THE UNIVERSITY OF NEW SOUTH WALES
SCHOOL OF MECHANICAL AND MANUFACTURING ENGINEERING

MMAN3200 LINEAR SYSTEMS AND CONTROL
LAB EXERCISE AND ASSIGNMENT A
Issued: 20/7/2023 Due: 06/8/2023
WATER TANK SYSTEM
Total marks: 20:
• Pre-task 2.5
• Attendance and conduct 2
• Assignment 15.5
Tasks - Rig 1
1 What is the horizontal cross section area of the process vessel? (0.5 marks)
2 When controlling the open-loop system,
a) How many attempts did it take to reach the desired value of the output?
b) How long (in minutes) did it take?
c) What was the accuracy of the final attempt?
(1 mark)
3 Using the value of the tank horizontal area, as well as the recording of the
response h(t) to the step change of the pump speed, determine the values of:
a) the valve resistance R;
b) magnitude of the step input in terms of the volumetric flow (in m3/s).
Assume the transfer function is the same as determined in the pre-task.
If the h(t) graph is incomplete, extrapolate the missing part until the steady state
value of h(t) is achieved. (2 marks)
4 Use the perturbation graph of h(t) (generated by the solenoid valve) to calculate
the magnitude of the perturbation in m3/s. (1 mark)
5 Once the negative feedback loop is applied, determine the steady state error of
the closed loop system:
a) In absolute terms;
b) In terms of the steady state gain of the open loop system (including KP).
(2 marks)
6 Observe the reaction of the closed loop system to the perturbation. Compare
(in up to 200 words) the difference between the open- and closed-loop systems
in the way perturbations are neutralised. (1 mark)
7 Plot the steady state error vs. the values of KI (while KP is constant). What
value if KI would ensure the steady state error to be zero? (1 mark)
A = nd , d= 188mm
2983/ 60t =minn=1-→ 6器
SSG =R =76. 02
Tasks - Rig 2
8 In order to establish the pump characteristics, plot the volumetric flow as a
function of the pump speed setting. Use only the steady state values and ignore
any transient processes. (0.5 marks)
9 When controlling the open-loop system,
a) How many attempts did it take to reach the desired value of the output?
b) How long (in minutes) did it take?
c) What was the accuracy of the final attempt?
(1 mark)
10 Using the recording of the response q(t) determine the time constant of the
system. (1 mark)
11 Once the negative feedback loop is applied, determine the steady state error of
the closed loop system in absolute terms. (1 marks)
12 Plot the steady state error vs. the values of KI (while KP is constant). What value
if KI would ensure the steady state error to be zero in this case? (1 mark)
Tasks -both rigs
13 Compare the values of the time constant of Rig 1 (presumably obtained in Task
3) with the time constant of Rig 2 (obtained in Task 10). Comment in up to 100
words on why there is the difference, or otherwise. (1 mark)
14 Use the relationship between the pump speed setting and the flowrate for Rig
1 (Task 3) and compare it with the pump characteristics obtained in Task 8.
What can be concluded about the similarity of the two pumps? Comment in up
to 100 words. (0.5 marks)
Submission Format (1 mark)
• All analytical work should be clearly presented as explained in the Course Outline. The
final results should be highlighted or underlined.
• The PDF version of the assignment should be submitted via Moodle by the deadline
indicated. Late submission penalties will apply.