Control Systems

Code:

EM0041

Acronym:

SC

Keywords
Classification	Keyword
OFICIAL	Automation

Instance: 2008/2009 - 2S

Active?	Yes
Responsible unit:	Automation, Instrumentation and Control Section
Course/CS Responsible:	Master in Mechanical Engineering

Cycles of Study/Courses

Acronym	No. of Students	Study Plan	Curricular Years	Credits UCN	Credits ECTS	Contact hours	Total Time
MIEM	214	Syllabus since 2006/2007	4	-	6	56	160
		Plano de estudos de transição para 2006/07	4	-	6	56	160

Teaching language

Portuguese

Objectives

BACKGROUND
Mechanical Engineering evolution in the last decades has been strongly influenced by developments in the areas of Material Science, Computer Science, Automation and Control Systems. The association of new materials, new design techniques and sophisticated control algorithms has provided the means to produce systems with increased capabilities and functionality. This complexity increment has been matched by increased usability and decreased costs, both investment and running costs. There are numerous cases with relevant social impact: transport means, burning systems, HVAC systems, robotic systems, commodity products, all with increased performances and energy efficiencies.

SPECIFIC AIMS
The present subject is the sole one on the area of control systems that is compulsory for all students of the mechanical engineering degree. All future mechanical engineers should be able to model, analyse, design and simulate classical automatic control systems. So, it aims to endow the students with nuclear and structuring knowledge on dynamic systems and automatic control, giving them the capabilities to: transdisciplinary model dynamic systems, taking into account the model aim – simulation, control or other; design and implement computer controlled systems; use Computer-Aided Control System Design tools, both in system simulation and controller design.

PREVIOUS KNOWLEDGE
EM0005: Vector Algebra; Matrices; Determinants; Systems of Linear Equations; Linear Spaces, Transformations and Matrices; Eigenvalues and Eigenvectors.
EM0009: Differential and Integral Calculus in R; Polynomial approximations to functions; Taylor series.
EM0010: Vector-valued functions of n variables; Differentiation: partial and directional derivatives, Jacobian matrix, Taylor’s formula.
EM0014: Properties of surfaces and bodies.
EM0015: Linear ODEs of order n; Systems of differential equations; The Laplace Transform; Fourier Analysis.
EM0016: Numerical integration: Newton-Cotes formulae; ODEs: Euler’s and Runge-Kutta methods; Matlab language.
EM0018: Kinematics and Dynamics.
EM0019: First and Second laws of thermodynamics.
EM0021: Fundamentals of electric circuits; DC and AC Circuits; Principles of Electromechanics; Introduction to Electric Machines.
EM0026: Fluid Power systems; Pneumatic and Hydraulic systems technology.
EM0029: Hydrostatics; Fluid kinematics; Fluid dynamics.
EM0031: A/D and D/A conversion; Programming and using PLCs.
EM0034: Internal Flows. Pumps and Ventilators.
EM0037: Heat Conduction; Convection.
EM0036: Measuring chains and systems; Measurement of physical quantities - transducers/sensors.
EM0038: Gears; Tribology.
EM0043: Single Degree of Freedom Systems; Vibrations Control; Continuous Systems.

PERCENTUAL DISTRIBUTION
Scientific component (establishes and develops scientific bases) – 70%
Technological component (apply to design and process operation) – 30%

LEARNING OUTCOMES
At the end of this subject students shall be able to:
i) write lumped parameter models of dynamic systems using ordinary differential equations from manufacturer provided and other design data (Knowledge and Understanding; Engineering Analysis; Investigations);
ii) draw and analyse block and simulation diagrams of linear dynamic systems (Engineering Analysis, Engineering Practice);
iii) carry out the analysis of transient and frequency responses of linear dynamic systems (Engineering Analysis);
iv) design classic controllers that enable the achievement of performance specifications (Engineering Design);
v) use Computer-Aided Control System Design tools on the simulation and design of control systems (Engineering Design; Investigations; Engineering Practice; Transferable Skills)
vi) determine the numerical algorithms needed for the computer implementation of the designed controllers (Knowledge and Understanding; Engineering Practice).

Program

1 Introduction to Automatic Control Systems
1.1 Automatic Control Systems: historical background; basic concepts and definitions; perturbations, uncertainty and error reaction; structure of a feedback system.
1.2 Regulators and servomechanisms.

2 Mathematical Modelling of Dynamic Systems
2.1 Lumped parameter models: models of mechanical, electrical, thermal and fluid systems; global versus local models; linearization at an equilibrium operating point.
2.2 Laplace Transform: transform of a signal; standard signals and their transforms; transfer function of a system; transient response computation.
2.3 Schematic Representation: block diagrams; determination of the overall transfer function; simulation diagrams.
2.4 State Space representation: concept of state; canonical forms; relation between transfer function and state space representations.
2.5 Introduction to dynamic systems simulation using Matlab/Simulink.

