EE561Spring2020
From CYPHYNETS
EE561: Digital Control Systems  

Spring 2020 
Instructors
Talha Manzoor, Assistant Professor, Center for Water Informatics & Technology (WIT)
Email: talha.manzoor@lums.edu.pk
Office: 9252, Tesla Wing, 2nd Floor, SSE Bldg
TA: Muhammad Mateen Shahid, MS Electrical Engineering
Email: 18060020@lums.edu.pk
Office: Control Systems Lab, Tesla Wing, 2nd Floor, SSE Bldg
Course Details
Year: 201920
Semester: Spring
Category: Graduate
Credits: 3
Elective course for electrical engineering majors. Core course for electrical engineering students pursuing an MS in the "Systems and Controls" stream.
Course Website: http://cyphynets.lums.edu.pk/index.php/EE561Spring2020
Course Description
This course involves the design and analysis of control to be implemented by digital computers for systems that operate on continuous signals. The first part of the course focuses on the analysis of sampleddata systems and the tools employed to study them. These include the language of difference equations, the ztransform, discretization methods for continuoustime systems, dynamic response of discretetime systems and the effects of sampling and quantization. The second part of the course covers the design of feedback control in discrete time domain which includes emulation of controllers designed in continuous time domain and direct design in discretetime domain using both transform based and state space techniques.
Learning Outcomes
 Represent and describe discretetime systems using difference equations and ztransforms
 Analyze discretetime and sampleddata systems in order to deduce system behavior
 Implement controllers designed using continuoustime techniques for application to discretetime systems
 Apply and evaluate different techniques for controller design directly in the digital domain
Prerequisites
 EE361. Feedback Control Systems (for undergrads)
 A working knowledge of ordinary differential equations and linear algebra will be assumed while delivering the lectures.
 Experience in programming with MATLAB will be required to solve some components of the assignments.
Text book
The course will be taught from the following textbook.
(Franklin) Digital control of dynamic systems by Franklin, Powell and Workman (3rd edition), Addison Wesley, 2000.
Other references
(Strang) Computational Science and Engineering, WellesleyCambridge Press, 2007
(FranklinF) Feedback Control of Dynamics Systems, Pearson Prentice Hall, 2013
(Astrom) Computer Controlled Systems, Prentice Hall, 1997
(Ogata) Modern control engineering, Pearson Prentice Hall, 2010
Grading Scheme (postcovid)
Homeworks+Quiz : 20% 35%
Course project: 25% 35%
Midterm: 25% 30%
Final : 30%
General Guidelines
 Quizzes will be announced. There will be no makeup quiz.
 Homework will be due at the beginning of the class on the due date. Late homework will not be accepted.
 You are allowed to collaborate on homework. However, copying solutions is absolutely not permitted. Offenders will be reported for disciplinary action as per university rules.
 Any appeals on grading of homeworks, quiz or midterm scores must be resolved within one week of the return of graded material.
 Attendance in lectures is strongly recommended but not mandatory. However, you are responsible for catching the announcements made in the class.
Course Delivery Method
Lectures (precovid). Mon, Wed: 12:30pm1:45pm. 10202. SSE Bldg
Online Lectures (postcovid). YouTube Playlist
Schedule
WEEK  TOPICS  REFERENCES 

Week 1 Jan 20  Lecture 1 Motivation: The control design problem, structure of a digital control system, the need for a dedicated theory of digital control, Categories of systems: discrete, sampleddata, digital; Overview of course contents
Lecture 2 Difference Equations: Difference equation of a resistive ladder (notes), numerically solving difference equations, Method of undetermined coefficients, From ODE’s to difference equations (approximating an integral), The computer solution to an ODE  Astrom Ch 1, Franklin Ch 1, Ch 4.1 
Week 2 Jan 27  Lecture 3 The ztransform: Definition of the transform, transform of elementary signals, the transfer function, interpretation of z as a timedelay operator, block diagram of trapezoid integration, Relation between transfer function and pulse response, convolution
Lecture 4 Pole location and system response: Poles and zeros, Stability (internal and external), Infering stability from the impulse response, Jury's stability test, transform of the general sinusoid, relation of pole locations with the time response (radius and angle). 
Franklin Ch 4.2, Ch 4.4

