Automatic control theory,A Course used for analyzing and designing a automatic control system,Chapter 1 Introduction,Figure 1.1,1) A water-level control system,21 century information age, cybernetics(control theory), system approach and information theory , three science theory mainstay(supports) in 21 century.,1.1 Automatic control A machine(or system) work by machine-self, not by manual operation.,1.2 Automatic control systems 1.2.1 examples,Chapter 1 Introduction,2) A temperature Control system (shown in Fig.1.3),Another example of the water-level control is shown in figure 1.2.,Chapter 1 Introduction,3) A DC-Motor control system,Chapter 1 Introduction,4) A servo (following) control system,Fig. 1.5,Chapter 1 Introduction,Fig. 1.6,5) A feedback control system model of the family planning (similar to the social, economic, and political realm(sphere or field),Chapter 1 Introduction,Fig. 1.7,Example:,1.2.2 block diagram of control systems The block diagram description for a control system : Convenience,Chapter 1 Introduction,Actuator,Process,controller,measurement (Sensor),Error,Feedback signal,Fig. 1.8,For the Fig.1.1, The water level control system:,Figure 1.1,Chapter 1 Introduction,For the Fig. 1.4, The DC-Motor control system,Chapter 1 Introduction,1.2.3 Fundamental structure of control systems,1) Open loop control systems,Features: Only there is a forward action from the input to the output.,Chapter 1 Introduction,2) Closed loop (feedback) control systems,Chapter 1 Introduction,Notes: 1) Positive feedback; 2) Negative feedbackFeedback.,1.3 types of control systems,1) linear systems versus Nonlinear systems. 2) Time-invariant systems vs. Time-varying systems. 3) Continuous systems vs. Discrete (data) systems. 4) Constant input modulation vs. Servo control systems.,1.4 Basic performance requirements of control systems 1) Stability. 2) Accuracy (steady state performance). 3) Rapidness (instantaneous characteristic).,Chapter 1 Introduction,1.5 An outline of this text,1) Three parts: mathematical modeling; performance analysis ; compensation (design).,2) Three types of systems: linear continuous; nonlinear continuous; linear discrete.,3) three performances: stability, accuracy, rapidness.,in all: to discuss the theoretical approaches of the control system analysis and design.,1.6 Control system design process shown in Fig.1.12,Chapter 1 Introduction,Chapter 1 Introduction,1.7 Sequential design example: disk drive read system,A disk drive read system Shown in Fig.1.13, Configuration Principle,Chapter 1 Introduction,Sequential design: here we are concerned with the design steps 1,2,3, and 4 of Fig.1.12.,Identify the control goal:,(2) Identify the variables to control:,Position the reader head to read the date stored on a track on the disk.,the position of the read head.,(3) Write the initial specification for the variables:,The disk rotates at a speed of between 1800 and 7200 rpm and the read head “flies” above the disk at a distance of less than 100 nm. The initial specification for the position accuracy to be controlled: 1 m (leas than 1 m ) and to be able to move the head from track a to track b within 50 ms, if possible.,Chapter 1 Introduction,(4) Establish an initial system configuration:,It is obvious : we should propose a closed loop system , not a open loop system.,An initial system configuration can be shown as in Fig.1.13.,We will consider the design of the disk drive further in the after-mentioned chapters.,Chapter 1 Introduction,Exercise: E1.6, P1.3, P1.13,Chapter 2 mathematical models of systems,2.1 Introduction,1) Easy to discuss the full possible types of the control systemsin terms of the systems “mathematical characteristics”. 2) The basis analyzing or designing the control systems. For example, we design a temperature Control system :,The key designing the controller how produce uk.,2.1.1 Why？,Chapter 2 mathematical models of systems,2.1.3 How get？ 1) theoretical approaches 2) experimental approaches 3) discrimination learning,2.1.2 What is ？ Mathematical models of the control systems the mathematical relationships between the systems variables.,Different characteristic of the process different uk:,For T1,For T1,Chapter 2 mathematical models of systems,2.2.1 Examples,2.2 Input-output description of the physical systems differential equations,2.1.4 types 1) Differential equations 2) Transfer function 3) Block diagram、signal flow graph 4) State variables(modern control theory),The input-output descriptiondescription of the mathematical relationship between the output variable and the input variable of the physical systems.,Chapter 2 mathematical models of systems,define: input ur output uc。 we have：,Example 2.1 : A passive circuit,Chapter 2 mathematical models of systems,Example 2.2 : A mechanism,Define: input F ，output y. We have:,Compare with example 2.1: ucy; urF analogous systems,Chapter 2 mathematical models of systems,Example 2.3 : An opera