3 Time Response of Dynamic Systems
3.1 Transient response of dynamic systems: first order systems; second order systems; location of system poles and zeros on the Laplace plane and its time response; stability; higher order systems; dominant poles.
3.2 Time response performance metrics: step response; steady-state errors.

4 Introduction to Controller Design
4.1 Basic control actions: P, I and D.
4.2 PID controllers: PID structure; PI-D and I-PD structures.
4.3 Controller selection and tuning in order to achieve steady-state error and transient response performance specifications; external perturbations influence.

5 Frequency Response of Dynamic Systems
5.1 Frequency Response of a System: concept and definition; relation between frequency response and transfer function.
5.2 Graphical representation of frequency response: polar diagrams; Bode diagrams.
5.3 Nyquist’s stability criterion.
5.4 Relative stability; gain and phase margins; robustness.

6 Frequency Domain Controller Design
6.1 Performance specification in the frequency domain: relation between transient and frequency responses; relation between open-loop frequency response and close-loop transient response; relation between open-loop frequency response and steady-state error constants.
6.2 Compensator design: compensator types and their selection; dimensioning of lag, lead and lag-lead compensators; relations with PID controllers.

7 Heuristic Tuning Rules for PID Controllers
7.1 Ziegler Nichols tuning methods.
7.2 Manual tuning of electromechanical servomechanisms.
7.3 Implementation using operational amplifiers.

8 Introduction to Discrete Time Control Systems
8.1 Structure of a discrete time control system.
8.2 Signal sampling: spectrum of a sampled signal; signal reconstruction; sampling frequency selection.
8.3 Implementation of PID controllers using finite-differences approximations.
8.4 Z transform: z transform of a sampled signal; transfer function of a sampled system; mapping between s and z spaces; sampled system stability.
8.5 Discrete time controller design: discrete approximation of a continuous controller using the bilinear or Tustin transform; controller design in the pseudo-frequency domain using the bilinear or Tustin transformation.

Mandatory literature

Ogata, Katsuhiko; Modern control engineering. ISBN: 0-13-261389-1
Ogata, Katsuhiko; Engenharia de controle moderno. ISBN: 85-87918-23-0
Van de Vegte, John; Feedback control systems. ISBN: 0-13-016379-1

Complementary Bibliography

Carvalho, Jorge Leite Martins de; Sistemas de controle automático. ISBN: 85-216-1210-9
D.Azzo, John J.; Linear control system analysis and design. ISBN: 0-07-066251-7
Kuo, Benjamin C.; Automatic control systems. ISBN: 0-471-36608-0
Carvalho, Jorge Leite Martins de; Dynamical systems and automatic control. ISBN: 0-13-221755-4
Kuo, Benjamin C.; Sistemas de control automático. ISBN: 968-880-723-0
Astrõm, Karl Johan; Computer-controlled systems. ISBN: 0-13-314899-8
Franklin, Gene F; Digital control of dynamic systems. ISBN: 0-201-33153-5

Software

Simulink
Matlab

keywords

Technological sciences > Engineering > Systems engineering > Systems theory
Technological sciences > Engineering > Control engineering
Technological sciences > Engineering > Process engineering > Process control

Evaluation Type

Distributed evaluation with final exam

Assessment Components

Description	Type	Time (hours)	Weight (%)	End date
Attendance (estimated)	Participação presencial	52,00
Modeling and Computer Simulation Report	Trabalho escrito	20,00		2009-05-15
Exam paper	Exame	3,00		2009-07-25
	Total:	-	0,00

Amount of time allocated to each course unit

Description	Type	Time (hours)	End date
Regular subject study	Estudo autónomo	47	2009-06-05
Exam paper preparatoty work	Estudo autónomo	40	2009-07-25
	Total:	87,00

Eligibility for exams

To respect the absence limit and to obtain a minimum grade of 9 on a report paper about a modeling and computer simulation work using Matlab/Simulink

Calculation formula of final grade

Report Classification: RC;
Exam Classification: EC;
Final Classification: FC;
FC = 0,3 RC + 0,7 EC

Examinations or Special Assignments

A Written Report of a group work on modelling and computer simulation using Matlab/Simulink. Each group shall be composed by 6 students.

Special assessment (TE, DA, ...)

The student must do the final exam and produce a report about a work identical to the one required to ordinary students

Classification improvement

The student may chose between improving the RC, by doing a new report, the EC, by doing a new exam, or both, by doing a new report and a new exam.