Bài giảng Cơ sở tự động - Chương 1: Giới thiệu về hệ thống điều khiển tự động

CƠ SỞ TỰ ĐỘNGGiảng viên: Nguyễn Đức HoàngBộ môn Điều Khiển Tự ĐộngKhoa Điện – Điện TửĐại Học Bách Khoa Tp.HCMEmail: ndhoang@hcmut.edu.vnMÔN HỌCNội dung môn học (10 chương)(14 tuần = 42 tiết LT + 14 tiết BT)Chương 1: Giới thiệu về hệ thống điều khiển tự độngChương 2: Mô hình toán học hệ thống liên tụcChương 3: Đặc tính động họcChương 4: Khảo sát tính ổn định của hệ thốngChương 5: Chất lượng hệ thống điều khiểnChương 6: Thiết kế hệ thống tuyến tính liên tụcChương 7: Mô hình toán học hệ rời rạcChương 8: Phân tích hệ rời rạcChương 9: Thiết kế hệ rời rạcChương 10: Ứng dụngTài liệu tham khảoGiáo trình: Lý thuyết điều khiển tự độngNguyễn Thị Phương Hà – Huỳnh Thái HoàngNXB Đại Học Quốc Gia TpHCMBài tập: Bài tập điểu khiển tự độngNguyễn Thị Phương HàTài liệu: Automatic Control SystemModern Control System Theory and DesignĐánh giáThi giữa kỳ : 20%Thi cuối kỳ : 60%Bài tập : 20% bao gồm: + về nhà có kết hợp mô phỏng Matlab + trên lớp : gọi lên bảng làm ( mỗi lần không làm được -1đ vào điểm thi GK, -0.5đ vào điểm thi CK )GIỚI THIỆU VỀ HỆ THỐNG ĐIỀU KHIỂN TỰ ĐỘNGCHƯƠNG 1Control Systems61769James Watt’s steam engine and governor developed. The Watt steam engine is often used to mark the beginning of the Industrial Revolution in Great Britain. During the Industrial Revolution, great strides were made in the development of mechanization, a technology preceding automation.ControlControl is a sequence of decisions aimed at the attainment of specified objectives in an environment of uncertainty and presence of disturbances.Control systemA control system is an arrangement of physical components connected or related in such a manner as to command, direct, or regulate itself or another system.InputThe input is the stimulus, excitation or command applied to a control system. Typically from external energy source, usually in order to produce a specified response from the control system.OutputThe output is the actual response obtained from a control system. It may or may not be equal to specified response implied by the input. History of Automatic ControlPrior to World War II A main impetus for the use of feedback in the United States was the development of the telephone system and electronic feedback amplifiers by Bode, Nyquist, and Black at Bell Telephone Laboratories.Prior to World War II The Russian theory tended to utilize a time-domain formulation using differential equations. World War IIDesign and construct:automatic airplane pilots, gun-positioning systems, radar antenna control systems. Sputnik and space age The time-domain methods developed by Liapunov, Minorsky, and others have met with great interest in the last two decades.Recent time Recent theories of optimal control developed by L.S. Pontryagin in the former Soviet Union and R. Bellman in the United States, and studies of robust systems, have contributed to the interest in time-domain methods.Terms and Concepts Two Types of Control SystemsOpen LoopNo feedbackDifficult to control output with accuracyClosed LoopMust have feedbackMust have sensor on outputAlmost always negative feedbackOpen-loop and closed-loop systemsOpen-loop control An open-loop control system utilizes an actuating device to control the process directly without using feedback. A common example of an open-loop control system is an electric toaster in the kitchen.Closed-loop control A closed-loop control system uses a measurement of the output and feedback of this signal to compare it with the desired output. A person steering an automobile by looking at the auto’s location on the road and making the appropriate adjustments. Control SystemsManual control systemGoal: Regulate the level of fluid by adjusting the output valve.The input is a reference level of fluid and is memorized by operator.The power amplifier is the operator.The sensor is visual.Operator compares the actual level with the desired level and opens or closes the valve ( actuator).29The level of fluid in a tank control. 30Multivariable control systemA robot is a computer-controlledmachine.Industrial robotics is a particular field of automation in which the robot is designed to substitute for human labor. The Honda P3 humanoid robot.The Control System Design ProcessDesign is the process of conceiving or inventing the forms, parts, and details of a system to achieve a specified purpose.Engineering designEngineering design Trade-off The result of making a judgment about how to compromise between conflicting criteria.Given a process, how to design a feedback control system?Three steps:Modeling. Obtain mathematical description of the systems.Analysis. Analyze the properties of the system.Design. Given a plant, design a controller based on performance specifications.Design examples Rotating disk speed controlControl SystemsStep 1. Control goalDesign a system that will held a rotating disk at a constant speed. Ensure that the actual speed of rotation is within a specified percentage of desired speed.Control SystemsStep 2. Variable to be controlledSpeed of rotation discControl SystemsStep 3. Control design specificationDesign a system that will ensure that the actual speed of rotation is within a specified percentage of desired speed.Control SystemsStep 4 Preliminary system configurationControl SystemsStep 4 Preliminary system configurationControl SystemsInsulin delivery systemThe blood glucose and insulin concentrations for a healthy person.Control SystemsStep 1. Control goalDesign a system to regulate the blood sugar concentration of a diabetic by controlled dispensing of insulin.Control SystemsStep 2. Variable to be controlledBlood glucose concentrationControl SystemsStep 3. Control design specificationProvide a blood glucose level for the diabetic that closely approximates the glucose level of a healthy person.Control SystemsStep 4 Preliminary system configurationsControl SystemsDisk drive read systemControl SystemsControl SystemsStep 1. Control goalDesign a system that will held the position the reader head to read the data stored on a track on the disk.Control SystemsStep 2. Variable to be controlledPosition of the reader headControl SystemsStep 3. Control design specificationDesign a system that will ensure that the head : - “flies” above the disk at a distance of less than 100 nm, - with the position accuracy is 1 m, - with speed from track to track 50 msControl SystemsStep 4 Preliminary system configurationControl SystemsP1.8 Student-teacher learning processConstruct a feedback model of the learning process and identify each block of the system. Control SystemsP1.8 Student-teacher learning processInverted pendulum controlE1.11 Sketch the block diagram of a feedback control system. Identify the process, sensor, actuator, and controller. The objective is keep the pendulum in the upright position ( = 0), in the presence of disturbances. Control SystemsControl SystemsInverted pendulum control