A new approach of multi-stage fuzzy logic inference

In general multi-stage fuzzy logic inference, there are three kinds of linguistic variables: input, output, and intermediate variables. When intermediate variables are present in a set of fuzzy rules to form multi-stage fuzzy rules, the inferring time involved is understandably lengthened. To achieve fast reasoning of multi-sta fuzzy logic, the number of fuzzy set operations of input, output, and intermediate variables must be decreased as much as possible without information loss. For the intermediate variables, the fuzzy logic operations of overlapped fuzzy value pairs on several multi-stage fuzzy rules may be pre-computed at compiling time. Furthermore, if the pre-computations have been done, the numbers of intersection and union scalar operations must also decrease in order to speed up reasoning at execution time. Moreover, whether fuzzy logic operations of multi-stage fuzzy rules are pre-computed or not, the types of fuzzy logic operators must be considered. Failing to do so may lead to information error. By using the Truck-Trailer Backer-Parking System, improvements over related methods are attained.