Unit Description and General Aims

The objective in presenting this unit is to provide students with the essential skills for identifying and analysing the characteristics of physical processes that are to be managed or constrained by control systems and to provide the theoretical basis for the design of feedback control systems.

The subject matter covered in this unit will include an introduction to the principles of mathematical modelling of simple dynamic systems that are widely used to represent physical and chemical process operations; block diagram modelling with transfer functions using Laplace transforms; frequency and time domain analysis methods for the identification of dynamic lags in typical processes; and, classical feedback control models with a review of methods for determining stability of controllers and suitable loop gains and compensation parameters.

Learning Outcomes

On successful completion of this Unit, students are expected to be able to:

1. Interpret and recognize the mathematical basis of 1st and 2nd order dynamic systems, and demonstrate by example the characteristic responses to disturbances.
   Bloom's Level 4
2. Explain and apply the principles of block diagram modeling using Laplace transforms in transfer functions.
   Bloom's Level 3
3. Design block diagram versions of feedback control applications and evaluate them for the stability of control using Nyquist and Root locus plots.
   Bloom's Level 6
4. Apply industry-standard software tools to expedite the design of a single loop control system.
   Bloom's Level 6
5. Evaluate and discuss the advanced process and digital control in typical industrial control systems.
   Bloom's Level 5

Student assessment

Overall requirements: Students must achieve a result of 50% or above in the exam itself to pass the exam and must pass the exam to be able to pass the unit. An overall final unit score of 50% or above must be achieved to pass the unit once all assessment, including the exam, has been completed.

Prescribed and Recommended Readings

Textbook

• N. S. Nise, Control Systems Engineering, 8th ed. Wiley, 2019 – ISBN: 978-1119474227

Reference

• B. Barraclough, K. Dutton, S. Thompson, The Art of Control Engineering. Prentice Hall, 1997 – ISBN-13: 978-0201175455
• L. Ferrarini, C. Veber, Modeling, Control, Simulation, and Diagnosis of Complex Industrial and Energy Systems. ISA, 2009 – ISBN 978-1-62870-506-5.
• Online version available at: http://app.knovel.com/hotlink/toc/id:kpMCSDCIE3/modeling-control-simulation/modeling-control-simulation

Notes and Reference Texts

IDC notes and reference texts as advised.

Other material advised during the lectures.

Unit Content

Topics 1 and 2

Introduction to Process Dynamics and Mathematical Models

1. Review of 1st and 2nd order linear differential equations
2. Representation of physical processes by linear differential equations
3. Examples of linearity and non-linearity in physical processes
4. Representation of dynamic processes using transfer functions
5. Derivation of Laplace transforms for impulse, step, and ramp functions
6. The transfer function in block diagram models

Topic 3

Time Response Modelling

1. Block diagram notations and examples
2. Representation of process dynamics by 1st and 2nd order transfer functions
3. Transfer functions for time delays in the process response
4. Determination of time responses to pulse, step, and ramp inputs
5. Modelling of feedback control systems
6. Higher order dynamic models and their simplification to approximate 2nd order plus dead time

Topics 4 and 5

Modelling of process characteristics in MATLAB

1. Steady state process model representations to identify inputs, outputs, and disturbance influences
2. Development of a 1st order model from typical physical process such as a stirred hot water tank
3. Development of a 2nd order model from a spring and weight model, and from a cascaded water tank process
4. Development of a feed heater model with disturbances
5. Detailed application model of a feedback control loop applied to a 1st order process

Topic 6

PID control and Frequency domain analysis

1. PID Control
2. Frequency response plots and their interpretation
3. Bode diagrams
4. Root locus diagrams

Topics 7 and 8

Stability analysis of single loop feedback controllers (SISO)

1. Stability criteria for feedback control
2. Nyquist Diagrams
3. Compensation by lead-lag elements to achieve stability
4. Configuration and tuning of feedback controllers using S plane models
5. Feed forward control techniques and benefits for disturbance rejection

Topic 9

Modelling, control, design and analysis of SISO systems using Matlab™

1. Case studies and exercises with Matlab to:
1. model, tune, and analyze 1st and 2nd order systems
2. verify stability and response of controllers

Topic 10

Advanced Process Control

1. Advanced vs classical control
2. Internal Model Control - IMC
3. Model Predictive Control - MPC
4. Reference models and Control model formulation

Topic 11

Digital (Discrete) Control System Fundamentals

1. Digital vs Analogue
2. Modelling a digital sampler and Zero-order Hold
3. The z-transform and transfer functions
4. Digital compensator and digital PID control

Topic 12

Project and Unit Review

In the final week, students will have an opportunity to review the contents covered so far. Opportunity will be provided for a review of student work and to clarify any outstanding issues. Instructors/facilitators may choose to cover a specialized topic if applicable to that cohort.

Software/Hardware Used

Software

• Software: MATLAB; SCILAB
• Version: N/A
• Instructions:  N/A
• Additional resources or files: N/A

Hardware

• N/A

Unit Changes Based on Student Feedback