Open loop adaptive fuzzy logic controller for elevator dispatching
AssigneeOtis Elevator Company
InventorKandasamy Thangavelu
Life of this patent
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Abstract
A group controller for controlling elevator cars in a building having a plurality of floors includes a traffic and traffic rate estimator for providing fuzzy estimates of traffic and traffic rate; an open loop fuzzy logic controller for providing a control parameter in response to the fuzzy estimates of traffic and traffic rate, the open loop fuzzy logic controller having membership functions for fuzzy sets of the control parameter; an adaptive controller for modifying the membership functions of the fuzzy sets of the control parameter in response to an elevator control system output variable; and an elevator dispatcher for controlling the operation of the elevator cars during single source traffic conditions in response to the control parameter.
Claims8
A group controller for controlling a plurality of elevator cars in a building having a plurality of floors, comprising:
- a traffic estimator;
- a fuzzy logic controller having membership functions for fuzzy sets;
- an adaptive controller for modifying the membership functions of the fuzzy sets;
- and
- an elevator dispatcher for controlling the operation of the elevator cars;
- characterized by the improvement comprising:
- said traffic estimator providing fuzzy estimates of the level of passenger traffic entering elevators at a lobby floor and the rate of change with respect to time of said level of passenger traffic entering elevators at said lobby floor;
- said fuzzy logic controller having fuzzy sets of an elevator control parameter as a function of said fuzzy estimates of traffic and traffic rate, said fuzzy logic controller providing said control parameter in response to said fuzzy estimates of traffic and traffic rate;
- and
- said adaptive controller modifying the membership functions of the fuzzy sets of said control parameter in response to values of pairs of elevator control system output variables and changes in said values of said pairs of variables.
A method of controlling a plurality of elevator cars in a building having a plurality of floors comprising the steps of:
- monitoring traffic in the building;
- and
- controlling the operation of the elevators in accordance with the traffic monitored;
- characterized by the improvement comprising:
- providing fuzzy estimates of the level of passenger traffic boarding elevator cars at a lobby floor of the building and of the rate of change with respect to time of the level of passenger traffic boarding elevator cars at said lobby floor;
- providing fuzzy sets, having membership functions, of an elevator control parameter as a function of said fuzzy estimates of traffic and traffic rate;
- modifying the membership functions of the fuzzy sets of said control parameter in response to values of pairs of control system output variables and changes in said values of said pairs of variables;
- providing a value of said control parameter in response to said fuzzy estimates of traffic and traffic rate;
- and
- controlling the operation of the elevator cars in response to the control parameter.
Dependencies are inferred from the claim text.