Automation Systems - Lecture 1 - Basic concepts / Control ...

Automation Systems

Lecture 1 - Basic concepts / Control system design

Jakub Mozaryn

Institute of Automatic Control and Robotics, Department of Mechatronics, WUT

Warszawa, 2019

Jakub Mozaryn Automation Systems

Programme

Information about lectures and laboratories

Automation Systems, lecture - Jakub Mozaryn, PhD, Eng.,semester IV - lecture (20 hours), Faculty of Mechatronics, room.346, e-mail: [email protected], webpage:http://jakubmozaryn.esy.es

Automation Systems, laboratory - Jakub Mozaryn, PhD, Eng.,Jedrzej Maczak, PhD, Eng., Przemyslaw Szulim, PhD, Eng.,Jikun Wang, PhD, Eng. - (10 hours)


Programe

Lecture information

Lecture: 20 hours

Laboratory: 10 hours

Work at home: 20 hours

Exam preparation: 10 hours

Conditions to pass the lecture: pass the writing exam andattend all laboratories

Exam evaluation: 20pts (pass - 12pts)

ECTS points: 3


Literature

R.C. Dorf, R.H.Bishop, Modern Control Systems, Prentice Hall,2008

G.F. Franklin, J.D. Powell, A. Emami-Naeini, Feedback Control ofDynamic Systems, Addison-Wesley, 1994

N.S. Nise, Control Systems Engineering, Wiley, 2015

Massive open on-line courses (MOOC): Coursera, EdX, Iversity


Introduction

Today, many devices are equipped with what is generally called automa-tion. Ranging from household appliances like iron (temperature con-troller), washing-machine (programmer) to devices with the most advancedtechnology as the aircraft (autopilot).

One of the first controllers, which has been applied in practice was Watt’scentrifugal governor to stabilize the rotation of the steam engine (1784).Since then, automation has become a type of science, and the numberof its practical application is constantly growing. The theory of automaticcontrol now includes:

theory of linear systems,

feedback control,

theory of nonlinear systems,

optimal control,

theory of discrete systems (logical automation systems),

robotics.


Steam engine

Figure: Steam engine with the centrifugal speed governor


Centrifugal speed governor

The valve starts fully open at zero speed, but as the balls rotate and riseon the rods. The central valve stem is forced downward and closes thevalve.

Figure: The detailed view of the centrifugal speed governor


Aims of the lecture

Aims of the lecture

Acquiring the ability to recognize and assess the problems ofautomation and control.

Understanding the basic concepts of automation of differentprocesses, methods to determine the nature and elements ofautomation with continuous and discrete action.

Understanding the basic principles of operation of control systemsand functions of the elements of these systems.

Understanding the requirements for control systems and methods ofensuring the fulfillment of these requirements.


List of lectures

Introduction: basic concepts, classification of control systems ofcontinuous processes, examples.

Description methods of dynamical systems: differential equations,transfer functions, time and frequency domains.

Static and dynamic features of the basic elements of the automationsystem.

Block diagrams.

Process / plant - model identification.

PID controllers.

Stability of control systems, stability criteria.

Static and dynamic indexes of control quality, selection ofparameters of controllers.

Design of the control system.

Complex control systems.


Natural and technological processes

Natural processes

Physical and chemical transformations of the state of matter that takesplace without human intervention. Examples: weather changes, watermovement in rivers, tectonic movements, chemical processes in thehuman body (eg changes in the level of insulin and glucose).

Technological processes

Processes carried out by a man with the use of appropriate devicesconstructed by him in order to obtain the intended changes in thestate of matter. Example: changing the temperature in the furnace,changing the water level in tanks in petrochemical installations.

During the lecture, issues related to technological processes andtheir control will be discussed.


Basic concepts

Figure: Block diagram of the process

Control System

Control System is an interconnection of components constituting asystem configuration that shall provide the desired system response(behavior).


Basic concepts

Open-loop control system


Basic concepts

Open-loop control system

Examples:toaster,cofee vending machine.

Signalsyr (t) - desired outputresponse,u(t) - control signal,x(t) - input signal,y(t) - output signal.


Example - filling the glass with water

Figure: Example of the process control - the control of the level in the tank(glass).


Example - filling the glass with water

Figure: Example of the processcontrol - the control of thelevel in the tank (glass).

Aim: Fill half of the glass withwater.

Function:sensors - eyes, force estimation(weight of glass),actuators - hand, valve,controller - brain.


Basic concepts

Closed-loop control system


Basic concepts


Examples:The temperature control inthe greenhouse.The water level control inthe tank.The autopilot.

Signalsu(t) - control signal,x(t) - input signal,y(t) - output signal,yr (t) - desired outputresponse,ym(t) - measured output,e(t) = yr (t) − ym(t) - errorsignal.


Basic concepts

Closed-loop feedback control system

The closed-loop feedback control system tends to maintain aprescribed relationship of one system variable (measured process outputvalue) to another variable (desired process output response) bycomparing functions of these variables and using their difference as ameans of control.

Error signal e(t) is amplified.The controller causes the actuator to modulate the process in orderto reduce the error e(t).

Feedback concept

The closed-loop control system uses a measurement of the output andfeedback of this signal to compare it with the desired output value(reference value or command).


Basic concepts


ElementsC - controller, A - actuator, O - process/plant, S - sensor

Main Path indicates always an essential input value of the system andoutput value. This path typically describes the main flow of material orenergy in the system.

Feedback Path is used to transmit information. Energy requirements ofthis path are usually small in comparison with the main path, and can beomitted.


Basic concepts

Closed-loop control system - disturbances and noise

Advantages of the closed-loop control system over the open-loopcontrol system

Rejection of external disturbances d(t),

Improvement of the measurement noise n(t) attenuation.


Basic concepts

Closed-loop control system - simplified scheme


Basic concepts

Multi-loop Feedback Control System


Basic concepts

Single Input Single Output (SISO) system

Multiple Input Multiple Output (MIMO) system


Control System Design

R.C. Dorf, R.H. Bishop, Modern Control Systems, Prentice Hall, 2009


Example - autopilot in cars










Example - DARPA Challenge, USA


Automation Systems

Lecture 1 - Basic concepts / Control system design

Jakub Mozaryn

Institute of Automatic Control and Robotics, Department of Mechatronics, WUT

Warszawa, 2019


Automation Systems - Lecture 1 - Basic concepts / Control ...

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