Week 3 Feb 03  Lecture 5 Pole location and system response ctd: The discrete sinusoid as a discrete version of a continuous signal, the implied mapping of poles from splane to zplane, damping ratio and natural frequency lines in the zplane
Kashmir Day Holiday 
Franklin Ch 4.4

Week 4 Feb 10  Lecture 6 Sampling related issues: placement of sampling and hold circuits in the digital control system, the phenomenon of aliasing (frequency folding), compensating for aliasing with a bandpass filter, practical antialiasing filters, taking into account the approximate dynamics of the filter
Lecture 7 The hold operation: Modelling the sample and hold device in a sampleddata system; C.T transfer function of the zeroorderhold; The D.T representation of a plant coupled with zeroorder hold; the spectrum of the sample and hold; Aprroximating the sample and hold with a pure time delay  Franklin Ch 5, Astrom Ch 7.4
Franklin Ch 4.3.1

Week 5 Feb 17  Lecture 8 Realization of Digital Controllers: Devising customized circuitry using adders, multipliers and delay elements; Realization through direct programming; Realization through standard canonical programming; Introduction of the state variables; Control canonical and Observer canonical realizations; Statespace description of the canonical forms
Lecture 9 State Space fundamentals: The concept of a state; State transformations; Relation with the transfer function; Poles and eigenvalues; Invariance of the transfer function under nonsingular linear state transformations Project proposal reports due  Franklin Ch 4.2.3, Ch 4.3.3 
Week 6 Feb 24  Lecture 10 State space descriptions of sampled data systems: Solution to the homogeneous state equation, the matrix exponential, properties of the exponential, Calculating the exponential by power series, diagonalization and the Laplace transform; Solution of the nonhomogeneous state equation; Discretizing the solution; Obtaining the discrete time state space description from the continuous time model with a Z.O.H.
Lecture 11 Discretetime equivalents to continuoustime transfer functions: Equivalents by numerical integration; forward, backward and bilinear rules; distortion of stable regions; frequency warping in the bilinear transform; Zeropole mapping equivalents; Hold equivalents  Franklin Ch 4.3.3, Ch 6 
Week 7 Mar 02  Lecture 12 Time delayed systems; Classification of timedelayed systems; Rational and irrational transfer functions; Pade's approximation; State space model for a continuous time delay line; Example of a time delay system: shower mixer; Discretetime equivalent for a timedelayed system; Equivalents for the transfer function representations.
Lecture 13 Equivalent statespace description for a timedelayed system; control design specifications; error coefficients for steady state accuracy; system Type  Franklin Ch 4.3.2, Ch 4.3.4, Ch 7.1 
Week 8 Mar 09 
Lecture 14 Transient response specifications for control design; Mapping response speifications to pole and gain values; Sample rate selection; Control design through emulation; Efficient coding of a discretetime transfer function; Evaluating the response for a designed controller Midterm Exam  Franklin Ch 7.1 Ch 7.2 
Weeks 911  Covid Lockdown.  
Week 12 Apr 06  Lecture 14 (Repeat) video System specifications; Classification based on system type; Determining error coefficients for sampleddata systems; Transient response specifications for sampleddata systems; Design by emulation (procedure); Guidelines for selection of sample time
Lecture 15 video Design example: Mapping system requirements to response specifications; obtaining a continuous time controller for the emulated system; obtaining the discrete equivalent controller; Implementation issues for discretetime controllers; Evaluation of design; Degradation in performance due to sampling and incorporating delays due to low sampling in the design process  Franklin Ch 2.1.1, Ch 2.2.2, Ch 4.4.5, Ch 7.1, Ch 7.2 m file (lec 15)

