Version 1.0, August 31, 2001, Copyright, Hugh Jack 1993-2001
· Control systems are present in most systems we see. Example - elevator height.
· Some systems are naturally unstable and tend to self destruct. Example - balanced broom.
· Other systems are self regulating, and tend to some stable state - these are good candidates for open loop control. Example - city water tank
· Other systems need some sort of regulation mechanisms added, these are called closed loop systems. Example - car cruise control
· If a system is simple we will say that it is linear. Example - perfect elevator
· A system can be subject to complicating factors that make it difficult/impossible to model mathematically. Example - elevator in tall building with stretchy cable
· If a system has switched states it can be described as discrete. Example - buttons to call elevator, open/close doors
· Temporal/sequential systems can change over time, this requires sequential control. Example - washing machine