Digital Control Systems [MEE 4003] - Kckong.info
Digital Control Systems [MEE 4003] - Kckong.info
Digital Control Systems [MEE 4003] - Kckong.info
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1.1. PROBLEM DEFINITION 3<br />
(a)<br />
(b)<br />
(c)<br />
(d)<br />
Figure 1.2: Examples of controlled systems. (a): a robot arm, (b): a helicopter;<br />
(c): an active suspension, (d): an air conditioning system<br />
[Example 1-1] The systems in Fig. 1.2 are examples of controlled systems. The robot<br />
arm in (a) is a tracking control system, because the reference of the robot joint is<br />
time-varying in general. On the other hand, the remaining systems are all regulation<br />
systems. For example, once the desired height of a helicopter is set, the rotor speed is<br />
automatically controlled to maintain the height. For (c) and (d), find the reason why<br />
they are regulation systems.<br />
Disturbance<br />
Disturbance is an undesired input that affects the performance of the overall control system.<br />
Disturbance includes an environmental change, an external force, a change in system<br />
parameter, etc.<br />
1.1.3 System<br />
System is a set of interacting components forming an integrated whole. Every system has<br />
input(s) and output(s). Most systems share common characteristics, including:<br />
• <strong>Systems</strong> have structure, defined by components and their composition,<br />
<strong>Digital</strong> <strong>Control</strong> <strong>Systems</strong>, Sogang University<br />
Kyoungchul Kong