离散时间控制系统课件

1-2 Digital Control Systems
❖ S/H and A/D (A/D)
Sample-and-Hold (S/H)
❖ Sampling Processes, replace original continuous-time signal by a sequence of values at discrete-time time points
❖Analog signal: A signal defined over a continuous range of time whose amplitude can assume a continuous range of values
❖A continuous-time quantized signal
❖ Also called an encoder, is a device that converts an analog signal into a digital signal, usually a numerically coded signal. A S/H circuit is often an integral part of a commercially available A/D converter.
❖Availablity of low-cost digital computers ❖Advantages of digital signals
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1-1 Introduction
❖ Types of Signals
Continuous-time signal: A signal defined over a continuous range of time
❖ a circuit that receives analog input signal and holds this signal at a constant value for a specified period of time.
Analog-to-Digital Converter (A/D)
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Contents
1-1 Introduction
1-2 Digital Control Systems
1-3 Quantizing and Quantization Error
1-4 Data Acquisition, Conversion and Distribution Systems
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1-5 3Concluding Comments
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1-1 Introduction
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1-1 Introduction
❖ Systems Dealt With in This Book
Linear and time invariant Discrete-Time Control Systems
❖one or more variables can change only at discrete instants of time. These instants may specify the times at which some physical measurement is performed or the memory of a digital computer is read out
❖Digital signal: A discrete-time signal with quantized amplitude
Comparison
❖Discrete-time, digital, sampled data signal (control system)
❖Continuous-time, analog signal (control system)
Course Information
❖ Time: 13:30-15:10pm, Wednesday
10:00-11:40am, Friday (even weeks)
❖ Venue: 综B204
❖ References:
离散时间控制系统(英文版第2版)，Katsuhiko Ogata，机械工 业出版社，2004
Described in linear difference equations with constant coefficients
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Hale Waihona Puke 1-2 Digital Control Systems
Figure 1-2 Block diagram of a digital control system 10
离散时间控制系统(中文版)，Katsuhiko Ogata，陈杰，蔡涛等 译，机械工业出版社，2006
❖ Grading Procedure:
in-term evaluation
experimental results
final paper examination.
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Chapter 1 Introduction to Discrete-Time
1-1 Introduction
❖ Digital Controller
A rapid increase in the use of digital controllers
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1-1 Introduction
❖ Digital Controller
The trend is due to
❖Digital control can achieve optimal perfor- mance, have Decision-making capability and flexibility in the control program
Discrete-time signal: A signal defined only at discrete instants of time
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1-1 Introduction
❖Sampled-data signal: A discrete-time signal if the amplitude can assume a continuous range of values