Method and apparatus for controlling a group of elevators using fuzzy rules

An elevator group control apparatus for controlling a plurality of elevator cars that service a plurality of floors, in which fuzzy rule groups are applied to a hall call when an elevator call is placed and an optimum elevator car is assigned to proceed to a floor from which said hall call originates based upon the application of said fuzzy rule groups, comprising:

• a knowledge base unit for storing a plurality of predetermined rule groups to which priority orders are given;
• a rule set selection unit for successively selecting rule groups according to said priority orders;
• an evaluation index calculation unit for calculating evaluation indexes in response to a traffic information signal when said hall call occurs;
• a fuzzy inference unit for obtaining a conformance degree of each elevator car for each rule group based upon said evaluation indexes and a membership function, and for obtaining, based upon said degree of conformance, an assignment aptitude value for each elevator car for each rule group;
• and
• an assignment aptitude evaluation unit for single step advancing selection operations of said rule set selecting unit at a time when at least one elevator car, in addition to said optimum elevator car, has an assignment aptitude value for a current rule group that differs from said optimum assignment aptitude value of said optimum elevator car by no more than a predetermined threshold value, and for stopping said selection operation of said rule set selecting unit when the difference in said assignment aptitude value for said current rule group is greater than said predetermined threshold value, thereby providing an assignment signal for selecting an elevator car having an optimum assignment aptitude value, and assigning said elevator car having said optimum assignment aptitude value to proceed to said floor from which said hall call originates.

An elevator group control apparatus for determining which elevator car from a plurality of elevator cars should proceed to a floor from which a hall call originates, comprising:

• means for storing a plurality of predetermined rule groups to which priority orders are given;
• means for selecting rule groups according to said priority orders;
• means for calculating indexes in response to a traffic information signal when said hall call occurs;
• means for obtaining an assignment aptitude value for each elevator car for each selected rule group so as to determine a degree of conformance of each elevator car for each selected rule group;
• and
• means for selecting additional rule groups when an assignment aptitude value of an elevator car for a current rule group differs from an optimum assignment value of an optimum elevator car by no more than a predetermined threshold value.