Classical control sheet (1)-converted

1. Cairo University Systems & Biomedical Engineering Dept.
Faculty of Engineering Third Year
Dynamic Systems
Classical Control
Sheet (1)
1. Give an example from the industrial and from the biomedical field for each of
the following control mechanisms:
a) Open loop control
b) Positive feedback control
c) Negative feedback control
d) Adaptive control
2. Give an example from the industrial and from the biomedical field for each of
the following devices:
a) Sensors
b) Actuators
3. Population growth is a positive feedback system. Consider the desired
population as the system's input (even if a truly unattainable goal), the actual
population as the output. Of course population growth control measures
(e.g., contraceptives, . . .etc.) are well appreciated.
a) In the sense of block diagram terminology (studied during the lecture), by
what kind of block would you represent the population growth rate?
b) Suggest a complete block diagram representing the system.
4. Consider the following piecewise continuous function between independent
variable x and dependent variable y.
𝑦 = {
2𝑥, 𝑥 ≤ 2
3𝑥 − 2, 2 < 𝑥 ≤ 4
2𝑥 + 2, 𝑥 ≥ 4
a) Sketch the curve.
b) Is this function considered linear or nonlinear?
c) If it is required to construct a strictly linear model of that function around x =
3, what is the restriction?
5. Dorf 11th ed., p. 30, Exercise E1.1.
6. Consider the CD player/disk drive control system, whose schematic is shown
in Fig. 1.a and whose block diagram is shown in Fig. 1.b.

2. Fig. 1
What changes would be necessary for the above system, if it is to be applied
to the control of the following devices?
a) A rotating conveyor belt for the passengers' suitcases at the airport
b) A rotating table for the control of a diffraction grating in an analytical
chemistry lab
7. Fig. 2 depicts a simple block diagram for a closed loop control system of
blood glucose.
Fig. 2
a) Which of the shown blocks is the controller, which is the actuator, and which
is the plant?
b) What is the physical nature of each of the sensor's input and output signals?
Please specify units.
c) It is desired to extend the controller to a powerful digital controller. How
would this be reflected in the block diagram?
8. Dorf 11th ed., p. 32, Problem P1.6.