16.7 Review/Preview

In this chapter we addressed the concern that fuzzy controllers are capable of providing only approximate solutions. A chaotic system requiring precise control actions has been effectively manipulated using a genetic algorithm-designed fuzzy controller. Although the particular application presented in this chapter required a large number of linguistic descriptive terms (29 for each of the condition variables), it is clear that fuzzy systems can provide precise control.

In the next chapter we turn our attention to another issue that should be considered when employing a fuzzy controller. The large number of linguistic terms used in the current chapter to describe the condition variables presented only a small problem. However, a bigger problem occurs when a large number of condition variables must be considered. In such a case, the size of the rule set can rapidly become unmanageable. Such a case occurred for the authors when we were asked by the U.S. Army to investigate helicopter flight-control problems. In the next chapter we will consider ways of exploiting domain knowledge to ease the development of fuzzy controllers; we will discuss the development of a flight controller for a UH-1 helicopter.

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