14 CHAPTER 1. A PRELUDE TO CONTROL THEORY
In summary, standard control theory emphasizes the absolute need to have
a suitable mathematical model for the plant in order to construct successful
control laws. Recognizing that in formulating a control law we might only
need weaker knowledge, neural and fuzzy control become useful alternatives in
situations where mathematical models of plants are hard to specify.
1.5 Exercisesandprojects
- In Heroís ancient control system, identify the controller and the plant.
Develop a block diagram and label various plant details. - For the examples shown for open-loop systems, how would you modify
each system to provide closed-loopcontrol? Explain with the help of
block diagrams both open- and closed-loop systems for each example. - The Intelligent Vehicle Highway System (IVHS) program for future trans-
portation systems suggests the possibility of using sensors and controllers
to slow down vehicles automatically near hospitals, accident locations, and
construction zones. If you were to design a system to control theflow of
traffic in speed-restricted areas, what are the major considerations you
have to consider, knowing that the highway system is the controller and
the vehicle is the plant? Draw a block diagram that illustrates your design
concept. Explain the workings of the IVHS system design. - A moving sidewalk is typically encountered in large international airports.
Design a moving sidewalk that operates only when a passenger approaches
the sidewalk and stops if there are no passengers on, or approaching,
thesidewalk. Discusswhattypeofsensorsmightbeusedtodetectthe
approach of passengers, and the presence of passengers on the sidewalk. - A baggage handling system is to be designed for a large international
airport. Baggage typically comes offa conveyor and slides onto a carousel
that goes around and around. The objective here is to prevent one bag
fromslidingontoanotherbagcausing a pile up. Your task is to design a
system that allows a bag to slide onto the carousel only if there is room
between two bags, or if there are no bags. Explain your system with the
aid of a block diagram of the control system. - A soda bottling plant requires sensors to detect if bottles have the right
amount of soda and a metal cap. With the aid of sketches and block
diagrams, discuss in detail how you would implement a system of sensors
to detect soda level in the bottles and whether or not there is a metal cap
on each bottle of soda. State all your assumptions in choosing the type of
sensor(s) you wish to use. - A potato chip manufacturing plant has to package chips with each bag of
chips having a net weight of 16 ounces or 453.6 grams. Discuss in detail
how a system can be developed that will guarantee the desired net weight.