디지털제어 강의실 담당교수 고경철 기계공학부 사무실

디지털제어 강의실 : 담당교수 : 고경철(기계공학부) 사무실 : 산학협력관 105 B 면담시간 : 수시 Email : kckoh@sunmoon. ac. kr 홈페이지:

강좌소개 Text : “디지털제어” 1주: 2주: 3주: 4주: 5주: 6주: 7주: 8주: 강좌소개 및 1장 서론 2장 Z변환 3장 역Z변환 4장 Z모델링 5장 시간응답 6장 오차분석 7장 안정도 중간시험 9주: 8장 피드포워드보상 10주: 9장 주파수응답 분석 11주: 11장 DC모터 제어기설계 12주: 12장 플랜트 매개변수 추정 13주: 부록B 제어보드 설계 14주: 부록A DC모터 구동시험 15주: 13장 PID제어 실습 16주: 기말시험

평가방법 A+: A : B+: B : C+: C : D+: D : F : 95%~100% 90%~94% 85%~89% 80%~84% 75%~79% 70%~74% 65%~69% 60%~65% 0%~59% or 출석미달 Closed book Cheating Paper A 4 1장 10 times HW’s After due: no point Mid Exam: 30% Final Exam: 30% HW: 10% Project: 10% Attendance: 20% Project Demo & Report F: More than 4 absences -1 point per 1 hr. absence 교재 및 강의자료 미준비 1 st = warning 2 nd = absence.

디지털 제어 DIGITAL CONTROL 목 차 1. Introduction to Digital Control System Kyoung-Chul Koh(kckoh@sunmoon. ac. kr) 4 of 32 Sun Moon University

강의진도 디지털 제어 [1주] 1장 서론 참고문헌 [1] 고경철, 이장명 저, “C로 구현한 디지털 제어 시스템”, 홍릉과학서적, 2004 [2] Ogata, Discrete-Time Control System, [3] Dorf, Modern Control Systems, Wesley, 1998 5 of 32 Sun Moon University

1 -1. Digital systems 디지털 제어 • Recently, - rapidly increasing use of digital controller in control system - digital controller > productivity > profit > low manufacturing cost > low energy consumption Environment system s/w electric mechanical chemical biological social Fig. 1. 1 Intelligent service robot 6 of 32 Sun Moon University

1 -2. Digital controller 디지털 제어 Computerized control > intelligence to industrial robots > optimal fuel injection control of automobiles > precise control of consumer electronics facilities • Merits of digital control systems > decision capability > flexibility • Dynamic systems > analogue control -> digital control > continuous signal -> digital signal Fig. 1. 2 Industrial robots controlled by digital controllers 7 of 32 Sun Moon University

디지털 제어 DIGITAL CONTROL 목 차 1. Introduction to Digital Control System Kyoung-Chul Koh(kckoh@sunmoon. ac. kr) 8 of 32 Sun Moon University

강의진도 디지털 제어 [1주] 1장 서론 참고문헌 [1] 고경철, 이장명 저, “C로 구현한 디지털 제어 시스템”, 홍릉과학서적, 2004 [2] Ogata, Discrete-Time Control System, [3] Dorf, Modern Control Systems, Wesley, 1998 9 of 32 Sun Moon University

1 -1. Digital systems 디지털 제어 • Recently, - rapidly increasing use of digital controller in control system - digital controller > productivity > profit > low manufacturing cost > low energy consumption Environment system s/w electric mechanical chemical biological social Fig. 1. 1 Intelligent service robot 10 of 32 Sun Moon University

1 -2. Digital controller 디지털 제어 Computerized control > intelligence to industrial robots > optimal fuel injection control of automobiles > precise control of consumer electronics facilities • Merits of digital control systems > decision capability > flexibility • Dynamic systems > analogue control -> digital control > continuous signal -> digital signal Fig. 1. 2 Industrial robots controlled by digital controllers 11 of 32 Sun Moon University

1 -3. Digital Signal 디지털 제어 • classification of signals, - continuous-time analogue signal > defined in continuous time domain > magnitude >> continuous domain X( t) X(t) - continuous-time quantized signal > defined in continuous time domain > magnitude 0 t (a) >> finite number domain : quantization X( continuous signal >>> finite word length: 32 bit, 64 bit t) 0 t (b) sampled signal X( t) - sampled analogue signal > discrete time domain > continuous value domain - digital signal > discrete time domain > quantized value domain 0 t (c) quantised signal 0 t (d) digital signal Fig. 1. 3 classification of control signals 12 of 32 Sun Moon University

1 -4. Terminologies 디지털 제어 • linear system • time variant vs. time invariant sytems • discrete time control system vs, continuous time control system • interpolation • differential equation vs. linear difference equation • sampling process - Radar tracking system : scanning by beam - Plant process control: very slow response - sampling vs. discretization • Digital control system Feedforward controller + + Plant Fig. 1. 4 Open loop control system 13 of 32 Sun Moon University

1 -4. Terminologies 디지털 제어 • Feedback control system + - Feedback Loop Controller + + Plant Fig. 1. 5 Closed loop control system 14 of 32 Sun Moon University

