the analysis of physical processes, emphasizing the elaboration of methodology, paying attention to the review and application of basic knowledge, and being meticulous and easy to understand.According to different professional requirements, there are 6 options (50~96 class hours).Each chapter of the book has a summary, thinking questions and exercises, which are mostly problems in production practice.The book also arranges more reading materials, case analysis and picture reading exercises to help students improve their self-learning, analysis and practical abilities.In addition, there are also the introduction of the content of practical projects and corresponding practical devices matching the teaching materials.In order to facilitate the use of the new edition of teaching materials, this book also comes with a supportingMultimedia CD（CAICD).The contents of the CD include Teaching Guidance and ReferenceElectronic teaching plan】, [Self study Tutoring], [Troubleshooting], [Example Analysis], and [Practice Devices and Experiments, Training Instructions].This disc pairTeacher teachingAnd students' learning will be of great help.This book is availableApplied undergraduate、Technician CollegeCollegeHigher Vocational and Technical College、Staff CollegeElectrical engineering, applied electronicsMechanical specialty、Mechatronics、numerical control machineThe maintenance specialty and computer application specialty are also availableEngineering techniciansReference and can be used as technician and senior technicianTechnical trainingTextbooks.
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preface
Part 1 Overview of Automatic Control System and Basic Components of Typical Automatic Control System
