Fuzzy Chaotic Systems / Studies in Fuzziness and Soft Computing Bd.199 (PDF)

noise-free inputs and can, thus, be fault-tolerant if a feedback sensor quits or is destroyed. The output control is a smooth control function despite a wide range of input variations.

ii) Since a fuzzy logic controller processes user-defined rules governing the target control system, it can be modified and tweaked easily to improve or drastically alter system performance. New sensors can easily be incorporated into the system simply by generating appropriate governing rules.

iii) Fuzzy logic is not limited to a few feedback inputs and one or two control outputs, nor is it necessary to measure or compute rate-of-change of parameters. It is sufficient with any sensor data to provide some indication of a system’s actions and reactions. This allows the sensors to be inexpensive and imprecise thus keeping overall system cost and complexity low.

iv) Because of the rule-based operation, any reasonable number of inputs can be processed (1–8 or more) and numerous outputs (1–4 or more) generated, although defining a rule-base quickly becomes complex if too many inputs and outputs are chosen for a single implementation, since rules defining their interrelations must be defined, too. Then, it would be better to break the control system into smaller chunks and use several smaller fuzzy logic controllers distributed on the system, each one with more limited responsibilities.

v) Fuzzy logic can control nonlinear systems that would be difficult or impossible to model mathematically. This opens doors for control systems that would normally be deemed unfeasible for automation. In summery, fuzzy logic was conceived as a better method for sorting and handling data, and has proven to be an excellent choice for many control system applications, since it mimics human control logic. It can be built into anything from small, hand-held products to large computerized process control systems. It uses an imprecise but very descriptive language to deal with input data more like a human operator. It is very robust and forgiving of operator and data input, and often works when first implemented with little or no tuning.