Page 36 - Modern Control Systems

1 0 Chapter 1 Introduction to Control Systems

1.3 EXAMPLES OF CONTROL SYSTEMS

Control engineering is concerned with the analysis and design of goal-oriented sys-
tems. Therefore the mechanization of goal-oriented policies has grown into a hierarchy
of goal-oriented control systems. Modern control theory is concerned with systems
that have self-organizing, adaptive, robust, learning, and optimum qualities.
Feedback control is a fundamental fact of modern industry and society. Driving
an automobile is a pleasant task when the auto responds rapidly to the driver's com-
mands. Many cars have power steering and brakes, which utilize hydraulic ampli-
fiers for amplification of the force to the brakes or the steering wheel. A simple
block diagram of an automobile steering control system is shown in Figure 1.9(a).

Desired Error Actual
course • o Driver Steeri ng Automobile •+• course
of travel mechiinism of travel
Measurement,
visual and tactile
(a)

SL' \ Desired
direction
Actual ~~ of travel
direction
of travel

(b)

FIGURE 1.9
(a) Automobile • Desired direction of travel
steering control • Actual direction of travel
system, (b) The
driver uses the
difference between
the actual and the
desired direction of
travel to generate a
controlled
adjustment of the
steering wheel,
(c) Typical direction-
of-travel response.