School of Engineering and Computing

Coursework Title: Control system design and simulation for a

chemical process

Module Name: Process control

Module Code: 6312ELE/6312MAN
Level: 6
Credit Rating: 20
Weighting: 30% (exam worth 70%)

Lecturer: Dr. Zahoor Ahmed

Contact: If you have any issues with this coursework you may contact your lecturer.
Contact details are:
Email: zahoor.ahmed@sbc.usst.edu.cn
Room: T606

Issue Date: Thursday 02 March 2023

Submission Deadline: Friday 31 March 2023 - Your coursework should be submitted on-line at
Canvas/Assignment on or before the Submission Deadline.

Feedback: Feedback will be given on the marked coursework.

Programmes: BEng Electrical and Electronics Engineering

1
Introduction

This coursework is to be carried out individually. It includes some questions and is designed to meet the
Learning Outcomes of this module, as presented in the module proforma, i.e.
Learning Outcomes:

LO1 Identify the principles of cascade, feed-forward and ratio control of process plants,
with typical applications
LO2 Appraise typical components in process systems and develop process models for
analysis and controller design
LO3 Characterise strategies for controlling systems possessing dead-time, inverse
response and interaction properties
LO4 Use computer based software packages for analysis, design and simulation of
process control systems

Additional learning outcomes:

1. Knowledge and understanding of scientific principles and methodology necessary to underpin
their education in their engineering discipline, to enable appreciation of its scientific and
engineering context, and to support their understanding of historical, current, and future
developments and technologies
2. Ability to apply and integrate knowledge and understanding of other engineering disciplines to
support study of their own engineering discipline
3. Understanding of engineering principles and the ability to apply them to analyse key engineering
processes
4. Ability to identify, classify and describe the performance of systems and components through
the use of analytical methods and modelling techniques
5. Ability to apply quantitative methods and computer software relevant to their engineering
discipline, in order to solve engineering problems
6. Understanding of and ability to apply a systems approach to engineering problems

2
Coursework Specification and Marking Scheme

A concentration control loop in an industrial chemical process can be represented by a second order
dynamics with a long transmission delay. The two time constants of the second order dynamics are T1 = 4
min and T2 = 6 min respectively. The steady state gain is 5 and the dead time is 12 min. The loop is to be
controlled to achieve a desired dynamics of first order with time constant Td = 2 min and zero steady-state
offset for a step reference. Produce solutions to the following questions.

(i) Identify the plant transfer function and the desired closed-loop system transfer function. Then,
design a feedback control system with the controller designed using Direct Synthesis method,
where the time-delay is approximated using the first-order Taylor expansion. Implement the
controller with a standard industrial PID controller.

Simulate the designed control system for 100 Minutes using a unity step input as the
reference signal. Display the output and the set-point in a top figure, and the corresponding
control variable (u(t)) a bottom figure.
[20 marks]

(ii) Design a feedback control system for the given plant with a PID controller designed using the
closed-loop Ziegler-Nichols empirical method. The Simulink model used in the experiment to
obtain the sustained oscillatory output curve should be displayed, and the output curve
should also be displayed. The controller design procedure should be presented.
Do the same simulation as in (i).
[20 marks]

(iii) Design a Smith Predictor control system for the given plant with the controller designed using
the Direct Synthesis method. A block diagram should be shown to demonstrate the control
system structure. The design details are also required. The designed controller should be
implemented using a PID controller. Do the same simulation as in (i).
[20 marks]

(iv) Compare the performance of the designed three control systems by displaying the three
outputs with set-point together, and three control signals together. Comment on the
performance and recommend the control methods.
[20 marks]

(v) Write a report with content, a brief introduction, description of the process to be controlled,
presentation of the control system design using each method, simulation models, control
systems outputs and corresponding control variables, and finally the comparison, comments
and conclusion.

3
 The assignment should be presented logically, clearly and completely. The assignment should
be written using Microsoft Word. Mathematical expressions must be presented using
Microsoft Equation. All figures must have title, labels and legends as appropriate.
[20 marks]

Recommended Reading

References

Course Material Book

Author: Seborg, Edgar and Mellichamp

Publishing Year: 2011

Title: Process dynamics and control

Subtitle:

Edition: 3rd

Publisher: McGraw-Hill

ISBN: 978-0-470-64610-6

Author: Ogata, K.

Publishing Year: 1997

Title: Modern Control Engineering

Subtitle:

Edition: 3rd

Publisher: Prentice Hall International

ISBN: 0-13-261389-1

4
Guide to Performance Criteria

70% and above:

Your work must be of outstanding quality and fully meet the requirements of the coursework
specification and learning outcomes stated. You must show independent thinking and apply this to your
work showing originality and consideration of key issues. There must be evidence of wider reading on
the subject.

Key words which may describe a coursework at this level include: appraises, compares, concludes, contrasts,
criticizes, critiques, defends, discriminates, evaluates, explains, interprets, justifies, relates, supports.

60% - 70%:
Your work must be of good quality and meet the requirements of the coursework specification and
learning outcomes stated. You must demonstrate some originality in your work and show this by
applying new learning to the key issues of the coursework. There must be evidence of wider reading on
the subject.

Key words which may describe a coursework at this level include: categorizes, combines, compiles, creates,
devises, generates, modifies, reconstructs, identifies, illustrates, outlines, synthesizes.

50% - 60%:
Your work must be comprehensive and meet all of the requirements stated by the coursework
specification and learning outcomes. You must show a good understanding of the key concepts and be
able to apply them to solve the problem set by the coursework. There must be enough depth to your
work to provide evidence of wider reading.

Key words which may describe a coursework at this level include: demonstrates, changes, applies, operates,
produces, predicts, shows, solves, uses, translates, comprehends, converts, generalizes.

40% - 50%:
Your work must be of a standard that meets the requirements stated by the coursework specification
and learning outcomes. You must show a reasonable level of understanding of the key concepts and
principles and you must have applied this knowledge to the coursework problem. There should be some
evidence of wider reading.

Key words which may describe a coursework at this level include: comprehends, defines, describes, identifies,
knows, labels, lists, matches, outlines, recalls, recognizes, reproduces, selects, states, rewrites.

Below 40%:
Your work is of poor quality and does not meet the requirements stated by the coursework specification
and learning outcomes. There is a lack of understanding of key concepts and knowledge and no
evidence of wider reading.

5
Plagiarism
Plagiarism is considered as academic misconduct. The University takes cases of plagiarism very seriously
and all alleged cases of academic misconduct will be investigated thoroughly by a School Investigatory
Panel. Students are advised to ensure that any coursework submitted is their own work or, where the
work of others is referred to (this includes any third-part material e.g. text, images, diagrams, drawings),
it is correctly referenced. The University defines plagiarism in the following way:
• The representation of the work, written or otherwise, of any other person, from any source
whatsoever, as the candidate's own. Examples of plagiarism may be as follows:
• The verbatim copying of another's work without clear identification and acknowledgement –
including the downloading of materials from the internet without proper referencing and
acknowledgement
• The close paraphrasing of another's work by simply changing a few words or altering the order
of presentation, without clear identification and acknowledgement.
• Unidentified and unacknowledged quotation of phrases from another's work.
• The deliberate and detailed presentation of another's concept as one's own.