1 -4. Terminologies 디지털 제어 • Sampling - Discretization > opp. data hold • A/D conversion - encoding - quantization - sample and hold -> AD conversion Environment system s/w electric mechanical chemical biological social • Sample and hold • D/A conversion - decoder • Plant - approximate mode - linearization - ex: furnace, chemical process, servo mechanism, aircraft, mechanical devices • Process - chemical, economical, biological processes 15 of 32 Sun Moon University

1 -5. Quantization 디지털 제어 • Quantization - nearest approximation where FSR is full-scale range Quantizer - MSB vs. LSB 0 Fig. 1. 6 Quantisation process 16 of 32 Sun Moon University

1 -5. Quantization 디지털 제어 • Quantization error - finite resolution - round-off error Fig. 1. 7 Quntisation error 17 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 Feedforward controller ++ Output D/A Hold Plant Clock Digital controller S. H and A/D + Digital Filter + _ Feedback controller ++ + input Disturbances Transducer or sensor Noise Fig. 1. 8 Block diagram of digital control system 18 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 _ 001 010 001 S. H and A/D converter 010 100 011 • Signal processing - multiplexing and demultiplexing - sample and hold - AD conversion (Quantization) - DA conversion (Decoding) - filtering Digital computer D/A converter Hold circuit Actuator Plant or process Clock Filter Fig. 1. 9 Signal processing of digital control systems 19 of 32 Sun Moon University +

1 -6. Digital Control System Physical variable Transducer Amplifier 디지털 제어 Low pass Filter Analog multiplexer Sample & Hold A/D converter To digital controller (a) A/D conversion process From digital controller Register Demultiplexer D/A converter Hold To actuator (b) D/A conversion process Fig. 10. Digital signal processors 20 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 • Demultiplexer Input channels • Analogue multiplexer - electrical swithes sample & Hold Select control Fig. 1. 11 Multiplexer 21 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 • Sample and hold circuit - hold capacitor - buffer with high input impedance - tracking mode and hole mode Anal og Amp. 1 Amp. 2 inpu t Anal og outp ut Sampler Sample and hold comma nd Fig. 1. 12 Sample and hold circuit 22 of 32 Sun Moon University

1 -6. Digital Control System • Sample and holer - tracking mode and hold mode - aperture time x(t) 디지털 제어 Input Sample to hold offset Hold mode droop signal output signal Aperture Tracking Mode time Hold t Mode Hold command Is given here Fig. 1. 13 Operation mode of sample and hold circuit 23 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 • AD conversion - quantization - types > successive approximation - MSB -> LSM - conversion time = 2 usec for 12 bit conversion > integrating type > counter type > parallel type D/A converter Digital output … …. . Successive Approximation register Analog input Clock comparator Fig. 1. 14 A/D converter circuit 24 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 • AD conversion error - offset - non-linearity - gain error 111 111 100 100 000 0 FS 1/2 FS (a) Offset error 0 1/2 FS (b) Linearity error FS 0 1/2 FS FS (c) Gain error Fig. 1. 15 AD conversion error 25 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 • DA converter - binary register R Vo 8 R b 0 4 R b 1 2 R b 2 R b 3 Vref Fig. 1. 16 Binary register circuit ref. [1] pp. 32 -33 26 of 32 Sun Moon University

1 -6. Digital Control System 디지털 제어 • DA converter - R-2 R ladder circuit 3 R 2 R R Vo 2 R b 0 2 R b 1 2 R 2 R 2 R br-3 br-2 br-1 -Vref Fig. 1. 17 R-2 R ladder circuit 27 of 32 Sun Moon University

1 -7. Hold circuits 디지털 제어 • Zero order hold Output 0 t Fig. 1. 18. Signal from zero order hold circuit 28 of 32 Sun Moon University

1 -7. Hold circuits 디지털 제어 • First order hold - efficient for slowly varying signal Output 0 Fig. 1. 18. Signal from the first order hold circuit 29 of 32 Sun Moon University

1 -7. Hold circuits 디지털 제어 • polygonal hold - instability problem Output 0 Fig. 1. 20 Signal from polygon hold circuit 30 of 32 Sun Moon University

디지털 제어 1. 8 The future evolution of control systems • Control system - flexibility - high level of autonomy HIGH • Sensory limitation - computer vision - no adaptibility to environment > need human supervision Automated society Improvements: NC Machines Robotics Improvements: Power tools *Vision *Man-machine *Sensors interface *Vision Autonomy • Advanced robotics system - task adaptibility - artificial intelligence - sensor integration - computer vision - off-line programming - human-machine interface > database management > communications > programming language Factory. Automation *Supervisory *Languages control Intelligent controller *Artificial intelligence Hand tools Electric Automatic Control machines Systems Computer Control Systems (programmable) Automatic machine LOW Flexibility HIGH Fig. 1. 21 Perspective of digital control systems 31 of 32 Sun Moon University

HW#1 디지털 제어 • 문제 1. 1, 문제 1. 3 • Due: Next week this time 32 of 32 Sun Moon University