US 4,790,412 AGranted

Anti-bunching method for dispatching elevator cars

AssigneeWestinghouse Electric Corp.

InventorsRobert C. MacDonald, Elsa Abrego

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Abstract

A method of assigning hall calls to a plurality of elevator cars in an ETA strategy in which up hall calls are scanned upwardly and down calls downwardly. A hall call floor at which the scan has stopped for the purpose of assigning or reassigning a hall call at the floor is called a "scan floor". The floor of the advanced position of the car being considered for assignment is called the "AVP floor". In order to favor the clustering of closely adjacent stops in a given car, and thus minimize car bunching, when a car has an intervening stop between the AVP floor and the scan floor, either the travel distance between the AVP floor and the scan floor, or the travel distance from an intervening stop to the scan floor, is used to develop a dynamic bias for the ETA of the associated car. The dynamic or variable bias is inversely proportional to the travel distance, i.e., the number of floors, between the relevant floors.

Claims5

Dependent claims

A method for assigning hall calls registered from floors of a building to a plurality of elevator cars which provide elevator service for the floors of the building, comprising the steps of:

selecting a travel path for each car relative to a floor having a registered hall call to be assigned,
preparing a trip list for each car using the travel path selected, including stops to be made for car calls, and previously assigned hall calls,
determining the time (ETA) for each car to service the associated trip list and arrive at the floor of a hall call under consideration,
and assigning each hall call to an elevator car based upon the relative ETA times,
said step of determining the ETA time for each car including the steps of:
determining if the car presently being considered has an intervening stop on its trip list, behind the floor of the hall call presently being considered,
calculating a dynamic bias value when the car has such an intervening stop, with the dynamic bias value being inversely proportional to a car travel distance between two predetermined locations,
and biasing the ETA time of the associated car by subtracting the bias value from the car's ETA time.

5 more elements

Dependencies are inferred from the claim text.