Week 13 Apr 13  Lecture 16 video Introduction to state space design: The control law and estimation design problems; Control law design through algebraic pole placement; Full state feedback in the control canonical form; Ackerman's formula and pole placement  Franklin Ch 8.1 
Week 14 Apr 20  Lecture 17 video Controllability: pole placement for an uncontrollable system; definitions and test for controllability; controllability and pole cancellation; weak controllability; Controller saturation and guidelines for good pole selection; Pole selection for higher order systems
Lecture 18 video Estimation: Introduction to the estimation problem, design of prediction estimators, observability in discrete time, design of current estimators, introduction to reduced order observers  Franklin Ch 8.1, Ch 8.2, Ch 8.3.2, Ch 8.7 m file (lec 17) m file (lec 18) 
Week 15 Apr 27 
Lecture 19 videoCombined control law and estimation: The separation principle of estimation and control; The equivalent transfer function representation for the compensator; comparison of compensators based on the prediction, current and reducedorder estimators; Evaluating closed loop system response in simulation; Computing steady state control effort for nonzero reference inputs Lecture 20 video Introduction of the reference input; reference input with full state feedback; The state command structure; The output error command structure; Comparison with classical compensation techniques  Franklin Ch 8.3 Ch 8.4 m file (lec 19) m file (lec 20) 
Week 16 May 04 
Lecture 21video Integral control and disturbance estimation; Integral control through state augmentation; Disturbance rejection through disturbance estimation; Rejection of sensor disturbances; Reference following through feedforward Lecture 22 video Effect of delays; Incorporating sensor delays in control design; Dealing with actuator delays; Summary of state space design  Franklin Ch 8.5, Ch 8.6 m file (lec 21) m file (lec 22) 
Week 17 May 11  Project report submission  
Week 18 May 18  Final Viva 
Project Policy
 Evaluation based on
2 presentations and a reportproposal report, final report and final viva.  Project title and scope to be proposed by the students and approved by the instructor.
 Project must be motivated by a reallife problem.
 Project must consist of at least the following steps
 Problem background and formulation of the control/estimation problem
 Specifications of the system response for control/estimation design, properly contextualized in the domain of application
 Sensing mechanisms, actuators and sampling related issues
 Discretetime/sampleddata model
 Controller/Estimator Design
 Evaluation of the designed controller/estimator w.r.t. the response specifications
 A commentary on the limitations and tradeoffs of the designed control/estimation scheme
Project Ideas
Power and Energy
 Multisampled Digital Average Current Controls of the Versatile Buck–Boost Converter Paper.
 Design and Implementation of Digital Control in a Fuel Cell System Paper.
 Digital Control of Resonant Converters: Resolution Effects on Limit Cycles Paper.
 Simple and Effective Digital Control of a VariableSpeed Low Inductance BLDC Motor Drive Paper
 Multisampled Digital Average Current Controls of the Versatile Buck–Boost Converter Paper Haider Ali Tauqeer 19060036
Robotics
 Robust digital control for autonomous skidsteered agricultural robots Paper. Muhammad Hammad Ullah 19060027
 Discretetime second order sliding mode with time delay control for uncertain robot manipulators Paper
 Receding Horizon Control for Convergent Navigation of a Differential Drive Mobile Robot Paper
 A comparison of continuous and discrete trackingerror modelbased predictive control for mobile robots Paper Arslan Hassan 19060016
Networked Control
 Variable Selective Control Method for Networked Control Systems Paper Maham Javed 19060024
 Consensus Problems for Discretetime Agents with Communication Delay Paper Mahnoor Aftab 18060035
 On KalmanConsensus Filtering With Random Link Failures Over Sensor Networks Paper
 Robust DiscreteTime Markovian Control for Wheeled Mobile Robot Formation Paper
Environment and Agriculture
 Optimal irrigation management for largescale arable farming using model predictive control Paper
 Adaptive Sampling for Energy Conservation in Wireless Sensor Networks for Snow Monitoring Applications Paper Hassam Arshad 19060045
 Distributed Model Predictive Control of Irrigation Systems using Cooperative Controllers Paper
 Ecological monitoring in a discretetime prey–predator model Paper Bilal Ahmad 19060021
Miscellaneous
 DataDriven Digital Direct Position Servo Control by Neural Network With Implicit Optimal Control Law Learned From Discrete Optimal Position Tracking Data Paper
 Structures within the Quantization Noise: MicroChaos in Digitally Controlled Systems Paper
 Chatter Stability in Robotic Milling Paper
 Chatteringfree discretetime sliding mode control Paper Talha Nadeem 19060015